As above really, have just got my hands on a new 100-300 lens for my 350d and being a noob would like some tips on testing it. Would appreciate some advice Edit: Basically wanting to make sure it works and is of the quality, sharpness etc i think it should be
Go to that link and print out that graphic. Strictly speaking it's a pattern to test something called Back Focus on video cameras but I find it's pretty good for testing dig lenses for any camera. Stick it up on the wall in a brightly lit area and stick your camera on a tripod. Focus and zoom through the entire range of the lens keeping a sharp look out at the centre of the pattern. If it starts to rotate at any point, you have some element distortions in the lens (could have been dropped, etc). if it all stays sharp and still then the lens is OK. Give it a try.
No worries. Some people use one of these to take a shot through a few zoom ranges and compare results. It's called an ISO12233 Chart and it's used to measure barrel distortion and general lens behaviour at different focal lengths. Here's the link: Again, print, stick on wall, fire a few off at it at different focal ranges and take a look at the resulting images, paying particular attention to the edges. Any deformities point to barrel distortion (although the wider angle you go the more prone even the most expensive lenses are). Anything that sticks out a mile however, is probably a fault or the result of damage, i.e. a drop. Don't go too mad though. The ultimate test for a lens is in the images you create. And if you like what you've created then it's a crackin' lens on a crackin' camera.
