Bad Bokeh - Discussion Thread and Sample Images

Due to a discussion in a different thread, I wanted to create a separate discussion about bad bokeh.

Lots of people acclaim bokeh... but when is it wise to avoid it or lessen it to a degree? Some questions to kick us off:

• What constitutes bad or distracting bokeh?
  
• What lenses render less than pleasing bokeh?
  
• What factors in the foreground or background should we aware of that might create busy bokeh?
  
• What are composition considerations when it comes to bokeh?
  
• When does bokeh detract from an image?

Here's an example where I wasn't paying attention and created some pretty distracting shinies. The image isn't particularly artful itself anyway - just my in-laws at an event.

Haha, this is bound to start arguements, with people saying XYZ lens had bad bokeh and then offended owners defending their lenses.

Anyways....

Nathan wrote in post #16787863

What constitutes bad or distracting bokeh?

Bad / Dristracting bokeh to me has repeating paterns, hard lines, a seenig double effect, hard edges to blurs, weird artifacts like onion bokeh in light sources, etc etc etc. There's lots of ways bokeh can be bad.

Nathan wrote in post #16787863

What lenses render less than pleasing bokeh?

The sigma 35 Art produces less than ideal bokeh in the right (or wrong!) circumstances very easily. And yes, I own this lens.

The sigma 85 in generally looks very good from the samples I've seen, but every now and then produces some very strongly textured bokeh that I really don't like. I bought he 85L instead. Lot and lots of lenses have onion bokeh and other odd effects - even some of the best like the 24-70 f2.8 II and the 35L (both have onions). nice bokeh overal on both though.

Nathan wrote in post #16787863

What factors in the foreground or background should we aware of that might create busy bokeh?

Busy bokeh tends to be worse with lots of small sharp lines or egdes -- things like tree branches, leaves, bark chippings, etc tend to give harsh bokeh on a lens that's prone to it.

Quick example from the Siggy 35 Art @f1.4. It makes makes my eyes hurt to look at this:

Nathan wrote in post #16787863

What are composition considerations when it comes to bokeh?

I try to look for backgrounds that will make good bokeh. That depends on what lens you're using;

With the Siggy 35 i try to get the background far away / subject near enough to me to blur strongly enough to take the harshness out of it if I'm outdoors, but I hardly ever use it outside anyway, so it's not so much of an issue.


The 85L will soften most things, and I like to try to get some bright points in there for it to play with, so I'm normally looking for a high contrast background with small(ish) hard bright points, eg a side lit bush with some leaves catching the light strongly (see below). I considder the 85L to have basically perfect bokeh... however you can over do it and have 'boring bokeh'; it can destroy a background to such an extent it's just a coloured smear and this can look quite boring and bland, esp if it's nutural colours like concrete etc.


85L @ f2.5 :

Nathan wrote in post #16787863

When does bokeh detract from an image?

when it actually makes your eyes hurt to look at it

Here is a shot I consider spoilt by the bokeh . To 'light' at the top

IMAGE LINK: http://s390.photobucke​t.com …/IMG_4417final-1.jpg.html

Most lenses have both good AND bad bokeh, one in front and the other behind the focus point (example here). Typically one is harsh and the other is soft (under corrected spherical aberration). Of course the bokeh behind the focus point is typically the most important so seems to be the only one that's considered. It's not very common, at least in my own experience, to find a lens with equal bokeh in front and behind the focus point.

You can easily create a harsh bokehif you want.

RMH wrote in post #16787936
Quick example from the Siggy 35 Art @f1.4. It makes makes my eyes hurt to look at this:

I try to look for backgrounds that will make good bokeh. That depends on what lens you're using.

With the Siggy 35 I try to get the background far away / subject near enough to me to blur strongly enough to take the harshness out of it if I'm outdoors, but I hardly ever use it outside anyway, so it's not so much of an issue.

You had a background that would have made good bokeh. Those trees, all leafed out in lush green. But you didn't put that behind the child by getting down and shooting from a much lower point of view. Instead, you chose to put the dirt behind the child, by shooting from an upright position.

I find that good or bad bokeh is primarily a product of the spatial relationships between your shooting position, the subject's position, and the subject-to-background distance. This stuff has much more effect on bokeh than what gear was used or what f-stop you had your lens set to.

I've never seen the spot filter effect before. That's actually kind of cool. Not pretty images, but cool.

Also "bad" bokeh is somewhat subjective as well. There are manual focus lenses from yesteryear that have very different bokeh characteristics. Some say distracting and some say amazing. Check out here.

Tom Reichner wrote in post #16788300
You had a background that would have made good bokeh. Those trees, all leafed out in lush green. But you didn't put that behind the child by getting down and shooting from a much lower point of view. Instead, you chose to put the dirt behind the child, by shooting from an upright position.

I didn't say it was a terrible lens bokeh wise, just less than ideal, but given the thread was about bad bokeh not good bokeh, I posted the worst example i could find. Was that not the whole point?

I was giving this as an example of how bad the bokeh can get, not the limit of how good it can get. Yes there's a lot one could do to improve it, was just a quick snapshot, but the trees look pretty aweful to me, so camera height alone wouldn't have helped much. I'd also suggest that unless you actually get the camera to the ground to shoot up and crop at the knee, then you are not going to be able to remove the ground from the frame entirely, though it can be made less prominant of course.

Getting a lot closer to her as well as getting lower down to throw the background further out of focus does help a great deal, ie like this:

Tom Reichner wrote in post #16788300
I find that good or bad bokeh is primarily a product of the spatial relationships between your shooting position, the subject's position, and the subject-to-background distance. This stuff has much more effect on bokeh than what gear was used or what f-stop you had your lens set to.

I think you're underplaying the effect of lens and f stop here. Spatial relationships only control the amount of blur, not the quality. Planning what your background actually is makes a big difference to the quality of the bokeh, but lenses do play a large role in it too, even if it's just from a FL point of view.

In my first example those trees look pretty aweful, but with me in the same place, my subject in the same place and background in the same place, my 85L would have turned it into a soft smear of green. Partly because it's a longer lens, partly because the bokeh is just smoother.

Nathan wrote in post #16788307
Also "bad" bokeh is somewhat subjective as well. There are manual focus lenses from yesteryear that have very different bokeh characteristics. Some say distracting and some say amazing. Check out here.

Dang, that thread reminded me that I really want that Trioplan 100mm f/2.8.

Want, not need... of course.

Nathan wrote in post #16788307
I've never seen the spot filter effect before. That's actually kind of cool. Not pretty images, but cool.

Also "bad" bokeh is somewhat subjective as well. There are manual focus lenses from yesteryear that have very different bokeh characteristics. Some say distracting and some say amazing. Check out here.

The majority of those give me a headache to look at

Here's one I took last year with my 70-200 f4L, notice the arms and legs in the background that look deformed. IMO that strangeness killed this photo, in hindsight I should have picked a different spot to take photos from.

HTTP response: 404 | MIME changed to 'image/gif' | Byte size: ZERO | PHOTOBUCKET ERROR IMAGE

^^^ What looks most weird is how hard-edged they are. I bit if you could blur the edges it'd look a lot less noticable.

groundloop - I wouldn't attribute that really to bokeh rendering. That's due to blowing out the highlights. The arms and legs also reflect light and you really blew out the background. That combined with a degree of chromatic aberration, there're some really abnormal looking background elements.

Nathan wrote in post #16790220
groundloop - I wouldn't attribute that really to bokeh rendering. That's due to blowing out the highlights. The arms and legs also reflect light and you really blew out the background. That combined with a degree of chromatic aberration, there're some really abnormal looking background elements.

You're right, Nathan. Much of that weirdness with the arms would have happened even if the arms themselves were in focus, so, it is not really a function of bokeh.

I sometimes get bad bokeh from the 50mm 1.8
but probably didn't keep the pic