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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Fast, weird lenses!
- Thread starter Pat Donnelly
- Start date
seakayaker
Active member
. . . . . post a link?
Did a search for a keoconsult on ebay with 'no results' returned.
Life is Grand!
Dan
~
Did a search for a keoconsult on ebay with 'no results' returned.
Life is Grand!
Dan
~
m3photo
New member
Re: EBay Search engine
Here are the goodies as announced:
http://shop.ebay.com/keoconsult/m.html?_nkw=&_armrs=1&_from=&_ipg=
Their search engine is pretty useless. Just googled the word and it's the second on the list.
Here are the goodies as announced:
http://shop.ebay.com/keoconsult/m.html?_nkw=&_armrs=1&_from=&_ipg=
photoSmart42
New member
X-ray lenses that will require modifications to even fit on an adapter of sorts to use as macro/close-up lenses. The faster ones will create a VERY dreamy look, which is cool for some special effects. As limited-use lenses they're pretty interesting.
V
Vivek
Guest
A gave away a few (all had some sort of a modified mount) for free, recently.
Almost all weigh ~3 (or more) times the weight of a G1 (including the battery). None would focus to infinity.
All are collimating lenses made for X-ray (phosphor) screen visualisation and most were corrected for only one specific wavelength of light.
Almost all weigh ~3 (or more) times the weight of a G1 (including the battery). None would focus to infinity.
All are collimating lenses made for X-ray (phosphor) screen visualisation and most were corrected for only one specific wavelength of light.
kds315
Active member
I know the seller since years and I guess he has finally accepted that these lenses are pretty useless, except for some very rare occasions. I have some modified and used it (like Vivek), but don't use them anymore. A good modification needs quite some effort but the results are not really worth it in the long run. How often can you look at "dreamy super macros" which is abouzt all they do...chromatic aberrations are massive, so for normal photography they are quite useless, wait, there is good use for them: paperweight and doorstops due to their weight!! Even without modification!!
And no, I don't think he will be selling off Canon 0.95/50mm lenses, as they can be very well used on rangefinder cameras - maybe he meanwhile understood that, so better not hold your breath...
And no, I don't think he will be selling off Canon 0.95/50mm lenses, as they can be very well used on rangefinder cameras - maybe he meanwhile understood that, so better not hold your breath...
kevinparis
Member
love the golf shoes as part of the other things he is selling... not that i am in the market for size 11 golf shoes... just smiling at the incongruity
K
K
apicius9
New member
I had asked about those a while back, see here: http://forum.getdpi.com/forum/showthread.php?t=7407 . I never really followed up on it. 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. We'll see.
Stefan
Stefan
photoSmart42
New member
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.
J
JoeBenjamin
Guest
Well you have to hold the camera by the lens in that case, just as you would with a similarly hefty SLR lens.
I have a few of these now, some Kowas and Rodenstocks. The only one I have modified so far is my Rodenstock TV-Heligon 42mm f/0.75. I just took a macro reversing ring made for the Panasonic 14-45mm (those little discs of metal that have the m4/3 mount on one side and a filter thread on the other and cost like $5 on eBay), ground down the filter thread on the ring and glued it to the back of the lens using J-B Weld metal epoxy. Even getting that close to the sensor the fixed-focus area is about a foot from the camera. The bokeh is crazy:
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
I've picked up a few old busted SLR lenses with the hopes of replicating what he's done but I need to procure a few metalworking tools and do more research first. You can find some of the Kowa and Rodenstock patents for their lenses online. They show the lens groups and which area's contribute to focusing. But cutting and grinding the original x-ray lens barrels, fitting some of the glass into an SLR lens barrel, incorporating the aperture and making a mount all seem like herculean tasks. :banghead:
I have a few of these now, some Kowas and Rodenstocks. The only one I have modified so far is my Rodenstock TV-Heligon 42mm f/0.75. I just took a macro reversing ring made for the Panasonic 14-45mm (those little discs of metal that have the m4/3 mount on one side and a filter thread on the other and cost like $5 on eBay), ground down the filter thread on the ring and glued it to the back of the lens using J-B Weld metal epoxy. Even getting that close to the sensor the fixed-focus area is about a foot from the camera. The bokeh is crazy:
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
I've picked up a few old busted SLR lenses with the hopes of replicating what he's done but I need to procure a few metalworking tools and do more research first. You can find some of the Kowa and Rodenstock patents for their lenses online. They show the lens groups and which area's contribute to focusing. But cutting and grinding the original x-ray lens barrels, fitting some of the glass into an SLR lens barrel, incorporating the aperture and making a mount all seem like herculean tasks. :banghead:
V
Vivek
Guest
The examples (lenses) you link are fabulously done! $499 (or thereabouts) for those lenses seem reasonable to me.
J
jwestra
Guest
I was actually thinking about buying a few of these lenses and cram them as far as possible in my e-p1 body as possible. I have read that some lenses can focus 1.5m away using this approach.
I also read somewhere that a lot of the "dreamy" look is caused by different refraction of the different colours in the spectrum.
Can someone make a picture by making a grey-scale image using only one of the colour channels? (so take only the information of the for example red subpixels and convert this to black and white)
These "jieying-usa" modifications look very nice. He seems to be able to get them to focus from 3 ft to infinity with a working apperture. It looks like he adds the the rear of a different lens to it. Anyone has any idea how to this kind of modification?
I also read somewhere that a lot of the "dreamy" look is caused by different refraction of the different colours in the spectrum.
Can someone make a picture by making a grey-scale image using only one of the colour channels? (so take only the information of the for example red subpixels and convert this to black and white)
These "jieying-usa" modifications look very nice. He seems to be able to get them to focus from 3 ft to infinity with a working apperture. It looks like he adds the the rear of a different lens to it. Anyone has any idea how to this kind of modification?
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kds315
Active member
The modification as shown I don't believe are purely mechanical ones. The register of these lenses are from about zero to some 20mm or so. In no way would it be possible to insert such a salvaged lens barrel between such an X-Ray lens and a camera and reach infinity. I would also assume he has used some negative (Barlow) lens to achieve this. I have done some conversions, I guess I know what I talk about.
If you look at the lens images showing the rear of the lens http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=320581913032 it shows a rear lens element, yet at the same time he talks about stopping down the lens. So either he has taken that X-Ray lens completely apart, split that lens in two halfes and has inserted that aperture of that salvaged lens in between, or he has used a negative lens or lens group for that. A tele extender lens group would serve well for that, but in either case it is neither a f1.0 lens anymore, nor a 55mm focal length.
Re-reading the auction text he even indirectly confirms, that he has used a negative lens/lens group: "After rework image little large than 50mm,..." Little??
If you look at the lens images showing the rear of the lens http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=320581913032 it shows a rear lens element, yet at the same time he talks about stopping down the lens. So either he has taken that X-Ray lens completely apart, split that lens in two halfes and has inserted that aperture of that salvaged lens in between, or he has used a negative lens or lens group for that. A tele extender lens group would serve well for that, but in either case it is neither a f1.0 lens anymore, nor a 55mm focal length.
Re-reading the auction text he even indirectly confirms, that he has used a negative lens/lens group: "After rework image little large than 50mm,..." Little??
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J
jwestra
Guest
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?
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?
photoSmart42
New member
+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.
kds315
Active member
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.
I have done some tests and with some Xray lenses that idea doesn't work, because their register length is too short. So beware...
This is a shot using a direct conversion of a 0.75/50mm Xray lens (no negative lens behind):
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