Ok, so sorry to post a "dumb" question like this but I'm definitely a newbie when it comes to some equipment... I've worked for a studio for a couple of years and used the studio equipment-- So why do lenses need calibration? Please explain! And how is it done? You don't do it yourself do you? And also, if you buy a new lens do you need to take it in to get it calibrated before it can be used? or do they just need to be calibrated after awhile because of a lot of use...?

Do bodies need any special prep work before they are usable too? Or, more specifically, before they can be "counted on" and consistent in their performance?

anyone?

It is possible for some lenses to need focus adjustments. I would say test any lens you buy for critical sharpness. Focus on something like newspaper print and zoom it up on screen. If it looks sharp then chances are the lens is ok. This is assuming that the newspaper is flat and that you are shooting perfectly parallel to the paper.

I have heard about some instances where zooms were sharp at one focal length but not others. With zooms there are different points on the zoom range that can be adjusted. All these adjustments are made by a tech with the proper equipment. If you buy the lens new from a reputable dealer, most of the time they will swap it out for you.

Camera bodies generally do not need adjusting other than possible the meter.

Thanks Tracy!

Also with the lens correction filter in PS, you can "calibrate" a lens for it's distortion and vignetting characteristics if you need to. I can see this for shooting done on a tripod whatever style it may be.