[LRflex] Re: R 2x APO Extender Question
- From: "a aa" <classwp@xxxxxxxxx>
- To: leicareflex@xxxxxxxxxxxxx
- Date: Sun, 1 Apr 2007 01:03:42 -0400
The old 400, 560 Telyts (all apertures) are cemented doublets, while the
800 is a triplet All are true long-focu lenses, not telephotos.
On 01/04/07, Frank Filippone <red735i@xxxxxxxxxxxxx> wrote:
>
> I think this is incorrect.... The image circle is huge for long FL
> lenses. ( think about any angle.. then move that angle farther
> from the film plane.. the image circle gets bigger.....) Long FL lenses
> have large image circles.
>
> .I was thinking about the fact that the 400 is a telephoto design, and the
> location of where the light rays converge may not be
> where we think they are. This might be in conflict with the way the 2x
> extender is designed to operate.
>
> David, does this happen with all 2x converters on the 400 in your
> setup? Say a Vivitar, or maybe a Canon Extender on a Canon body?
> Or alternatively, if you put the setup on a Canon/Nikon/something else
> film body, do you still get vignetting?
>
> Note.. it does NOT happen with my Nikon 2x and regular film camera ( F4).
>
> Frank Filippone
> red735i@xxxxxxxxxxxxx
>
> I had the same problem. It probably has to do with the fact that the lens
> elements are so far away from the rear lens flange that you have a greatly
> magnified, itty-bitty image circle that can't help but be vignetted.
>
>
>
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