Experience with Sigma 18-35mm f/1.8?

Started 8 months ago | Discussions thread
DavidB77 Forum Member • Posts: 60
Re: Experience with Sigma 18-35mm f/1.8?

I purchased 3 copies of this lens for my K3II, in 3 different shops,  and sent them back.

None of the 3 copies focused properly using viewfinder, but they focused correctly using Liveview.

1st copy was amazing at 35mm, 28mm, excellent at 24mm but strangely not good below 24mm. Edges were totally crap at 18mm. I tried a Nikon version of the lens on a D7100 and image was excellent at every focal length, so I send my lens back and purchased another copy.

2nd copy was heavily decentered, left was out of focus from 18mm to 24mm and right was out of focus above 24mm.

3rd copy was also decentered but the opposite of the 2nd copy. Right blurry below 24mm and left above 24mm.

I gave up...

So I would say that the lens could be amazing if you could get a good copy, but finding a good copy is not easy! It is a pitty.

I also noticed that the lens was not usable at all at f/16 (it's min aperture) because of too much diffraction. And f/11 is heavily diffracted too. I would say that f/11 is like f/16 on others lens, and f/16 is like f/22 or more...

 DavidB77's gear list:DavidB77's gear list
Pentax smc DA 70mm F2.4 AL Limited Pentax smc DA* 300mm F4.0 ED (IF) SDM Pentax K-3 II Pentax smc DA 35mm F2.4 AL Pentax smc DA 50mm F1.8 +2 more
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