[gus_the_mouse]

Does anyone know if there is any optical different between the Leaf-shutter and non-LS version of the 6x7 90mm F2.8 lens? I would assume the LS version is the same optical formula with the shutter mechanism added, but haven't found anything to confirm this. However the leaf-shutter version was released nine years earlier (1971 vs. 1980) than the non-LS version according to the info in the 'lens reviews', leading me to believe that it may have other differences. I have been considering the purchase of this lens, but probably would not use the leaf-shutter very often (it certainly is not essential), so I'm not sure if it would be worth paying more for it, or go for the later lens without the LS.

Any knowledge would be appreciated.

[Paul Ewins]

There is an extra element in the later (non-LS) design. Generally speaking, the later versions are always the ones to get.

[Ed Hurst]

I have both and my general experience (albeit not determined scientifically) is that the latest (non-LS =) version is sharper than the LS version. However, for applications where you need LS...

[gus_the_mouse]

Ok, thanks. I'm going to have to determine how much I want the LS then.

[Paul MaudDib]

Be aware that parts are no longer available for the 90mm LS lens. If it breaks, getting it serviced will be a crapshoot and may have an unhappy ending. Pentaxs.com is very good and would have parts if anyone did.