While I mainly shoot in studio at f8.0 or so, using studio lights, I arranged a bit of a bench test for y’all to see and judge for yourselves a bokeh and performance of contrast and sharpness test.
My subjects were three Nikon lens boxes… The chosen point of focus was the middle box, the yellow square Nikon logo, just right of box’s mid line.
Camera was Nikon D7000. This is a crop sensor camera.
This means that perspective will be like a 127mm lens on a full frame. It does not effect the bokeh of the lens… Only the perspective. The lens functions, bokeh-wise, exactly the same regardless of the body on which it is placed.
Focus mode was 9 point, AF-C. D7000 was mounted to a tripod.
The very first shot, at f1.4 using the 85mm 1.4D missed the focus point… Second shot refocused to the correct point… The miss was by a mile…
Once the focus was on, the bokeh looks great yes?
Creamy, smooth, buttery… everything we would expect from the bokeh king. Right?
So, what happens @ f1.8 shots with the 85mm 1.8G and 85mm 1.4D??
Seemingly, bokeh is perhaps slightly more buttery on the 1.4D… Clearly, the 1.8G has better contrast and sharpness.
In fact, this increased contrast is perhaps the reason for the difference in apparent bokeh. The 1.4D bokeh looks as smooth as it does as a function of its lack of contrast.
Contrast is also what auto focus systems use to focus the lens…
Is this perhaps why the 1.4D misses a few focus points? Sometimes by a mile? Maybe…
I would expect the 1.8G will focus significantly more accurately, particularly in low contrast situations, like in subdued light.
Where are we in the comparison by f2.8?
Practically impossible to see difference in bokeh… However, we do see better sharpness and contrast with the 85mm 1.8G.
What happens at a studio like f8.0?
Impossible to tell on a small shot a difference. However, on a large blow up, I can see a sharpness difference. The 85mm 1.8G is sharper…,
Here are some center crops to demonstrate sharpness and contrast differences …
Clearly, the 85mm 1.8G is sharper and crisper with more contrast than the 85mm 1.4D.
Bokeh on both lenses are superb. The 85mm 1.4D has a more buttery feel to the bokeh, I postulate, due to the lens being kind of buttery smooth, as opposed to crystal clear, when wide open.
While I haven’t had a chance to test the 85mm f1.4G, I will surmise that it’s improved sharpness and contrast vs the 85mm 1.4D, will make the bokeh on the 85mm 1.4D seem superior, in the buttery sense, to that of the 85mm f1.4G‘s… In any event, to those keeping score, the 85mm 1.8G has better MTF curves, click here to view, than the 85mm 1.4D and better than the 85mm f1.4G…