10d and speedlite

[Jonathan Wienke]

Interesting question. Set your lens for 50mm, then manually zoom the flash until you notice vignetting. If 80mm flash zoom doesn't vignette, then you do need to manually compensate for the crop factor to get most out of your flash, and Canon has something to fix in their next round of firmware updates.

[Jonathan Wienke]

What it would appear to mean is that Canon is doing some kind of trickery behind the scenes to make the displayed focal length on the flash the same as the displayed focal length of the lens while keeping the crop factor of the camera in consideration, so that all the numbers match, but the flash coverage still matches the lens coverage. Interesting.

[icke]

Hi,

Newbie question…

I’m a proud owner of a 10d now. After lurking around the 1ds for about 6 month, I finally settled my craving for top notch quality with the (for me affordable) 10d. I must say though that I’m very happy with what I’ve got now.
I got a Speedlite 550ex with it and have a question regarding its operation together with the 10d.
If the lens is zoomed to let’s say 50mm, the flash (set to automatic zooming) zooms to 50mm too. With the magnification factor due to the less than full frame imaging sensor in the 10d, the actual focal length is rather 80mm though. So the flash’s focus is rather wider then the actual subject and thus I would assume that the light reaching the subject is weaker as if the flash would zoom to 80mm.

Should I rather use the flash’s zoom in manual mode???

It surprises me though if that’s not taken into account by the firmware….
I guess this problem was the same with the d30 and d60, so I guess someone out there must have come across that issue before.

Or am I missing something here?

Thanks in advance for any comments.

olaf

[icke]

i just did a quick test. took a few shots of a white wall. 3 with the flash set to autofocus and three with manual focus to 80mm while the lens was zoomed to 50mm. interestingly enough, the shots with the flash set to 80 mm showed significant vignetting while the autofocus shots didn't...

does this make sense?

olaf