Sigma Ultra Wide angle used..

[vicious1]

Ok I just got back from Japan and bought a 10-20mm Sigma lens for my Nikon D90.
I think the lens is nothing short of spectacular (I am an amateur), but the lens was used (though in absolutely perfect condition) when I bought it for ~220 euros.
Now my question is, how can I check that the lens is in perfect working order since new this thing costs used about 375 pounds in the UK.

Any ideas?

 

[Cliff3]

I would probably run a focus test (link) and a resolution test (link) with the lens. Perform the test again with another lens of known quality to establish a baseline. Comparing the two results with each other should be enough to give you an indication of whether the lens is ok or not.

 

[toxic]

when you do tests, forget about front/backfocus and just look for optical aberrations, and probably uneven sharpness across the frame (as in the left is sharper than the right, not the center is sharper than the corner). test for focusing issues if your "real" images come out misfocused all the time. a lens can "fail" a focus test but be fine when you actually go take photographs.

make sure you expose the same way for every photo (so manual mode), and make sure your shutter is fast enough if you don't have a tripod.

and like cliff3 said, a second lens for comparison is always a help.

 

[Cliff3]

and make sure your shutter is fast enough if you don't have a tripod.

If a tripod isn't available, then setting the camera on a table (on top of a towel or a beanbag) and using the self-timer would be preferred. It is largely pointless to test for optimal resolution when the camera is not absolutely steady.

 

[Mr.Noisy]

Ok I just got back from Japan and bought a 10-20mm Sigma lens for my Nikon D90.
I think the lens is nothing short of spectacular (I am an amateur), but the lens was used (though in absolutely perfect condition) when I bought it for ~220 euros.
Now my question is, how can I check that the lens is in perfect working order since new this thing costs used about 375 pounds in the UK.

Any ideas?

It's a great lens, used at f8-11, nothing short of fantastic, I've got one, and it's really sharp, use it on a D70s & D300, what surprised me is how much jessops sell it for now, i paid £329 about 3 months ago...........

 

[ChrisA]

....how can I check that the lens is in perfect working order...

Don't be to upset if the lens will not focus on test targets on a wall. Many lenses are not "flat field". In fact most are not. Flat field means that there is a plane of focus. That is rare with a zoom. Most likely the "plane" is a curved surface. test the lens on real three dimensional subjects

 

[vicious1]

Thanks

Thanks for all the replies guys, I will test the lens tomorrow with a tripod and analyze the results. Really appreciated.

//Vic

 

[Doylem]

Ok I just got back from Japan and bought a 10-20mm Sigma lens for my Nikon D90.
I think the lens is nothing short of spectacular (I am an amateur), but the lens was used (though in absolutely perfect condition) when I bought it for ~220 euros.
Now my question is, how can I check that the lens is in perfect working order since new this thing costs used about 375 pounds in the UK.

Any ideas?

You think the lens is "spectacular". So what else do you need to know? Trust the evidence of your own eyes and enjoy your new lens...

 

[vicious1]

just for those who are interested..

the lens came out excellently, the tests showed no "bad optics " or " bad focus", so overall I am very happy as this was a steal considering the shape the lens is in.

Anyone looking for a super wide angle for Nikon Cameras, this is an excellent choice.

 

[Abstract]

You think the lens is "spectacular". So what else do you need to know?

Exactly.