Originally posted by dtsui I can't resist chiming in...can anyone please do a quick test to confirm the following on your K5/K7 + AF540/AF360:
Fix a focal length on your lens, set aperture to f/4 or f/5.6
Set camera to M mode, ISO between 200-400
Point flash to ceiling, pull out the reflector card but not the diffuser panel
Change the zoom setting on your flash (by pressing the ZOOM button) and observe whether exposure varies in accordance with the zoom setting.
On my K7+AF540+Sigma 17-70mm, the exposure will steadily decrease from 16mm to 58mm (on the flash), normal exposure is usually achieved at 34mm.
G'day Dtsui
I may be a little late to the party here, but I just did exactly what you asked.
K-5 rather than K-7, but when progressing the zoom through the range (on camera, pointed straight up, reflector card out, but not diffuser) I get almost exactly the same exposure for each frame. The histogram has a peak on the right at approximately the 2/3 mark. It seems my 540g/k-5 is working as it should, adjusting the flash output with change in flash angle with relation to the subject.
I'll try the same with my k-7 and see if there is any difference.
Cheers