Does a Canon Speedlite affect focusing?

[neverhood311]

I've noticed that the focusing on my 7D is fairly consistently wrong when I use my Canon Speedlite 430exII on-camera. Has anyone else had this problem? Does the camera glean some sort of focusing data from the Speedlite?

This is kind of a continuation of my thread from last summer: 7D focusing issues

[Donald]

Justin

I cannot think of any reason why the Speedlite should impact on focusing.

[rpcrowe]

http://www.the-digital-picture.com/r...sh-review.aspx
"The Canon Speedlite 430EX Flash and other Canon Speedlite Flashes provide a red patterned focus assist beam - enabling focusing in complete darkness within range (up to 20-30' depending the flash model, camera body/lens being used and available light). See the red window on the front of the flashes? The built-in flashes can provide focus assist as well, but they use a far more dramatic series of bright white flashes."

Perhaps your 430EXii focus assist beam is malfunctioning. Do you have this problem under only a set of circumstances such as when shooting in low light levels or does it happen every time you have the flash mounted and turned on.

Along that line, do you have focus problems if you are using the flash for fill outdoors?

Here is another Google search hit using the search parameters: "430EXii focus problems"

http://forums.dpreview.com/forums/re...1&changemode=1
"i just bought a 4030EX II and when i have the IR assist beam on, the lense seems to seriously front focus (we're talking several inches!!!) when i turn off the IR beam the issue goes away, also using the built-in flash didnt facuse this problem. Is this a known issue? I'm going to assume the problem is with the 50d and not the flash since the flash only emits an IR beam, it doesnt actually affect the focus."

You might try doing a Google search with the above parameters...

Perhaps it might also be of benefit for you to call a Canon Service Center and discuss your problem with one of their representatives. I have had good service from the Irvine, California Service Center at:
15955 Alton Parkway
Irvine, CA 92618
USA
949-753-4200