I have a T1i mated with a 550ex I bought second. whenever i try to bounce the flash off any surface, the auto-focus seems very soft. If the flash is directed straight at the subject, then the focus is crisp. When bouncing the flash and using manual focus i can get crisp focus.
I'm not an expert by any means, so wondering if it's user error or bad equipment. It doesn't seem to matter which lens i use (50 m2, 24-70L, 70-200L).
Without seeing the photos it's hard to say for sure.
When you bounce the flash, the light intensity drops and so the camera could be setting a wider aperture, decreasing the depth of field enough to look soft, or it might be slowing the shutter down, leading to motion blur.
Check your EXIF data on the shots to see if this might be the case.
try setting your shooting mode to M, bump up the ISO a bit so the flash doesn't have to work too hard, then make a comparison bounce vs direct. that way you can isolate the "bounce" as the cause, rather than any change in camera settings based on bounce.
Hmm. pictures were taken in full manual mode, so the camera did not do any adjustments as far as i can tell. I used the center focusing point. ETTL with no changes to any of the standard flash settings.
Generally the shutter speeds are 125-200/sec on non-moving subjects. ISO 400-800. F2.8-5.6.
Could be lots of things - first, look at the exif files on some of the "sharp" and unsharp
images - is there a big difference in shutter speed/aperture? Second, are all the images
correctly exposed? Also, are the images fuzzy, or are you seeing motion blur, or...?
Also, when you are bouncing, are you using the flash off camera? the 550EX does
have an autofocus assist light which might be helping when the flash is on the
camera...
Other "dumb" stuff - what mode are you shooting in? If you're using AV mode, I think
the camera will meter for the existing light and use the flash as a fill. Its supposed to
do better in "P" mode, forcing the camera to try and use the flash as the main light
if it things it can't obtain a correct exposure with a reasonable shutter speed and aperture for what it thinks the situation is.
If you are trying to use flash as the main light, you're usually better off (with the
canons anyway) setting the camera to M and dialing in an acceptable shutter
speed/aperture/iso, which forces the camera to add flash until the exposure is
correct (if you have enough power). You have to watch the meter to be sure
you're not overexposing as the no-flash case, but...
I also don't know about your sample population of images where this is exhibited - is
this consistent, or are you talking about a couple of "zingers", or...? (I've found
Canon's flash metering to not be as consistent as one would hope, and...
(lengthy diatribe about ettl vs. ettl2 vs. nikon deleted).).
Some representative images/exif data would indeed be helpful.
Are you using One Shot? If not you are not getting help from the AF assist light. I'm not sure if that is what is going on, but that is often a help in low light situations.
I shoot with the 550ex on the 40D all the time using bounce flash. Never seen any softness or misfocus, it works beautifully all the time. Maybe we can help if you post 100% crops of the misfocused / soft-focus shots side by side with the shots taken with straight-on flash.
