GH1 + CCTV Lens + macro / diopter (diy Focal Reducer) = no vignetting ?

[CRFilms]

I was doing some late night searching on various topics for the GH1 and I came across a topic on Focal Reducers.
http://www.dvxuser.com/V6/showthrea...eze-all-your-FOV-and-Light-on-your-GH1-Sensor

The ideas were interesting but ultimately I didn't see the benefit on regular lenses BUT....on these CCTV lenses, especially on 25mm or below....would it reduce or eliminate vignetting so you can use some of these faster lenses on the GH1 that can't do the GH2 crop?

If you were to take two c mount adapters sandwitch a macro / achromat like these:
http://photography.shop.ebay.com/i....+lens&_osacat=625&_trksid=p3286.c0.m270.l1313

Here's a quick mock up of what it would look like using my EPIC paint skills. :tongue:


Would that allow you to use a 25mm or 12mm / something in the 1.4 or 1.2 or faster lens? Would it act as a focal reducer and make the lens even faster?

The main thing that worries me is since the c-mount lenses all fit real close to the body, would moving the lens further away with the adapter remove the benefit of macro close up or would it just not work at all and you couldn't focus.

Appreciate any ideas. I really don't want vingetting, I'm not a fan of that look, but no CCTV lens that's faster than 1.4 is avaliable over 25mm at a cheap price and I'm wondering what you guys think?

 

[Perder]

since no one is answering you, I thought I'd try share my limited knowledge:
- full frame optics and typical c-mount optics are very different in that FF are built for larger sensors/film than µ4/3, while c-mount is typically used for smaller sensors/film. So focal reducers can be used to squeeze the FF-optics' FOV down to the µ4/3 smaller sensor, while you need something that gives basically the opposite results for c-mount - like GH2's ETC. Focal reducer on c-mount with GH1 would give MORE vignetting.
- theoretically, I'm sure there's something like a focal increaser/teleconverter thing-a-ma-jig that could work, but without modifying the internals of the lens I doubt you could fit it between a c-mount and the sensor without critically shifting the focus plane.

I'm not 100% sure about all this, I've only read a little on the subject, but this is how I understood it - might be wrong..

 

[CRFilms]

Thanks for the reply. Yeah, I just realized why the lens adapters put so much space between the body and the lens...for the focus, so that wouldn't work on CCTV lenses. I do have a macro laying around somewhere and an extra nikon adapter. I may try and cut the adapter in half and putting the macro in it and see how that works.