Canon 40D AEB

[pono]

My understanding of AEB is that the camera takes three photos at different exposure lengths so you can find out which one you want to use. Correct me if I'm wrong.

Is the camera supposed to take three different photos, like click click click, when you press the shutter button once? If so, my camera is just taking one.

What's wrong?

[Colin Southern]

My understanding of AEB is that the camera takes three photos at different exposure lengths so you can find out which one you want to use. Correct me if I'm wrong.

Is the camera supposed to take three different photos, like click click click, when you press the shutter button once? If so, my camera is just taking one.

What's wrong?

Hi Pono,

The AEB feature has a couple of uses:

1. It's useful (especially if you're shooting JPEG) and you want to "spin the exposure wheel" up to 3 times (as you mention) - and (2) it's also useful with HDR photos when you need to capture a wider dynamic range.

Yes, it will go "click click click", but you need your camera in continuous drive mode for that to work (then it'll take 3 shots and stop) ... otherwise you need to press the shutter release 3 times.

[pono]

Thanks! I didn't know it needed to be in continuous shooting mode.

[rpcrowe]

Auto exposure bracketing is one of the handiest, but probably one of the least used, tools in the Canon inventory of neat tricks. I expect that other brand cameras also have this capability but, I am most familiar with the Canon cameras and will speak specifically on the 40D since I own and use one of these fine DSLR's.

Auto exposure allows three shots of varying exposures to be made. This can facilitate getting the correct exposure in chancy situations and will also, if the camera is not significantly moved between exposures, allow for high dynamic range compositing.

The handy thing is that when you are in burst mode or self timer mode; the camera will take three sequential images - each with a different exposure and then stop after the three bracket shots are made. You can vary the exposures by as much as 2-EV. If you are in Programmed exposure, the exposure bracketing may change the exposure by modifying either shutter speed or f/stop. If you are in shutter priority mode, the camera will change the f/stop to modify the exposure. In aperture priority mode; the camera will change the shutter speeds, not the f/stop, in order to modify the exposures. The last mode is the best to use if you are considering possible HDR compositing because the focus and depth of field will not be changed by increasing or decreasing the shutter speed, but might be changed by modifying the f/stop. This will ensure that all three images are identical, except for the exposure.

You can also combine AEB with exposure compensation. By setting your camera at a -1 EV exposure compensation and AEB at 1 stop intervals, you will get an exposure two stops under what the camera's meter reads, one stop under and right on what the meter reads. I have found that this is often great for night photos, since the cameras meter will often read the generally black portions of the scene and over exposure the lighted areas. You can, of course select either exposure compensation or AEB of more or less than one stop if you desire.

You can also choose in what sequence the bracketing will be accomplished by selecting Custom Function 1-5 through the menu. Choose "0" and you will get the default setting which is metered exposure - under exposure - over exposure. Choosing "1" will give you under exposure - metered exposure - over exposure... I use "1" because it is easier for me when I am viewing my images to have them in underexposed, right-on and over-exposed sequence. That is just how my brain works. However another possible advantage is that when you work with quite slow shutter speeds, the second shot of a three shot sequence is often the sharpest since it is the least influenced by camera movement due to presing the shutter button. The Canon metering system, correctly used, will often give you the oprtimum exposure as the meter reads. So you have the best chance for the optimally exposed image to also be the sharpest.

Custom function 1-4 lets you select if the AEB is to be retained. The default setting for AEB is "0" or "on" in that the AEB will shut off when you turn the camera off, change lens, replace battery or change CF card. The "1" or "off" selection retains the AEB even when the camera is shut off until you physically change the settings by using AEB on the menu. This is the way I keep my camera set. I want to have total control of my settings and do not want the camera to change anything without my selecting the change.

I love the way Canon handles AEB, but I wish that it had a five shot AEB capability. This would facilitate even better HDR compositing.

With today's high capacity memory cards available at reasonable prices, there is really no reason why a photographer could not shoot in AEB for the majority of shooting. That way the photographer could choose the optimum exposure or opt for doing an HDR composite for virtually any shot in which there is not significant movement of the camera between the shots...

[Colin Southern]

I love the way Canon handles AEB, but I wish that it had a five shot AEB capability. This would facilitate even better HDR compositing.

The 1D3 and 1Ds3 give you a choice of 2, 3, 5, or 7 shot AEB

[RichB]

Is that useful?

Just wondering what you'd need it for.

[Colin Southern]

Is that useful?

Just wondering what you'd need it for.

Very useful for landscape when I'm pushing the limits of the dynamic range (which I often do).

[rpcrowe]

I just read a "trick" which I will use on my 40D the next time I want a 5-image HRD string. Set the camera to 2 stop AEB and select -2EV exposure compensation and fire off three frames... Then set the camera to +2EV exposure compensation and fire off an additional three frames (or use 1 stop AEB and + and - 1EV exposure compensation and do the same). Discard one of the two middle shots of the string (they will be duplicates in exposure) and you will end up with a five shot AEB string with images differing by either one or two stops. This seems easier than adjusting the individual shots...

[Ross]

if you use software "dslrp182", you can take at least 15 samples (with many level separating for each shot). So that, it is very good for HDR.

Ross

[rpcrowe]

dslrp182 is quite interesting. I wish that this capability could be transferred to an IPOD or IPHONE or some other smaller and lighter in weight hardware.

I am not often in the position to have even my notebook computer with me when I am shooting pictures.

Do you know of any more compact device to use with the dslrp182 program?

[Ross]

Oh, You can get more information from here http://www.breezesys.com/products.htm#dslr
Ross

[russellsnr]

Hi, Didn't see a mention of this reading through but if I use AEB I always place the lens to manual mode after AF has done it's job this is just incase you wish two combine 2 or more photographs and if the focus moves between any of the shots it can make life difficult in PP afterwards. JMO