Testing lens

I just got two new lens. How do you test if the lens are good or not?

take a few pictures and look at them? if they dont seem as good as u expect, post them here and we'll see if we can see what the problem is either the lens or the shooter?

Congratulations on the 17-70 and the 50 1.8. I normally test my lenses by taking photos in the conditions that I plan to use the lens. If I like the colors, the focus, the bokeh, all-around IQ; then it's good enough for me.

Yes, real life situaitons for testing. Is there not other factors than just sharpness invloved? How did it feel, is the AF fast and accurate enough, etc.

The most likely problem with a new lens other than electrical or obvious mechanical issue is element decentering.

The traditional test is to shoot some newsprint taped on the wall. Ideally use a tripod and make sure the newsprint target is parralel to the sensor. Look at the shots at 100% and make sure all the corners have similar sharpness.

Some decentering is to be expected, at least wide open, but by eye it should reasonably sharp all over.

BTW make sure to do three sets of tests with a new AF each time and use the sharpest of these, this eleminates the variation in AF performance.

I'm new to photography and have a similar question. I recently had an opportunity to get a 24-70mm f/2.8L. Although I'm very excited to get this lense, I've heard a lot of folks talking about "good copies" and "bad copies" and wondering how I can differentiate whether I got a good one or not. Thanks everyone for your enlightenment!

docchaez wrote in post #2196024
I'm new to photography and have a similar question. I recently had an opportunity to get a 24-70mm f/2.8L. Although I'm very excited to get this lense, I've heard a lot of folks talking about "good copies" and "bad copies" and wondering how I can differentiate whether I got a good one or not. Thanks everyone for your enlightenment!

The trouble with this is you need a standard to compare it to, even if you use a computer aided method you still need to know what to expect.

One hears of good and bad copies of some lenses and this can make people paranoid. Try the above sort of tests and check against other lenses you have, perhaps the kit lens which it should be sharper than.

Don't worry if it is not dramatically better, it is much harder to grade fine levels of sharpness than most people realise.

i just do real life shooting as my test....no charts or no lab setup. go out and take some pictures with different settings. go home and look at the pics. if you're satisfied, then she's a keeper. if most of the images are not good, then you could have gotten a bad lens.