Non Nikon Lenses
Why use a non Nikon lens, well there are a couple of reasons. Either Nikon doesn’t make the required range such as the 120-300mm f2.8 zoom or Nikon does make the lens but it cost two or three times more than non Pro’s can afford to pay. I have found that certain non Nikon lens can be a great value and deliver fine results. The down side in some cases can be a particular lens has front of back focusing issues and is widely reported. A camera store that I use to deal has the solution, just send it back under warranty and the manufacturer will fix the lens.
I guess I have a few concerns over the repair suggestion: One is they may or may not fix the lens correctly and then I have exceeded my return window. Too often tech support will require both the camera and lens to check how the two work together. That’s fine as long as they don’t adjust the camera, which then adversely affect how all my other lenses focus. Next how difficult would it be to have a mechanism to adjust the lens firmware to fine tune the lens at home with your PC. Why should I have to send off a brand new lens for warranty repair, when I could program it at home.
If a store receives lots of marginal products and they are returned, that hurts their bottom line. So rather than telling customers to send off their brand new lens for a warranty repair. They would be better off asking the manufacture to improve their own QC process. Granted the task is tougher because generic lens manufactures are trying for compatibility across multiple brands, not just Nikon. I asked Sigma about their sample variations, and was told that their lenses are calibrated properly. The real issue is with camera to lens calibration and system performance.
Cameras of course have their own range of tolerances, and there can be system issues that combine to present a worst case focus problem. Better cameras have fine tune adjustments, but those only tend to work well with the camera’s brand specific lenses. I would like to add that in general I just have not seen the same problems with several Nikkor lenses. So the software being used by Nikon to test lenses across several bodies, might be worth duplicating to provide consistent lens performance.
“In short I think there is room for improvement, not that every lens should be perfect, but not more than a few percent should have compatibility issues. A test software investment would pay for itself in increased sales, win over market share, and improve customer satisfaction.”