Cannot seem to get clear shots in low light - HELP

[superbee15]

Have always been challenged by night shots. Late last year wanted to take candids and people pics at a night (outside) and so purchases a Canon EF 50mm 1:1.8 - I know it's at low end of market but this was 1st additional lens to 550D kit lenses. Did not know much about the lens and as not had any practice I just used in Auto. While party was under blue fairy lights I was totally disappointed in shots - mainly due to clarity - some color issues. In early July (lens had not seen the light of day since Dec due to issues) I decided to try it again this time in a restaurant at night. Again I was disappointed in quality of shots. I am obviously doing a few few things wrong but at other times it seems to lack clarity when focus should have been right?

I used an Aperture of 2.

I would like to be able to have a shot of 2-3 people at a time but this most always may mean they are/may be at different distances from camera. To achieve this is it a simple matter of a higher app and therefore does this negate the benefit of buying the quick lens? I would also prefer no flash but that means more challenges.

Included 3 samples which seem to have reduced clarity due to resizes.

The 1st shot actually has the best overall look but still not as clear as I would have thought. The second does not have any area focused correctly and 1 focus point is on the male. The 3rd has the best focus of any shot which is the girl in front. The rest are out of the DOF.

Any help appreciated.


110464110465110467

[mudman]

i would say you need a greater DOF, especially when the subjects are not on the same focal plain
#3 the left hand person has reasonable sharpness and then the others are ever more OOF.
use a higher F number, say F8

[Granville]

This worries me a little. To get higher DOF you need a smaller aperture. The 1st photo is taken with a flash, at ISO400, aperture f2, yet the shutter speed only came out at 1/20 sec. The exposure looks okay but the shutter speed with all those other variable looks way too low.

Am I missing something?

[fess67]

As a general rule you will need to increase your ISO to then allow your shutter speed to come up. This will help with camera shake problems but does increase noise slightly. Of course as you increase your f-stop you will need to keep increasing your ISO to hold the same shutter speed and that of course introduces more noise. It is a balance thing.

I know you said you would prefer no flash but take one anyway, once you have some 'keepers' you are free to experiment without flash. <<edit>> I assumed you had an external flash in that statement.

Play with the camera tonight. Put the ISO on 1600 or higher at f5.6 and see what results you get. Shoot in RAW and you can reduce the noise in post processing.

[superbee15]

All shots taken in RAW with camera in M. I set 1/20 thinking it may be ok. I changed some ISO's. I realise upping the f-stop will improve the DOF but is this then negating the benefits of the fast lens or am I mis-understanding things?
Only have built in flash.
Use DPP and not investigated reducing noise yet.
Will try some things as suggested in next few days.

Thanks

[arthurking83]

So far some good answers, and I'd agree with all of them, but with a few variations on how you could try some of those shot types again(ie. practice a bit to get your technique right).

Any number of subjects can be used for practicing .. not just people too!

In #1, the shutter speed hasn't helped to get 'ideal sharpness'.
Either or both camera shake and subject movement will have caused the blurry look, and lack of clarity you may seek.
Try to stick to a minimum of 1/60s of you can(which is quite easy to do).

#2 same as #1.

#3, as already mentioned f/2 will give a shallow DOF, which is obvious in this particular shot, but needn't have been.
That is, you could(possibly) still have used f/2 and hence shallow DOF, but only if you had focused differently.

Look carefully at the image and take note of the woman on the left(our LHS, not theirs) and the woman in the centre.
The woman on the left, is sharp(ie. focused) and the woman in the centre seems to have her hand around the one on the left.
The hand is also in focus .. ie. suggesting a deep enough DOF could have been captured if focus was set differently.
Had you focused on the woman in the centre, the DOF may have been sufficient to have the woman on the left and the man on the right rendered sharp enough.
(f/2.8 - f/4 could have ensured this too).

But I'm only guessing here, I have a feeling you may have used an auto focus mode. That is, not auto focus, but a mode of focusing that automatically selects the subject, and hence the focus point.
If this is so, then try a manual focus point selection mode.
That is, a focus mode where you choose which point in the viewfinder is the one that will focus. For starters the centre point is the easiest one to work with(whilst you learn your way).
Then using this focus point, let the camera/lens do the focusing .. all you do is choose which point will do the focusing.

Also, set the camera to Auto ISO. Don't worry about the technicalities of exposure control yet. The camera can do a reasonable job of it. Learn compositions, and focus point selection and the moment to shoot, etc.
Shoot in Aperture Priority mode, choose and vary only the aperture value. Shutter speed should be set to a min of 1/60th in such situations, more if your technique or the people are moving too fast.
This can be(or should be able to be) set in the Auto ISO area.
So you can set the upper limit of Auto ISO to something like ISO6400, and it should let you specify a minimum shutter speed from where to start boosting ISO.
If you set the camera to a min of 1/60s in A/ISO, what happens is that, if the light is low and shutter speed drops, the camera automatically boost ISO to keep the shutter speed at a min 1/60s.
if ISO tops out at 6400, then the shutter speed drops.
This is a good mode to learn about how to 'control' your cameras controls without getting frustrated about not getting shots.
As long as you don't want to view your images at the pixel level, or print 1 meter wide prints .. higher ISO is where the advantage of having a DSLR is. ISO6400 on your camera is very usable.

(ps, turn off the flash .. especially if its an onboard flash if it's an external flash and you can vary the angle of the head .. experiment with various angles of tilt to soften the flash light quality).


(side note)
Now having said all that .. I think there could be the possibility that your camera/lens is front focusing.
I say this because all three images have misfocused a bit compared to what one would have expected to see .. but more importantly by about the same amount in each three images.

in #1, the two people's faces are slightly blurred, but to my eyes there seems to be some focus on the mans shirt. This could be an illusion to us at the posted image sizes.
Also in #2: the woman's face is blurred, but it appears to me that there is again some detail rendered better on her jacket/jumper arm and shoulder.
As already said in #3, the woman on the left is sharp enough, and the other womans hand on the shoulder seem to have more sharpness than the other two faces.

All those points are forward of what would be expected to be the points of focus.
The problem is that it looks like an auto focus selection point mode may have been used tho, and so it's hard to confirm this possibility.

Can you see the focus points via the software you've used to convert the images?(which looks to be DPP).

[jev]

The thing seems to be focussing incorrectly. DPP says the focus points are where you would want them, not where the image is sharpest (e.g.: on image #2, focus point is on the nose of the man, but focus on the ladies' shoulder seems sharper).

Note that f/2 gives you a very shallow DOF when you're close to your subjects. I expect the subject-distance of the third for example not to exceed 2 meters. Entering these parameters in DOFmaster says the DOF is just 12 cm, 6 cm before and 6 cm after the focus-point. As Arthur explains, training the focuspoint on the person in front is not the wisest thing to do than. You seem to have the camera select the focus point, next time select a focus point by hand.

You ask what f/1.8 is good for if it has this shallow DOF? Well, to be able to focus at low light to begin with, but also to provide that shallow DOF. You may not like it now in this specific application, but when shooting landscapes in the dark for example it might make a lot more sense to shoot at f/2 (at 20 meters distance for example, the DOF has increased to 13.4 meters - just toy around with DOFmaster here (http://www.dofmaster.com/dofjs.html) to get a feeling of what could work for you).

As with most lenses, the nifty fifty needs to be stopped down a stop or two before it reaches it's "sweet spot" - at f/4 it is mighty sharp. It's popularity stems from this sharpness in combination with affordability - it costs just some $100 or so. Compare that to the hefty price of a 24-70/2.8L for example, which (at 50mm) does not really outperform the 50/1.8.

[superbee15]

With all shots on the night I let the the camera select the focus point - as suspected - as a result the following were focus points:
#1 Very point of the females nose;
#2 The side of the males nose just below his left eye;
#3 Just under the young girls left eye.

Would there have been any benefit in changing to different 'Metering Mode' - I was on 'Evaluative'?

#2 was no flash, others were with flash (built in) and ISO on #2 was 3200 with others ISO400.

'arthurking83'
So you can set the upper limit of Auto ISO to something like ISO6400, and it should let you specify a minimum shutter speed from where to start boosting ISO.
I have camera set at 6400 max (which I think is max for the camera) and I could not find a way to set a minimum on the 550D.

in #1, the two people's faces are slightly blurred, but to my eyes there seems to be some focus on the mans shirt.
Yes that's true but not sure why there was blur. This and #2 were some of reasons to question what I and camera are doing.

Also in #2: the woman's face is blurred, but it appears to me that there is again some detail rendered better on her jacket/jumper arm and shoulder.
Yes that's also true but one is very puzzling given the focus point. The male may have moved as he does not want to stay still while photo's are going on! This also questioned by 'jev' in post.

As already said in #3, the woman on the left is sharp enough, and the other woman's hand on the shoulder seem to have more sharpness than the other two faces.
Yes again agree with that and my limited understanding says that that is just DOF.

Now having said all that .. I think there could be the possibility that your camera/lens is front focusing.
What is front focusing?

'jev'
I expect the subject-distance of the third for example not to exceed 2 meters.
Yes all shots were between 1.2 and 2 meters at max. The room was very narrow and long so using fixed lens meant moving and going sideways.

Thanks for some great comments and observations.

[MissionMan]

I think this is one of the benefits of using manual mode. You can set both your shutter speed and Aperture and let the camera compensate with the ISO.

The reality is you will get a better outcome with a higher ISO and more noise, than a lower ISO and movement blur unless this is your targeted outcome which is sometimes the case. The reason for this is you can correct noise in post production, but you can't correct issues with motion blur.

The other potential issue is what method of focus you are using. I.e. Continuous focus. I generally find continuous focus is better because if your subject moves forward after you have locked focus, the camera will continue to compensate by refocusing where as this may not have happened if you had the shutter release partially depressed.

My recommendation is to experiment in a controlled environment (without people) to get to grips with how the system works and gain a slightly better understanding as there might be a large number of variables that are impacting the outcome.

[arthurking83]

......

'arthurking83'
So you can set the upper limit of Auto ISO to something like ISO6400, and it should let you specify a minimum shutter speed from where to start boosting ISO.
I have camera set at 6400 max (which I think is max for the camera) and I could not find a way to set a minimum on the 550D.

....


I think this is one of the benefits of using manual mode. You can set both your shutter speed and Aperture and let the camera compensate with the ISO.

......

Apologies about the min shutter speed then.

if the camera doesn't allow the min shutter speed selection, then do as MissionMan says too .. that's what I'd also do.

Note that some cameras such as the lower end consumer oriented types may not have super accurate focusing systems.
That is, I don't think that off centre focus points use cross type sensors which are more accurate than the more commonly used single line phase detect sensors.

It's not unusual to get focusing innacuracies with the non cross type sensors when focusing.
I suppose this could be another reason to use manual focus point selection.

Low light makes AF systems more inaccurate.

Even tho there may be a possibility that your camera/lens combo here is front focusing .. don't take that as a certainty.
There too many other factors here that could have contributed to the final outcomes.

[bitsnpieces]

The metering mode shouldn't matter in terms of image quality, but will matter in terms of result - that is, on evaluative, it may see the overall scene as dark (since you're doing night shots), and then compensate accordingly, meaning, lower shutter speed, increased ISO, use a larger aperture, smaller DOF, etc, to get as much light in - this can lead to issues like blur from camera shake due to slower shutter speed, or a DOF too small to get a group, so lack of focus. On the other spectrum, if it's bright, you may get faster speeds, etc, but I'm excluding this as you're referring to indoors and under low light. Using spot metering will make the subject you want correctly exposed, and not care about everything else. This can be good as the decisions the camera decides to make may work better to properly expose the subject you want and not worry about the negative effects to the background, but that means you do lose the background, if that was something you wanted in the photo too.
I would still recommend spot metering anyways as the subject is most important. Maybe to practice first, try the centre weighted one, which is spot, but also evaluates a little around the spot - then move unto spot when you know how it works.
Arthur posted a great post about this - I'll have to find it again for you.

Regarding having a fast lens - from my understanding, it isn't about getting fast lenses for night shots. The way I look at it is, it all depends on the DOF you want. If you want a big DOF to capture a group, you use a smaller aperture. If you want a small DOF to isolate a subject from the background, you use a larger aperture (oh, and maybe I got the terms mixed up, is f1.8 big or small aperture? And vice versa, f8 for example, big or small? Terminology... >_>) Anyways, hopefully you know what I mean. Having a fast lens basically gives you the ability to do better isolations in shots - I don't see it as the 'go to' for night shots. But, one advantage is, if people were in a line, then yes, put on that 1.8 or 2 or whatever you want, then you can use a lower ISO, so less noise, higher quality image.

So as other users have mentioned, for your images above:

1) It could be just your DOF is too small, so you need more DOF to capture the group, especially if they're at different distances. As mentioned by others, don't be afraid to use a higher ISO. As Arthur said, put it on aperture priority, so you can choose the aperture you need to make sure everyone is focused, and then let the camera pick the ISO and shutter speed required. Regarding the minimum shutter speed, I think some cameras have it automatically set to a certain speed, until their Auto ISO hits its limit and can't go higher, then the shutter speed starts slowing down - some cameras probably allow you to manually set it - yours may be automatically set, I'm guessing since you weren't able to find any option for this.

2) It could be your camera just isn't focusing properly. Do you use the AF lamp assist or anything? That little bit thing just between the shutter button and lens, is that for IR remote only? Or does that function as a little light to assist in auto-focus? Try using that. One guess I have could be that it's not being used, so when the camera is trying to focus, it's probably a little too dark for the camera to figure out where the exact point of focus should be, and in the end, when you take the photo, it's in the wrong spot.
My camera for example uses the flash to do it as it doesn't have the little lamp. So check to see what yours has because if it's done via the flash, it'll fire some small bursts of light, focus during those bursts, then when you take the photo, it'll be focused more correctly.

3) Are you using wide auto focus or selective? So wide, or whatever it may be called on the Canon, is when it looks at the overall image, and then picks what it thinks it needs to focus on. Sometimes it's right, sometimes it's wrong.

4) My other guess is what Arthur said, and what I'm also leaning towards, but not the definitive answer here, is front focusing. What this is is say you've focused the eyes, you know it's focused there - should be good. You take the shot, but the focus in the photo isn't on the eye, it's on the nose instead - that's front focus - although the camera is trying to focus on the eye (software), the end result due to the mechanics inside (hardware) is actually on the nose. This is the same for 'back focus' if the end result was on the eyes instead, for example.
So although on the camera, you may have seen the focus box on the eye, the results will be different.
Going through the focus points you gave, I'm guessing that's where the camera had it's little green box on? If that's the case, then this looks like it could be a front focus problem, where the camera is set to focus on a spot (tip of the nose, just under the eye, etc), but the end result, it's the things in front of it more in focus (like the shirt, jacket, hand, etc)
This in turn rules out my guess of #2, where it just isn't focus on the right spot as you've now specified where your focus boxes were.
This is something you'll need to take to the repair shops to fix, unless the 550D has an access point for you to do it yourself, like my a55 (though it's dangerous because if you mess it up, it can be very tough to fix it or a world of hassle nonetheless).

Now, this is only speculation. If I was to test and find out, I'd have these in mind:

Does this only happen with the lens you purchased? Have you tried another lens? So even if it means you'll use a higher ISO, the main point is to see if the images are clear though.
So if on a different lens, you are getting the same result, then maybe it is front focusing.
Next test - try it during the day - that way ISO and shutter speed isn't a problem or anything, you can purely focus on where it's focusing. Maybe grab a few objects and point them together, some in front, some behind, and take a few photos at different distances. Again, if it's the same results, then it could be front focusing problems.
One way to really test if there is a problem or not is with a test chart, something like this:
http://regex.info/blog/photo-tech/focus-chart
There's a free one you can print on this forum somewhere to make yourself - I've done it, but I can never remember the name or find it - I should probably favourite it next time I come across it - hopefully someone else knows and can link you to it.

This is a very good way to test if there is front/back focus on your lenses or not.
Hopefully this also helps explain for you what front and back focus is.

MissionMan's suggestion on continuous focus is definitely an option. Lets say everything is okay, there isn't a huge problem - maybe you just needed to use the lamp to assist in focusing the right spot - maybe you just needed to pick the points you want to focus on yourself rather than using a wide auto focus and letting the camera do it itself, with the aperture of 2 you've set, the DOF is small, so if the subject moves a little, maybe a cough, adjustment of chair, etc, they're not in focus anymore. If your 550D has tracking, maybe use that, or using continuous autofocus to keep subjects in focus.

But as everyone has said, just keep testing. Good luck

[ameerat42]

Skimmed through the thread...
To me this is missed focus. There needs to be a reason.
Have you tried any using manual focus? Shoot some non-person subjects - a fruit or a vase or so - in similar conditions?

Perhaps there's some focus misalignment in the lens. At the wide f-stops you want, this may be exaggerated.
AM.

[arthurking83]

.....
Have you tried any using manual focus? Shoot some non-person subjects - a fruit or a vase or so - in similar conditions?

....

Personally I wouldn't recommend manual focus in this situation. There could be a possibility that you would nail it, but in reality it'd be a bit more of a fluke, than a skilled effort.

Reason is, that the camera is setup in std form to make it hard to focus with a wide aperture lens set to a wide aperture. This helps to auto focus and gives a brighter image through the viewfinder.
What you see through the viewfinder is akin to an f/4-f/5.6 aperture setting, but if the lens is set to f/2(hence a shallow DOF) you can't really tell exactly which part of the image is properly along the plane of focus on the rendering of the image.
And FWIW: the focus confirmation indicator in most cameras is also a bit hit and miss too. To a lesser degree than judging it by eye through the vf tho.

[bitsnpieces]

Only reason I ruled out one of my thoughts for being mis-focused was that superbee mentioned where the focus point was locked onto, so comparing that with the image, the sharpest bit isn't where the point superbee mentioned, but more in front of it. Again, still worth a try to test out - I don't think manual focus will ever prove much because it's always going to be spot on where you've out it right? It's the auto-focus that can mess up because that's based on the camera itself. Just a hunch from when I was calibrating my a55 :confused013

I guess one question is, reading am's post on misalignment in lens, can focus problems be the lens itself? Or is it always the camera?

So I wondered what the results would have been like if we try a different lens on that camera. :)

[Mark L]

Get a good flash with ETTL to put on top of your camera. (from AP site sponsor ... http://www.protog.com.au/buy/yongnuo-yn568-ttl-high-speed-sync-flash-for-canon-dslr-camera/YN568C) Bounce the wonderful extra light off the ceiling or wall to get a more even light.
That wonderful extra light will get you to a higher f/# for DOF and keep the ISO down a little. The ETTL lets the camera and flash figure a lot of the equation out for you.
For noise reduction, this software probably works better than DPP ... http://www.imagenomic.com/download.aspx The download at the bottom (Community Edition) is free.;):)

[bitsnpieces]

That plugin works independent of Photoshop though right?

The plugin doesn't appear in my Photoshop, and I tried copying the plugin which was in the folder into the Photoshop plugin, so it appears, but it isn't free (I didn't know about the community one and had a standard one, which requires me to pay now to unlock it... so I don't know if that's affecting the community version or not...)

I'm currently using Colormancer which is free and comes as a plugin inside of Photoshop - isn't as good as Imagenomic, but still does a good job

[dtmateojr]

Your lens/camera has a front-focusing issue.

[ricktas]

Your lens/camera has a front-focusing issue.


All these were taken at 1/20th second. Perhaps you might like to reconsider your conclusion?

[superbee15]

Wow lots of info through those replies!

Still to do more tests but some comments are:
So far the high ISO shots with the 550D have not impressed me.
Will be getting a 'proper' flash soon!
Tested in AI Servo (my interpretation of continuous focus) and the 50m lens was a bit slow in keeping up with movement but at at least I would know that focus is not correct.
Shooting in One Shot AF (which I did) with people moving may have been part of my problem as well.
The 550D only has cross AF point for center point and all shots happened to have locked with outer ring points so focus may have been reduced. I found this in research: "The center AF point is a cross-type center point sensor while the other 8 AF points are horizontal line-only sensitive. With an f/2.8 or faster/wider aperture lens, the center point operates with greater precision."
I would not try manual focus as eyes are not good enough.
I have not found the kit lens to be as hit and miss yet but still inexperienced at low light shots in general.

I will try some experiments over next few days with some static objects using the 17-55 kit lens and the 50 to see what happens.

Thanks

PS how do you do a number of quotes in the 1 reply (like Arthur did)?

[arthurking83]

Quickly .. multiple quotes are made with the + sign with the quote icon at the bottom far right of the person's reply.
You add them and finally quote the final reply you want and they all appear in your reply screen.


....
Shooting in One Shot AF (which I did) with people moving may have been part of my problem as well.
....

This is the reason I would hesitate to conclusively say that your camera/lens combo is front focusing.
The previous reply stating this with certainty is misleading!
lenses don't front/back focus on their own to begin with .. it's the combination of camera and lens that does this.

But because you used single shot AF, there is a very high probability that you or your subjects moved before the point of exposure!
If I ever use single shot AF(extremely rare!!) I use it with a dedicated action.
That action is what I think is not how many folks do it .. but should.
The action is to press and expose at the same time.
That is, I think many people do the half press to acquire focus, hold it at that point and then full press to acquire exposure.
While it's not the wrong way to do it .. it's definitely more wrong, than the alternative.
The way I use single shot focus mode is to fully press the release. That this does is to acquire focus and expose with the shortest possible delay between the two functions.
This is a form of focus trap. Focus trap is a method of exposing a shot at the moment focus is acquired(save for a 0.01s delay in the camera's operation).

The reason you don't want to use the half press to focus and then full press to expose, is that your delay between the two actions could see you or your subjects move fractionally fore/aft of where you think you should be.
if your action is to naturally sway fore/aft and more accurately aft(backwards) a teeny weeny amount .. then in the time between focusing and shooting, you have moved the plane of focus back just enough to make focusing look inaccurate.

While AI servo mode may seem a bit slow, in general it can make for more accurately focused images.
I use AI, or continuous focus mode exclusively .. the only time I use single shot focus mode, is with an old manual focus lens! :p(too long story to explain it fully here).

If you need any info on how to check your lens for focusing accuracy, just ask.
If you want to do really quick tests, just shoot any medium/large sized targets(teddy bears, toy models .. whatever) but be sure to have the camera solidly planted on something.
A tripod is best, but if you don't have one a table is good enough for preliminary testing.

One last question, does this model camera have live view mode?

edit: I forgot to add .. if you do some tests, don't worry so much about the kit lens. Work with the 50mm for now .. try to keep it all at the most basic level and take it from there.
And be sure to post back with any data you acquire or questions you have.

[Kieran]

Superbee you have plenty of good advice sent your way. I have the 550D so this relates specifically to your camera dials and would be the setup I would use in the situation you have described
Use the eye-piece not live view to compose & focus your shot
Set ISO to AUTO
Set Camera to M
Scroll wheel to 1/50 seconds or faster (using a 50mm lens)
Push the AV button and scroll the f/stop to your desired (for a single head shot f/2.8 for a group f/5- f/8)
Press the right magnifying button (top right corner of camera back) This will show what focus sensors are on. Scroll until you have only the middle one highlighted
Press the Q button - select evaluative metering and AI SERVO for focussing
Now your camera is set to avoid camera shake (faster than the lens) & the depth of field is set to keep focus on only those people you want in focus. The focus point is exactly in the middle of the shot. The camera will automagically adjust the ISO for each shot. You can now concentrate on composing & focusing the shot.
You will find that sometimes there is just not enough light to get a good image and this is where you give up and put the flash on.
One other thing that I find useful is to not use the shutter release button to focus. Push the menu button. Go across to custom functions. Push the set button then arrow across to 9 "Shutter/AE lock button" Select option 3 "AE/AF, no AE lock" now when you want to focus push the de-magnify button (top right corner of camera back) and take the shot with the shutter release button as normal. This is useful because you keep the focus button pushed down constantly in AI servo to track someone on the move and push the shutter release button at exactly the right time hopefully, often just a little too early or late.
With low light shots you may find you get a more consistent result by taking shots with a little extra room around the edges with the intention of cropping latter. The reason for this is that it makes you step back a little more, allowing you to use a wider aperture without having the depth of field let you down. The distance to subject is really important as well as the f/stop in giving your depth of field, it is something that didn't dawn on me as soon as it should. Hope this is of some help. Good luck

[arthurking83]

Some good sounding tips from Kieran there.

The only thing that would concern me tho is the use of evaluative metering.
I remember years ago trying to help a couple out in the bush with setting the camera up so that it would expose 'correctly' .. and by that I mean that it didn't try it's best to protect highlights.
Not being a Canon person I had no idea on how to find the menu item to stop it doing this in Evaluative mode.
Anyhow, the person was trying to get a shot of the other against the distant landscape, but the camera tried harder to protect the highlights only .. hence the other person in the portrait was all in shadow(ie. black).
I told them to switch to spot metering, but that the background would look washed out. We tried flash(on board) but it didn't do a good job of it. Camera was one of the thousand series cameras .. maybe 1100D or something. Very hard to get to any controls coming from a D300.

Anyhow .. I'd prefer to recommend using spot or centre weighted metering, especially if the ISO value risks being at an elevated value.
As ISO level increases, the exposure of your subjects is far more important not to under expose(any subsequent processing to brighten/recover will only yield more noise levels, or blurry looking details).
In fact, as ISO increases up to a point .. I tend to over expose the subject by a small amount, and keep it that way in PP(a bit of over exposure hides or masks high ISO noise a bit).
On my D300 at above ISO 1600 I'd start to over expose, normally by about 1/3Ev .. even tho ISO 3200 and even 6400 may have been usable enough at low web sized images.
So far on the D800, I've yet to do it, and I don't mind shooting at ISO6400 if I have too.

Kieran's tip on setting a button on the back of the camera to continually press whilst leaving the AF function off the exposure release is one I'd highly recommend to do also(I didn't know the Canon had this feature).
:th3:
Takes just a bit of getting used too it, but well worth it.

[superbee15]

One last question, does this model camera have live view mode?



Yes it does but I do not use as I figure that would be more prone to camera shake.



Use the eye-piece not live view to compose & focus your shot

One other thing that I find useful is to not use the shutter release button to focus.

Always use left eye on eyepiece - right eye not good enough!
Have tried back focus previously and it was a bit hard to use. I will retry.

I tried a simple test with the 50 this afternoon and set camera on kitchen bench and focused on some food on bench (camera set to AI Servo). Sometimes the lens would lock and sometimes it just continued to hunt even though everything is static. I was using the center focus point from about 500mm and looking at same point on food. Light was not bad. Is this normal for AI Servo?

[Kieran]

No that isn't normal unless the food was very old and walking out of your kitchen:D. Try with AI SERVO again, then change to AI FOCUS, then to ONE SHOT to see if there is any difference between these 3 options on the amount of hunting going on. Low light is when it should have trouble so if you then put some decent light onto the subject the hunting should go away. Do you have AF-assist beam firing enabled? This is in Menu-Custom functions-7 "Autofocus/drive" select option 0 Enable. Then put on another lens and check to see that it is not a problem with this lens only.

[dtmateojr]

All these were taken at 1/20th second. Perhaps you might like to reconsider your conclusion?

The parts that are in focus are reasonably sharp which rules out camera or subject movement. The parts in focus are in front of their faces.

[arthurking83]

..... Sometimes the lens would lock and sometimes it just continued to hunt even though everything is static. I was using the center focus point from about 500mm and looking at same point on food. Light was not bad. Is this normal for AI Servo?

Actually! .. it can be.
It depends on your stability.
The is the rocking to a fro(or back and forth I wrote about previously.(apparently I do this .. so I think it's normal).
This is why you'd want to use this AI servo focus mode. It counteracts any fore aft movement you may naturally do when you're photographing.

Your movement may only be small, but it could be significant enough to make a difference.
Again, you can do this deliberately as a test to get a feel for it.
AI servo mode, find a static target and you deliberately rock yourself closer and further from the subject as you continually focus.
If you can manage the same target with the camera on a steady support(as before, even a solidly planted table will suffice, but tripod is better) .. and find a nice large target and using continuous focus then you will see that the focus system will not hunt(well it shouldn't!).

Also the type of target or the subject being focused on will have an impact on the focusing system and side issues like hunting and stuff like that.

[superbee15]

Well did some test shots this afternoon. Following method:

Tripod for all;
No shots with flash;
Shots taken mid afternoon with light varied with blinds and fluors;
Used a wired remote controller;
Always focused over Snoopy's left eye - centered on the black;
Used only the Center Focus Point;
Tried the 50m lens then the 18-55 kit set (did not include any shots from this lens as seemed ok) at 50m then swapped back to the 50m all without moving camera to any large degree;
Camera placed 1.63 meters from eye of Snoopy;
Red figurine 65mm in front of plane of the left eye of Snoopy;
The leading edge of the apple in fruit bowl is 160mm in behind of plane of the left eye of Snoopy.


First shot and all not bad was with the 50 and was set at


ƒ/2.0
50.0 mm
1/20
100
One Shot AF

https://farm3.staticflickr.com/2928/14765515475_ca5701d008_b.jpg (https://flic.kr/p/ouM8k2)IMG_4776 (https://flic.kr/p/ouM8k2) by Superbee15 (https://www.flickr.com/people//), on Flickr

Next shot review shows more DOF and seems good and was set at


ƒ/9.0
50.0 mm
0.6
100
AI Servo AF


https://farm3.staticflickr.com/2917/14578873938_32ccbb95ac_b.jpg (https://flic.kr/p/odhxiu)IMG_4795 (https://flic.kr/p/odhxiu) by Superbee15 (https://www.flickr.com/people//), on Flickr

3rd Shot
This was the 3rd shot with reduced light and increased ISO. The 1st 2 seemed ok but this seems to have not focused correctly with the camera/lens hunting a bit (inadvertently used 1.8) and settings were


ƒ/1.8
50.0 mm
1/250
1600
AI Servo AF

I do feel there seems to be much more focus of the red figurine in this shot when compared to the 1st shot!

https://farm6.staticflickr.com/5556/14762326391_5c2bf5daf3_b.jpg (https://flic.kr/p/ouuMjP)IMG_4800 (https://flic.kr/p/ouuMjP) by Superbee15 (https://www.flickr.com/people//), on Flickr

4th shot
After the hunting with previous shot I opened up to light again and went back to better light settings. This is where things do seem to be wrong. It should have improved focus but did not, it even may be worse. The shot then ends up with more focus on the red figurine. Settings were


ƒ/1.8
50.0 mm
1/60
200
AI Servo AF


https://farm4.staticflickr.com/3860/14785354743_6710b80922_b.jpg (https://flic.kr/p/owwNRn)IMG_4801 (https://flic.kr/p/owwNRn) by Superbee15 (https://www.flickr.com/people//), on Flickr

In between previous and next shots I did download shots and I moved the camera and then reset back in same place to retake some.

5th Shot
This shot seems to be reasonable although the red figurine still seems to have very slightly more focus than the 1st shot. Settings were


ƒ/2.0
50.0 mm
1/30
100
AI Servo AF


https://farm4.staticflickr.com/3883/14785345133_cb49e2006a_b.jpg (https://flic.kr/p/owwKZF)IMG_4803 (https://flic.kr/p/owwKZF) by Superbee15 (https://www.flickr.com/people//), on Flickr

Thoughts ?

[fess67]

My personal thought is you are looking for a camera focus issue when I think it is much more likely to be a user error. Please do not take that personally, I have done exactly the same with my cameras.

I think a better way for you to check your focus is to use the set up you already have but use a ruler on the bench as your subject - or one of a number of focus cards easily found online. Have the 0 of the ruler closest to you and the end of it furthest, use single point focus on One Shot. Throw lots of light on it and make sure the shutter speed is 1/60 or higher (preferably higher). Focus on the 10 cm mark and see if that is the point in focus.

You may also consider using mirror lockup to ensure no anomalies are thrown in due to mirror slap.

AI Servo is designed for moving subjects, using that mode may induce errors as well when mounted on a tripod.

Of course you may well have a focus issue as well, just worth while doing some more scientific tests and give the camera a chance by increasing your shutter speed above that which you have been using so far.

[superbee15]

My personal thought is you are looking for a camera focus issue when I think it is much more likely to be a user error. Please do not take that personally, I have done exactly the same with my cameras.



No offense taken as the post was commenced under assumption I was the one doing something wrong and I am trying to determine what. I had also never heard anything about front/back focus.

I took your advice and found a card and tried some more shots. Again like yesterday following method:


Tripod (http://www.ausphotography.net.au/forum/showlibrary.php?title=Indexes:Stability_-_Why_use_a_Tripod_or_monopod) for all;
Used Mirror Lockup - new;
No shots with flash;
Shots taken mid afternoon with 1 set done outside to ensure good light and the reduced light with blinds and fluors inside to take higher ISO;
Used a wired remote controller;
Always focused on center line;
Used only the Center Focus Point;
Used the 50m lens (http://www.ausphotography.net.au/forum/showlibrary.php?title=New_To_Photography:Using_different_lenses) only;
Camera placed 0.63 meters from center focus line.


I took 3 sets (covering ISO 100, 6400 and 1600) of 8 shots covering following f-stops - 1.8, 2.0, 2.8, 4.0, 4.5, 5.0, 9.0 and 13.

Analysis - to my limited experience - seems to display slightly more focus consistency in good light around f4 and f4.5. An example is the 1st photo below.

I only seemed to achieve 1 shot at both ISO6400 and 1600 that I could call balanced focus. All other shots varied from slightly front focus to definite front focus. Mind you I am NOT saying there is a lot in it. I also could NOT get any shot to come out as bad as the worst shot from yesterday. After taking the 3 sets I set mirror back to normal and varied between AI Servo and one shot and also tried one with flash and all seemed consistent with other shots taken.

The 2nd and 3rd photos below are to me front focused and were shot at ISO 6400 and 1600.

It also seems to me that in low light and large aperture the lens tends to have more front focus while in good light the smaller aperture seems to have more front focus.

Shot 1


ƒ/4.0
50.0 mm
1/60
100


https://farm4.staticflickr.com/3849/14774183345_8a9ec25b02_b.jpg (https://flic.kr/p/ovxxZ4)IMG_4812 (https://flic.kr/p/ovxxZ4) by Superbee15 (https://www.flickr.com/people//), on Flickr

Shot 2


ƒ/2.0
50.0 mm
1/500
6400

https://farm6.staticflickr.com/5578/14773828682_3b3f9e197f_b.jpg (https://flic.kr/p/ovvJyb)IMG_4824 (https://flic.kr/p/ovvJyb) by Superbee15 (https://www.flickr.com/people//), on Flickr

Shot 3


ƒ/1.8
50.0 mm
1/125
1600

https://farm3.staticflickr.com/2934/14794026573_df9ed20bd1_b.jpg (https://flic.kr/p/oxifFF)IMG_4833 (https://flic.kr/p/oxifFF) by Superbee15 (https://www.flickr.com/people//), on Flickr

[arthurking83]

One thing .. be careful with your terminology.
Smaller aperture = larger number. If you mean smaller aperture number .. call it f/stop. f/stops are the actual ratio values .. such as f/5.6 or f/11(smaller aperture)
(the aperture is the physical opening of the lens! .. technically it's called the diaphragm .. but that's not important).

Larger aperture means bigger opening .. smaller f/stop number(eg. f/1.8 f/2 .. etc).

Your preliminary tests seems to indicate that the lens may be front focusing .. but it's still as yet inconclusive.
If it was, it would do so all the time(unless something went awry in the first test shot).

In the lower light test shot, the conclusion would be that the combination of the 50/1.8 and the 500D aren't perfectly suited for perfect and consistent low light AF!

So in Ai mode, the camera(+ this lens) seems to struggle to maintain focus.
This shouldn't be an uncommon situation .. although not one you want to have to put up with.
Now that you know this, you can 'teach yourself' to work around it.

If you can ... just one more quick test which shouldn't take up too much time for 'ya.
Switch the subject matter around.
Put the red figurine up on a pedestal(she seems to be the star of the moment anyhow! :p) .. and use her as the focus point.
Put Snoopy on the sidelines still in the frame, as a gauge on focus depth.
The red figurine has more contrasting patterns and lines for focus not get confused, whereas snoopy can cause focus locking errors.
Keep it low light. F/2 and f/4 or f/5.6 should be sufficient for determining if you do have a focusing issue with this lens on this camera or not.

Something else that you can do as well. You don't need to actually take the shot .. this is more for confirmation purposes and posting questions to others.
As you have liveview, what you can do is to focus, using Ai mode, briefly .. say a second or so, stop and then switch to Lv mode.
Zoom in to 100% view and determine if the image looks sharp on the review screen. If it's sharp, great. If it looks slightly blurry, you can 'jimmy' the lens' focus collar to get a sharper looking image.
The trick is to determine which way you need to adjust focus on the lens, and by (roughly) how much.
two or three runs should be enough .. but be sure to defocus the lens before each run .. and do so both ways(that is, throw focus out towards infinity and then the next attempt towards minimum focus distance too).

Repeat the above test in Single shot AF mode too .. just to see what happens, and if it works differently to Ai mode.

FWIW: the reason for the above test again is to discount that Snoopy wasn't the issue here!
The way focus systems work is that they see lines. Basically they see a series of pixels, which make up lines and try to render these pixel lines with as much contrast as possible.
The less fine the pixel/line subjects are .. the harder the AF system has to work to achieve consistently accurate focus.
The red figurine has a lot more detail for the AF system to 'see'.

If you want to understand another technical aspect that can affect focus systems .. read my reply to THIS (http://www.ausphotography.net.au/forum/showthread.php?130477-Nikon-D7000-Back-Focusing-Issue) thread too.
My reply with the large red squares, apparently, is a common problem that probably affects all cameras in some way .. some less so, others more so. The tolerances are so tiny in AF systems, that this can't be helped.

FWIW Pt II: the best outcome with your issue will be that it is a user error issue, and not a physical issue with your gear! User errors is easily fixable .. gear issues cost you $$$!(hope for the former! :D)

[superbee15]

Larger aperture means bigger opening .. smaller f/stop number(eg. f/1.8 f/2 .. etc).


Yep was across that even though it has taken a bit for it to sink in. Will refer to as f/stop in future.

Thanks, will look at further tests.
Cheers

[superbee15]

One thing .. be careful with your terminology.
...Put the red figurine up on a pedestal(she seems to be the star of the moment anyhow! :p) .. and use her as the focus point.
Put Snoopy on the sidelines still in the frame, as a gauge on focus depth.
The red figurine has more contrasting patterns and lines for focus not get confused, whereas snoopy can cause focus locking errors.
Keep it low light. F/2 and f/4 or f/5.6 should be sufficient for determining if you do have a focusing issue with this lens on this camera or not.

Something else that you can do as well. You don't need to actually take the shot .. this is more for confirmation purposes and posting questions to others.
As you have liveview, what you can do is to focus, using Ai mode, briefly .. say a second or so, stop and then switch to Lv mode.
Zoom in to 100% view and determine if the image looks sharp on the review screen. If it's sharp, great. If it looks slightly blurry, you can 'jimmy' the lens' focus collar to get a sharper looking image.
The trick is to determine which way you need to adjust focus on the lens, and by (roughly) how much.
two or three runs should be enough .. but be sure to defocus the lens before each run .. and do so both ways(that is, throw focus out towards infinity and then the next attempt towards minimum focus distance too).

Repeat the above test in Single shot AF mode too .. just to see what happens, and if it works differently to Ai mode.

Well did some more shots this afternoon and again have come across a miss on focus. Had same setup as yesterday in terms of tripod and mirror and remote.

However substituted Snoopy for bottles on basis that they may show focus better than him. Included ruler as a backup - which I think was just as well. The focus was over Reds eyes and nose. The vertical plane for that focus ends up on the 23 of the ruler markings.

I guess I did 22 shots and just near the end when changing from 5.6 to 1.8 it did not focus as it should (I think it was short) the next at 2.0 was same (missed focus) and the next shot was ok. All four shots were comp[leted inside of a 2 minute period with only changing some settings. Have included 1st 2 shots of this 4 shot group.

I also tried the 2nd test and I did adjust minutely the focus- it was very fine and I know my eyes are not the best. However when pushed to infinity to the right (is that correct) I adjusted slightly back to infinity on live view and when pulled to minimum I have to adjust slightly back to minimum - this was in 'one shot'. In AI Servo it seemed to perform ok.

I also think it did very well in live view - I tried a few re-focuses while zoomed so not sure if this a different circumstances.

Overall I do not think I did anything wrong on these shots but again seem to have come across random misses.

Shot 1


ƒ/5.6
50.0 mm
1/15
1600

https://farm3.staticflickr.com/2930/14597119199_c8b67d3649_b.jpg (https://flic.kr/p/oeU3YX)IMG_4861 (https://flic.kr/p/oeU3YX) by Superbee15 (https://www.flickr.com/people//), on Flickr

Shot 2


ƒ/1.8
50.0 mm
1/160
1600

https://farm4.staticflickr.com/3922/14597254577_bd6e46f17e_b.jpg (https://flic.kr/p/oeUKe4)IMG_4862 (https://flic.kr/p/oeUKe4) by Superbee15 (https://www.flickr.com/people//), on Flickr

[jev]

Seems to me you definitely have some front-focus issues in this setup. Unfortunately, the 550D seems to be missing microfocus-adjustment features... *sigh*

[arthurking83]

Yep! As jev said .. 99.9% front focus issue with this lens.
If you have the time an patience to check any other lens you have .. it'd be recommended. This step will just confirm if it's the camera or the lens that's causing the misfocus.
(in almost all instances, it'll be the lens .. but this is not set in stone).

Liveview focusing will be immune to any AF issues, as the AF system in Lv mode is the actual sensor.
When using the viewfinder, there is a separate AF module that does the focusing. This tells the lens where to set the focus distance.

The two possibilities are that the AF sensor is slightly out of whack and tells the lens to move to an apparently correct focus distance .. which in reality is not.(camera issue)
In this instance you can confirm this by testing another lens.
The other possibility is that the lens is slightly out of whack, and is simply not setting itself to the correct focus distance that the camera tells it too. It can be adjusted by the Canon service department.
The question is, the price of this service relative to the cost of the lens.

Other things you can do to work around the issue for now are to stop the lens down a bit more(say f/2.5-f/4) .. or use Lv mode for more accurate wide open settings.
More DOF will slightly mask the effects of misfocusing.
This is one thing to watch for if you use a kit type lens as the other lens you test with. The smaller inherent aperture values of these lens types mask the effects of misfocusing.

[superbee15]

Ok will check both kit lens as they are all that I have.

The 50mm lens is just 9 months old so if there is an issue with just this one would it likely be covered? If not at just over $100 bills it most likely not worth worrying about.

And thanks for your advice and help.

[arthurking83]

.....

The 50mm lens is just 9 months old so if there is an issue with just this one would it likely be covered?

....

I think it should(but I don't know the conditions).
Because it's still under warranty, for sure take it to get it checked out, or replaced or whatever.

if you check your other lenses and they work OK .. if you take it back be sure to explain to them that this 'back focus' issue is limited to this lens only!

What they can sometimes do is to ask for the camera and lens to calibrate them.
There is a way to quickly adjust the camera so that it makes the lens focus correctly(or at the correct point) by adjusting the mirror.(this is easy enough for most folks to do it themselves!)
problem is tho, if the other lenses work OK now, if you adjust the camera to compensate for the one lens, the other lenses will almost certainly be out of whack. (as you'd expect . not ideal)
So it's important that they know that this(or any other) lenses focus OK, or not.
If you have this written down in a service agreement form(or something like that), and they stuff it up(to try to cheap out on costs) .. you have something to come back on.

The lens can be adjusted to focus correctly .. it's just more time consuming.

good luck with it all.

[superbee15]

Thanks Arthur

Have finally checked the other kit lenses and they both perform better overall than the 50mm lens. I took quite a few shots with both and the majority of the time they seemed very close to even. There were a few that had slight front focus and a odd one that had slight back focus. But I did not get any misses like what has happened with the 50mm lens.

Going away soon for a short trip and would have liked the 50 to be true - but not enough time to put in to a service agent. So I guess I will do that when I return.

Thanks to all for input.

Cheers

[arthurking83]

.....

Have finally checked the other kit lenses and they both perform better overall than the 50mm lens. I took quite a few shots with both and the majority of the time they seemed very close to even. There were a few that had slight front focus and a odd one that had slight back focus. But I did not get any misses like what has happened with the 50mm lens.

.....


Just remember that if you compare your other lenses to the 50/1.8, they should be at the same focal length(or very close to it) and aperture settings.
eg. your 18-55 should be at f/5.6 and 50-ish mm and your 50/1.8 should be set to f/5.6

if your other lens is a 55-200(for example) then 55mm is OK, but if it's f/3.5 then compare it to the 50/1.8 set to f/5.6(just to be sure that it's not hazy when set wide open).

if you don't compare them at the same apertures, then the naturally deeper DOF of the other lenses will fool you into thinking that they focus more accurately.

Faster lenses are harder to test wide open because of this lack of DOF when set wide open .. and stopping them down isn't much help as they can also be affected by focus shift as aperture values change.

If you had access to another camera to assess that the lens positively misfocuses .. then it would be cut and dried! But faster lenses can be harder to focus perfectly on less capable camera bodies.

[swifty]

There are already a lot of good diagnostic info in this thread but I'll add just one observation I've noted in your tests.
Not only does it appear you have some front focussing with your 50mm lens, it appears to have a small degree of focus shift.
Your wide opened test shots (@f1.8) appear to be clearly front-focussing.
In your stopped down test shots, you do get an overall sharper image due to the increased DOF but if you look closely at the plane of focus, it appears to have shifted, compensating for some of the initial front focus issue.
In ruler test 1(2nd test), max sharpness at f1.8 appears around the ruler 1.4 whilst max sharpness at f4 appears around 0.6 to my eye.
In ruler test 2(3rd test), the f1.8 shot appears to have max sharpness around the 15cm but shifts to around the 17/18cm mark in the f5.6 shot.
Both are a bit hard to see at these images sizes but you get the point there's a shift. But these are not definitive since this isn't the correct way to test for focus shift. Nor do I think this is your main issue but just making the observation that if focus shift is present on your lens, even if you can get focus spot on at max aperture, you may notice some slight inconsistencies stopped down (although this may be largely hidden with the increased DOF) except maybe around minimum focusing distance when DOF is pretty thin.

[arthurking83]

I think you're right swifty .. an element of focus shift needs to be taken into account too. In fact it's quite common for fast lenses to have a degree of focus shift inherent(my three all have some).
But also! .. what's not so obvious and a bit hard to determine is the straightness of the sheet of paper.
You can clearly see the curvature of the sheet at the lines, but obviously not on the plain section. This could have an impact.

But it's being pedantic, and I think there may be a small amount of front focusing on this combo.

What is going to be hard to figure out (without some cost) is if it's the lens alone(ie. just out of adjustment!) or is the combo of this lens on this camera :confused013

ie. there's no point in paying money if it's the combination of both, just taking the lens in for service and then finding the camera itself is causing some of the issue.