I have an issue with my Nikon SB600, which always overexposed the pic ONLY at 35mm (flash zoom head). When you set the flash zoom head to automatically zoom together with the lens' zoom, essentially all images on 35mm are always overexposed. It's not my exposure settings as even on P or full Auto mode, it still overexposes the picture. I used TTL / TTL-BL mode on the flash. The rests of the range are all okay.
My initial inference is that only at 35mm the flash output is nearly maximum (which means the TTL metering screws up at 35mm, thus the overexposed pics). I then tried the Manual mode on the flash (say I put at 1/4 power) and tried shooting at different zoom level. Interestingly, the rests of the zoom range are perfectly exposed with the settings, except at 35mm which is slightly underexposed instead :s
TTL / TTL-BL: metering screws up at 35mm and hence overexposing the pictures
Manual: Flash power is the least strong at 35mm and hence underexposing the pictures
I also tried not to mount the flash into the body, and flashed manually at each flash zoom range. I observed that the flash power was the least when it was set to 35mm.
Tried resetting all the settings on my flash, but the problem persisted.
I also tested Nikon SB800 on my camera to see if it's the camera's problem, but no issues detected. It was all normal when I mount SB800.
Any expert here could give me a shed of light on what has happened to my flash? Could anything had happened to the zoom head when it is set to 35mm?