The Xpan Mad Project, Summicron adaptor

I put out a post calling for an old removable head rigid 'cron mount

for my latest Xpan lans project. The Chinon was a) a bit too fast for

reliable shooting wide open and b) I had an idea, use my 'cron head in

a mount on the Xpan. This ended up in a forum member very kindly

giving me a very beat up 'cron, thanks Neils.

 

The idea was to fix the 'cron mount on a Hassy flange, recess the lens

and add a helical correction cam at the back. There is just enough

room if a couple of bits are thined a bit and the lens rotates with

the focus mount, no room for the holdy still thingy.

 

The mount was turned down a bit and so was the Hassy flange.<div></div>

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I then soldered the two together, a strong demountable join.<div></div>

And just for fun I pushed the old 'cron head into the mount to see what it look like. Not too bad!<div></div>

Wow, Huw! That looks promising, please keep us posted. What's next? the helical correction cam? How are you going to calibrate that one? Cheers, Lutz

Lutz, and all,

 

I have measured the movement of the Xpan RF roller using a depth micrometer at various distances and have come up with a 'focal length' of 49mm, no reply from Hassy regarding what they think it is, would be nice to know though. The mount I have is for a 51.9mm focal length (funny it's the same as my good one), the helix is for 51.6 though and has a small helix on it's RF face, this will go. Focus movement for 51.6mm from infinity to 1m is 2.807mm and for 49mm 2.525mm, rotation for infinity to 1m 135 degrees, so the cam has 0.752mm slope for 360 degrees. Make this on a mill with a rotary table, Murphys law says I will get it the wrong way round though. Finaly adjust the cam by rotating it until the rangefinder is OK, probably do this at 2m.

I wonder if this would work with the new Voigtlander 40/1.4 Nokton. The Xpan's framelines would be close enough.

Another Steve Grimes in the making.

 

www.skgrimes.com (for those that may not know the company)

The VC 40/1.4 would be a good idea but I think it may be a bit too near the film plane for use on the Xpan. I am getting one so I will let you all know. The framelines for 45mm at 85% will be almost perfect for a 50.

 

The big question is what to call it, Semipanicron? anyone got access to a lens ring engraving machine?

Semi-panic-ron? How about a Huwicron?! :-)

Flange-i-Pan?

Lutz,

 

Pure vanity!

 

Huwge Ego

Trevor,

 

Sweet....

What are we doing, it's Saturday night (9:30pm UK) we should be out pulling birds (or blokes depending on sex/preference) spouse permitting, taking drugs, drinking beer etc. etc.. (Al probably will be later!) I have been out with my Helene had a couple of beers and a Thai dinner, back by 8:30, must be getting old. Or, heaven forbid, sensible.

Huw, I just look stoned/wasted/drunk in those pix. It's all acting! I had a shot glass of Maker's Mark bourbon at the stroke of midnight New Years. I'll have another this coming New Year. When I got my Coast Guard issued boat captains' license 7 or 8 years back I had to pass a drug test, and I'm subject to random drug testing. I'm drug free!

Never taken random drugs.

But have pulled birds.

We (the UK) don't even have drink captaining (drink driving for boats) here.

I would love to use a finneycron!

or a funneycron...

Well it's Sunday morning here in Amsterdam, birds pulled and drink and drugs taken, so now I can talk about lenses without sounding too much like a sad lemon. Huw, I'm impressed! Not that I really understand your procedure or measurements, but it sure sounds like you do.

 

I'm assuming from your working methods that this is a lens adaption and not an adapter - something that must be individually done for each lens. Is it, or would it be theoretically possible to make an adapter, or are the film - flange distances too similar between the M and the Xpan?

 

How about Fujicron or Panacron?

It's more of a SOMKY for the Xpan but not close up. The correction cam would be diferent for each focal length group of the 'cron. I am lucky to have this spare mount for a removable head 'cron and can use my good glass on it. The Xpan flange is about 6mm further forward than the M, hence the problem of an adaptor. It would be interesting to survey pnet rigid 'crons to see the distribution of focal lengths. The true focal length is scratched on the lens near the screw thread.

Huw: DR 51.9mm.

 

Cheers.

"19" scratched inside and engraved on the barrel, next to the "m"/"feet" engraving - I suppose that means 50 + 1.9 mm = 51.9mm (for a 245**** rigid 'cron). Cheers.

Huw, I understand that the <i>helical correction cam at the back</i> is going to correct the RF issue, but since <i>The Xpan flange is about 6mm further forward than the M, hence the problem of an adaptor</i> - how would you acchieve infinity focussing?<br> <i>The mount was turned down a bit and so was the Hassy flange.</i> Can you take off that much? Or am I missing something?

Hi Lutz, good point.

 

Isn't this the same problem, though reduced, of putting M lenses on SLR's with their longer film plane to flange distances? I would have thought the only way to acheive infinity focus with M lenses on anything with a longer FP to F distance would be to somehow mount the M lens inside the flange, nearer to the plane of the film.