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Old Dec 10, 2003, 9:26 AM   #1
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Default Help on Exposure Comp on Rebel

Lets start by saying I am far from a professional when it comes to photography. I recently purchased a Canon Digital Rebel and love the camera. I am having one problem that is probably user error. Exposure Compensation does not seem to be working. I have been taking some test shots inside in low light and even when adjusting the EV up to +2 the exposure does not seem to change. I am making the changes while in either P – TV or Aperture mode. I even noticed it seems like when I stop of the EV the shutter speed and aperture are changing to justify for the exposure difference. I was always under the assumption that you could set the exposure up and it shouldn’t change the aperture and shutter settings, but make the picture brighter. Any suggestions or help would be appreciated. Thanks
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Old Dec 10, 2003, 10:03 AM   #2
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To review how to operate exposure compensation

With the Mode Dial set to P/Tv/Av, press and hold the shutter button 1/2 way to activate the displays. Then hold down the AV/Exposure Compensation button with your thumb as your turn the Main Dial to moe the marker on the exposure scale displayed in the viewfinder or LCD

- to darken, + to lighten


Assuming this is what you are doing to activate the exposure compensation, are you checking results in the LCD or after you download your pictures to the monitor or print them out? How about your histograms? Do they shift to the right when you increase exposure?

The aperature and/or shutter speeds should not change as a result of the exposure compensation, but will change as you compose your camera right up until you press the shutter if conditions change even slightly.
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Old Dec 10, 2003, 10:30 AM   #3
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Thank you for your reply, it may be the case that I was not pushing the shutter button half way down first and then adjusting the EV. I am also using the flash for indoor shots, will this make any difference in the EV not working or working?

To answer the question about checking the photo, I checked it on the display and on the computer. The histogram does not seem to be moving to the lighter side like it should. I will try it tonight again by pressing the shutter key half way down first and see what happens.

If I go from 0 to +2 should I see quite a noticeable change in exposure that it will really show up on the histogram or display screen?
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Old Dec 10, 2003, 11:24 AM   #4
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I got my cam out and played a bit with the settings. I gave some incorrect information out actually. If you adjust the exposure compensation while composing, you will see either the shutter speed or the aperature moving to compensate for the effect you're trying to achieve. It is possible to set the exposure compensation prior to composing and that will remain in effect until you change it (i.e. set 1/3 underexposed).

I don't really understand why you're not being overexposed at +2 stops unless you're shooting a dark subject. Try shooting a neutral subject in good lighting with various settings and see what happens as you adjust the exposure compensation. It should be pretty obvious (particularly when looking at the histograms)


Regarding flash:

In the P mode, the camera will try to adjust for a speed of 1/60 or so to expose the subject and not concern itself with the background (i.e. in a dark setting, the background will be black or dark)

In Tv mode, the flash will expose the main subject and the background will be exposed based on the shutter setting.

In Av mode, the camera will attempt to expose the main subject with the flash and the background will be a function of the shutter speed, which will probably be a slow speed if the background is darker.

Both the Tv and Av modes are best suited for a fill flash mode where available lighting is within working ranges. For fully automatic (snapshot type) flash, P mode works best. Personally, I prefer to shoot in M mode, particularly for flash, giving me control of both the shutter speed and aperature.

If I'm not mistaken, the exposure compensation button will have no effect during flash mode. The ETTL function will try to expose the subject based on the meter reading it sees. Since flash exposure compensation is not possible with the DRebel (unless you're using the 550EX -- I think that can be set on the flash unit), the flash will perform at fully automatic mode. Perhaps someone more fluent on flash compensation will offer some input on this matter.
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Old Dec 10, 2003, 11:31 AM   #5
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ohenry is correct the exposure compensation does not work with flash. Flash exposure compensation is only available on the 10D... (although there's trick you can do from connecting the camera to the PC)

What you might want to try is to use FE lock, Flash Exposure lock, which is available on the Digital Rebel! ie aim for a darker subject, lock the flash and then recompose and shoot the real thing. You should be able to do a quick increase in EV this way... (no need to overide with a 550EX). If you want to underexpose do an FE lock on something brighter that what you want to shoot... The flash exposure lock only use the center area contrary to normal flash where the meter is coupled to the AF point (and could vary all over the place)! 8)
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Old Dec 10, 2003, 12:42 PM   #6
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http://revolution.cx/rcx/fecset.htm

I found this that just does the Flash Exposure on the Rebel. It sounds like the setting sticks and most are setting to +2/3 and leaving it for Flash Exposure. I have not tried it yet.
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Old Dec 10, 2003, 1:05 PM   #7
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Quote:
Originally Posted by NHL
ohenry is correct the exposure compensation does not work with flash. Flash exposure compensation is only available on the 10D... (although there's trick you can do from connecting the camera to the PC)
DownloaderPro v 1.2 also has a feature to do that. I haven't used it so I can't comment on how easy it is to use. Paying attention to the tonality of the scene and FEL is probably the best option with the DR -- just as adjusting for tonality in any exposure (with any camera)

I generally shoot in M mode and have been pleased with the few flash shots that I have taken using the 420EX. I guess if I start using the flash more often, I'll have to take a hard look at the 550.
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