Film-Tech Forum ARCHIVE: Image quality loss with Isco converter?

This is topic Image quality loss with Isco converter? in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Rob J. Buskop (Member # 3338) on 10-22-2012, 01:15 PM:

It's in the planning to extend my private screening room about 2,5 feet. Problem is, two years ago I acquired two new Schneider Premiere base optics for my CScope format.
Their f is 80mm. My new requirement would be somewhere between 86 and 90mm. This could be achieved with Isco's fixed converter of 1.09x
The question is: Do any of you know of any detoriation in picture quality when using these converters? Would this be an advisable step?
I would be grateful to learn about your experiences in this area.
Thanks for your attention!

Posted by Tony Bandiera Jr (Member # 2365) on 10-22-2012, 06:31 PM:

Rob, with so many places converting to digital (and with 90mm being a pretty common focal length) why waste time and money on a converter? It would be pretty easy (and a lot cheaper) to get a good used 90mm lens (Put up a Wanted post in the Equipment wanted forum for example.)

Yes, you will lose some image quality with a converter. (Usually focus uniformity but sometimes also contrast.)

So, IMHO , forget the converter and just get a 90mm lens.