Nikkor 18mm f4 AI sharpness on corners?

Started Jun 20, 2013 | Discussions thread
brightcolours Forum Pro • Posts: 14,342
Re: makes no sense

gammada wrote:

brightcolours wrote:

A 18mm prime on APS-C? Why? You are better off just using a 18-55mm VR kitlens, to be frank.

If you were talking about a D700 instead, it would make sense.

Just look at an UWA zoom for APS-C. Either the Tokina 12-24mm f4 DX, or the Sigma 10-20mm f4-5.6 DC. Or if you have a bit more money to spend, either the Tokina 11-16mm f2.8 DX or the Sigma 8-16mm DC.

Any idea on how sharp is the Tokina on the corners? Price is spot on for me.

As for why would I want an 18mm lens on an APS-C sensor, well, it all has to do with geometric distortion. Since the photos I sell must have perfectly aligned horizontal and vertical lines, I'm a bit afraid of going wider and then having to do extensive work fixing that distortion.

Ok, now I kinda understand why you are considering the 18m Nikkors, you hope them to be free of barrel distortion. It is hard to know how they perform on APS-C, the 18mm f3.5 for instance bulges a little bit in the center according to Ken Rockwell, but is relatively straight at the edges.

Both Tokinas (12-24mm f4 DX and 11-16mm f2.8 DX) are sharp enough in the corners, but both can need good CA correction (not the coloured edge masking kind) to get the most out of them.

The Sigma 8-16mm is good also:

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