30D, AF points, and the 580EX, 550EX and 420EX

Here's a little piece of trivia (or maybe it's more like an annoyance) I just discovered today. Do you have the 30D? Do you manually select AF points other than the center AF point? And, lastly, do you own the 550EX and/or the 420EX flash and use the focus assist lamp? If the answer to these questions is "Yes", read on.

Did you know that when you have the 420EX mounted on the 30D, the focus assist lamp will not light when you have manually selected the AF points marked with an "X" in the diagram below? In other words, you will have no focus assist from the 420EX when you are using the AF points marked with the "X" below.

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Interesting , I confess I dont use flash much , but I will try it just so its not an issue if the need arises.

hmm... interesting. I wonder why?

Wow, never knew that. I'm really glad I spent the extra for my 580ex, because I use manually selected AF all the time when using small DOF.

How did you happen across this discovery?

...and I wonder what does it all mean for users of non-Canon flash?

Gotta be just a bug that will get fixed with the next firmware update, assuming Canon is aware of the problem.

Carzee - Send me your 30D, I'll try it with my Sigma flash and let you know.

I think that's just how the flashes are made and marketed. The 580EX being the top dog covers all focus points.

Nope, I don't think so. When the 550EX was king, it worked fine for all the cameras that were availabe at the time. For example, on the 1DmkII, the focus assist of the 550EX works for all the 45 AF points. Since the 580EX came out about the time the 20D came out, I'm thinking that the 550EX wasn't working 100% on it, like it doesn't on the 30D, and that's probably the reason they came out with the 580EX to rectify that, along with adding new features. But this is just conjecturing on my part.

Funny you mention this but I don't believe my focus assist lamp works when I put my metz on the cam. I thought I had something off in the cam and just forgot about it, I don't use the flash that often so I just forgot about it. I will check it out later to see if it is just with certain af points.