I recently dug-up my old a1 which was idle for almost 5 years. I sent it for a routine service - the only obvious thing they did was changing the foam sealing and cleaning the focusing screen. Getting it back it was obvious that in AE mode the camera was underexposing with all lenses. After some tests (the usual shoot in auto then turn to manual and stop down), I realized that the auto aperture was set average 1 fstop smaller although there is no particular pattern in the error. In very wide aperture (eg. f1.4 with the 50mm lens) it is spot on. From there and up to f4 it closes half an fstop more than required with all lenses. from f4 to f8 it closes 1 fstop more than required and sometimes even more especially with the 135mm lens. Finally above f8 it closes down 1 and a half fstop more than required. Any ideas about the cause and how to fix it?
As you say the camera has just been serviced - Send it back and tell the firm to do the job properly! Sorting out this type of fault can be complicated, and I am guessing - as you sent the camera away for a routine service - that you may not have stripped an A1 down before. The A1 is not the ideal subject for one's first major repair, especially the AE functions.
