Be extra careful with IS builit into a lens ?

Started 4 months ago | Discussions thread
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jamesm007
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Be extra careful with IS builit into a lens ?
4 months ago

Maybe...

I have written in the years past about lens with image stabilization built in. According to Klaus of Photozone often have optical alignment problems. Klaus started this some years back. Really he seems to be saying on average those lens are not aligned as accurately as non-IS lens types.

Here is a link to one post of mine written in May 19, 2011.

http://www.dpreview.com/forums/post/38467233

Here is a recent writing from Klaus reviewing a lens. I won't say what lens because I am not trying to degrade a brand name or system. I do think Klaus is seeing a pattern, and this pattern of lens with built in image stabilization is real in his testing and his opinion. He continues to show and write of those problems. Klaus just tells it like he sees it. Yes he can be hard on lens like the DA18-135mm or DA50-200mm. But he is correct technically at serious pixel peeping levels. In real world use things are different. But to be fair he will note that sometimes(!) in his final comments.

This is a quote from a lens tested this year. Obviously its not Pentax even though some Pentax 645 lens do have IS.

"As far as the centering quality is concerned, it was as bad as it gets with the first sample that we purchased. The lens also suffered from a mechanical breakdown. Fortunately ##### replaced it and this 2nd sample had a far better centering than average for a image stabilized lens."

I am looking for objective IMOs. Nothing is perfect. And according to Klaus Pentax has never made a lens with good alignment... well... he can be tough. None the less he keeps writing of this issue(?), if it is one. I can't see what benefit it would bring him to be negative on purpose.

What is he seeing. If an optical element has to move and move quickly it would be much harder to keep it perfectly perpendicular to the sensor. Because it not only has to be flat in the middle position but all other positions in any direction of movement away from the center. And the mechanical system has to be as close to perfect as can be. That's much harder to achieve if I am to take Klaus word, I 80% do. And logically it would be harder to make a lens well aligned in a lens body moving a len element.

Its just interesting, that's a strong statement. It kind of stops me, and makes me go hmmm.

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