Sigmas "Optical Stabilizer"

voodoochild529

voodoochild529

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Does using the OS on a sigma lens (or any stabilization on any lens or camera) effect the quality of the image? I have been going through a selection of my shots and noticed some horrible blur in the corners as if it were out of focus.
 
Yes, stabiliation is supposed to cause weird bokeh affects.

Its been documented on Nikon lenses.
 
I think from now on I will try never to use it. The results were shocking! At first I thought I had a rubbish lens.
 
Someone correct me if I'm wrong but I think with any optical stabilisation system you have to give it time to kick in. The OS takes a moment or two to settle down, if you just raise the camera to your eye focus and fire you're likely to get blurring in the image. That's why stabilisation is not recommended for action shots.
 
I've never seen this effect with IS Canon lenses.
 
voodoochild529 said:
Does using the OS on a sigma lens (or any stabilization on any lens or camera) effect the quality of the image? I have been going through a selection of my shots and noticed some horrible blur in the corners as if it were out of focus.
Click to expand...

post some examples then we know what to look for
 
Steep said:
Someone correct me if I'm wrong but I think with any optical stabilisation system you have to give it time to kick in. The OS takes a moment or two to settle down, if you just raise the camera to your eye focus and fire you're likely to get blurring in the image. That's why stabilisation is not recommended for action shots.
Click to expand...

Oh that's what that weird noise is :thinking: i tried my new 150-500 last night through the window at night on a lit window across the courtyard !
 
voodoochild529 said:
I think from now on I will try never to use it. The results were shocking! At first I thought I had a rubbish lens.
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Just take a few comparison shots with and without. I think you will find OS is extremely useful at slower shutter speeds. I know it is never turned off on my 18-55.
 
It sure steadies up the image in the viewfinder on my Sigma 150-500, wouldn't really want to be without it., albeit a tad noisy compared to my Canon IS lens, but at least you know it's working :D
 
I have a Sigma 120-400mm OS lens and have never had any wierd effects as a result of using the stabilisation system. I never turn it off to be honest.
 


Observe the tree's in the first 2 and then the mesh in the last one (Colin the chicken!). It mostly seem's to be in the top right hand corner, but in the picture of the arched brick bridge I also noticed the tree's on the left to be blurred. Perhaps the lens is a bit naff, looking sharper in the middle and softer around the edges. I hope not :'(
 
Are you sure it is the OS, it just seems that the lens is not sharp in the corner(s).
Is this wide open?

Try the same shot:
1. with and without OS
2. wide open and stopped down to f10
 
Steep said:
Someone correct me if I'm wrong but I think with any optical stabilisation system you have to give it time to kick in. The OS takes a moment or two to settle down, if you just raise the camera to your eye focus and fire you're likely to get blurring in the image. That's why stabilisation is not recommended for action shots.
Click to expand...

Erm, I think you might find it's the opposite.

Certainly IS for Canon should be off, if used on a tripod.

In fact, there is a separate IS mode for panning.
 
I had a Sigma 18-50 OS and it was dreadful, took it back for a refund
Did some comparison shots with a non stabilised 17-70mm and the latter was far better

Doesn't seem like the Tamron 17-50 VC is that great either, some people prefer the non VC

Just got my mitts on a s/hand Canon 17-55 IS and that is superb, think they have cracked the stabilisation business, but not sure the others have quite yet
 
Personally I don't see it.
I have a Sigma 18-200 and wouldn't be without the OS - I went on holiday recently and left the OS off for the first few hours on a nature trip - the results were not good!
Note to self - always check your kit!
 
artyman said:
I get the impression from the shot that the top left chicken wire is not on the same plane as the rest of the shot
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Optical IS diverts the light more the further you get away from the plane of focus, which is why it can mess up the bokeh. High-contrast patterned subjects (e.g. chicken wire) can look weird, but it should not be overstated, it is only in certain circumstances.

I have a suspicion that optical IS, given it is probably the most complex bit in a lens to make and calibrate, could well be the source of many of the QC issues seen in lenses. There is no doubt that optical IS lenses have more optical elements. Given the IQ of any given lens will be affected badly if any of its elements are out of alignment, the IS element(s) would be the first to come under suspicion for IQ problems because they move.
 
As an Olympus E-series shooter I enjoy the benefits of an in-camera-body IS system, which has not resulted in any weird bokeh effects or image quality loss, not even when using the Zuiko 70-300mm (35mm FC Equivalent to 140-600mm).
 
I have never seen any strange bokeh effects on either of my stabilised canon lenses, and those example shots look like poor optics / focus issues rather than any IS issues.
 
Steep said:
Someone correct me if I'm wrong but I think with any optical stabilisation system you have to give it time to kick in. The OS takes a moment or two to settle down, if you just raise the camera to your eye focus and fire you're likely to get blurring in the image. That's why stabilisation is not recommended for action shots.
Click to expand...

It is true that a settling time should be allowed when using OS, about a second I think after the whirring starts. I've not seen it not recommended for action shots. if panning then the switch should be in position 2 on Sigma lens.
 
Mikesphotaes said:
Certainly IS for Canon should be off, if used on a tripod.
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That is only true for certain Canon lenses - just about all the super tele's are tripod sensing and it is recommended that you leave I.S. on when using a tripod as they can compensate for the mirror slap vibration.

Among the lenses that are tripod sensing are:

EF 200mm f/2L IS USM
EF 300mm f/2.8L IS USM
EF 400mm f/2.8L IS USM
EF 400mm f/4 DO IS USM
EF 500mm f/4L IS USM
EF 600mm f/4L IS USM
EF 800mm f/5.6L IS USM
 
Roy C said:
That is only true for certain Canon lenses - just about all the super tele's are tripod sensing and it is recommended that you leave I.S. on when using a tripod as they can compensate for the mirror slap vibration.

Among the lenses that are tripod sensing are:

EF 200mm f/2L IS USM
EF 300mm f/2.8L IS USM
EF 400mm f/2.8L IS USM
EF 400mm f/4 DO IS USM
EF 500mm f/4L IS USM
EF 600mm f/4L IS USM
EF 800mm f/5.6L IS USM
Click to expand...

Pretty much all new Canon IS lenses are tripod sensing. My EF-S 18-135 IS has it, I think its pretty much standard these days.
 
odd jim said:
Pretty much all new Canon IS lenses are tripod sensing. My EF-S 18-135 IS has it, I think its pretty much standard these days.
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Yep, pretty much standard these day's, my list was from 2008. But there are certain older lenses (like the 100-400 for instance) that do not.
 
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What lens are you using? And do you have a filter on it?
 
If it was simply the OS system affecting things you'd expect it to be the same over all the lens. looking at your pics, it appears to be on the right hand side only. For example, looking at the one of the sluice gate, the tree on the right is out of focus. The tree in the middle, which appears further away from you is sharp. I'd suspect something out of alignment slightly on one side of the lens. If you have a filter on it, take it off and try again. If it clears up, blame the filter. If you still have the issue, it needs to be looked at IMHO.
 
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