Nikon AF-S 20mm f/1.8G ED - issue with focal plain ??

fussy_III

Dear all,

Yesterday I received my long awaited Nikon 20/1.8 for DSLR. It turned out to be my first Nikon lens . Before I was using the Sigma on Canon but never was happy with the lens wide open or for landscape due to corner-weaknesses.

Now I briefly tested the new nikon-lens. I was pleased with contrast and sharpness wide open - reason enough perhaps to keep it. But even stopped down to roughly f9 I was unable to get subjects at infinity to be equally sharp in the center AND in the corners. When I refocused for corner-sharpness, the corners looked alright but the center is out of focus. Seems like for landscapes, I would have to work with multiple focal-layers - a big inconvenience. However, that was just a rough testing adapted to a Canon 5D II.

So I am left wondering: Does anyone else see the same issues with their copies??

I do not want to cause a great stir, but maybe this is truly an issue with an otherwise great lens.

Regards

fussy_III

If anything, the adapter is responsible. (I am not quite an amateur when it comes to testing, was simply lacking time.) The issue seems to apply to all four corners equally. I used liveview, handheld between ISO 200 and 400, no exposure longer than 1/250. Plus I know to tell shake from defocusing. The corners were out of focus and chromatic abberrations were wide in the corners while the center was sharp. Focused to all for corners, the center was out of focus. A brief test inside my room at ISO 1600 gave me similar indication of strongly curved focal plain at short distances.

I am used to testing lenses for centering etc., but I cannot go back to testing the lens before tuesday. Until than, I am hoping for feedback by other owners. You know the limitations of my testing now. But please trust I have reason for my question.

KnockKnock

Could it be that you're testing in a near field environment (14-ft studio) vs outdoors?

f/9 outdoors, with a correctly gauged hyperfocal point should be no problem getting corners (for the most part) and center in focus.

But in a smaller room, with a really wide lens, you could be looking at corners that are 4' in front of the plane to 12', and f/9 won't be enough depth-of-field.

So choose your focal point carefully between near and far, or let us know if you did.

http://www.cambridgeincolour.com/tutorials/hyperfocal-distance.htm

fussy_III

Please read my statements before posting. I was hoping for usefull comments by people who have yet another sample of the lens at hand. Thank You

Msmoto

You may be waiting a long time on this forum. Not too many use Nikkor lenses on Canon bodies. Maybe reading some of the "experts",Thom Hogan, and others will find a note about this. I would not see how an adaptor could do this unless it has an optical element in the light path.