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CJ
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, June 13, 2005 - 11:47 pm: | 
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Hi All,
I purchased a Yashica J Penta SLR recently, knowing it well may be destined for the parts bin. The shutter fires, but the speeds cannot be changed. Also the shutter curtains show about 1x.5 cm of 'looseness' at the top edge (don't know how else to describe it). Essentially, the cloth doesn't lie flat, like the rest of the cloth.
The the main reason for this post is that the Yashica f/1.4 lens won't fit my Fujica ST605: On attaching it to the ST605, the top markers on the lens don't go to 12 o'clock; they stop at about 10:30 and I'm loathe to try and force it.
Putting the lenses next to each other, the backs look to be exactly the same; both have that aperture lever/pinion, etc. that I've read about...no otber distinguishing marks.
So to any of you with experience with the M42/Contax/Pentax/Praktica kingdom of lenses: Do Yashica lenses not fit Fujica bodies, and vice-versa? I've seen a pic somewhere out there on the Web of a Fujica body with a Mamiya/Sekor lens mounted on it...leading me to think that Fujica never deigned to 'tweak' their M42 form factor into incompatibility. What gives?
/confused
-CJ |
John Farrell
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, June 14, 2005 - 02:48 am: |
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There are 2 slightly different families of M42 lenses. Edixa and the early screw mount Yashicas are in one, and Praktica, Pentax, Fujica etc are in the other. Edixa and similar lenses fit on Prakicas etc with the focus mark, as you note, at 10:30. I have a variant of the Penta J, called the Reflex 35, and it uses semi-automatic lenses, which need to be cocked for each shot. Although these lenses appear to be the same as normal M42 lenses, the spring which closes the diaphragm can not be cocked if the lens is mounted on a Fujica, so the lens is always stopped down to the selected aperture. |
CJ
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, June 14, 2005 - 03:08 am: |
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Interesting...so it looks as though you're saying that yes, I can mount this Yashica lens onto the Fujica, but--
a.) the nature of the beast dictates that the normally 12 o'clock markings will be at 10:30, and--
b.) I'll need to keep the Yashica lens set to M, where I'll need to stop the lens down for making the exposure, after focusing the lens at full aperture?
Thank you for your explanation--have I understood it correctly?
-CJ |
John Farrell
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, June 14, 2005 - 03:12 am: |
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It sounds like your Yashica lens is of the normal fully automatic type - the semi automatic doesn't have M and A settings. If there is no spring cocking lever on the lens, it should work fine on automatic. Give it a try! |
rick oleson
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, June 14, 2005 - 05:47 am: |
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I wasn't aware of the difference in Edixa and Yashica M42 lenses, John! I wonder why they did that........
: ) = |
Glenn Middleton
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, June 14, 2005 - 07:51 am: |
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The original Edixa M42 Thread spec dates from the days of preset lenses.From rough translations of early Pentax patents/specs it appears that the different stop point allowed the linkage in lens/camera to work better or be simpler.Why this would be so I cannot say.I would have thought that it was just a case of makers' individual take on a fitting,until it started to become universal.By that time Pentax was sweeping all before and that spec became the norm.How you fit Praktica into the equation I do not know.
Of course a simple answer might be that some makers just copied the Edixa semi-auto mount configuration and others the Pentax.With a few noted exeptions,mostly in the semi-auto configuration,the specs are interchangeable.
There is a similar story with the very early FED M39 mount. |
rick oleson
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, June 14, 2005 - 02:52 pm: |
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The M42 mount actually came from Praktica, or more precisely the Contax/Pentacon which was pretty intimately related to Praktica by the early 1950s. Even the auto diaphragm interface was in the Pentacon before it got into the Pentax, and it's nearly identical in those two. I can't think of any reason why Edixa, living in Pentacon and Praktica's shadows from its inception, would have wanted to have an oddball variation of the mount.
I suppose it COULD be that the Pentacon folks had a patent on the specific interface and licensed it to Asahi but not to Edixa. They had the original trademark on the Pentax name, and licensed it to Asahi after deciding not to use it themselves (when they changed the camera name from Contax to Pentacon)
: ) = |
Glenn Middleton
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, June 14, 2005 - 07:51 pm: |
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Rick,
Thanks for that information,always wondered where Pentacon sat in scheme of things.Somebody once told me he thought it was because many of the preset lenses for the Edixa were also available for the Exakta and it was all to do with how the actual mounts were attached.Cannot see this is correct as surely they could locate any tapped holes in correct location.
However I have three A.Schacht Ulm preset Em-Travegar lenses,all M42.When you remove the mounts,there are TWO sets of four tapped holes in the end of barrel.Using one set to attach mount gives you the Edixa location of focus datum ie 10.30 on Pentax/Praktica.Using other set locates the datum at 11.58!I have never got round to obtaining an Exakta lens by Schacht to see how the datum lines up on the holes.I use the 11.58 position to use lenses on a F.X 2,but you do have to relocate infinity stop screw as the actual stop is machined into the mount and thus is out of phase with datum.
Glenn |
Glenn Middleton
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, June 15, 2005 - 06:32 am: |
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Rick,
Had another thought on the Edixa/Pentacon relationship.As you state it is puzzling because Edixa was located in Pentacon country,so to speak.Was this small difference a way of getting round any patent/license fees,on the part of Edixa?As the cameras in question are slr the small difference does not really matter,you can still see depth of field info etc.For all intent and purpose the lenses are interchangeable.
Whilst I can see patents being granted on a thread mount that was machined in such a way, that focus datum etc were located at a specific point.I cannot see a grant being given to just the screw thread.Screw threads have been used since the early days to attach lenses to optical equipment.There are similar cases in the engineering world,especially in use of the interrupted thread breech lock.Here the patents cover the angle of the interruption and their number,not the actual thread form. |
Robert
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, June 19, 2005 - 12:28 pm: |
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Going the other way, my SMC Taks won't work in on my Penta J.
They won't open to full aperature or stop down beyond about f5.6, because those old semi-auto lenses were just triggered to stop down in a two-step release sequence.
I've delegated the Yasica to preset lenses, unless I find the original maker's lenses. I guess semi-auto was up to the maker, not standardized like the later M42 auto lenses. |
John Farrell
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, June 20, 2005 - 02:50 am: |
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I have seen a suggestion that the semi-automatic 50mm lens on the Penta J was actually made by Pentax - it is almost identical to the standard lens for the K and S2(H2)cameras of the late 1950s. |
Glenn Middleton
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, June 20, 2005 - 04:43 am: |
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I precis an article in Sept 1963 BJP by Godfrey Crawley on reviewing Yashica J-3.'J-3 used the Edixa Register (lens flange to film-plane distance).Pentax lenses will screw past the 12 oclock position and stop at about 2 oclock.Will not normally hinder focus of lenses with any depth of field at infinity.ie long lenses for Edixa/Yashica will not focus correctly on Pentax.'More significant is this comment'Diaphram tripping pin on J-3 will not work Super Takumars.'Also stated that he thought 50mm f2 Auto -Yashinon made by Pentax.
In AP 24/4/04 in article on early Yashica slr,Ivor Matanle states that 'in 1967 as Wirgin faltered financially and Edixa slr became less of a force,Yashica went over to the Pentax register for TL-Super or TL-Electro cameras.'
So that is the story from two world renowned authors.Why Pentax did not use same 'register'has still not been explained though. |
