Suggestions for comparative testing of bokeh quality

[Arkku]

Hi,

I've been thinking of putting together a comparison of my various M42 lenses, especially the many different 50mm's and 135mm's. The part where I'm having most difficulty deciding how to proceed is the testing of bokeh. Obviously it's very subjective and even depends on the scene (e.g. sometimes a “swirly” bokeh creates a nice special effect, sometimes it's very distracting). However, I'd like to come up with a series of “scenes”, which would then all be photographed with each lens, that could be used to form a gallery illustrating the bokeh of each lens in various different situations.

Since each test scene would need to be shot with a couple of dozen lenses, it would need to be fairly stable so that it doesn't change between shots. This probably means artificially lit indoor scenes, which would also eliminate the major difficulty of transporting all lenses at once, but it becomes more difficult to come up with suitable tests scenarios because of limited distances. Perhaps these indoor “lab tests” could be augmented with a selection of similar (but non-identical) outdoor shots, e.g. “forest background with sun shining through the trees”, but the primary goal would be to come up with the indoor scenes I could set up.

So, any ideas on what kind of scenes to set up to obtain the most useful comparison? I mean useful in the sense that it would, for example, help someone decide between two otherwise similar lenses.

So far I've been thinking of something along these lines:

– Small objects close behind the point of focus, e.g. office supplies, perhaps a computer keyboard, etc.

– Glasses and/or glass bottles at different distances behind the point of focus, lit so as to produce some bright highlights. (Should the background be dark or light?)

– The keyboard of a piano with the focus on one key in the middle. (Perhaps too dull?)

- Close-up of a flower or a plant? (Needs extension tubes to work with most lenses, so perhaps unsuitable for a “natural” comparison? Also, close-ups often seem to give a false impression of high quality bokeh, or is it just my imagination?)


Edit: If you have done similar comparisons or tests with your lenses, please post or link to them! (Edit 2: By similar, I mean something which could be re-created and used for comparison; there's an excellent thread already on this forum for showcasing bokeh, which I have read through. =)

[Attila]

Hard question I like smooth green background for bokeh tests some people don't so really mater of personal taste.

[estudleon]

[Arkku]

[Arkku]

[aoleg]

Why do you need to 'test' it? I mean, isn't it better to simply go and shoot your usual subjects, and then see whether you like the results? Bokeh is never 'good' or 'bad'. It depends widely on shooting conditions, background, and personal taste of the photographer / viewers. I for one have a lense with extremely smooth bokeh (Samyang 85/1.4), and find that portraits I shoot with it sometimes lack the 'punch', but sometimes (depending on the background and subject to background distance) find it very pleasing. I have lenses with harsher bokeh (such as Zeiss 85/1.4), and find them perfectly usable in one situation yet a loss in others.

Having too many lenses does not help either. Isn't it better to know your gear well and what to expect of it in various conditions?

[Attila]

[no-X]

btw. I noticed, that many modern DSLR cameras do an automatic boost of microcontrast to make the pictures look better, but it quite harms bokeh

[Arkku]

[Arkku]

[orly_andico]

measuring the brightness as you go outward from the center of a defocused distant (or extremely close) point light source.

most modern lenses are overcorrected for distant OOF point sources, so there's a hard edge to their OOF highlights which is easy to measure.

[Arkku]

[themoleman342]

To offer you a little guidance, I would suppose the rendering of highlights is the most contentious area of bokeh judging. In my experience, most people believe these make or break a photo and most photographers can't see past them (or in front of them more correctly). So that would be something to test. Other types of tests seem less than worthwhile: Both renderings are smooth, but which is SMOOTHER? Slightly better oof areas shouldn't make a photo. Bokeh isn't a subject. If it was, set your lens wide open, deliberately mis-focus, and click away.

That being said, I understand your intentions and your desire to approach this scientifically perfectly. I'm as guilty as everyone in searching for 'better' lenses (meaning they fit my criterion as 'better'). In this case I would encourage you, as aoleg had, to test your lenses through your shooting. Time would be better spent working on your skills as a photographer (this is not meant as an insult in any sense - I'm confident you're a better photographer than I) and seeking out better subjects than a constructing a test that couldn't possibly encompass the infinite amount of circumstances that may arise.

[Arkku]

[Anu]

http://www.rickdenney.com/bokeh_test.htm is a nice link - interesting (considering the nature of this forum) lenses tested.

Still, it is somewhat subjective - I kind of like this bokeh too:

[aoleg]

[poilu]

[Arkku]

[Arkku]