Interesting zoom behaviour on AF500 & AF360 flashes

Hi all,

I just noticed some interesting zooming behaviours between the AF500FTZ and the AF360FGZ flashes when used on the *ist-D.

The 500FTZ zooms to the nearest focal length AFTER the ~1.6 magnification. Meaning, with a 50mm lense, the 500 flash would zoom to 70mm; with a 28mm lense it settles to 48mm and so on and so forth. I would conclude that the 500FTZ has the ability to interpret the 'magnified' focal length of a lense on the *ist-D, and I think this is a neat logic!

On the other hand, the AF360FGZ does not behave in this manner. It auto zooms the same way it would on a 35mm film slr camera. That is, its settles on the next wider step closest to the lense' ACTUAL focal length. For instance, with the 50mm lense attached, it would zoom to 48mm.

That said, I am now confused as to how the lens focal length information is retrieved by both flashes. I would think the 500FTZ auto-zoom setting is more logical. After all, why would you need a 48mm flash coverage when your 50mm lense actually sees only around ~70mm on the *ist-D.

Maybe I haven't set it correctly or what? This issue doesn't hurt at all, I just find it interesting.