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01-04-2015, 08:14 PM   #1
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SR and lens type - curiousity question

A question for the SR gurus out there:

Is there any way for the SR system to account for the lens being used and not just the focal length? For example, if I'm shooting at 40mm using the 40 XS or 40 Limited (which might allow for better two hand holding of the camera), it is quite probably that I'm going to have a lot less shake than if I'm using a 18-250 superzoom extended to 40mm. This is an extreme example, but you can think of other lenses - say the 35 vs 35 macro or 50 vs 50 macro where the length and weight will differ and thus so will the stability in the users hands.

Just a curiosity that crossed my mind.

01-04-2015, 09:09 PM   #2
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Doubt it. SR compensates for the perceived movement. I can't imagine it evaluating anything else.
01-04-2015, 09:13 PM   #3
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I would doubt it too. So rephrasing my question and using the first example - which 40mm lens is the SR calibrated for? Could it do more harm than good for a significantly different lens?
01-04-2015, 09:15 PM   #4
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The SR system measures the amount of movement and will compensate accordingly. If you shake less with the 40mm prime the SR system will compensate less.

01-05-2015, 08:50 AM   #5
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SR needs to know the focal length because it bases its range of corrections on the Field of View given by that focal length. The correction for hand-induced motion in a 40mm Field of View will be less than the amount of correction necessary for the same motion in a 100mm Field of View. It doesn't matter what the physical appearance or dimensions of the lens are.
01-05-2015, 09:14 AM   #6
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QuoteOriginally posted by AquaDome Quote
SR needs to know the focal length because it bases its range of corrections on the Field of View given by that focal length. The correction for hand-induced motion in a 40mm Field of View will be less than the amount of correction necessary for the same motion in a 100mm Field of View. It doesn't matter what the physical appearance or dimensions of the lens are.
The need for FL is something I understand and makes sense. But I think you've missed my question - for a specific focal length the likelihood and extent of shaking motion will to some extent depend on the physical dimensions of the lens. It is quite possible that the camera won't include this in its calculations, although @Ole suggests that the camera does take it into account by measuring the shake (and then presumably using the FL in the correction algorithm).
01-05-2015, 09:37 AM   #7
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There has as been a lot of discussion in the Q forum about shake reduction and it being over active, with better results being produced by setting the focal length up to 30% shorter than the actual.

I suspect this has a lot to do with what lenses are being used and how the camera is held. For example, using the standard kit lenses for the Q and holding at arms length will have one motion, generally translations only, where as using a viewing shade, (holding at eye level like an SLR) and holding a long lens by the lens, will tend to also add pitch and yaw to the movements, which are different than simple shifts you get with the standard Q lenses.

I suspect the same applies with an SLR, but with a possibility of up to 5 degrees of freedom (sometimes referred to as axis of movement) in ht e correction it may not be as important.
01-05-2015, 10:18 AM   #8
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QuoteOriginally posted by MSL Quote
The need for FL is something I understand and makes sense. But I think you've missed my question - for a specific focal length the likelihood and extent of shaking motion will to some extent depend on the physical dimensions of the lens. It is quite possible that the camera won't include this in its calculations, although @Ole suggests that the camera does take it into account by measuring the shake (and then presumably using the FL in the correction algorithm).
Physical dimensions of the lens aren't part of the calculation. The camera determines its need to correct based on the camera's actual motion. There is a sensor in the camera which keeps track of this motion. When it senses this motion, it needs to know the focal length to know how much to correct. Any effect caused by the weight or other dimensions of the lens all contribute to the total motion sensed by this sensor. Thus, the camera only needs to know the focal length, since it is already gathering its own information for the other half of the calculation.

01-05-2015, 10:40 AM   #9
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QuoteOriginally posted by AquaDome Quote
Physical dimensions of the lens aren't part of the calculation. The camera determines its need to correct based on the camera's actual motion. There is a sensor in the camera which keeps track of this motion. When it senses this motion, it needs to know the focal length to know how much to correct. Any effect caused by the weight or other dimensions of the lens all contribute to the total motion sensed by this sensor. Thus, the camera only needs to know the focal length, since it is already gathering its own information for the other half of the calculation.
So indirectly the dimensions of the lens are involved in the calculation, but in a user specific way. This is also good to know as it means that a person has to be cognizant of how they hold a camera when composing a shot, vs how they might change their grip just before hitting the trigger. It could be why I have more luck with 2nd + 3rd shots rather than the first one I take. Or maybe I'm still just not very good :0
01-05-2015, 11:25 AM   #10
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Focal length is the only variable.


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01-05-2015, 11:34 AM   #11
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QuoteOriginally posted by MSL Quote
vs how they might change their grip just before hitting the trigger.
That's a big no no, you shouldn't change ANYTHING (not even direction of aim) right before hitting the trigger, if SR is active that is.
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