Testing Lenses? (newbie question)

[Chris G]

I see a lot of you guys say you test your lense when you buy a new one. Can you expain your testing methods?

Also, is it comon that most lenes are not that sharp when they are wide open? And is there a certain fstop that is sharp? I quess it would depend on the lense right?

Thanks,

Chris

[cmM]

Well, the most common tests done are for focus. If you do a search on the forum you'll find many threads on that. Then you can take certain test shots to see how a lens behaves under certain conditions (testing for chromatic aberations for example), distortion (wide angle lenses), etc...

As for sharpness, all lenses have a "sweet spot" where they are sharpest. Better quality lense are sharp throughout a larger range of apertures while worse/cheaper lenses suck wide open and suck when they're stopped down too much.... and so on :)

BTW I like your avatar.

[whchan]

All depends on the lens. If sharpness is the most important thing, the old rule of thumb is to stop down to f/8 and most lens would peform their best at 8. Of course, better lenses, as mentioned by cmM, have a much bigger sweet spot.

[Chris G]

BTW I like your avatar.


Thanks. That Ferrari badge is off a 1960's GTO. I was a terrible rainy day at the car show I was at. I came up with the idea of shooting car badges. All I had was my S330 point and shoot (pre 20D). They came out pretty good for a 2 megapixal point and shoot camera.

Here are some of the shots.

http://911cg.myphotoalbum.com/view_album.php?set_albumName=album03