The classic Nikkors: 28 mm f/2

[Airy]

Back to the main subject. This is an uninteresting picture, but for test purposes. 28/2 wide open on D800. The photo shows that
- resistance to backlight is very good (many lenses would fail that test) in the sense that the highlights would not contaminate the shadows in a significant way. This only applies to the bigger surfaces;
- Distortion is conspicuous but regular barrel, and easily corrected "by hand" (typically +6-+8 in Lightroom)
- Vignetting is moderate (compared e.g. with Zeiss lenses)
- central sharpness is very good, and the "center" is not that small !
- however, the "bleeding" caused by highlights is massive at the borders of dark parts ; the "cross" at the top of the organ case is completely blurred, although the same wood carvings below are OK
- in the upper left corner, you will see that there is some preserved detail smeared by tons of mush
- CA is visible above the top part of the organ case (orange fringes at the edges of the window frames), but moderate - remember it's a 36 Mp sensor we got here

Bottom line : far from ridiculous ! but for working against the light, better stop down a bit. The issues are the coma & astigmatism, plus the "bleeding" issues. Concerning the latter, I do not precisely know the driving factors (reflections between surfaces of adjacent lenses? hence the efficiency of modern coatings?)

[Airy]

Still wide open, but using the Df. The degraded quality of corners is apparent. However, CA is low and correction is not even useful. And the Eiffel tower struts in the background still look decent.

[Bjørn Rørslett]

Bleeding is strongly exacerbated by overexposure ....

[Airy]

The shot is rather underexposed, since the subject is the organ, not the stained glass window. These are my normal shooting conditions. You'll certainly understand why I struggle finding suitable lenses (and many excellent ones catastrophically fail here). The 28/2 is, as I wrote, relatively good in fact.

Now about the bokeh : two shots, close and less close, D800. As usual, sharpness is high in the focussed zones. Transitions are progressive, providing a good perception of depth. The bokeh is not bad, but can deliver sharp edges (see for instance the twigs and the foliage in the background).

[Airy]

I do not want to appear aas the guy always providing counter-examples illustrated by bad shots, so -

The sweet spot for night shots is definitely f/4, as stated before by others. Coma is gone (that's the least one would expect), contrast is very good, so is overall sharpness well into the corners.

[Tristin]

Stopped down performance looks nice, but unless the background is quite simple, as in Nick's beach shot, the bokeh looks quite barfy to me.  Though I wouldn't be leaning on a 28mm for bokeh shots I suppose.

[John Geerts]

One can make use of the fine bokeh of this lens.  Two examples wide open,

City Mushrooms with Df   and Autumn tree with D700

[Airy]

At f/11, the lens still delivers very high detail, retaining a good contrast. Good colors, too. Here on D800

[Airy]

Stopped down performance looks nice, but unless the background is quite simple, as in Nick's beach shot, the bokeh looks quite barfy to me.  Though I wouldn't be leaning on a 28mm for bokeh shots I suppose.

Agreed. The bokeh quality is very much subject-dependent, as exemplified in many shots here. But in general it is rather nervous. Taking bokeh shots with this lens feels rather natural, given its good close focus performance.

[Airy]

One can make use of the fine bokeh of this lens.  Two examples wide open,

City Mushrooms with Df   and Autumn tree with D700

In the second shot, the bokeh is indeed somewhat nervous (and interesting). The 28/2 is no cream machine.

[John Geerts]

Yes, but keep in mind that in the second shot the bokeh is exaggerated in PP. (with purpose) Originally it's softer.

[Airy]

... f/8. Certainly "overprocessed", but the RAW file lends itself well to such processing.

[Bjørn Rørslett]

Looking for something overcooked but cannot observe ...

[Airy]

Precisely. For reference, this is the original, nearly unprocessed shot.

[ColinM]

City Mushrooms with Df 

Lovely shot John.
It would never occur to me to use a 28mm for mushrooms, but obviously in the right hands (and with the right eyes) it's not a problem