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Old Dec 5, 2010, 7:18 PM   #61
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Originally Posted by John.Pattullo View Post
most stablisation system both in lens and in camera claim (not sure how accurate these claims are but ususally more experianced testers than me seems to back them up) a 4 stop advantage
Up to 4 stops. ;-)

The newest Canon and Nikon systems claim "up to" 4 stops. Some of the lenses with VR II like Nikon's 18-200mm VR II is actually pretty good. But, the older VR systems are not that good. Ditto for the latest Sony and Pentax body based systems (up to 4 stops).

But, I wouldn't count on more than 2 with any of them.

But, from most tests I've seen, the Pentax system is lagging behind the others with their newer models. For example, dpreview.com mentioned 1 stop for the Kr in it's review here:

http://www.dpreview.com/reviews/pentaxkx/page13.asp

From what I gather from reading user reports, the changes Pentax made to add the horizon leveling feature might have degraded SR effectiveness.

There have been a number of articles comparing specific lenses. popphoto had some test results online for a number of lenses at one point. But, now, all I see is a summary here:

http://www.popphoto.com/Reviews/Came...Shake?page=0,1

None of them except for a lens with the latest VR II from Nikon managed 4 stops in their tests.

Amateur Photographer Magazine did a test in their January 21, 2010 issue comparing stabilization systems, including body based systems using models like the Pentax K7, Sony A550 and Olympus E-620

For the Pentax and Sony models, they included tests using the Sigma 50-200mm f/4-5.6 DC OS lens, to compare the effectiveness of body versus lens based stabilization with the same lens, measuring number of shots that were sharp at various shutter speeds, measuring the increase in resolution each stabilization system provided.

The Sigma OS system in the 50-200mm f/4-5.6 DC OS performed much better than Pentax SR (Shake Reduction), but it was beaten by the SSS (Super Steady Shot) system in the Sony A550.

I'm seeing similar results elsewhere. For example, dpreview.com's test of the A550 with it's 18-55mm kit lens showed that 70% of it's shots were still sharp at 1/15 second on the 55mm end of the Sony 18-55mm kit lens, and roughly 60% were still sharp at 1/6 second, while still able to get 30% of it's photos sharp all the way down to 1/4 second.

Yet, if you look under their lens reviews for the Canon 18-55mm IS lens, it was down to 60% of it's photos in the sharp category on the long end of the lens by the time you got to 1/13 second, and down to around 20% of it's photos in the sharp category at 1/6 second (where the Sony A550 still had 60% of it's photos in the sharp category). They didn't test it at slower shutter speeds (or if they did, they didn't publish the results).

IOW, the Sony A550 still had more photos in the sharp category at both 1/8 second and 1/4 second compared to Canon 18-55mm IS lens at 1/13 second (the Sony in body system in models like the A550 using a 18-55mm kit lens is more than a stop better than the Canon 18-55mm lens with IS built into it from tests I've seen). Both of these systems (Canon lens based stabilization, and Sony body based stabilization) outperformed the Pentax SR body based system by a pretty good margin in more than one test (tests done by Amateur Photographer Magazine and tests performed by dpreview.com).

From what I can gather from reading multiple tests using different lenses, you can expect a high percentage of images to be sharp at approx. 1 stop slower shutter speeds with the Pentax SR (body based) System compared to images without stabilization turned on, with a high percentage of shots to be sharp at 2 stops slower with the Canon IS (lens based) system, with a high percentage of shots to be sharp at 3 stops slower using the Sony (body based system), when testing newer models like the Sony A550. Usable (i.e., only mild blur) images were at higher percentages from all of these models.

You're going to see effectiveness vary by specific camera, lens used, focal length, and focus distance with any of them.

But, rarely are you going to see consistently sharp photos taken 4 stops slower than you can hand hold a camera (which will vary by individual) with any of them in practice.
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Old Dec 5, 2010, 7:46 PM   #62
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wow thats alot of info - think i'll still try my unscientific experiemtn though - personally found the shake reduction on my k-7 to be pretty good but dont have much to compare it to non of my lenses got OS in them - got my sigma 150-500mm about 2 months to early =( hate it when you buy something and then they announce newer version almost immediately

anyway i doubt the horizon leveling feature is responcible for any lack of sr perfromance as unless things changed since the k-7 released you cant use the horizon level feature if you have sr activated - would explain the poor performance though if they had it turned on and sr wasnt =)
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Old Dec 5, 2010, 7:54 PM   #63
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I'm thinking they probably made some changes to the actuators to allow for horizon leveling that may have impacted how SR works (that's speculation I've seen from some users anyway), since some of the newer tests I've seen imply it doesn't work as well as it did before Pentax started including that feature.

Anyway, the best way to see how well it works is to take a number of photos without SR turned on at various shutter speeds, then take a number of photos with it turned on a various shutter speeds.

The idea is to figure out how many stops slower you can shoot with it versus without it (since how slow you can shoot without it is going to vary by individual, lens, etc.).

You can't go by the "1/focal length rule of thumb" to tell how well it works, since that's only a rule of thumb, and some users hold a camera steadier than others. Instead, you'd have to see how much slower *you* can shoot with it turned on versus without it turned off to determine stabilization effectiveness.
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Old Dec 5, 2010, 8:27 PM   #64
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BTW, here's an interesting discussion that implies that you may need to use even faster shutter speeds than the old "1/focal length" rule of thumb if you want to "pixel peep" with higher resolution cameras.

http://forums.steves-digicams.com/ge...n-cameras.html
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Old Dec 5, 2010, 8:27 PM   #65
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ok yeah just did a quicky test and jsut judging from the lcd screen yeah at 200mm i'm getting about 2 1/2 stops benefit on average - did it several times as once at 1/15 with no SR got a beautifully sharp image so random change certainly has a say in things

but was finding that at 1/8th sr couldn't quite manage it (close but no cigar) by 1/15 it was was getting good sharp images - hand held needed to up it to 1/60th to reliably get sharp images
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Old Dec 5, 2010, 8:53 PM   #66
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If you're getting sharp images with it at 1/15, and need 1/60 without it, then that's 2 stops. Not bad at all. But, I wouldn't judge effectiveness by what you see in the LCD, as blur is going to be more obvious at larger viewing sizes. ;-)
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Old Dec 5, 2010, 9:45 PM   #67
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Fell of the grid on March 2009 and revived in Dec 2010, is that a new record for threads coming back from oblivion! Good topic but surprising that it reappeared.
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Old Dec 6, 2010, 2:50 PM   #68
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yeah but was almost there at 1/8th of a second if i had run intermediate's of about 1/10th or 12th think the image stablisation might have got it so 2 to 2 1/2 stops is my guess at 200mm f4
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