You bought a 35-80mm f/4-5.6 lens, but on looking closely at our lab test measurements, it turns out to be closer to a 38-81mm f/4.3-6. We report it has a barrel distortion of over 3 percent at 35mm and pincushion distortion of more than 2 percent at 80mm.
The lab check of your camera revealed three quarters of an f-stop exposure inaccuracy at EV 14 in program exposure, but shutter speeds were right on the money throughout. And while the camera produces an image on film that measures 24x36mm, our test results show you only see 21x31mm in the viewfinder. Image magnification was measured to be only .70X.
Are you justified in returning your camera and lens for a refund, or are these findings within design of manufacturing tolerances?
Secret: All cameras and lenses are off spec to some extent, but some are off more than others.
Yes, there are tolerances. Every camera and lens maker has them for each product and specification. But these tolerances are as closely guarded as the crown jewels of England. Why? Here are a few reasons, but probably not all:
1. Some photographers might be horrified to learn that the camera and lenses don't perform just as they are marked and advertised.
2. Some owners may find the tolerances (shall we call it leeway?) far greater than they imagined.
3. A few individual camera or lens samples when tested by outsiders may indeed be beyond even camera and lens makers' specifications.
4. Some manufactureres' products might be so far off the mark that they wouldn't want consumers to know about it. (It might happen most often with cheapo point-and-shoots and off-brand SLR lenses.)