"Exposure locking"

[Mr Felix]

On my 550D (and 300) there is an "Exposure lock" button marked * on the back of the camera.

Reading the manual, it is used of you are going to take panorama shots to keep the larger picture with the same settings.

Ok, I thought I understood that, but now am not so sure.

I once did a pan' shot with my Nikon but when I joined the two pictures, they didn't look that good. I put that down to the exposures being different.

Slowly working my way through the 32 GIG of pictures from my holiday, I am constructing the pan' shots and am seeing possible problems with exposure locking.

But what really interests me is: Alghough I am guessing this is the "Idiot's way of doing it", why wouldn't you just put the camera in MANUAL mode and take the shots without changing the shutter/appature?



Anyway, with the exposure lock, there would be problems if there were DARK and BRIGHT areas in the bigger shot, as the dynamic range would/could be too high.

So, thinking about that, and HDR, I am confused with this question:

HDR is where you take several shots of the same thing with different exposures. The program then takes the best of each and gives you a composite. But basically the range is "flattened"/reduced. Which is what HDR is sort of about. - right?

The subject has a large dynamic range - which exceeds the range of "usable" on the camera - or something.
Taking the multiple shots the program gets the "normally exposed" parts and melds them together to make one shot which has the highlited dark parts of one and the darkened parts of the other.....

So, if I am taking a pan shot which goes from DARK to BRIGHT, locking the exposure will give extreme dark areas and extreme bright areas. If that could be taken in ONE frame, you would/could/should do a HDR on it and get the resulting composite.

I guess it could be possibe with a pan shot - doing each with HDR - but it would be complicated. Right?



Am I digging my self into a hole?

[kiwi]

Yes

Exposure lock s usuall used for metering on someone's face, lockin that exposure then recomposing without affecting the metering

[Mr Felix]

Ok.

But it seems more difficult to me than metering the face on MANUAL and then re-composing the shot.

The time "exposure lock" is valid is short and hardly gives you enough time to re-compose the shot before it de-activates.
Well, that is how I have noticed it behaving.


Or am I still at the bottom of the learning curve?

[kiwi]

On a Nikon ae lock also is af lock which is handy

I never use them much either and usually meter manually too

Whatever gets you the shot

[Mr Felix]

Yeah, ok.

I guess while on holidays, I found my self in spots where it was maybe worth trying these "extra" functions.

Looking at the results, I am trying to understand what is going on, what I did, and where the confusion happened. And I guess is it worth using it and not doing it the "harder way".

[Ezookiel]

On my Finepix, it was a simple case of fully depress the button for the first shot in the pano sequence, and then only bring it back up to the halfway mark, which kept the same settings, and then each shot in the sequence had the same settings. This seemed to work very well, and most of my earlier panos appear seamless, or very nearly.
I experimented myself yesterday with the exposure lock to try a pano on the mountain above me, and yet once they were stitched, there are areas in the sky where you can detect the change in images. There are minor changes in the brightness of the sky that are the primary giveaways. So you're not the only one finding it doesn't work perfectly for putting pano's together. I'll be interested to see the solutions people come up with, because making pano's of scenery is one of my favourite things to do.

[arthurking83]

.......
I guess it could be possibe with a pan shot - doing each with HDR - but it would be complicated. Right?



....

It's probably easier to do it this way in the long run.
You simply take some bracketed images of each shot, load them all into your dedicated software and you're all done.

The AE button isn't used for situations such as you describe(such as panoramas).
That is, it's not for locking exposure from one image to the next image, it's only used to lock the exposure to a specific value for that first exposure.
In subsequent images taken after the initial exposure(with exposure lock activated) the exposure lock unlocks itself and the camera is working back into a form of normal mode.



Ok.

But it seems more difficult to me than metering the face on MANUAL and then re-composing the shot.

The time "exposure lock" is valid is short and hardly gives you enough time to re-compose the shot before it de-activates.
Well, that is how I have noticed it behaving.


Weird. I've never seen a timeout feature for this feature on my Nikons. So once set, it stays locked until one of two things happen.
one is that you take the shot(where the exposure lock is reset and you're back in normal metering mode, OR that you press the AE button again and it's now unlocked and operating in a normal metering mode.

[Mr Felix]

I'm back.

SO what's happened?

Honestly. not much, alas.

I need to sit down and really try these things more and more and really look at the differences.

I have found myself recently in "new" situations and stupidly shot myself in the foot by not taking the auto focus off before I did things. Chalk another thing up to experience.

But I got some great shots of the snowy mtns. :)

Wow there is still a lot of snow there even this time of year.

[ricktas]

I hope with more practice you get an understanding of this. Looking forward to seeing some of your Snowy Mtn shots soon.

[ameerat42]

Mr Felix. I use manual mode for panos, simply to reduce the chance of anything going wrong in the exposure area. BUT, lighting conditions can change quicker than you can take the separate photos, and this can sometimes be a problem in the pano PP. See if some of your panos had long intervals/drastically changing light in the individual shots.

For HDR, well, I haven't really tried, but an HDR pano... :eek:
Am.

[Rattus79]

It's probably easier to do it this way in the long run.
You simply take some bracketed images of each shot, load them all into your dedicated software and you're all done.

You've never tried this with a pano then obviously. It's not that simple.
for HDR pano's theres 2 schools of thought.
creating a series of tonemapped HDR images and then stiching them together - which will often destroy the exif and make it alot more difficult to stich as the HDR software will bend images to make them fit together

or
Creating a series of panoramas and then HDRising them. which rarely works well because the Panorama's rarely line up because the Pano software bends the images to make them fit together.

you also have the option of just dumping all the images into autopano (or similar) and hoping for the best .... this rarely works.

from my experience, the best way to capture a scene with a hi dynamic range in a panorama is to use a GND filter.

[ameerat42]

Rattus, I opine that you are Caracticus (read "correct", but since it's all Latin) in your analysis above. My experience is mainly with the variability of almost everything in trying to do panos, and then considering that consistent tonal variation across all the images could be readily attainable.
Am.

[arthurking83]

I think PTGui has a HDR feature, so it's not as hard as is made out to do both HDR and Pano at the same time.

I've never tried the HDR feature in PTGui tho, so my comments are from the point of view of the stitching component only .... not the stitching and exposure/HDR tools available in that program.

[Mr Felix]

Yikes.

I am not disputing what you are saying, but it seems like a lot of work.

Making HDR pictures, and then combining them.

I guess it is the way. I don't know if my computer can handle all that. Though it has a bit of memory, it is a '98 model mo-bo and it starting to show its age.

Anyway, thanks.

Shall study it and hope to learn.

[Rattus79]

Rattus, I opine that you are Caracticus (read "correct", but since it's all Latin) in your analysis above. My experience is mainly with the variability of almost everything in trying to do panos, and then considering that consistent tonal variation across all the images could be readily attainable.
Am.

What??

I dont' think I understood a word of that.

[Film Street]

When using manual settings, be sure to turn 'auto ISO' off.