bokeh tests

Samuel H

Samuel H

Major Contributor
I've spent a couple of days running bokeh tests with all my lenses; as with most stuff I upload to my site, it's something I did for myself, in order to learn about my lenses, what they can do and what they can't, and how best to use each one of them; but it may be useful for other people too, so, there you go:
http://www.similaar.com/foto/lenstests/bokehtests.html

I've already drawn some conclusions, but I'm not totally sure about some details so please tell me what you see



I ran several scenarios:
* neutralizing both aperture and perspective:
http://www.similaar.com/foto/lenstests/bokehtests1.html
* neutralizing perspective:
http://www.similaar.com/foto/lenstests/bokehtests2.html
* keeping subject-to-background distance constant:
http://www.similaar.com/foto/lenstests/bokehtests3.html
* keeping camera-to-background distance constant:
http://www.similaar.com/foto/lenstests/bokehtests4.html


some early conclusions and things I learned:

* I always thought my Carl Zeiss Jena Pancolar 50mm f/1.8 and my Carl Zeiss Jena Sonnar 180mm f/2.8 had great bokeh; it turns out, they both have pretty bad bokeh, they're just making up for quality with quantity: the 50mm is my fastest lens at f/1.8, and the Sonnar, at 180mm f/2.8, is both long and fast

* vintage glass is a lottery with regards to bokeh too: that Sonnar that came out so bad in my tests is considered one of the mythical "best bokeh ever" lenses:
http://www.rickdenney.com/bokeh_test.htm
(the other possibility is that other people also got fooled by the focal length and speed of this lens, but the fact that my other two sonnars, the 135 and the 300, have much better bokeh, seems to point to my 180 being sub-par)

* another thing that points to vintage glass being a lottery: I expected to come out of this with a conclusion to the tune of "how I learned to stop worrying and just buy Leitz glass"; but the 135mm (which I just bought about a month ago) is actually not stellar: at f/2.8 it's not great, and at f/4 the much cheaper sonnar 135 is actually better; if my next camera is not a nikon, I think I'll sell that leitz

* aperture affects both bokeh quantity and bokeh quality: I hardly ever use the pancolar wide open, because it becomes relatively soft in the corners; as it turns out, that's also helping with bokeh big time (stopped down to f/2.8, it is both sharp and pretty nice in terms of bokeh)

* slow lenses can have very nice bokeh; they just have very little of it

this bokeh thing is a very complex issue...

next step is to test my father's modern glass and see how it does; I'm pretty downbeat about some of my lenses right now, so I suspect my old motto "vintage glass gets you much nicer bokeh for the price" is bound for some detailing and redrafting
 
Interesting! I'd love to see a comparison to all my lenses. Your test just begs to compare with all the lenses folks suggest on a regular basis :)

Also another question, what is "good" bokeh?

Cheers,
Pete
 
c3hammer said:
Interesting! I'd love to see a comparison to all my lenses. Your test just begs to compare with all the lenses folks suggest on a regular basis :)

Also another question, what is "good" bokeh?

Cheers,
Pete
Click to expand...


if anybody is in Madrid and willing to lend me some lenses so I can run them through these tests (and the sharpness ones too), I'll be glad to add them (if time constraints allow)

now, about what is good bokeh... it's somewhat subjective, but in general it's anything that makes out-of-focus objects be as non-distractive as possible

on these tests, on the left side I look for smoothness, lack of lens-generated contrasty patterns, and lack of recognizable patterns; and on the right side I look for plain highlights, without shiny fringes or shiny centers, without color casts, and less bright being better than pretty bright

it's a very complex issue; for a start, the lenses with good background bokeh can have pretty bad forefront bokeh, and viceversa
http://www.lensrentals.com/blog/2011/03/fun-with-thumbtacks-for-advanced-photogeeks
(I only tested background bokeh, as it's the most commonly required)

in any case, I must say I'm no expert: I'm just experimenting with my lenses as I learn about these things myself
 
Martin Oller said:
Really? I thought it was about picking the one you like... ;)
Click to expand...

the more I look at these results, the more I believe bokeh is really complex, and this kind of tests really useful (for the owner of the lenses, in this case me)

take that sonnar 180mm f/2.8: even without neutralizing aperture, and unless the background is being totally obliterated, it looks softer at f/4.0 than at f/2.8, at least to my eyes
http://www.similaar.com/foto/lenstests/bokehtests2.html
 
update: I've just added a few modern lenses:
* tokina 11-16 f/2.8 (not that you'll get a lot of bokeh from this one, but I was curious and had one at hand)
* tamron 17-50 f/2.8 non-VC
* canon 50mm f/1.8 II
* tamron 70-300 f/4-5.6

the results are here:
http://www.similaar.com/foto/lenstests/bokehtests0.html

summary: I'm fully happy again with my vintage lenses (except for the sonnar 180mm, I expected more from that one) (not that I was unhappy anyway, but I had some mixed feelings and my head was wondering whether my faith in vintage glass had been misplaced)
 
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