40D pictures always blown out with onboard flash

[canonfanatic]

I recently bought a 40D used. Most of the time when I take pictures with the onboard flash, the picture is completely blown out. I've updated the firmware, and reset everything to factory settings. Am I doing something wrong or is the camera broken? This happens most often in Full Auto mode, but also seeing it in AV. It appears to be inconsistent, as 2 shots with the same conditions sometimes, one is whited-out and the other is fine. 

Camera: 40D

Lens: CANON EF 50 1.4 (USM) LENS

See attached .... as you can see it's almost all white. Others are 100% white.  

ISO 400

50mm

f/1.4

1/250sec

flash

AV mode

[cicopo]

Switch to Program mode, read the manual about how to set / change FLASH EXPOSURE COMPENSATION, & set it as necessary for the different conditions you'll encounter. You can't use FEC in Auto.

[ScottyP]

Hmmm.

That is REALLY blown out.  I agree with Cicoppo that you should see if maybe you have flash exposure balance cranked up to +3 or something.  If you are shooting so close you might actually want to adjust it down a couple of negative stops.

Of course, your camera is also awfully close to the subject here (a "selfie"?), and you are shooting wide open on top of that.  Does it do any better at a more reasonable distance, and/or with a more moderate aperture like f/8?

[amfoto1]

I wonder if the pre-flash isn't working or something like that. Canon flash often use a quick, lower powered pre-flash to "measure" the flash output needed, a fraction of a second before firing the actual flash.

But, that close with ISO 400 and f1.4, 1/250, I'm not really surprised. Especially if you don't have the flash set to ETTL. Make sure you don't accidentally have it set to Manual. Also check that the Flash Exposure Compensation (FEC) isn't dialed up, you might need to dial in some minus FEC.  Even if you have the flash set correctly, you still might be way too close to use f1.4 and ISO 400. (I don't know the exact specifications or range of the 40D's on-board flash). Stop the lens down a lot more, say to f5.6 or f8. And adjust the ISO down to 100 or so. It is possible the camera is unable to speed up the shutter enough to compensate, unless you enable High Speed Sync (HSS) which allows the flash to work at speeds above the camera's sync speed (i.e., above1/250)... but it seriously reduces the distance the flash is effective... which even at it's best aready is pretty short with the built-in.   

It's possible that the flash is malfunctioning. I wouldn't bother fixing it. Instead my suggestion would be to get an accessory flash and stop using the on-board flash.

Accessory flash have a lot of advantages over the built-in:

- More powerful, so can reach a lot farther.

- Most are much faster recycling.  

- Most are more easily adjustable, have more direct controls than the on-board flash.

- Have their own source of power, so they don't drain the camera's batteries (on-board does... rapidly).

- The falsh head is higher above the lens axis, or even better flash can be used on a flash bracket to greatly reduce redeye and ugly shadows.

- Many accessory flash heads rotate and/or tilt to allow various bounce effects. There are also a wide range of light modifiers and other accessories available for accessory flashes, allowing you to tailor them more to your liking. There are few accessories that work with on-board flash.

***********
Alan Myers

San Jose, Calif., USA
"Walk softly and carry a big lens."
GEAR: 5DII, 7D(x2), 50D(x3), some other cameras, various lenses & accessories
FLICKR & PRINTROOM 

[canonfanatic]

Thanks, all for the feedback. I checked FEC and it was set to 0. I'm seeing this blow out in auto-mode as well. I'd be willing to accept that I'm the source of the problem when in creative modes, but I think I should assume that the camera handles things on it's own in full auto. Is that a good assumption about full auto? That the camera should do the right thing? 

[amfoto1]

Well, I'm the wrong one to ask about "full auto"... I'm guessing you mean the "green box" and I just never use it on any of my cameras that have it. I would expect the camera to try to "handle everything" (even if a bit poorly), but don't know what that means in terms of flash. It might be limited to certain distances. Maybe you are too close for "full auto" as well.

Just from looking at the example you posted, if that's what "full auto" is doing, if the camera automatically set 1/250 and f1.4 with ISO set to 400, that close to the subject... it's clearly wrong and obvious to me that it's going to completely blow out the image. Way too big an aperture and way to high an ISO, for flash that close.

In Av and Tv modes the camera will set exposure according to the ambient light, and then try to use the flash as "fill" (i.e, minus about 1.5 to1.7 stops). P or Program mode also treats the flash as "fill".

When using flash, if you set the camera to M mode, the flash will be treated as the only source of light... perhaps call it "full" flash. You'll have to set the shutter speed (doesn't matter so long as it's the sync speed or slower, tho higher can be used if HSS is set on the flash, if your camera's built in can even do HSS, I dunno). But basically the flash duration acts as the shutter, when using flash as the sole light source (if ambient light is bright enough and/or your ISO high enough and aperture large enough, the ambient light can still be recorded along with flash). Set the ISO, and then set the aperture based upon the distance to the subject (most accessory flashes show the distance range of the flash on their LCD screen... I dunno if the 40D has any means of telling you the distances the flash is set up for).  

I don't know if any of this helps.... maybe someone else uses their 40D and it's flash in full auto and can tell us more.

***********
Alan Myers

San Jose, Calif., USA
"Walk softly and carry a big lens."
GEAR: 5DII, 7D(x2), 50D(x3), some other cameras, various lenses & accessories
FLICKR & PRINTROOM 

[cicopo · Accepted solution]

From my experiences of trying out the Auto mode I consider it useless way more often than not. For whatever reason the camera makes terrible decisions on what settings to use. Try this & please report back.

Take several photos in the following way, using Auto for one & then Program for the second, then switch back to Auto  and take another photo of a different scene, & then switch back to Program & shoot that scene again, and do this at several different types of scene, both indoors & outdoors & where flash will be needed for some. Keep using both Auto & Program at each location / scene and then compare which mode did better. By always starting with Auto at each scene you'll know which photo in the sets was shot using Auto.

[canonfanatic]

Thanks, all for the help. Based on the information I found here and at dpreview, I've returned this camara. Another one is in the mail.