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Makonde
24th August 2008, 01:31 PM
So - when you use image stabilization, is there a price to be paid in terms of image quality? Or anything else? How exactly does it work when correcting an image for shake?

The manual (E520) says to turn it off when using a tripod. Why? I assume the reason is that there is some price for IS. Otherwise why bother to turn it off when not needed.

I must experiment but you E-experts might save me the trouble.... and I have grown used to that passionate little shudder the camera gives on power-down with IS on, that was frightening at first. (Does that also dislodge the bigger bits of dust I wonder LOL?!)

theMusicMan
24th August 2008, 01:34 PM
Nope, no price to pay. It is an added feature of the e-system cameras that will allow you, on the E-510/520 - an additional three stops of light (5 on the E-3).

I have never bothered to turn mine off when using a tripod, but then again, I rarely have the need for a tripod!!

As long as you don't forget that IS is no substitute for subject movement, and that you will still get out of focus or blurring if the subject moves. IS is designed to reduce camera shake from its operator... and it works a treat.

shenstone
24th August 2008, 05:20 PM
So - when you use image stabilization, is there a price to be paid in terms of image quality? Or anything else? How exactly does it work when correcting an image for shake?
It moves the sensor - using the SSWF that is also used in cleaning the sensor

The manual (E520) says to turn it off when using a tripod. Why? I assume the reason is that there is some price for IS. Otherwise why bother to turn it off when not needed.

I have read this as well and I can't see any reason for it - the IS will be trying to correct for motion and if there is non it should recognise that and do nothing. I never turn it off on my 510 and I've not seen any problems

I must experiment but you E-experts might save me the trouble.... and I have grown used to that passionate little shudder the camera gives on power-down with IS on, that was frightening at first. (Does that also dislodge the bigger bits of dust I wonder LOL?!)
It's just parking rather than operating at full speed so I wouldn't expect that it was removing dust any more than you shaking the camera ( not recommended!)

Regards
Andy

tlove
24th August 2008, 05:48 PM
Right - I'm totally talking through my hat here I suspect, but I must admit I thought I read somewhere not too long ago (can't for the life of me remember where - perhaps I imagined it :o:o), that the reason for turning IS off when using a tripod is because the IS system itself can cause some vibration if left on on during tripod operation, leading to slight blurring of images :confused::confused:

Discuss.....!

shenstone
24th August 2008, 05:57 PM
Right - I'm totally talking through my hat here I suspect, but I must admit I thought I read somewhere not too long ago (can't for the life of me remember where - perhaps I imagined it :o:o), that the reason for turning IS off when using a tripod is because the IS system itself can cause some vibration if left on on during tripod operation, leading to slight blurring of images :confused::confused:

Discuss.....!

That's the reason given, but I suspect that it depends on the quality of your tripod and whether it's up to the task @ hand as many still allow some movement. This is expecially the case if you are not using a shutter release cable e.g. when doing wildlife shots where you may beusing it not fully locked off and are using it as a stablisation aid not a complete solution.

Regards
Andy

tlove
24th August 2008, 06:04 PM
Thanks for that Andy, makes sense!

250swb
24th August 2008, 08:09 PM
Try this everybody.

In a quiet room set your camera on a tripod and set the exposure for a few seconds. Listen carefully and you will hear the IS trying to work and moving quickly if you have the IS switched on. This is why it says switch it off when on a tripod. The IS does not detect that the camera is on a tripod but it does always assumes there is work to do if switched on, and so goes about finding work to do. If you do critical macro work you will find the images are much softer or downright blurry if the IS is left on, or if you haven't seen any difference you should question if you need a new tripod because it must be moving ;-)

Likewise IS should be switched off when using high shutter speeds. Why? Because as soon as you press the shutter the IS goes into operation but never has a chance to stabilize the image before the shutter finishes its sweep, so again producing blurred or softer images.

The IS works fine with no ill consequences if used sensibly in the normal shutter range that would benefit from IS under normal circumstances.

Steve

photo_owl
24th August 2008, 09:10 PM
Try this everybody.

In a quiet room set your camera on a tripod and set the exposure for a few seconds. Listen carefully and you will hear the IS trying to work and moving quickly if you have the IS switched on. This is why it says switch it off when on a tripod. The IS does not detect that the camera is on a tripod but it does always assumes there is work to do if switched on, and so goes about finding work to do. If you do critical macro work you will find the images are much softer or downright blurry if the IS is left on, or if you haven't seen any difference you should question if you need a new tripod because it must be moving ;-)

Likewise IS should be switched off when using high shutter speeds. Why? Because as soon as you press the shutter the IS goes into operation but never has a chance to stabilize the image before the shutter finishes its sweep, so again producing blurred or softer images.

The IS works fine with no ill consequences if used sensibly in the normal shutter range that would benefit from IS under normal circumstances.

Steve

I was sceptical about the tripod issue but have managed to prove to myself that it's possible on a totally solid environment to get a tiny degree of softness through the use of IS and long'ish exposures and really really solid tripod set ups (MLU/remote trigger etc) but in general tripod use with manual triggering it's a plus not a minus. Looking through the viewfinder, or LV magnification, with any long fl lens on 3 of my 4 tripods the IS still has work to do!

As for switching it off at high shutter speeds - I can find no practical evidence of it degrading images at all. At 1/8000th I am not actuall sure it's got much chance!

250swb
25th August 2008, 08:15 AM
I was sceptical about the tripod issue but have managed to prove to myself that it's possible on a totally solid environment to get a tiny degree of softness through the use of IS and long'ish exposures and really really solid tripod set ups (MLU/remote trigger etc) but in general tripod use with manual triggering it's a plus not a minus. Looking through the viewfinder, or LV magnification, with any long fl lens on 3 of my 4 tripods the IS still has work to do!

As for switching it off at high shutter speeds - I can find no practical evidence of it degrading images at all. At 1/8000th I am not actuall sure it's got much chance!

Yes I agree, there obviously has to be some common sense involved, so if your tripod and lens is moving around indeed have IS switched on, that it is what it is for. And it may well be the case that 1/8000th is faster than the IS can start to operate, but I did say 'faster shutter speeds', not 'the fastest'. I was only trying to put paid to some myths that seemed to be solidifying into 'fact'.

Steve

PeterD
25th August 2008, 08:37 AM
The main discussion about IS has been about its use on a tripod and also fast shutter speeds. One other situation you should consider whether or not to use IS is when you are panning a moving object. In these circumstances, it seems obvious (as the manual says) to turn IS off otherwise it would be fighting your panning motion.
In practise I have never turned IS off but then again I tend to use high shutter speeds which would avoid blurring anyway.
I guess the choices are for the individual camera man to make but one of the reasons for upgrading to the E3 from the E500 was the IS. I am pleased to have made that transition as it would be virtually impossible to use long lenses, hand held, without it. This is where I think the IS wins outright.
Peter

theMusicMan
25th August 2008, 08:41 AM
For panning shots, there is a specific IS mode, 'IS Mode 2' which should be selected for this type of shot. It then only applies IS on the vertical plane and allows you to pan across the horizontal. Very useful - if only I could remember to use it when I am panning.

Most of my panning shots are spur of the moment i.e. when a bird passes by. I guess I should set up Custom Mode 2 and change the Fn key assignment when I am birding.

PeterD
25th August 2008, 08:58 AM
For panning shots, there is a specific IS mode, 'IS Mode 2' which should be selected for this type of shot. It then only applies IS on the vertical plane and allows you to pan across the horizontal. Very useful - if only I could remember to use it when I am panning.

Most of my panning shots are spur of the moment i.e. when a bird passes by. I guess I should set up Custom Mode 2 and change the Fn key assignment when I am birding.

Thats fine for say motor sports or field events but not so for the type of shots we take John.

The IS works to stabalise horizontal and vertical movement separately. The camera movement we make is in both directions e.g. diagonal movement. IS2 would not be effective in this case. I would stay with IS1 when shooting hand held. At least its my preference. In our favour we need high shutter speeds to take bird flight shots.

Peter

Peter

Makonde
25th August 2008, 09:04 AM
Thanks for all your interesting replies. SWB50's points are more along the lines of what I expected; but as I have a really cheap tripod, and no remote as yet (I use a shutter delay when I have to) it seems I shouldn't worry about turning off the IS.

The 520 btw has a third IS mode where you can pan vertically without the horizontal being stabilised (or pan horizontally with the camera in portrait rather than landscape position). I haven't tried these out yet.....

Nobody has clarified exactly how the sensor/in camera processing compensates for shake. The fact that it can be done selectively in one plane or the other strikes me as interesting......

(As a matter of passing interest, do the in-lens systems adopted by rival manufacturers offer IS in horizontal or vertical plane separately?)

PeterD
25th August 2008, 09:17 AM
Thanks for all your interesting replies. SWB50's points are more along the lines of what I expected; but as I have a really cheap tripod, and no remote as yet (I use a shutter delay when I have to) it seems I shouldn't worry about turning off the IS.

The 520 btw has a third IS mode where you can pan vertically without the horizontal being stabilised (or pan horizontally with the camera in portrait rather than landscape position). I haven't tried these out yet.....

Nobody has clarified exactly how the sensor/in camera processing compensates for shake. The fact that it can be done selectively in one plane or the other strikes me as interesting......

(As a matter of passing interest, do the in-lens systems adopted by rival manufacturers offer IS in horizontal or vertical plane separately?)

Now thats interesting. What does the manual say about this mode?

Peter

Makonde
25th August 2008, 10:36 AM
Now thats interesting. What does the manual say about this mode?

Peter
Not much! Here are the relevant quotes:
I.S. 1 Image stabilizer is on.
I.S. 2 This is used for panning with the camera in the horizontal direction to achieve a blurred background. The horizontal image stabilizer is turned off, and only the vertical image stabilizer is activated.
I.S. 3 This is used for panning with the camera in the vertical direction to achieve a blurred background (tilting). The vertical image stabilizer is turned off, and only the horizontal image stabilizer is activated.


Notes
The image stabilizer cannot correct excessive camera shake or camera shake that occurs when the shutter speed is set to the slowest speed. In these cases, it is recommended that you use a tripod.
When using a tripod, set [IMAGE STABILIZER] to [OFF].
When using a lens with an image stabilization function, turn off the image stabilization function of either the lens or the camera.
If [IMAGE STABILIZER] is set to [I.S.1], [I.S.2] or [I.S.3] and you turn off the camera, the camera will vibrate. This is due to the camera initializing the image stabilizer mechanism. Without this initialization, the image stabilizer may not be able to achieve the proper effect.
If the image stabilizer icon is displayed in red on the monitor, it indicates a failure of the image stabilizer function.

PeterD
25th August 2008, 11:43 AM
Not much! Here are the relevant quotes:
I.S. 1 Image stabilizer is on.
I.S. 2 This is used for panning with the camera in the horizontal direction to achieve a blurred background. The horizontal image stabilizer is turned off, and only the vertical image stabilizer is activated.
I.S. 3 This is used for panning with the camera in the vertical direction to achieve a blurred background (tilting). The vertical image stabilizer is turned off, and only the horizontal image stabilizer is activated.


Notes
The image stabilizer cannot correct excessive camera shake or camera shake that occurs when the shutter speed is set to the slowest speed. In these cases, it is recommended that you use a tripod.
When using a tripod, set [IMAGE STABILIZER] to [OFF].
When using a lens with an image stabilization function, turn off the image stabilization function of either the lens or the camera.
If [IMAGE STABILIZER] is set to [I.S.1], [I.S.2] or [I.S.3] and you turn off the camera, the camera will vibrate. This is due to the camera initializing the image stabilizer mechanism. Without this initialization, the image stabilizer may not be able to achieve the proper effect.
If the image stabilizer icon is displayed in red on the monitor, it indicates a failure of the image stabilizer function.

This now opens the debate a bit more. It would seem that the purpose of the IS 2 & 3 modes is to ensure that stabalisation assists hand held panning to give a true horizontal or vertical pan respectively. If your pan deviates from this then the IS kicks in. This probably why they say to turn IS off on a tripod as its assumed no unintended movement of the body will take place. From some of the tripods I have seen, this is a dangerous assumption, particlarly if not using a remote. As for the 'blurring' of the background, I am not sure that you will get this unless your shutter speed is low. Even if this were strictly true, how do you track the subject accurately to ensure it is a sharp image?

Peter

Makonde
25th August 2008, 12:22 PM
This now opens the debate a bit more. It would seem that the purpose of the IS 2 & 3 modes is to ensure that stabalisation assists hand held panning to give a true horizontal or vertical pan respectively. If your pan deviates from this then the IS kicks in.
Peter
That wasn't how I read it... I thought that it meant IS mode 1 worked to reduce shake all round. IS mode 2 (horizontal panning) would reduce shake only in the vertical plane while stabilisation in the horizontal plane would not occur. IS mode 3 would reduce shake only in (the camera's) horizontal plane so as well as conceivable but unlikely panning in the vertical plane (helicopters, grouse ?! LOL) you could pan in the usual horizontal plane with the camera held in portrait rathr than landscape orientation.

And that you would retain a blurred background only in the plane in which IS was deactivated.

Which brings this Idiot Boy back to the question: how is it effected? Clearly the camera knows which way up it is (the playback on Live View is another example) and clearly the IS is calibrated by the controlled shudder on power-down. Gyroscopes of some description?? Or what? Once calibrated, I suppose that the camera must be able to record and measure shake and the results of that are applied to the image when processing the pixellated output from the sensor. Which leads me back to the first question: at what cost if the IS is on when the camera is not moving at all? If the IS detects no movement, then there should be no correction to be made, so why do they tell you to switch it off? Or is it the process of correction, even if for no motion, such that there's a price in image sharpness or lost detail in the processing; it's a great improvement on blur from shake but a deterioration from rock-steady quality?

I think we may need Ian and Olympus for definitive comment here - what do you think?

PeterD
25th August 2008, 12:35 PM
That wasn't how I read it... I thought that it meant IS mode 1 worked to reduce shake all round. IS mode 2 (horizontal panning) would reduce shake only in the vertical plane while stabilisation in the horizontal plane would not occur. IS mode 3 would reduce shake only in (the camera's) horizontal plane so as well as conceivable but unlikely panning in the vertical plane (helicopters, grouse ?! LOL) you could pan in the usual horizontal plane with the camera held in portrait rathr than landscape orientation.

And that you would retain a blurred background only in the plane in which IS was deactivated.
Which brings this Idiot Boy back to the question: how is it effected? Clearly the camera knows which way up it is (the playback on Live View is another example) and clearly the IS is calibrated by the controlled shudder on power-down. Gyroscopes of some description?? Or what? Once calibrated, I suppose that the camera must be able to record and measure shake and the results of that are applied to the image when processing the pixellated output from the sensor. Which leads me back to the first question: at what cost if the IS is on when the camera is not moving at all? If the IS detects no movement, then there should be no correction to be made, so why do they tell you to switch it off? Or is it the process of correction, even if for no motion, such that there's a price in image sharpness or lost detail in the processing; it's a great improvement on blur from shake but a deterioration from rock-steady quality?

I think we may need Ian and Olympus for definitive comment here - what do you think?

Thats exactly what I said.

I seem to recall that two gyros are fitted into the body to detect movement, The error signals from the gyros are used to correct for movement. When the camera is fitted to a good tripod, no movement should take place and therefore no corrections are applied. As you say, why switch IS off then? I guess it depends on the stability of the stabalisation circuitry.

Peter

Dick Bowman
25th August 2008, 03:02 PM
[... deleted ...] When the camera is fitted to a good tripod, no movement should take place and therefore no corrections are applied. As you say, why switch IS off then? I guess it depends on the stability of the stabalisation circuitry.

Peter

My guess (and it's purely speculation) is that there may well be some sort of servo in the electronics - it needs something a little bit "off" in order to make a correction. If the body isn't shaking it has nothing to correct and in its electronic daftness may decide to make a little movement in order to put it right.

It's a line of reasoning that was popular some years ago in criticism of hifi turntables with servo control - that the rotation speed was never "just right" but always being nudged one way or another. What the servo did (or so it was alleged) was to make sure that the speed never got outside acceptable fast/slow limits. The allegation being that the cure was worse than the problem.