I have been after this set of extension tubes for years, a set of Ken Corfield's Periflex extension tubes, M39 Leica thread. I bought the set on Ebay UK, I hope it is the full set, there was a separate 10m single tube as an extra I believe. Unlike the Leica, the Periflex worked fine with extension tubes, the reflex periscope worked OK, if a bit dim, or you could used the accessory focus finder screen. Stephen.
The sizes were 52mm, 34mm, 26mm, and 18mm. This gives reductions of 1:1, 2:3, 1:2, and 1:3. There was also a separate 10mm tube available for a 1:4 reduction, not sure if it is with the purchased set as yet. The only other missing accessory I am still after, is the microscope adaptor, which used a glass screen for focusing, the same method as the Periflex focus checker. Stephen.
Last Edit: Dec 15, 2012 20:04:08 GMT -5 by Stephen
Having bought this set for £16, I was very surprised to see a seller on ebay selling individual Periflex tubes for the grand total of £80, the price of the Ken Corfield equipment sometimes goes through the roof these days. I have got a Corfield Isco wide angle coming, but it is Pentax M42 fit, (they supplied both fits, plus Exakta), but it will work with an adaptor on the Periflex. Stephen.
The Extension set as arrived, full set in perfect condition, including the Corfield Perifex name plates in recesses in each tube. All Leica thread fit of course.
But there is a mystery, there is a fifth tube, which is Leica screw at the bottom, and M42 at the top, at first glance an M42 lens adaptor to fit Leica, or Periflex.
But the thickness is all wrong, too thick to focus to infinity, so what was the short tube intended for? It is not marked as made by Periflex, but is close in finish. By why would you want to mount an M42 lens on a Leica camera with a balance of 10mm extension.
It does allow an M42 lens to work on the Periflex with focusing, but only close ups, there exist other adaptors which allows full range focusing with Periflex, they can take most lens via an adaptor.
The Periflex has precisely the same register as Leica, 28.80mm to 1/10th thou tolerance, or better, Ken Corfield was proud of the standard they achieved.
M42 has a register of 45.64mm to the film plane, Leica is 28.80mm, so a true infinity adaptor is 16.84 mm thick, and the shot shows my own adaptor from Leica to M42, which is 16.64.
The tube that came with the Periflex Extension set is exactly 23 mm long, too long for a Paxette screw, (Leica pitch thread with 44mm register) to M42 converter , which would be a thinner converter at only 1.64 mm thick.
Adding the 23mm to the Leica register of 28.80mm gives a total of 51.80mm for this odd extension tube. There is no listed camera register of 51.80mm........
With this figure of 51.80mm less the M42 register of 45.64, then the extension is 6.16mm..... a very strange figure!
I can only suspect it was a general tube to go with others to give the chance of putting an M42 on a set of Leica fit tubes.
Last Edit: Dec 21, 2012 13:04:58 GMT -5 by Stephen
Looks like the mystery adaptor is not be Periflex product, as the 10mm extra tube was fully engraved, and all other Corfield made accessories have markings. So a strange length Leica to M42 adaptor..... for what purpose? Maybe Nova flex made it to connect M42 bellows to a Leica, a real puzzle item.