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04/12/2005 10:36:37 AM · #1 |
Greetings,
I've seen a couple references to lenses where they say "great bokeh (IS off)" and being extremely new to lenses (looking at buying my first one this week).
I am curious, how does image stabilization effect bokeh? so that you'd want it turned off? can all IS lenses have the IS mode turned off? is this fairly standard?
- Jason "The Saj" |
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04/12/2005 10:47:00 AM · #2 |
After reading your post I did a couple of tests with my 100-400 IS on a couple of different subjects shooting them with IS on and IS off. From what I can tell from my quick and dirty tests there is no difference in the bokeh with IS on or off. Maybe someone could show an example where the IS did affect the bokeh, maybe it just happens under certain conditions.
Tom
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04/12/2005 10:48:36 AM · #3 |
IS can cause streaks and lines in bokeh. I think it's more obvious when used on a tripod because the camera tried to compensate for movement which is not actually there. I've definately seen the lines in the bokeh though and they don't look very nice.
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04/12/2005 11:00:16 AM · #4 |
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04/12/2005 11:18:24 AM · #5 |
When the extreme Action challenge is done, look at my entry. There are telltale signs of the IS effect on bokeh. I don't see this discussed much, but it is real.
For those interested, I do have a technical hypothesis as to why this happens. When the IS moves the lens elements, it is trying to compensate for the angular movement of the lens/camera, as measured by accelerometers. This should cancel the movement of the subject in the frame. Objects behind (or in front of) the focal plane, however, may not move in the same manner, and thus the IS may not cancel the movement of these objects. the net result is that if IS is active, BG or FG objects, though OOF, may show doubled or smeared images at 45° to the frame edges (the direction of movement of the IS elements).
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04/12/2005 11:23:38 AM · #6 |
Originally posted by kirbic:
When the extreme Action challenge is done, look at my entry. There are telltale signs of the IS effect on bokeh. I don't see this discussed much, but it is real.
For those interested, I do have a technical hypothesis as to why this happens. When the IS moves the lens elements, it is trying to compensate for the angular movement of the lens/camera, as measured by accelerometers. This should cancel the movement of the subject in the frame. Objects behind (or in front of) the focal plane, however, may not move in the same manner, and thus the IS may not cancel the movement of these objects. the net result is that if IS is active, BG or FG objects, though OOF, may show doubled or smeared images at 45° to the frame edges (the direction of movement of the IS elements). |
kirbic honey...put down the slide rule and back away from the protractor...and no one will get hurt. ;o)
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04/12/2005 12:04:56 PM · #7 |
Originally posted by laurielblack:
kirbic honey...put down the slide rule and back away from the protractor...and no one will get hurt. ;o) |
Never, NEVER I tell you! They'll get my HP 15C when they pry it from my cold, dead fingers! [kirbic backs away with a wild-eyed look]
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04/12/2005 12:05:10 PM · #8 |
This makes sense as many of the IS lenses are not designed to have the IS turned on while using a tripod. I only use IS when hand-holding the lens (mine is a 100-400 IS) so maybe this is why I couldn't see a difference.
Would you be so kind as to post a sample or two of the streaks. I would like to see if I can find them in any of my images.
Tom
Originally posted by Konador:
IS can cause streaks and lines in bokeh. I think it's more obvious when used on a tripod because the camera tried to compensate for movement which is not actually there. I've definately seen the lines in the bokeh though and they don't look very nice. |
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04/12/2005 12:08:11 PM · #9 |
I know its technically not a very good shot, but this was done with IS on. You can clearly see some kind of circular effect around the cat on this shot. That's what Konador was refering to.
[/url] |
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04/12/2005 12:09:58 PM · #10 |
Originally posted by kirbic:
Originally posted by laurielblack:
kirbic honey...put down the slide rule and back away from the protractor...and no one will get hurt. ;o) |
Never, NEVER I tell you! They'll get my HP 15C when they pry it from my cold, dead fingers! [kirbic backs away with a wild-eyed look]
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There, there Kirbic, calm down, no one is trying to hurt you [slowly advances towards Kirbic while flipping the guard off a huge syringe of expired horse tranqulizer]. GET HIM!
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04/12/2005 12:20:06 PM · #11 |
Thanks for posting this.
Did you take another shot with the IS off and the effect went away? To be honest I am having a tough time seeing what you are talking about. The bokeh doesn̢۪t look very good in this picture but I think it has more to do with the lighting, and setup of the picture than anything else. I was able to get crummy bokeh with the EF 85mm f/1.2 and EF 200mm f/1.8 when I wasn̢۪t careful about lighting and background and both of those lenses are supposed to have wonderful bokeh and do not have IS.
Tom
Originally posted by RedOak:
I know its technically not a very good shot, but this was done with IS on. You can clearly see some kind of circular effect around the cat on this shot. That's what Konador was refering to.
[/url] |
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04/12/2005 12:22:14 PM · #12 |
Actually that's not exactly what I meant but it's similar. I dont have an IS lens myself (too expensive) but here are some squirrel shots that Mag took which show diagonal streaks in the bokeh:
//www.pbase.com/magnetic9999/image/15505660
//www.pbase.com/magnetic9999/image/15664151
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04/12/2005 12:30:00 PM · #13 |
Thanks for posting these. Do you happen to know what lens was used for these and if the streaks when away if the shot was repeated with IS turned off?
Maybe I am just dense but I am having difficulty seeing abnormal looking bokeh (I am looking at a pretty crummy monitor now so maybe that is the problem). In these shots there is a very busy background that is close to the subject. I will suggest that the bokeh might be just the result of that.
This subject interests me a lot so I would like to fully understand what I am looking for to see if I can reproduce it.
Tom
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04/12/2005 12:57:32 PM · #14 |
Here is a crop of an image where the "IS Bokeh Effect" is apparent. I thought I had the original shot posted as well, but apparently not. Notice how the grass blades are doubled in one direction only. This was shot hand-held, at relatively low shutter speed.
I do want to do more testing of this, in a more structured manner. Tripod vs. non-tripod is probably a non-factor with the 70-200 IS, since the 3rd generation IS turns itself off when the vibration levels fall below a certain threshold.
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04/12/2005 12:59:36 PM · #15 |
There are lines in the bokeh of this shot that, to my eyes at least, are similiar to what is being discussed here.
But this was not taken with an IS lens.
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04/12/2005 01:18:36 PM · #16 |
Thanks for posting that sample. Did the doubled grass blades go away when you turned off IS and re-shot? That almost looks like camera shake but I assume that the subject was perfectly in focus and not blurred? Was there any wind blowing or anything at the time of the shot?
Tom
Originally posted by kirbic:
Here is a crop of an image where the "IS Bokeh Effect" is apparent. I thought I had the original shot posted as well, but apparently not. Notice how the grass blades are doubled in one direction only. This was shot hand-held, at relatively low shutter speed.
I do want to do more testing of this, in a more structured manner. Tripod vs. non-tripod is probably a non-factor with the 70-200 IS, since the 3rd generation IS turns itself off when the vibration levels fall below a certain threshold. |
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04/12/2005 01:22:02 PM · #17 |
Wow that is a very interesting. I can't recall ever having seen anything like that in any of my pictures.
Thanks for the data.
Tom
Originally posted by coolhar:
There are lines in the bokeh of this shot that, to my eyes at least, are similiar to what is being discussed here.
But this was not taken with an IS lens. |
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04/12/2005 01:32:37 PM · #18 |
Originally posted by coolhar:
There are lines in the bokeh of this shot that, to my eyes at least, are similiar to what is being discussed here.
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But this was not taken with an IS lens. |
Actually, that doesn't look like the problematic IS-bokeh. It just looks like bad bokeh combined with an already distracting background (upper left). |
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04/12/2005 01:40:24 PM · #19 |
Originally posted by dwoolridge:
Originally posted by coolhar:
There are lines in the bokeh of this shot that, to my eyes at least, are similiar to what is being discussed here.
...
But this was not taken with an IS lens. |
Actually, that doesn't look like the problematic IS-bokeh. It just looks like bad bokeh combined with an already distracting background (upper left). |
What makes it "bad bokeh"? Is it the nature of the background or the lens?
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04/12/2005 02:13:31 PM · #20 |
Originally posted by coolhar:
What makes it "bad bokeh"? |
I guess the problem is that it's entirely subjective, although there's often agreement in the most extreme cases. In your example image, the deep out of focus elements get blurred almost beyond recognition but not enough to smooth out the edges and that makes them distracting.
Originally posted by coolhar:
Is it the nature of the background or the lens? |
Both? Can you get bad bokeh with an entirely black background? It's mostly the lens, but you can sometimes work around it by choosing your background carefully and/or changing your aperture to smooth out the background or bring it into focus, depending on your goals. Some lenses can't get wide enough, so one has to rely more heavily on composition. Another option, depending on your equipment, is to use flash with a small aperture (i.e. background removal). |
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04/12/2005 02:21:45 PM · #21 |
Has anyone actually done a controlled experiment to determine that it is indeed the IS that is causing this "bad bokeh?" I have been playing around with my 100-400 IS taking pictures of the same thing with IS on and off and haven't yet been able to see a difference.
Does anyone know how to induce this effect?
Thanks,
Tom
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04/12/2005 02:24:00 PM · #22 |
Originally posted by ovenbird:
Thanks for posting that sample. Did the doubled grass blades go away when you turned off IS and re-shot? That almost looks like camera shake but I assume that the subject was perfectly in focus and not blurred? Was there any wind blowing or anything at the time of the shot?
Tom
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When I shot the original, I was unaware of the IS effect. I do plan on doing a structured test, both with and without IS, and with a non-IS lens as well. Since this thread has brought it back to mind, I'll try to complete the test this week and get the results posted.
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04/12/2005 02:33:47 PM · #23 |
I am looking forward to reading your results. I will also continue to play around with it myself to see what I can figure out.
Tom |
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04/12/2005 02:56:05 PM · #24 |
| I've read about the streaking thing...but I've never experienced it myself, for this to occur the exposure would need to be fairly long. |
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04/12/2005 06:30:43 PM · #25 |
Thanks all for some great explanations and examples...
(i have a feeling I created an unofficial DPC challenge, "To bokeh, or Not To Bokeh with IS on....that IS the question!") *lol*
And i take it that IS can be turned off on most all lenses. |
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