I picked up one of these from my local camera store yesterday. It seems to work perfectly on my T90. When I set the T90 to program it sets both the aperture and shutter speed, so when I switch the flash from the f8 setting to the f4 setting, the camera automatically chooses the aperture set on the flash. That's super kewl, to me. On the A-1, it seems to do something similar, but the aperture is just a bit off. On the f8 setting on the flash, it sets the A-1 aperture (in P mode) to f6.7, and at the f11 setting, to f9.5. Does anyone know if the flash will expose correctly with those settings? I personally bounce the flash nearly every time, so the extra light will be fine, but on the rare occasion when I need direct flash, will I get overexposed pics? I'll look for a manual online. Anyone know, is the flash TTL on the T90?