What are good starting settings to store for exposure bracketing shots?

Question

I started experimenting with the Custom Functions (C1,C2,C3) on my Canon 7D and I decided a useful one to have may be setting it up for exposure bracketing. So it's a quick switch if I ever need it, as opposed to going through the menu to set it up.

I realize the settings would vastly depend on the situation, but do you have any suggestions for some good all round settings to program in as a starting point?

Examples: 1 stop vs 1 1/3 vs 2 stop brackets / ISO choices / Metering mode / shooting mode and so on.

Answer 1

If bracketing for HDR, between 1 1/3 and 2 stops if doing 3 exposures, or 2/3 to 1 stop if doing a 5 exposure set. Depending on the situation. I do 3 exposures at 1 1/3 stops and that covers most situations (I believe that's the default on my D90)

If you aren't doing HDR, but want to bracket for safety reasons, probably +/- 2/3 of a stop.

If you are doing HDR or blending multiple images, you want a fixed aperture, so use Aperture priority or Manual. If the aperture varies you'd get images with different DOF and probably weird effects when you try to merge them.

I usually prefocus, then set to MF, metering set to Manual, and use the high setting for 4-5 frames per second and fire them off quickly. I can avoid using a tripod that way. Too much movement and most HDR programs don't do a good job in aligning and ghost removal in my experience. My self timer will take multiple shots, so I often set that to 3 shots, then I can steady the camera and let it take the shots without having to mash down the shutter release 3 times.

If on a tripod I always use the self timer trick to take the 3 exposure set.

I don't really give ISO any more thought than usual, just keep as low as I can for the situation.

Answer 2

I was always told that -1 1/3, 0, +1 1/3 are good settings for bracketing, but sometimes if the light is very contrasty (bright sky, dark landscape) I will go to -2, 0, +2.

There is also a custom function somewhere buried on the 7D that controls the ordering of bracketed photos. By default it is 0,-,+ I think. Change it to -,0,+ and when reviewing pics later they make a whole lot more sense!!

There is also a custom function that controls whether the camera 'forgets' bracketing mode when the camera is turned off and on again or whether it retains the bracketing settings. I chose to keep them retained. Personal choice of course, but it's nice to know the option is there if you are using bracketing.

Answer 3

I don't familiar with a thumb rule for that, but taking 3 shots with 0, +2, -2 should cover the dynamic range you need and Photomatix knows how to handle it very good.

When I use bracketing I sometimes set the compensation (meaning it's not 0) because for one shot the auto light measurement usually does a good job, but in HDR you might want more details from the darker parts then the bright parts (It happens to me in a sunny day HDR shots), so compensating -2/3 or -1 does the job for me.

I'm guessing that in low light scene a 0,+2,-2 with +2/3 compensation will give you nice results but it definitely depends on the scene - just start with no compensation and look at the results you got, than set a compensation if needed.

I'll add that more than 3 shots (5-7) will give you better result in terms of noise reduction and smooth transition between the dark areas and the bright areas.

The downside of many shots is that you can't do it automatically (at least in most common DSLR cameras) and it takes more time. It means you'll have to use a tripod, whereas, with 3 shots and high speed burst you can take some nice HDR photos without a tripod.

Answer 4

Well, it depends on your darkest dark and brightest bright you want to capture without hitting the sensor's and signal processor's limit.

In general you will have to answer this: why do you do exposure bracketing? E.g. a Nikon 5100 has an EV range of 13.7 by itself, and also uses Active lighting, emphasizing details in shadows and bright areas, so why bother with exposure bracketing?

The answer is:

1. you want to capture details in highlight areas and
2. to capture details in shadow areas with acceptable noise.

Basically the highest and lowest EV is determined by these two considerations. You have to make shots until you are satisfied with the highlight details, and make shots until you have enough details in shadow without unacceptable noise.

This way you get the highest and lowest EV you need. If your camera has a decent EV (dynamic performance) you could as well live with two shots instead of three or more. E.g. with a typical EV performance of 10, two shots can cover an enormous dynamic range (you take them at +5 at -5 - a hardly improbable scenario :-) ).

So all the other shots are somewhat redundant, except for one thing: the sensor and the signal processing subsystem somewhat prefer light (obviously), and you will see a nonlinear response in the incoming light-to-pixel value mapping. This is partly physics, partly electronics, partly signal processing. So what you want to know is: where is the sweet spot of your camera, where a little change in incoming light is reflected by a large change in pixel luminousity/etc. value change. There, your sensor is the most sensitive. More important is: the range of that sweet spot.

Now, let's say you know that your camera has a 5 EV range of very nice detail capture, and the highlights and darks capture somewhat coarse. (You do not have to guess this, usually you can dig up documentation about this or measure it for yourself).

Also, you have established (as I briefly described previously) that for a specific scene you need 10 EV.

And let's say your camera has a native dynamic range of 11 EV (meaning the total, not the sweet spot dynamic range).

So if you make a single shot, in the photo, a range of 5 EV will have great details, the rest is not so nice, in the darks and highlights.

What you should do then is: the current example scene needs 10 EV, you divide that with your 5 EV camera sweet-spot range, and so that means: you make two shots, at +2.5 and -2.5 EV to the middle point (with the assumption that the manufacturer put the middle sensitivity point to the middle of the sweet spot of the sensor). Now, that is kind of tricky, to not have any overlap, so the usual way to go about this is: do +2.5, 0, -2.5. And that's all.

You could make 11 shots for this, but you are just collecting redundant data mostly...

The only other consideration you can make is that in low light condition, the longer you are open, the more thermal noise you will pick up, so making shorter shots there as well could be useful to remove noise from the final image except from the darkest parts.

Answer 5

You are right in saying the bracketing depends on the lighting situation. It also depends on the sensor (you might say "the camera", but the lens doesn't matter here), as it determines the dynamic range -- how far the sensor can stand before loosing detail or blowing out the whites.

The other thing to consider is how many artifacts you are willing to see in Photomatix. I don't quite like HDR results, so I can't help you there. I had a NEX, so I'll give you my pointers, but there's no rule, you have to test. Anything less than +/- 1 EV is too little for the NEX sensor. If you have a difficult situation (backlit portrait w/o fill flash under natural light, bright but interesting background), "bracket your bracketing" (!!): do +/- 1, 1.3, 1.7, 2.0

I wouldn't use 3 EV but there's no rule "against" that - it's just I know it sound too fake for me. You might like it and there's nothing wrong with that! I hope that helps.

Answer 6

I have used the Custom function on a Nikon D7000. I prefer keeping the color settings different. Usually, slight desat for portraits and vivid for landscapes. Helps me quickly move from one type of photograph to another.

But, if you want to bracket, 1/3 exposure brackets would be good. Followed by White-Balance and finally ISO.

From my experience in JPEG post processing, I have always wished i had a taken it at a different exposure. Color tones can be varied to some extent using the filters.