420 EX Speedlite with Canon Rebel XT problem

[Carol32]

Good morning--I just joined this neat forum and didn't see any previous threads on this subject. I just purchased a Canon Rebel XT (also have a Canon A75). The camera's speed and resolution are great but I am having alot of trouble with the flash and proper indoor exposure. When using the Speedlite on setting "P" it usually underexposes the subject, even when I am not far away. I have no outdoor exposure problems, just indoors. I've used a slr before without any problems like this. Any recommendations?

[Camo 757]

what mode are you in? AV TV will meter for the background not your subject.

[slin100]

Canon DSLRs deliberately underexpose flash. Quick tip: Bump up flash exposure compensation by +2/3 or +1 stop.

[Mark_48]

Canon DSLRs deliberately underexpose flash. Quick tip: Bump up flash exposure compensation by +2/3 or +1 stop.
Does the Rebel XT have flash exposure compensation? I have the original DRebel which doesn't (without hacking). Just wondering if it was implemented in the XT. And the 420EX doesn't have it either.

[ddelallata]

you might have to download and install the newest firmware to correct your problem. here's a link
http://photography-on-the.net/forum/showthread.php?t=76635

[Bob_A]

Good morning--I just joined this neat forum and didn't see any previous threads on this subject. I just purchased a Canon Rebel XT (also have a Canon A75). The camera's speed and resolution are great but I am having alot of trouble with the flash and proper indoor exposure. When using the Speedlite on setting "P" it usually underexposes the subject, even when I am not far away. I have no outdoor exposure problems, just indoors. I've used a slr before without any problems like this. Any recommendations?

Do a search on this forum using the word "underexpose" and you will see that this has been discussed before at length. Canon DSLR's are designed to slightly underexpose (to help ensure you don't blow the highlights) plus there can be differences in "taste" as to how photographers want their images exposed. Given this, some might use 1/3 to 2/3 stop FEC and others may use +2/3 to +1 stop FEC. Often the histogram on the LCD screen can be a big help for determining how much FEC to add. Use it carefully though since on the 350 and 20D it only displays luminosity, and it is still possible to blow out one of the three color channels when the luminosity curve looks ok. Read the following Luminous Landscape article:

http://www.luminous-landscape.com/tutorials/expose-right.shtml

ETTL-II also takes a bit of getting used to. It works well, but if your scene has a lot of white or a lot of black you can still get images that are under or over exposed. Something that can help if you have a tricky exposure is to focus your subject, then:


with focus locked (shutter release pressed half way) recompose so that the partial metering circle (center 9% of the viewfinder) is on something that should be close to18% gray.
push the Flash Exposure Lock button (*)
recompose and fully press the shutter release.
This article may also help:

http://www.garageglamour.com/tips/graycard.php

Sounds more complex than it actually is ... just takes some practice.

[Carol32]

what mode are you in? AV TV will meter for the background not your subject.

Wow this is all really useful. To answer a question asked by Camo, I was using "P" mode. I guess compensating is an option. I had no idea the Canon deliberately under-exposed flash.

Oh, thank you so much for these replies. Very helpful! I will read the links suggested. That is very helpful. The flash also completely washed out some of my other shots, so I can understand the deliberate underexposure. Once washed out, I guess they are ruined, while an under-exposure can be compensated for relatively easily in Adobe software. However, there's also a possibility of a flash malfunction?

[Bob_A]

However, there's also a possibility of a flash malfunction?

My guess would be that it is more of a user error problem than a flash malfunction. It takes a bit of effort to understand how to get good results when using flash with ETTL-II, but the nice thing with digital is you can shoot a few hundred test shots and try different things out and all it costs you is some time :D

As I mentioned before, flash can be really tricky when you are shooting something with a lot of dark areas or a lot of white areas. Maybe if you think of ETTL-II wanting to make your subject 18% gray this will make sense. So, if the ETTL-II is being used to meter something that is very dark the result will be an overexposure ... if you meter on something almost white, underexposure. This is where flash exposure lock (and maybe using a gray card) can be very useful.

The above is a pretty simplistic explanation of course, because ETTL-II does a lot of complex calculations to try to determine what the subject is, what the background is, what should be excluded, etc. Hopefully it's enough to get you going though ...

[Michaelmjc]

Does the Rebel XT have flash exposure compensation? I have the original DRebel which doesn't (without hacking). Just wondering if it was implemented in the XT. And the 420EX doesn't have it either.

The XT does have flash compensation, -2 - +2.