Pat Donnelly
New member
keoconsult is selling more than just the Heligon glass on ebay. It is too heavy to post to Australia, but all you septics can avail of them? A kinoptic is up for sale too.
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Their search engine is pretty useless. Just googled the word and it's the second on the list.Did a search for a keoconsult on ebay with 'no results' returned.
These are not lenses you want to have hanging freely off any mount attached to your MFT camera. They'll snap the camera mount off. These are situations in which the lens has to hold up the camera, not the other way around.Recently I was thinking about just gluing the rear section into a c-mount extension tube but I am a bit worried that the small c-mount thread may be too weak to hold the chunk of glass.
The examples (lenses) you link are fabulously done! $499 (or thereabouts) for those lenses seem reasonable to me.Anyway there's this seller on eBay, used to go by "jr-usa" but now he's "jieying-usa", that ships out of California and sells random rare modified lenses for use on everything from Canon to Leica and m4/3. He keeps posting x-ray lenses that have somehow been adapted to m4/3 with a regular SLR lens barrel and m4/3 mount on the back, focusing helicoid, aperture and all. He posts them for absolutely ridiculous prices (usually ~$700) though I don't know how much work goes into adapting them so maybe there's some justification in his costs. I sent him a message asking how he does it but never got a response, I think he might actually be in/from China because some of his postings have inexplicable Chinese paragraphs in their description.
Here are a couple of examples:
Kowa 55mm f/1: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=320581913032
Kowa 77mm f/1: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=320568138012
+1 on that! When I first ran across an example of one of these modified lenses I was in awe. Very nicely done, and definitely a significant amount of work went into making these conversions. It's worth the price if you can afford it IMO.The examples (lenses) you link are fabulously done! $499 (or thereabouts) for those lenses seem reasonable to me.
Yes, the aperture would be placed behind the rear of the lens (not optimal at all, because of vignetting) and the teleconverter optics very tight behind (otherwise it won't work). That would make a 1.4/70mm indeed.Thanks for the elaborated explanation.
I also think that he adds some extra optical elements to achieve infinity focus. Without this the lens would need to be crammed into mount (and thus the camera) much further. (and I also noticed the "little large" part)
Using a negative lens also allows the apperture to be placed behind the original lens? (I guess so because all teleconverters have there own apperture blades?)
So if he used a complete 1.4x extender, would the resulting lens be a 70mm f1.4 lens?