Lens Repairs

Hi,

I have the following: D7000, 17-55mm 2.8, 50mm 1.4, 35mm 1.8 and 70-300mm.

I initially had focus problems with my body, so had everything calibrated by a well known repair centre before their warranties ran out. Everything came back as no fault, except the body and one lens. After the check/repair everything worked perfectly, no complaints, absolutely spot on focusing every time. I was told that all had been calibrated to the centre's standard lens.

Then, 2 months later, I proceeded to drop my camera... viewfinder took the brunt and was fubar. It was replaced.

Unfortunately, the replacement was front focusing on all lenses, by some way. It was calibrated by Nikon and the front focusing was reduced but not gone.

I then sent the body to the repair centre, as I believed that their standard must have been slightly different to Nikons'. So, if they were to calibrate it, the focus would match my lenses and everything would work. But, it was sent back with no fault.

Ok... so, 3 months after the accident, I sent all lenses and body to the same repair centre to have them checked together.

I was told that all the lenses needed calibrating again.

I wasn't happy, I understood that these lenses had previously been calibrated not more than 5 months earlier to the centre's standard. I let them know this, and was told that the focus on lenses can simply drift over time and everything needed to be re-calibrated back to the new body, rather than the other way round.

They are also charging me for the privilege, whereas the body is under warranty.

Am I being taken for a ride? Can 4 lenses that 5 months earlier focused perfectly (2 pro grade), now have drifted and not be focussing right?

Thanks in advance.

Alex