Help with ND filters please

[Ms Monny]

Okay, I think I am now ready to tackle the ND filters!! That may sound absurd to you, but I have tried to use them, and to no avail!!

What exactly do I do?

What I have been doing is this:

Set camera up as normal - Auto focus, Av priority, live view.

I focus on the sky and look at the reading, I focus on the ground and get the reading. I try to work out how many stops between the two....and end up just guessing because it usually is such a big difference anyway!

I then put into manual focus. I focus on the ground or at least below the horizon.

I slide the Cokin ND filter in but not all the way down. I manually focus again, then I slide down the filter until I THINK it is meeting the horizon. I actually can't tell by looking at the screen/viewfinder!

I take the picutre and it is crap!! LOL :lol2:

HELP! :scrtch:

Don't know if I am just doing too much or not enough.

[ricktas]

Do you mean ND filters or ND Graduated filter? If you are using straight ND filters partially across the lens, this will not work, you will end up with a distinct line across your photo where the filter edge is. What you need are Graduated filters.

ND filters are designed to darken the entire scene, for things like slow shutter speed waterfall effects. ND Graduated filters are for balancing the exposure between sky and earth.

[Ms Monny]

Do you mean ND filters or ND Graduated filter? If you are using straight ND filters partially across the lens, this will not work, you will end up with a distinct line across your photo where the filter edge is. What you need are Graduated filters.

ND filters are designed to darken the entire scene, for things like slow shutter speed waterfall effects. ND Graduated filters are for balancing the exposure between sky and earth.

I only realized this morning I was meant to say GRAD ND filter.

[Ms Monny]

So, no-one can tell me what I am doing wrong with ND Grad filters? I then presume no-one uses them and fixes overly bright skies in PP.

I have looked on youtube but they all just give you the basics - what it is and where you put it! I know that (hmmm, even a monkey knows that).....but what do I set the camera at? Do I focus on the sky and get a reading for that, or the ground or wait till it is in position and the focus above horizon or below horizon?????

[William]

:) It's easy Monika , I dont do any technical stuff like doing a reading for the sky and then the FG and work out the difference in stops , To much work and by the time you have worked all that out the moment is gone , Just screw your holder on to the lens with the filters in , Line up the shot (Compositionally) Adjust the filters/filter with the horizon or just below , Focus and take the shot (As normal) with the filters fitted , I use as you probably know 5 stops for Sunrises up here , Which is two filters stacked in the holder, If it's overcast I generally use one, Either a 2 stop or 3 stop because there is'nt much difference between the sky and FG , Just pretend your fitting sunnies to the top third of the image to balance the exposure out , If you go to dark just bring some lightness back in in PP , Got any more questions , just ask - Bill

[wilko61]

Hi Monika, another tip along with Bill's explanation above. If you are having difficulty 'seeing' where the actual 'graduation' is, when sliding the grad filters up and down is with your '3rd' hand (:lol2:) - depress the DOF button to stop down the lens/aperture so you can actually see the darkness. Because you are using a Canon, it shall be of the left-hand side on the front of the camera as you look through the view-finder. It is a small dome button next to the lens on the camera face.

Hope this helps :)

Wilko

[arthurking83]

It's best to BEGIN by taking meter readings of the extreme brightness levels, for sure, but as Bill said this becomes redundant once you've had some experience with them.

So to begin with, do the meter readings!!

Now as I understand with cheaper end Canon cameras, you don't get spot metering with the focus point.
So you have to manually take readings with the camera making sure you point the camera to the appropriate area you want the meter reading of.... using the centre point for taking the meter reading.

So as an example ... you point at the sky and you see 1/500s.
Then point to the darker area and get a reading.. eg. 1/40s.
(of course aperture stays the same, so you are measuring the difference in brightness levels, and hence what amount of graduation you then need!!)
Best to stay with Aperture priority mode here too.

From this the difference between 1/500s and 1/40s in terms of exposure is close to 3Ev, 3 stops or an ND8. I think the actual difference may be something like 2.5 stops, but that's moot for now.

What's important to know tho is that this GND8 or 3 stop grad is only 3 stops from the clear part of the filter to the darkest area of the filter which is near the top of the filter.
So if you take your reading from lower than the top of the filter it'll make a difference to how you've read the metering.
That is, if the 1/500s reading is from just above the horizon and the graduation is near the horizon, the filter is graduated and hence not uniformly dark from he middle of the filter to the top!!
The lower part of a 3 stop grad may only give you 1 or less Ev of equalisation.
To account for this you need to pull the filter down lower until the darker portion of the filter is now affecting the area you want to expose properly.

If you had a Nikon camera(I'm sure Pentax work similarly too), the method is slightly easier in that you set your camera up, set the filter into place and use the focusing point to take a meter reading.
So you take the meter readings with the filter in place and try to get all the different zones as close as possible to the same exposure level.
This can make for boring images in terms of contrast, but easy to work with in PP.

Important points to watch for is where is the scene dark, and where is it bright and how you place the filter to balance these areas to achieve an even lighting value for the resultant image.
And also that even tho the filter is rated at say 3 stops or 2 stops, this rating is from the clear to the darkest section of the filter. You slide them up and down, and rotate them to suit the individual scene.

[Ms Monny]

:) Got any more questions , just ask - Bill

Thanks Bill. For a minute there I thought no one was going to reply!! Now after reading yours and the others, it is making a bit more sense...sort of. I think I need to now get some good ol fashioned practice in. I don't know why my images look flat and crappy when using the filter? Oh, well, maybe manual mode not a good idea. I'll stick to Av I think.

- - - Updated - - -


Hi Monika, another tip along with Bill's explanation above. If you are having difficulty 'seeing' where the actual 'graduation' is, when sliding the grad filters up and down is with your '3rd' hand (:lol2:) - depress the DOF button to stop down the lens/aperture so you can actually see the darkness. Because you are using a Canon, it shall be of the left-hand side on the front of the camera as you look through the view-finder. It is a small dome button next to the lens on the camera face.

Hope this helps :)

Wilko

Great idea!! Thanks Wilko. I actually know where that button is (:D) and I do have trouble 'seeing' where the graduation is on the filter when looking through the lens or on the screen - will put that into practice as well!! :th3:

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Arthur - I won't quote yours...it will take up too much room!! Only joking....I thank you very much for the indepth tutorial on working out the readings. That is something that has really got me bugged!!

I don't' think I have spot meter with the focus point, so I am happy to move the camera to get the readings. So if 3 stops is ND8, 2 stops is ND4 and 1 stop is ND2?? No? I think I can google that question anyway....yep, just googled that and it is correct. Will write that down in my little black book of knowledge.

Question.....

It doesn't matter one iota where I am focussing on, does it?? So I presume I can focus on 1/3rd into the image without changing how the camera will meter? I presume I have my metering (after taking the inital meter with a spot meter mode) set to evaluative? I think this is what is confusing me.

[arthurking83]

If you want to rely on your instinct and learning for when and how to use the grads, don't use evaluative(Nikon calls it Matrix).

Matrix metering is taking a whole scene general reading, taking into account both highlight brightness and shadows dimness and giving you an all round best exposure value setting.
Not really a good idea when using grads as you want to understand how and how much to use it.

Spot metering and to a lesser degree centre weighted are the metering modes to use .. more importantly as you are learning or getting the feel for how to best use your grad filters.

Like William said tho, get a feel for when and how to use them, you just instinctively know how much you need, but this takes some practise.

To begin with tho, I still reckon stick with spot metering, take your readings.
Do the calculation in 'yer head... 1/40s .... and 1/500s ... 1/40->1/80 is 1 stop. 1/40->1/160, is 2 stop. 1/40 -> 320 is three stop .. so 1/500 is therefore just over three stops(oops my bad earlier :D .. and so you need this filter and that filter and lower this filter by that much and the other filter a little higher .. and so on.

Having said that tho, I do as William says and sort of know that for this 'nicely exposed' scene, I need a filter at least.

FWIW too, I generally tend to always meter on the shadows(as this is what I'm usually trying to maintain and balance for).
As an example, I know that I need 1/40s for the shadows in a scene, and I know that I need 4 stops of grads for the bright sky, so I slot in 1 ND8 plus 1 ND2 and keep metering on the shadows making sure I have the filters set to keep this 1/40s exposure speed.
Note too that as you add filters, even tho it's clear on one side you will still lose some light through it, so your 1/40s exposure may end up requiring 1/30s.
Not very important, just some thing to be aware of and as you stack grads you lose more light through that clear section too.

Do you have your camera's controls set to indicate and adjust by 1/3rd stop increments, 1/2 stop increments or full one stop increments?
It may also be important.

[Rattus79]

I like to use live view to allign my filters. I find it a little easier then stopping down (depending upon light and how easy it is to see your screen)

I also still exposure bracket when using Filters. I figure the more data/options the better. (Hey, Pixels are free right?)
That way if you haven't gotten the balance between sky and foreground right, you have all that extra tonal range available to you.

Please dont' say HDR... I prefer to "Exposure Merge" :D

[Ms Monny]

Thanks again Arthur......Ah, spot metering! I usually only do this to blow out the background when focusing on a person near a window for a soft, ethereal effect....never used it in landscape. Wow, I actually think I am ready for this next step....if I asked this last year, all this would have sent me running.....the other way! :D

I think I need to write down the speeds and keep it with me to remind me how they increase (1/40, 1/80, 1/160 etc). So many other things to remember, this will come in handy to have on hand.

Why meter on the shadows? I know that metering for shadows is preferred with film, but I thought it was the opposite with digital as blown highlights are harder to recover than getting detail back into shadows?? Maybe I read about this wrong.

Thanks so much for your detailed explanation....it actually is making sense! :th3:

The 60D can adjust by 1/3rd stop increments. How does this fit in? For bracketing?

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Thanks Greg. I use live view when doing landscapes but for some reason used the viewfinder first to see if I could see the graduation!! Duh! Forgot that live view shows how the image will look....as I found that out today when I increase the exposure, the live view showed the image brighter. Learning new things everyday with my camera!!

Bracketing the exposure is probably a smart thing - yes, pixels are free! Hopefully I can then learn what looks the best from the options.

[arthurking83]

.....

Why meter on the shadows? I know that metering for shadows is preferred with film, but I thought it was the opposite with digital as blown highlights are harder to recover than getting detail back into shadows?? Maybe I read about this wrong.....


Contrary to most landscapers, I tend to use Aperture priority for the majority of my shots.
I generally find my exposure point and use that to determine both exposure, exposure compensation and amount of filtering needed.

I found that when using a polariser as well(which I do regularly) a grad filter, the difference that a grad makes to the shadow detail is consistent between having the polariser on or off the lens.
That is, in brighter sections of the scene, the difference that a polariser makes has three levels. Pol on, Pol off and Pol on and rotated for max effect. all three conditions can give slightly different exposure effects.
Whereas in the shadows(where there is little or no light) the two different exposure states when a Pol is used or not, is only on and off. so rotating the polariser doesn't affect shadow detail as much as it does highlight details.
Note that this is only true when a polariser makes a difference ... so, not for every occasion.

And because of this, I've always used the shadows as my 'point of reference'.
That is, I decide on how much shadow detail I'm willing to lose and vary the amount of filtering for the brighter areas.
Note too tho, that if you choose to meter on the shadow parts of a scene, that you will almost invariably need to dial in exposure compensation.
For green grass in shadow I may use something simple like -0.3 to -0.7 EV for slightly richer colour (I hardly ever use saturation in PP), and if there are literally shaodws(dark blacks) and I want a very small amount of detail to poke through, I may use say -2.0 Ev and meter from there. Even tho they will expose black, with a small amount of PP, you can pull back at least 1 to 1.5Ev of detail from these dark shadows.

All other exposure based decisions come from that workflow. Add grads, add CPL, slide grads up/down, add more grads ... etc, etc.

may sound complicated, but in reality its not.
It may take a few seconds to finally decide what to use to get the exposure as I want, but I usually take many more minutes, sometimes hours just to get the composition I want .. so a few seconds of technical stuffing about is of no consequence.

[Ms Monny]

Well, that makes sense then, to meter for the shadows. I use Av in landscape too. I find that I am changing my dof more than wanting to change my speed. I have yet to use my Polariser but I have found later that I wish I had more than not.

I think I might just print out this thread and keep it for reference.....so much valuable information that has been given!

Thank you so much!