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Old Sep 6, 2006, 12:32 PM   #21
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Making the lens and the camera work together would require the two to 'communicate' to each other which will lenghten the control loop for IS. We don't want the IS in the lens to be out of sync with the IS in the body and fight each other do we? Beside the existing IS lenses do not provide any feedback to the camera so you would need to upgrade to a new lens anyway for this 'combined' IS to work
I confess I'm not sure I understand why they would need to communicate with each other.

If the IS in the lens operates completely independently of the body then I don't see why having a moving sensor would be likely to cause conflict.

With lens IS the image is already stabilised by the time it reaches the sensor. Or is it the case that the gyros are not in the lens and rely on information provided by the body?

If the two operate completely independently then shouldn't they work OK together?
On the other hand if the two are not completely independent and body is able to detect that the lens has IS it should be easy enough to simply switch off the body IS at that point - or switch to a different mode perhaps. Certainly you could manually switch off the lens IS if there was a conflict.




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Old Sep 6, 2006, 5:23 PM   #22
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peripatetic wrote:
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If the IS in the lens operates completely independently of the body then I don't see why having a moving sensor would be likely to cause conflict.
It does, the IS in the lens assumes the sensor stayed in one place to work with existing dSLR or film - Now if the sensor is moved isn't that the same thing as rolling the film as the 'corrected' image is projected onto it ?



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With lens IS the image is already stabilised by the time it reaches the sensor
Exactly my point - the image is already stabilized by the lens -> moving the sensor at this position will add motion to the projected image (see above). Whereas the IS in the body presumes it received an uncorrected image (i.e. moving the sensor or film to follow the movement of the projected image)



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Or is it the case that the gyros are not in the lens and rely on information provided by the body?
That's why they need to share the info: the gyro in the lens is a self contained device and is different from the gyro (or accelerometers) in the body which controls the sensor. At this moment they don't communicate and they move at a different rate - Imagine a tandem bicycle where the two riders pedal indepently from one another and not in unison -> An asynchronous system in another word!



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If the two operate completely independently then shouldn't they work OK together?
No: Unless the lens and the body are synchronized, one of the two need to be turned off (i.e. either turn the the lens IS off or the body IS). To synchronize they need to communicate what each other is doing
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Old Sep 6, 2006, 5:41 PM   #23
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OK I think I see.

They would need a different type of stabiliser. Currently the stabiliser works by detecting motion in the camera or lens and adjusting accordingly.

For Canon to produce a system that worked in conjunction with the lens IS they would need to develop a system that worked by measuring the movement in the image hitting the sensor - rather than by detecting motion in the body itself (as I presume the other manufacturers do).

But that might not be impossible, though I can see how it would be much harder than for the other manufacturers.

If someone can think of a method I'm sure Canon would be interested in hearing about it.
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Old Sep 6, 2006, 8:37 PM   #24
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I'm thinking about an optical mouse... Doesn't it detect "movement" by the change in contrast on the surface it's on? Maybe a new IS can depend on the contrast of a picture? That would be interesting... except for moving objects... :roll: ... Well IS is only useful for static objects in the first place (excluding the telephoto advantage)...:-)
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Old Sep 6, 2006, 11:29 PM   #25
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This is a digression, I but I once read an interview with 3 of the designers for the D100. When asked what feature they each thought was best, one of them said the battery life. And I would have to agree. The battery life of that camera was way better than anything else at the time (at least, in the price range I was researching) and they seem to have keep improving that in some of their newer bodies as well (All? I don't know the battery life of the D70 & D50.)

As to the TC which gives you IS... I seem to remember, in the back corners of my mind, that some people predicted that nikon would offer such a product. Clearly it hasn't appeared yet.

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Old Sep 7, 2006, 9:09 AM   #26
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BoYFrMSpC wrote:
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Maybe a new IS can depend on the contrast of a picture? That would be interesting...
Been there, done that -> That how most video camcorder with 'digital' stabilizer work (i.e. not optical)
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Old Sep 7, 2006, 9:32 AM   #27
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Been there, done that -> That how most video camcorder with 'digital' stabilizer work (i.e. not optical)
But difficult - perhaps impossible for a SLR?

Because the sensor is only exposed at the time the shutter is tripped.


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Old Sep 7, 2006, 10:51 AM   #28
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Correct - This only works with EVF cameras (which already exist) or camcorders
-> A second sensor a' la Oly may be for a dSLR... (which can then also give real-time histogram info)
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Old Sep 18, 2006, 10:12 AM   #29
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Canon's view on the matter...

http://www.robgalbraith.com/public_f...hite_Paper.pdf

Search for the text "in-body image stabilization".

The extract:
Quote:

[align=left]Some of Canon's competitors have chosen to use in-body image stabilization. The technique[/align]
[align=left]involves moving the image sensor in a controlled fashion, based on signals from[/align]
[align=left]movement detecting sensors in the camera body. The obvious advantage of this system[/align]
[align=left]is that users have some sort of stabilization available with almost any lens they connect[/align]
[align=left]to the body. Short focal length lenses require smaller sensor deflections; 24 or 28 mm[/align]
[align=left]lenses might need only 1 mm or so. Longer lenses necessitate much greater movement;[/align]
[align=left]300 mm lenses would have to move the sensor about 5.5 mm (nearly 1/4") to achieve[/align]
[align=left]the correction Canon gets with its IS system at the same focal length. This degree of[/align]
[align=left]sensor movement is beyond the range of current technology. Short and "normal" focal[/align]
[align=left]length lenses need stabilization much less often than long lenses, so the lenses that[/align]
[align=left]need the most help get the least. Further, in cameras with smaller than full-frame, 35[/align]
[align=left]mm film size sensors, equivalent focal lengths become longer, by a factor of 1.5 or 1.6,[/align]
[align=left]exacerbating the problem by making all lenses longer.[/align]
[align=left]Less significant but still worth mentioning is the fact that in-body stabilization is not visible[/align]
[align=left]through the finder, whereas Canon lens-based stabilzation definitely is. Also, while[/align]
[align=left]in-body stabilization works for many lenses, it does not presently work for all; high magnifications[/align]
[align=left]and macro lenses have caused it difficulties.[/align]
[align=left]In the Canon IS system, the Image Stabilizer has an actual[/align]
[align=left]lens group that can be moved up and down, or side-toside,[/align]
[align=left]in parallel to the imaging sensor or film plane. A pair[/align]
[align=left]of sensors in the lens can detect horizontal or vertical[/align]
[align=left]shake. Signals from these sensors are sent instantly to a[/align]
[align=left]microprocessor in the lens and analyzed. The microprocessor[/align]
[align=left]then causes a group of lens elements, held in[/align]
[align=left]place by a device called a coil, to move at the same amplitude[/align]
[align=left]and frequency of the shake to cancel it effectively.[/align]
[align=left]Canon is able to generate excellent image quality by stabilizing the image optically[/align]
[align=left]before it ever reaches the imaging sensor in a digital SLR.[/align]
[align=left]With the optical IS used by Canon, each lens with IS has a stabilizer unit designed for[/align]
[align=left]that lens's needs. The unit in a lens such as the EF 28-135 f/3.5-5.6 IS USM or the EF-S[/align]
[align=left]17-85 f/4-5.6 IS USM is vastly different from the powerful, broad movement stabilizers[/align]
[align=left]
[/align]
[align=left]in lenses such as the EF 400mm f/2.8L IS USM or the EF 600mm f/4L IS USM. All over[/align]
[align=left]the world, photographers depend on Canon IS to help them achieve the highest possible[/align]
[align=left]image quality.[/align]
[align=left]At some point, in-body stabilization may improve to the point at which such technology[/align]
[align=left]may be appropriate for certain segments of Canon's DSLR range. It would be senseless[/align]
[align=left]to rule out such a possibility. Even now, differences in unit cost are not enough to be[/align]
[align=left]significant factors in such a decision. The bottom line is performance.[/align]
[align=left]
[/align]
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Old Sep 19, 2006, 1:42 AM   #30
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300 mm lenses would have to move the sensor about 5.5 mm (nearly 1/4") to achieve
Minolta view on the matter: http://www.dpreview.com/news/0408/04...7interview.asp
Ishizuka: No. We can make it move more than 1cm (i.e. 10mm!)
-> There are already several links which showed how well the in-body IS work with the 500mm Bigma...

BTW the Pentax in-body IS not only can compensate for x-y direction, but also rotational movements (in-case some one do twist their hand white taking a picture) :-)
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