Another problem w/20D (Flash exposure) (UPDATE!)

[Hatem Eldoronki]

I really thought a lot before I decided to post this, because I didn't want to be starting any more controversy to what's already around..

In full auto mode the flash is quite a bit underexposed. I've seen two users complain about this before, but that didn't quite concern me a lot, until I tried it. I don't think that I'll ever use the auto mode, but even in the other "creative modes", if I don't up the exposure compensation by like 1 stop, the picture comes out dark.

I wanted to send Canon an email about this, but was afraid that I might be the only one to complain about it, then they wouldn't pay it enough attention.

Anybody else notice this?

[Jack W.]

Got it here too, with the on board flash and a 420EX. It's not really a concern for me, as I do very little flash photography and it's easy enough to adjust with fec. Also, one click on auto levels in Photoshop fixes the picture fine for me. However, it should be better. I'm not considering sending it in for adjustment right now; I'll wait and see what Canon does (maybe another firmware update-don't know if it can be fixed that way).
Jack

[scottbergerphoto]

ETTLII takes a while to get used to. You have to understand the quirks of Canon flash as well. In Av and Tv, the camera uses an automatic fill flash reduction. In P/Auto the camera decides whether to use fill reduction or not. You have no way of knowing if it will or not, although it usually occurs in bright ambient light. The best way to use flash in ETTLII is with the camera in Manual Mode and the flash in ETTLII. That is the only mode with no automatic fill flash reduction. In addition, if you consistently get underexposure of let's say 1 stop, then just dial in +1 FEC. You can also switch your Flash Metering from Evaluative to Averageing in the Custom Functions. The very same issues have come up with the Mark II.
Regards,
Scott

[Hatem Eldoronki]

I understand that Scott, but in Auto/P mode, you can't adjust any of that, it's fully automatic..

[roanjohn]

................I've been pretty happy with my flash pics.............with both the 550 and the onboard flash............I don't even have to compensate on my exposure.............they all come out properly exposed.........

Ro1

[tommykjensen]

The few flash shot I have done also look ok also in P mode.

[Hatem Eldoronki]

The few flash shot I have done also look ok also in P mode.

Guys, the problem is in Auto mode...just when you need to leave everything up to the camera. Did you test it on Auto? Please let me know.

[tommykjensen]

The few flash shot I have done also look ok also in P mode.

Guys, the problem is in Auto mode...just when you need to leave everything up to the camera. Did you test it on Auto? Please let me know.


Ok just tried greenbox and portrait and to me the photos look ok but definately not underexposed. Shot with 50 mm f1.8

greenbox
http://photo.klein-jensen.dk/public/20dflashtest1.jpg
portrait
http://photo.klein-jensen.dk/public/20dflashtest2.jpg

[CyberDyneSystems]

I've been very happy with the results of the 20D's onboard flash... really it's like having a built in 420EX :)

What's your subject distance? Are you simply to far away? Also.. are you using a lens that reports the focal lenght/focus info? (in other words is your lens ETTL2 compatible)

There are so many variables when using flash.. distance, shutter, EC, FEC, ISO .. don't for get ISO... this can have a profound effect on how the image comes out.. just like shutter speed....

[Hatem Eldoronki]

CDS, I've been using the 17-40mm @ 17mm. I actually just tried the 50mm, and I got better results (although there is more light outside now). It is still underexposed in my opinion..
Taking into considerations all the factors you mention (ETTL-II, etc), I think that the 10D renders a better exposure with that same lens...

[slin100]

This topic is, indeed, a recurring one. I, too, get consistently underexposed images with my 10D and 550EX.

You may not like it, but my suggestion is to not use the full auto (green box) mode. Use P mode instead. You'll sacrifice little in the way of automation but gain a lot of control, including the ability to dial in FEC. I find that +2/3 FEC does the job for me.

[MagnusH]

Ok just tried greenbox and portrait and to me the photos look ok but definately not underexposed. Shot with 50 mm f1.8


If I'm not mistaken that lens is not ETTLII compatible, hence the camera was not in ETTLII mode.

[slin100]

Ok just tried greenbox and portrait and to me the photos look ok but definately not underexposed. Shot with 50 mm f1.8


If I'm not mistaken that lens is not ETTLII compatible, hence the camera was not in ETTLII mode.
Not so. ETTL-II is not solely dependent on receiving distance info from the lens in order to function. ETTL-II is an entirely new algorithm that not only incorporates distance info, when present, but also uses evaluative (or center-weighted if enabled by Custom Function) metering instead of a focus-point centric metering as found on ETTL-I.

When a lens does not report distance info, ETTL-II can still rely on the evaluative metering to calculate a good flash exposure. Distance info is helpful in situations where a highly reflective object is in the frame.

[AzzKicker]

Who buys a 20D only to use AUTO "green" Mode ? maybe the A75 would have been better? :D

[Hatem Eldoronki]

Who buys a 20D only to use AUTO "green" Mode ? maybe the A75 would have been better? :D

I'll say it again: what if my wife wanted to use it?
The issue is not major to me, because I don't think I ever used the auto mode, not even on my 10D..

[slin100]

I'll say it again: what if my wife wanted to use it?
The issue is not major to me, because I don't think I ever used the auto mode, not even on my 10D..
If your wife insists on using it, then probably the only option is to use a 550EX and dial in the FEC on the flash.

Otherwise, just set the camera to P mode, dial in the FEC, hand it to your wife, and have her shoot away. :D

[Hatem Eldoronki]

I did some comparison shots between the 20D's built in flash and the 10D, and I realized soomething quite good about the 20D. Yes, it still is underexposed, BUT there is a whole lot more detail in the HIGHLIGHTS than with the I'm-happier-with-the-10D's-flash exposure! The thing is, the background exposure with the 20D is much darker than the 10D, but the highlight might even be just like how my eyes see it in reality. With Photoshop, I can easily brighten or do curves on a 20D shot, to give a better outcome.
Please keep in mind -again- that this whole flash 'problem' I'm talking about was only in relation to shooting with the auto mode (green box) -that I will probably never use!!