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Image Stabilisation Test

johnriley
Posted 06/03/2011 - 12:01 Link
http://www.youtube.com/watch?v=KPdy52mR6Io

This is showing a test with an Olympus camera, but it is interesting because I suspect it gives clues as to why we are urged to switch off SR when using a tripod. See what happens when in-body is switched on with an already stabilised image.

I also thought that the in-body version seemed to act much more quickly than the in-lens version.

We can probably extrapolate this information to be of use when we use our Pentax cameras.
Best regards, John
hefty1
Posted 06/03/2011 - 14:16 Link
I kind of expected that result but it's the first time I've actually seen it so clearly demonstrated. Good find!
Joining the Q
Cisco
Posted 06/03/2011 - 14:28 Link
Had my K10 on tripod with long lens and live view last week and wondered what was wrong as image was moving slowly around frame ! Then realised SR was on !!

Problem solved
K-7 | K10 | DA 18-135 | DA 18-250 | DA 55-300 | DFA 100 |
ChrisA
Posted 06/03/2011 - 16:01 Link
johnriley wrote:
I suspect it gives clues as to why we are urged to switch off SR when using a tripod. See what happens when in-body is switched on with an already stabilised image.

Trying to use sensor SR at the same time as lens IS is futile, and a moment's thought shows why:

- Each system is using accelerometers to measure the amount of shake

- The design of each is independent.

So, while the lens IS is ensuring that the image that arrives at the sensor is still, the sensor SR is still experiencing the same accelerations whether the lens IS is on or off. Therefore it assumes that it still needs to move the sensor to compensate.

Clearly, moving the sensor around when the image isn't moving, is going to reintroduce the shake that the lens removed.

The sensor-based SR isn't watching the image move or not move, as we do on live view - it's measuring accelerations which are still happening, so of course it can't tell that the image has been stabilised already.

So sure, if you use SR when the camera is moving around, but the image is still, then you'll get shake in the image.


Nothing at all like the tripod situation, where the camera is still, and there aren't any accelerations to measure.
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Pentax K-3, DA18-135, DA35 F2.4, DA17-70, DA55-300, FA28-200, A50 F1.7, A100 F4 Macro, A400 F5.6, Sigma 10-20 EXDC, 50-500 F4.5-6.3 APO DG OS Samsung flash SEF-54PZF(x2)
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Edited by ChrisA: 06/03/2011 - 16:10
ChrisA
Posted 06/03/2011 - 16:04 Link
Cisco wrote:
Had my K10 on tripod with long lens and live view last week and wondered what was wrong as image was moving slowly around frame ! Then realised SR was on !!

Was this a lens without IS?

And did the wander stop when you switched SR off?

If so, then this might be the first piece of actual, reproducible evidence (as opposed to the usual waffle and hearsay), to suggest that SR on Pentax cameras does introduce movement when there's actually none.


However, the K10D doesn't have live view.
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Pentax K-3, DA18-135, DA35 F2.4, DA17-70, DA55-300, FA28-200, A50 F1.7, A100 F4 Macro, A400 F5.6, Sigma 10-20 EXDC, 50-500 F4.5-6.3 APO DG OS Samsung flash SEF-54PZF(x2)
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Edited by ChrisA: 06/03/2011 - 16:09
Smeggypants
Posted 06/03/2011 - 17:13 Link
johnriley wrote:
http://www.youtube.com/watch?v=KPdy52mR6Io

This is showing a test with an Olympus camera, but it is interesting because I suspect it gives clues as to why we are urged to switch off SR when using a tripod. See what happens when in-body is switched on with an already stabilised image.

I also thought that the in-body version seemed to act much more quickly than the in-lens version.

We can probably extrapolate this information to be of use when we use our Pentax cameras.

Why is that? Comment Image
[i]Bodies: 1x K-5IIs, 2x K-5, Sony TX-5, Nokia 808
Lenses: Pentax DA 10-17mm ED(IF) Fish Eye, Pentax DA 14mm f/2.8, Sigma 17-70mm f/2.8, Pentax-A 28mm f/2.8, Sigma 30mm F1.4 EX DC, Pentax-A 50mm f/1.2, Pentax-A 50mm f/1.4, Pentax-FA 50mm f/1.4, Pentax-A 50mm f/1.7, Pentax DA* 50-135mm f/2.8, Sigma 135-400mm APO DG, and more ..
Flash: AF-540FGZ, Vivitar 283
johnriley
Posted 06/03/2011 - 18:04 Link
Smeggypants wrote:
johnriley wrote:
http://www.youtube.com/watch?v=KPdy52mR6Io

This is showing a test with an Olympus camera, but it is interesting because I suspect it gives clues as to why we are urged to switch off SR when using a tripod. See what happens when in-body is switched on with an already stabilised image.

I also thought that the in-body version seemed to act much more quickly than the in-lens version.

We can probably extrapolate this information to be of use when we use our Pentax cameras.

Why is that? Comment Image

Because it demonstrates that when the actual shake is not what the system expects, it can act in a spurious manner. I presume that to avoid the possibility of this we are recommended to play safe and switch SR off. Indeed, when the self timer is used a tripod is presumed and the camera makes sure by doing that for us.
Best regards, John
ChrisA
Posted 06/03/2011 - 18:11 Link
johnriley wrote:
Because it demonstrates that when the actual shake is not what the system expects, it can act in a spurious manner.

It really doesn't demonstrate this at all.

As I explained above, the SR is just moving the sensor in response to the accelerations it's detecting, just as it usually does.

It can't tell that the image isn't moving, because it doesn't work by detecting image movement.

It works by detecting camera body movement, and then on the assumption that this would move the image relative to the sensor, moves the sensor accordingly to compensate.

So it's not at all acting in a spurious manner.

Sorry John, but whether or not there's something funny about Pentax SR on a tripod, this video doesn't show it.
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Pentax K-3, DA18-135, DA35 F2.4, DA17-70, DA55-300, FA28-200, A50 F1.7, A100 F4 Macro, A400 F5.6, Sigma 10-20 EXDC, 50-500 F4.5-6.3 APO DG OS Samsung flash SEF-54PZF(x2)
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Edited by ChrisA: 06/03/2011 - 18:15
Don
Posted 06/03/2011 - 18:12 Link
I leave the IS "OFF" unless I'm absolutely positive I need it.
If I am sure I need IS, and my tripod is handy, then the IS stays off.

I was getting sharp images long before IS hit the market.....
The only places I've used it is indoors at museums and some events for candle lit shots, where the tripod was too inconvenient or not allowed.
Fired many shots. Didn't kill anything.
Edited by Don: 06/03/2011 - 18:13
johnriley
Posted 06/03/2011 - 18:15 Link
Whatever the reasons, and it's all been debated before, it's interesting and we'll have to glean from it what we will.
Best regards, John
ChrisA
Posted 06/03/2011 - 18:16 Link
johnriley wrote:
Whatever the reasons, and it's all been debated before, it's interesting and we'll have to glean from it what we will.

Indeed. Regardless of the physics, as usual

Actually, this particular point hasn't been discussed at all, AFAIR. We've always argued about whether non-existent shake fools the SR into making some.

This is quite different - there is actual shake in this case, and the sensor SR is working *exactly* as it would without an IS lens on the front.
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Pentax K-3, DA18-135, DA35 F2.4, DA17-70, DA55-300, FA28-200, A50 F1.7, A100 F4 Macro, A400 F5.6, Sigma 10-20 EXDC, 50-500 F4.5-6.3 APO DG OS Samsung flash SEF-54PZF(x2)
.
Edited by ChrisA: 06/03/2011 - 18:20
Smeggypants
Posted 06/03/2011 - 19:08 Link
If keeping the camera still fools the SR system into shaking the sensor then what about when the camera is still when hand holding it? Not easy but it is possible even transiently.

This would indicate you'd always have to have some movement when the SR is enabled otherwise you'd get sensor movement.

Which of course makes no sense.

Maybe the SR system is just inherently wobbly on it's own volition, but just less wobbly than normal camera shake?
[i]Bodies: 1x K-5IIs, 2x K-5, Sony TX-5, Nokia 808
Lenses: Pentax DA 10-17mm ED(IF) Fish Eye, Pentax DA 14mm f/2.8, Sigma 17-70mm f/2.8, Pentax-A 28mm f/2.8, Sigma 30mm F1.4 EX DC, Pentax-A 50mm f/1.2, Pentax-A 50mm f/1.4, Pentax-FA 50mm f/1.4, Pentax-A 50mm f/1.7, Pentax DA* 50-135mm f/2.8, Sigma 135-400mm APO DG, and more ..
Flash: AF-540FGZ, Vivitar 283
Don
Posted 06/03/2011 - 19:15 Link
Smeggypants wrote:
If keeping the camera still fools the SR system into shaking the sensor then what about when the camera is still when hand holding it? Not easy but it is possible even transiently.

This would indicate you'd always have to have some movement when the SR is enabled otherwise you'd get sensor movement.

Which of course makes no sense.

Maybe the SR system is just inherently wobbly on it's own volition, but just less wobbly than normal camera shake?

link
Quote:
I leave the sr off unless/until I know I need it.
reason:
I can see the difference. I have actually tested and found that in some instances, I'm losing sharpness on handheld shots in low light.
It seems that the camera tries to compensate, in areas where my hands are steady enough. (even started a thread on the subject).

link
Quote:
ok here's one for all you low light shooters:
if using sr with a tripod causes blur in the images...
what happens if you have good technique, and steady hands....no tripod...will sr induce blur, or improve your shots?
I've been experimenting. With shots in low light, 1/2 sec exp at f2 iso 100, I'm getting sharper images without sr....
any steady handed shooters out there care to try also, and let me know how it works out for you?
I'd like to rule out any problems with my cameras before drawing conclusions.

that dead horse has been beaten to death, revived and beaten again...
But yes, I noticed a difference.
Fired many shots. Didn't kill anything.
Edited by Don: 06/03/2011 - 19:16
Smeggypants
Posted 06/03/2011 - 19:33 Link
From your links it doesn't look like the Horse is dead yet.
[i]Bodies: 1x K-5IIs, 2x K-5, Sony TX-5, Nokia 808
Lenses: Pentax DA 10-17mm ED(IF) Fish Eye, Pentax DA 14mm f/2.8, Sigma 17-70mm f/2.8, Pentax-A 28mm f/2.8, Sigma 30mm F1.4 EX DC, Pentax-A 50mm f/1.2, Pentax-A 50mm f/1.4, Pentax-FA 50mm f/1.4, Pentax-A 50mm f/1.7, Pentax DA* 50-135mm f/2.8, Sigma 135-400mm APO DG, and more ..
Flash: AF-540FGZ, Vivitar 283
Don
Posted 06/03/2011 - 19:38 Link
Smeggypants wrote:
From your links it doesn't look like the Horse is dead yet.

if you mean the issue got settled conclusivly, the answer is no.
I believe one person's testing on tripod concluded an intermittent camera lock up that required pulling the batteries and restarting the camera... but as for the low light, handheld, wide angle lens SR causing blur issue... it was impossible to prove conclusively, but... subjectively, I and others felt there was a blur induced, and that the number of blurred shots increased noticeably over the number of blurred shots with sr off in real world shooting situations....
Fired many shots. Didn't kill anything.
Edited by Don: 06/03/2011 - 19:41

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