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04/03/2006 03:30:19 AM · #1 |
Yesterday, at the zoo, I was using my (relatively) new 2x teleconverter. At the tiger enclosure, I rested the end of the lens hood against the glass to help stabilise the camera even further. All of the pictures taken in this way were almost offensively blurry - not any part looked to be in sharp focus. This was with the aperture wide open. I closed down the aperture for shooting in other parts of the zoo (no glass to lean against) and got relatively sharp shots (as sharp as could be expected with a 2x TC). As it got a little darker, I opened the aperture again. These latter shots were considerably sharper than the first ones.
My conjecture is that, with the lens hood effectively anchored onto the window, the camera is rotating about a point some short distance in front of the lens. Normally hand-held, the camera would be expected to rotate about a point much closer to the photographer. If the IS system is constructed to correct for rotation about a point say, just about the lens mount, then the fact that the camera is, indeed, rotating about a much different point would account for the blurriness.
This seems to me to be the only explanation and I will brace myself, rather than the camera in future.
Any thoughts? Am I wildly wrong here?
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04/03/2006 03:34:18 AM · #2 |
I would guess that it was either focussing on the window itself, rather than through it, or maybe if the camera mechanism for focusing is external (the lens itself moves, rather than just the internal components) you pressing it against the glass was stopping it from moving.
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04/03/2006 03:36:19 AM · #3 |
Originally posted by AJAger:
All of the pictures taken in this way were almost offensively blurry - not any part looked to be in sharp focus. This was with the aperture wide open. I closed down the aperture for shooting in other parts of the zoo (no glass to lean against) and got relatively sharp shots (as sharp as could be expected with a 2x TC). |
WEIRD. I've always gotten faster shutter speeds with a larger aperture. Your experience above seem to be the other way around?
Say I shoot at F3.2, I can get away with 1/500sec, while the same scene
taken at F8, I can only do it with 1/50sec...
Can you share the EXIF info here? |
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04/03/2006 03:39:30 AM · #4 |
funny you mention that. i was just at the pet store taking some photos. here's a full crop and a resize. no post processing here.
i used my 50mm 1.8 shooting at ISO 200 ;)
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04/03/2006 03:39:37 AM · #5 |
Originally posted by Konador:
I would guess that it was either focussing on the window itself, rather than through it, or maybe if the camera mechanism for focusing is external (the lens itself moves, rather than just the internal components) you pressing it against the glass was stopping it from moving. |
It was focussed on the intended subject all right, as a minimum, the subject was the least blurry part ofthe image. The lens is internal focussing, so pressing against the glass will not affect that.
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04/03/2006 03:44:05 AM · #6 |
Originally posted by crayon:
Originally posted by AJAger:
All of the pictures taken in this way were almost offensively blurry - not any part looked to be in sharp focus. This was with the aperture wide open. I closed down the aperture for shooting in other parts of the zoo (no glass to lean against) and got relatively sharp shots (as sharp as could be expected with a 2x TC). |
WEIRD. I've always gotten faster shutter speeds with a larger aperture. Your experience above seem to be the other way around?
Say I shoot at F3.2, I can get away with 1/500sec, while the same scene
taken at F8, I can only do it with 1/50sec...
Can you share the EXIF info here? |
The reason that I stopped down later is that the sun came out and I had more light to play with. Yes, given the same light, one will get a faster shutter speed at a larger aperture.
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04/03/2006 03:49:07 AM · #7 |
Originally posted by Rikki:
funny you mention that. i was just at the pet store taking some photos. here's a full crop and a resize. no post processing here.
i used my 50mm 1.8 shooting at ISO 200 ;)
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Yours is a somewhat different case to mine. You appear to have taken these shots some way away from the window. Indeed, the 50mm 1.8 does not lend itself to being leant against a surface, as it extends during focussing. I imagine that this was taken at f/1.8 and, given that the glass is probably not antiseptically clean, this looks OK to me as far as a 100% crop goes.
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04/03/2006 04:23:17 AM · #8 |
How close were the animals and your lens? It seems like you were trying to shoot closer than your lens allows. Were you using auto focus?
Message edited by author 2006-04-03 04:23:49.
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04/03/2006 04:24:53 AM · #9 |
| you sure it's not glare from the window-glass or anything causing the "blur" ? |
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04/03/2006 04:36:05 AM · #10 |
Originally posted by crayon:
you sure it's not glare from the window-glass or anything causing the "blur" ? |
Looking at Rikki's images it seems that could be a possibility but since he mentioned "offensively blurry" I figured it's more than just that. Of course a pic might shed some light into this...
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04/03/2006 04:40:51 AM · #11 |
Originally posted by yanko:
Originally posted by crayon:
you sure it's not glare from the window-glass or anything causing the "blur" ? |
Looking at Rikki's images it seems that could be a possibility but since he mentioned "offensively blurry" I figured it's more than just that. Of course a pic might shed some light into this... |
yeah, sample photos and their EXIF info would be very helpful right now. |
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04/03/2006 04:42:15 AM · #12 |
use a polarizer to shoot through glass, that way you get rid of the reflection from the glass and thus your lens wont focus on the reflection ;)
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04/03/2006 08:47:30 AM · #13 |
Thanks everyone, but I know that the lens was not focussed on the glass or any reflections, indeed, the fact that the hood was pressed against the glass obviated any reflections. Shooting at 400mm focussed some 20 metres away, even dirty glass would not make any difference. My point revolves solely around the fact that the camera/lens system is revolving about a different point than would normally be expected. I'll try to find some samples (I deleted most) and I'll be back.
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04/03/2006 08:59:53 AM · #14 |
| I don't know a lot about image stabilization systems. But I remember a friend telling me that if he used a tripod, he had to turn the image stabilisation off, else the picture got blurred! Could be the same in your case... |
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04/03/2006 09:01:17 AM · #15 |
Originally posted by MistyMucky:
I don't know a lot about image stabilization systems. But I remember a friend telling me that if he used a tripod, he had to turn the image stabilisation off, else the picture got blurred! Could be the same in your case... |
I'm thinking along those lines, definitely.
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04/03/2006 09:06:51 AM · #16 |
Originally posted by MistyMucky:
I don't know a lot about image stabilization systems. But I remember a friend telling me that if he used a tripod, he had to turn the image stabilisation off, else the picture got blurred! Could be the same in your case... |
It's true, the manual of my IS lens says to turn the IS off when using a tripod....your bracing off against the glass seems to have had the same effect as using a tripod.
Steve |
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04/03/2006 09:08:26 AM · #17 |
I took these at the zoo through glass this weekend too.
 
 
I had to place my lens right against the glass to avoid glass reflections (no flash used). I just used the "action" setting on the camera to get fast shutter speed. Whenever I tried to use the manual settings inside with glass it came out blurry.
edit: sorry...when I added my 2 cents I thought you were using a p&s, I didn't realize you actually were using a dslr. I only looked at the camera you had listed as your primary. After reading some other responses I looked at your profile.
Message edited by author 2006-04-03 09:54:46. |
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04/03/2006 09:35:39 AM · #18 |
It's my understanding that the IS on the 70-200 is second generation, and it supposedly can be left on while mounted on a tripod, or for that matter on a solid support. I haven't tried it myself, so I can't confirm, but that's what I've heard numerous times. No luck looking at the Canon site or anywhere else. I'll check my manual when I get home to see if it's in there.
Message edited by author 2006-04-03 09:36:16. |
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04/03/2006 09:45:04 AM · #19 |
Originally posted by Telehubbie:
It's my understanding that the IS on the 70-200 is second generation, and it supposedly can be left on while mounted on a tripod, or for that matter on a solid support. I haven't tried it myself, so I can't confirm, but that's what I've heard numerous times. No luck looking at the Canon site or anywhere else. I'll check my manual when I get home to see if it's in there. |
That is what I thought and thanks for that, but my query is about the camera rotating about a different point in space to that which the lens corrects for, which possibly leads to an error in the 'correction' applied by the IS system.
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04/03/2006 09:49:46 AM · #20 |
I don't think the OP's problem is related to IS at all. The root cause of the blurriness was most likley the optical effects of the glass. Those glass panes can be VERY thick, and the surfaces are not that flat. Shooting through such glass is guaranteed to have unwanted effects. You're essentially adding a lens element.
If you're slightly off-axis (the lens is not perfectly perpendicular to the glass surface) you'll get CA, badly. If the glass is the slightest bit wavy, you'll get distortion and blurring. This will be amplified when using a long lens, because the slight refraction of the light rays by the glass is magnified. The use of the teleconverter compounds this.
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04/03/2006 09:54:44 AM · #21 |
Originally posted by kirbic:
I don't think the OP's problem is related to IS at all. The root cause of the blurriness was most likley the optical effects of the glass. Those glass panes can be VERY thick, and the surfaces are not that flat. Shooting through such glass is guaranteed to have unwanted effects. You're essentially adding a lens element.
If you're slightly off-axis (the lens is not perfectly perpendicular to the glass surface) you'll get CA, badly. If the glass is the slightest bit wavy, you'll get distortion and blurring. This will be amplified when using a long lens, because the slight refraction of the light rays by the glass is magnified. The use of the teleconverter compounds this. |
The glass is only about a quarter of an inch thick, as it is well above where the animals can reach. When I took more shots later, actually hand held, they came out much better, even those shot at quite an angle to the glass. As I say, the only ones I noticed these problems with were those where I leant the lens hood actually against the glass. Unfortunately, I binned all the bad ones.
Message edited by author 2006-04-03 13:34:25.
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