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Watching the photos made using Sony a7 cameras with fast lenses, I've noticed one interesting thing about the bokeh. It seems to be that its shape is more geometric, more "banded" in comparison to smooth bokeh of full-frame DSLR cameras.

Sony A7 + Helios-44-2 58/2.0

Sony A7 + Helios-44-2 58/2.0, (c) kafka hsu

Sony A7 + Jupiter-3 50/1.5

Sony A7 + Jupiter-3 50/1.5, (c) robbiehn

Sony A7 + Nikkor 50/1.8

Sony A7 + Nikkor 50/1.8, (c) BoXed_FisH

Is it real, and if yes, what is the reason of it?

UPDATE: I have found some pictures from another cameras using the same lenses I've metioned above, and their bokeh is very different from the first three photographs in this question. Look at this:

Zorki 4 + Jupiter-3

Zorki 4 + Jupiter-3 50/1.5, (c) undercharged

Canon 5D Mark II + Helios 44M 58mm

Canon 5D Mark II + Helios 44M 58mm, (c) lifestalking

Nikon D610 + Nikkor 50/1.8

Nikon D610 + Nikkor 50/1.8, (c) netzanette

As you can see, there is no "banded" bokeh anymore. Opposite, it is smoother and more swirly in the last three photos, made using full frame SLRs.

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    \$\begingroup\$ I'm pretty sure it's just those lenses - it's hard to see how the camera body would affect the bokeh rendition in any obvious manner. \$\endgroup\$
    – JohannesD
    Aug 12, 2014 at 9:24
  • \$\begingroup\$ The A7 only has a handful of compatible native lenses at this time, so, a lot of folks are adapting vintage glass to it. All of those images are taken with adapted vintage lenses which would look like that on any digital body. See also: toothwalker.org/optics/bokeh.html \$\endgroup\$
    – inkista
    Aug 12, 2014 at 17:01
  • \$\begingroup\$ I've updated the question and added 3 photos from SLRs to it. To me, bokeh difference is obvious, however the same lenses were used. \$\endgroup\$ Aug 12, 2014 at 17:27
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    \$\begingroup\$ Without an apples to apples comparison (same subject, same background, same lighting) it’s tough to tell whether the camera body is actually responsible for the difference. \$\endgroup\$ Aug 12, 2014 at 17:44
  • \$\begingroup\$ @BraddSzonye, maybe someone has Sony A7 and some full frame DSLR and can do such test? It would be very interesting to see the results. \$\endgroup\$ Aug 12, 2014 at 18:04

2 Answers 2

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It's called "Nisen Bokeh" and is mainly due to the lens design (though the background plays a part, it's possible to "provoke" this effect with any lens with the right background).

Overcorrected spherical aberration (blur disks which are brighter in the periphery than the centre) is usually to blame. It's showing up more often with the A7 due to the use of legacy lenses. People shooting with DSLRs are more likely to be using modern autofocus lenses with aspherical elements (which reduce this effect) whereas the A7 series appeals to people with large collections of old lenses.

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  • \$\begingroup\$ Please look at the three additional photos I've added to my question. The bokeh in the last 3 photos (taken with the same lens) is much different. That's what I was asking about. Bokeh from SLRs look "rounder" than from mirrorless A7. That is the question. \$\endgroup\$ Aug 12, 2014 at 17:22
  • \$\begingroup\$ @SunnyRebornPony - there is more than one Nikkor 50mm/1.8; the newer AF-S G version has rounded aperture blades and much better bokeh behind the plane of focus. The older AF D version (and its even older siblings) have a pronounced outline and less-curved aperture blades. \$\endgroup\$
    – user28116
    Aug 13, 2014 at 7:59
  • \$\begingroup\$ Anyway, it would be great if someone could make a side-by-side comparison of this camera and some full frame DSLR, let's say, Canon 5D Mark II. With the same lens and aperture settings, of course. \$\endgroup\$ Aug 18, 2014 at 13:21
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I don't have any link but I'm an sony A7 user and if you have it try to experiment at the highest speed (1/8000) with and whitout the first electronic curtain shutter. if your picture has bokeh you'll the shape modified by this factor. It may depends on the electronic speed of reading/writing. From 1/1000 to 1/8000 there is a clear effect, the faster the worse, at least on my A7 but I've seen this effect on others A7 and A7s.

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