7D owners - is the anti-shake worth $300?

[cmphoto1]

<p><i>"With zero running costs?"</i></p>

<p>Except for for the hidden costs such as software, extra hard drive

space, printer paper, ink, perhaps a printer upgrade.</p>

<p>Yes, going digital may be cheaper than film, but it is not the freebee it is

often made out to be on photo.net.</p>

<p>chad</p>

[david_bedell]

I know, I know. I'll probably get one, and soon. But I'm not selling my 35mm stuff just yet, in case I want to go back to it... ;-)

<p>

<img src="http://www.lbbfamily.com/albums/February-2005/006_31a.sized.jpg">

<p>

<em>The viewfinder is TOO SMALL!</em>

[aaron_bredon]

"This is precisely the problem: it cannot compensate more. The stabilisation is achieved by moving the sensor. How much can the sensor be moved? 1/2 mm? Unlikely as much as 1mm."

 

Significantly more. The Antishake mechanism in the 7D can move the sensor 5mm in any direction from the center point - basically over the entire 35mm image circle. (This could be useful as a shift lens effect if KM put controls into the firmware to support this)

 

"With a wide angle lens, the camera has to be moved quite a lot before the image on sensor moves even 1/2mm. So the anti-shake system can do its thing and works very well. But with a long lens, a very small lens movement will move the image on sensor much more than the sensor can move to compensate."

 

Counteracting this is the fact that the 1/f.l. handheld base number is faster with a long lens - 1/35 with a 35mm lens exhibits about the same amount of shake as 1/300 with a 300mm lens. AS doesn't have to try to counteract 1/6 second shake on a 300mm lens the way it does on a 35mm lens, it only has to counteract 1/50 second shake to produce the same result. So, the AS system generally has to move the sensor about the same amount regardless of the focal length.

[ilkka]

"Now if I can only convince myself...spend nearly $2,000 on an SLR body...with a teeny squinty viewfinder..."

 

The 7D viewfinder is among the biggest and brigthest on the market. It is certainly not squinty. And well worth the price difference between a 350D or D70, both of which do have small and squinty viewfinders.

[ilkka]

"Significantly more. The Antishake mechanism in the 7D can move the sensor 5mm in any direction from the center point - basically over the entire 35mm image circle. "

 

Okay, I rephrase, and then raise a related question...

 

The image stabilisation in KM 7D does work as advertised and does provide 1-2 stops of additional stability when handheld. However, it is not a complete solution to the problem. It works very well with short focal lengths, say from wide angle to about 100mm. But its ability to reduce camera shake with long lenses is much less pronounced and I believe the system used by Canon and Nikon is indeed superior for long lenses. There is, of course, nothing to stop Minolta building long lenses with separate optical stabilisation to overcome this issue. So what is the problem? The stabilisation is achieved by moving the sensor. How much can the sensor be moved? 3mm from side to side? Unlikely more than 5mm. With a 20mm lens (30mm equivalent), the camera has to be moved quite a lot before the image on sensor moves 5mm. So the anti-shake system can do its thing and works very well. But with a long lens, say 400mm, a very small lens movement will move the image on sensor much more than the sensor can move to compensate. As it is in KM 7D, I would roughly estimate the anti-shake gives 2 stops benefit with lenses less than 50mm, 1 stop with lenses from 50-100 mm and some but very little benefit with lenses longer than about 200mm.

 

And now to the question: KM has recently introduced three digital only lenses. They are supposed to work (only) with the 7D. No mention has been made that they would not work with the anti-shake system. Indeed, it would be strange if they didn't having been produced specifically for that camera. They have a reduced image circle, making it possible to produce a rectilinear 11mm focal length lens. If the sensor moved 6mm diagonally to both directions (equal to 5mm side-to side again in both directions), the lens would need to produce an image circle of 29mm (sensor diagonal) + 2x6mm = 41mm. This is almost exactly the required image circle for a 24x36mm lens (43mm). If the new lenses do indeed produce such a large image circle at their widest setting, why are they sold as digital only? It is likely that the sensor does not move quite as much as 5-6mm, making it possible to use a smaller image circle.

 

And no matter what is the amount that the sensor moves, it still cannot compensate enough when a long lens is used. The fact is, the AS system works well with short lenses and less well with long ones. I have tried it with both and so have others. The results have been similar.

[blueform]

I think the 7d is worth the extra regardless of the i s system.

Its just a better all round camera.

 

Ergonomics,style,function, innovation, the rest look and feel like they have come out of a jelly mould.

 

 

James

[j_kami]

Would someone be able to post a link to the article(s) with the reviews of KM's AS performance with longer telephotos? Thanks.

[blueform]

Here is my answer to improve long lens stability.

 

Put a 7d on top of this and you will be shooting at 1 sec.<div></div>

[yakim_peled1]

<P> It's the same old question - "which camera body should I buy?" - and the same old answer. It's not the specific body which counts or the specific features it contains, it's "Which <b>system</b> is better for <b>you</b>?". Changing a system is a very costly move so I advise you to this check well. I believe that for most amateur photographers, every system will do. However, if you really want to make this a serious hobby than Canon and Nikon have the largest selection of lenses and accessories. </P>

<p>HTH. </p>

 

 

<p>Happy shooting, <br>

Yakim.</p>