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Rhys
08-27-2006, 05:40 PM
How long is the longest lens the recommend for use with shake reduction?

I heard from somebody that Canon weren't planning it because on lenses of 300mm the distance the sensor would have to be moved is about 1 centimeter.

Rex914
08-27-2006, 05:47 PM
Rhys is referring to Canon's explanation inside this White Paper (http://www.robgalbraith.com/public_files/Canon_Rebel_XTi_White_Paper.pdf). Scroll down to the part where it discusses in-body IS versus lens IS.

I'm interested in knowing just how effective this technology is in practice for a variety of focal lengths. While it would be overly optimistic to expect any major advantages with say, a Bigma :p, how about the average 70-300 f/4-5.6 consumer telephoto lens, an 80-400 type of lens, or even a Sigma 70-200/2.8?

jeisner
08-27-2006, 05:56 PM
It is consistantly effective with my F*300mm f4.5... in my estimation it gives me a good 3 stops..

Thats the longest lens I have though...

If I get home early enough tonight (still light) I can do some comparisons with SR on and off with the 300 if you like? I could also use the Tamron 1.4x on that to give you 420mm

Rex914
08-27-2006, 06:06 PM
I can do some comparisons with SR on and off with the 300 if you like? I could also use the Tamron 1.4x on that to give you 420mm

Sounds good to me. ;)

MatH
08-28-2006, 01:39 AM
If one uses a 500mm lens at 1/160 time one wil probably se shake blur with radius about 20 pixels or less on 6mp sensor. 10 pixels on 16x24mm 6mp sensor are 20*16/2000=0,16mm long. Even if sensor travels twice as much, that's far from 1cm. Of course Canon wil devaluate sensor shift blur reduction and promote in lens solution.

jeisner
08-28-2006, 02:19 AM
OK so I put my Tamron 1.4x teleconverter on the F*300/4.5 and took two shots, sorry just boring indoor shot of a pill packet (was dark before I got home).. obviously both handheld and at ISO 800 and f4.5 and 1/125... These are 100% crops of camera generated JPEGs..

I took a couple of shots and the results were consistant... So it seems even at 420mm in body IS still works...

SR OFF
http://i.pbase.com/o4/79/522179/1/65882641.oim2xcAn.sroff.jpg

SR ON
http://i.pbase.com/o4/79/522179/1/65882617.LNvya2R6.sron.jpg

jeisner
08-28-2006, 03:29 AM
P.S. I couldn't feel any movement, pretty good considering the > 1cm sensor movement ;-)

Sorry couldn't help myself, I love how much stuff marketing departments can just make up :cool:

WightWalker
08-28-2006, 04:10 AM
P.S. I couldn't feel any movement, pretty good considering the > 1cm sensor movement ;-)

Sorry couldn't help myself, I love how much stuff marketing departments can just make up :cool:

10mm of sensor movement, I doubt it very much given the size of the APS sensor.

Check out this url:
http://www.pentaximaging.com/files/scms_docs/SHAKE_REDUCTION_FACT_SHEET.pdf#search=%22lens%20sh ake%20reduction%22

MatH
08-28-2006, 04:59 AM
If memory serves me right, you can manually dial in focal lenght for older lenses up to 800mm. Anything loner than that requires tripod or Arnie ;)

jeisner
08-28-2006, 05:28 AM
If memory serves me right, you can manually dial in focal lenght for older lenses up to 800mm. Anything loner than that requires tripod or Arnie ;)

LOL, yeah I think I can manage without a stabalised 1000mm lens...

Rhys
08-28-2006, 06:56 AM
It looks like that Canon white paper is a load of hogwash then, designed to cover up the fact they prefer to charge more by selling IS lenses.

Quite honestly I don't see why Canon doesn't put in body IS and then on the lenses it claims won't benefit from in-body IS simply put IS on the lens itself.

In any case, thinking Canon's claims through logically, if 1CM of movement is needed then the lens elements (much heavier than a sensor) would have to move 1CM also. That would use a lot more power.

I think we can rest assured that Canon's white paper is a load of poo!

MatH
08-28-2006, 08:41 AM
Some of Canon’s competitors have chosen to use in-body image stabilization. The technique involves moving the image sensor in a controlled fashion, based on signals from movement detecting sensors in the camera body. The obvious advantage of this system is that users have some sort of stabilization available with almost any lens they connect to the body. Short focal length lenses require smaller sensor deflections; 24 or 28 mm lenses might need only 1 mm or so. Longer lenses necessitate much greater movement; 300 mm lenses would have to move the sensor about 5.5 mm (nearly 1/4”) to achieve the correction Canon gets with its IS system at the same focal length. This degree of sensor movement is beyond the range of current technology. Short and “normal” focal length lenses need stabilization much less often than long lenses, so the lenses that need the most help get the least. Further, in cameras with smaller than full-frame, 35 mm film size sensors, equivalent focal lengths become longer, by a factor of 1.5 or 1.6, exacerbating the problem by making all lenses longer.

It's logical that each manufacturer praises it's own product, but such devaluation of other solutions is IMHO far too decieving to be tolerated.

Rex914
08-28-2006, 12:59 PM
To be fair to both sides, Canon is also waiting for the right time to include in-body IS (on top of monetary reasons). As I said somewhere else, it's not a mature technology yet (though it seems to be working pretty darn well for first generation), and Canon tends to wait for these new technologies to go through a few generations before jumping in. A concrete example is the sensor cleaning. It's a late entry for Canon, but at least based on paper, is well-thought out.

Rhys
08-28-2006, 01:34 PM
Even if it is a maturing technology, the results I have seen are pretty good.

My Canon S1 IS has built-in stabilisation. That's absolutely fantastic. I did a test at 1/20th at max zoom and the image was really crisp. I took the same shot without IS and it was exactly as one would expect - soft and blurry. Now I had my S1 IS back in 2004. It's now 2006 so why isn't IS in dSLRs universally? IS has been used in camcorders since the 1990s!

Spot focus
08-28-2006, 04:38 PM
jeisner thanks for the trial, quite impressive ;) maybe there's hope for me with 70-300apo and 2x coverter :rolleyes:

MatH
08-29-2006, 12:50 AM
S1 IS has in lens shake reduction as far a I know.

Rhys
08-29-2006, 06:58 AM
S1 IS has in lens shake reduction as far a I know.

As I stated earlier :)

I've compared IS on and IS off on the same subject. With IS off the subject is blurred. With IS on it's sharp :)