Lens Mod. and Framelines

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I'm thinking about buying a bugeyed Summaron. I'd like to take the eyes off and have the mount modified to bring up the 35 lines in my M2/4/6. The question is: If I have this done, can I have it restored to original M3 spec 50 lines) in the future for resale?

Is material removed from the mount or added for the frameline actuator?

I suppose I could get a whole new mount, so that's not the answer that I'm looking for.

-- chris chen (chrischen@msn.com), March 21, 2002

Answers

You have to remove material and it will be very difficult to replace it. I did it 1 time with a screw-bayonet adapter but I would never do it with a lens.

-- Michael Bohn (michael.bohn@skynet.be), March 21, 2002.

Chris. This doesn't make any sense to me. First of all, they made M2 versions of the 35/3.5 and 35/2.8 (you don't say which) Summarons, which you can buy at similar prices. These lenses bring up the 35 mm frame on all Leica M cameras that have that frame. Why would you want to remove the eyes and then put them back.

Secondly, it seems to me that the 35/3.5 RF lens is calibrated for use with a lens over the RF window, so if you just removed the "eyes", the lens would not focus properly. I may be wrong about this, but I think it is the case. As a rule, Leica products are best left for their intended uses, unless you are an expert like Tom Abrahmsson.

-- Eliot (erosen@lij.edu), March 21, 2002.


Eliot,

Another 2.8 is not avail. at the moment, esp. at the price of this mint one (cheap). It's an 8-element too.

I guess I was just curious to know what is possible and how the mod. is done and if it is reversible for resale. Make sense?

BTW, what institution/where is lij?

-- chris chen (chrischen@msn.com), March 21, 2002.


Chris,

cheap ? cheaper than a new VC 35/2.5 ? I have the VC (pancake), and also the 2 summaron's (2.8 and 3.5) and the the VC is definately the best. Not so good as the summicron, but this is another story.

Michael

-- Michael Bohn (michael.bohn@skynet.be), March 21, 2002.


Chris. Now I'm more confused. There is no 8-element 35/2.8 Summaron. [The first version 35/2 Summicron was 8-elements.] There was only one optical version of the 35/2.8, which was 6-elements. To my knowledge the eyes from the M3 version of the 35/2.8 lens were not removable. [Or at least they weren't supposed to be removed.] Only the 35/3.5 RF Summicron had removable eyes (fastened by two screws), so I thought you must be referring to the 35/3.5 RF.

In general, if you are concerned about resale value, it is not a good idea to make modifications to Leica lenses or cameras.

-- Eliot (erosen@lij.edu), March 21, 2002.



I guess I stand corrected on the 2.8 being six rather than 8 elements, but haven't done any research on it, yet.

The chrome 35 mm, 1:2.8 Summaron I looked at had two mounting screws which holds on the eyes; removing these would be a trivial operation. However, I do remember a previous thread regarding focusing w/o eyes; I'll have to reread that one as I still don't fully understand the function of the rangefinder lens. My DR works with and w/o the eyes, and it too has this second lens.

I wanted to try the 2.8 vs. my 2.0 to see if has similar great performance, but with the lingering doubt, I will pass on this one. It is the price which has tempted me. BTW, I have an M3 too, if that explains myself further.

And, I did have a BM 35, 1:3.5 once. Another case of sellers regret.

The original question tried to deal with the options available, as I never had a lens modified before.

-- chris chen (chrischen@msn.com), March 21, 2002.


I'll give you a direct answer from my own experience. Yes, you can file a bit of material off of the frame-selector actuator on the lens mount, take off the eyes, and you'll have a standard 35mm that works fine in all respects. I've done this myself with a 35/2.8 summaron. Filing is easy since the material (at least on this particular lens) is brass. You'll want to cover as much of the rest of the mount with masking tape first, to keep metal filings away from vulnerable parts, and blow extraneous material away before removing this tape. Getting the mount restored to its original configuration is another matter, and would necessitate replacing the entire rear mount. But why would you want to do this, other than using the lens on an M-3? I say if the lens is going for a good price - go for it!

-- John Layton (john.layton@valley.net), March 21, 2002.

The front element of your lens comes off, too, but that doesn't mean you can use the lens without it. The RF cam on the goggled lens is ground to be used with the goggles--remove them and the lens will no longer actuate the focusing mechanism properly. The DR Summicron works with or without goggles because it was designed to do so; the 35mm RF lenses are a totally different case, and not comparable.

-- Michael Darnton (mdarnton@hotmail.com), March 21, 2002.

I must take exception to Michael Darnton's last post. If I take ten different M-lenses, regardless of configuration or focal length, and set each at ten feet, the cameras focus-cam will be in the exact same position for each lens. In other words, distance is a constant, and is measured by the camera, not the lens in question. Michaels post implies that if I set the bug-eyed lens at ten feet, and then took the eyes off, the focus would change. How could this be? The focus scale would read ten feet. I could measure with a ruler to the filmplane and get ten feet. Why would this chage by taking off the eyes? TEN FEET IS TEN FEET!

-- John Layton (john.layton@valley.net), March 21, 2002.

John. I believe you are wrong and Michael is correct. Everything you say is right except that if you focussed on an object at ten feet with the eyes on and (correct focus) then removed the eyes and left the lens set at ten feet, the image in the RF patch would no longer be superimposed. Stated in other terms, when the focussing ring is twisetd to superimpose the image with the eyes off, the focussing scale would indicate a different (wrong) distance. And even though the A magnifying or demagnifying lens over the RF window affects whether or not the image is properly superimposed when the lens is focussed to the correct distance. Thus, I believe the lens coupling cam would also have to be adjusted if one were to use the lens with the eyes off. Clearly, Leica did not intend the lens to be used this way. Otherwise, they would have made a lens with a slide off finder, like the 50/2.0 DR.

Incidentally, you can't use the 50/2.0 DR finder with the lens set at 1 M or longer distances. The built-in interlock system prevents you from doing this. But if the DR finder were to be used at > 1 m, it would not give accurate focus either.

-- Eliot (erosen@lij.edu), March 21, 2002.



These are the types of "answers" I was looking for to set the record straight. I've read a lot of theories, but have yet to find someone who actually tested this "problem". Regardless of framelines - one could go aux. - is the focus REALLY involved? I NEED a lens to focus properly.

As far as the DR is concerned, I have one. But, when in close range w/eyes, the focusing helical still seems linear, i.e. angle of turn on the focus ring produces the same relative lens extension (?). I didn't measure it, so I guess I'm asking for more quality info than I'm willing to provide, sorry.

-- chris chen (chrischen@msn.com), March 21, 2002.


Since it's already established that I'm right, I won't go into that. :-)

The peculiarity of both the 35mm and 135mm RF lenses is that in building in the viewfinder magnification, to fit the 135mm view in the 90mm frame or reduction, to fit the 35mm view into the 50mm frame, the geometry of the RF is disturbed, and this must be compensated for by machining the RF cam on the back of the lens differently.

Of course removing the goggles changes nothing about the distance setting and focus of the lens, that should be obvious--but it does change the way the RF interacts with the outside world, and that's where the problem lies.

-- Michael Darnton (mdarnton@hotmail.com), March 21, 2002.


1) The bugeyes do not affect the focus of the lens itself using the focusing scale - set it at infinity or 10 feet on the scale, and (assuming the lens is actually calibrated correctly) it will be in focus at infinity or 10 feet. The scale is based on the position of the glass and focusing helix relative to the mount and film plane and has no direct relationship to the rangefinder (see the V'lander 15mm and 25mm, e.g.)

2) Purpose of the 2nd bug-eye lens. A rangefinder shows you a double image, which you align for focusing. If you only had a bug-eye over the main viewfinder window, the 2nd image coming from the RF patch would be higher-magnification than the direct-view part of the image (i.e. in the RF patch you would see a large and small version of your subject's eye, for example). There is no way to align two images of different magnifications, so both images have to be reduced by their own goggle.

3) The focusing cams of all bug-eye lenses are calibrated for use with the bug-eyes in place.

The lenses will not focus correctly with the bug-eyes removed.

The whole Leica RF system of levers, prism, cams etc. is based on geometry - measuring angles compared to the 'set' distance between the two camera windows. Change the 'effective base length' by putting 'minifying or 'magnifying' windows over the FRONT of the system, and the geometry changes - so the 35 and 135 bug-eye lenses have special camming that works with (and only with) this modified geometry.

The 50 DR has a cam with a 'step' in it, and an interlock that prevents using the 'eyes' in the normal range, and prevents using the normal range with the eyes in place, for just this reason. In effect it contains BOTH normal and 'special' cams in one unit.

4) The 35 'bug-eye' has MORE metal on the flange that selects the framing than a regular 35 does, so you could machine away the small extra amount so that it no longer moves the frame to 50mm and would give you the 'default' 35mm frames of the M2 and later finders. It would be very difficult to 'restore' this later in any form that retains the physical integrity of one piece of metal - you'd have to braise on replacement metal and then machine it back to the correct shape and length - a complete kludge! The costs involved in the whole process would make the lens more expensive than a 35 f/1.4 ASPH!!

5) The acid test, of course, would be to take the lens you're considering, remove those two simple screws - if the seller allows - and shoot a roll using your camera and no eyes. Tell us what happens.

-- Andy Piper (apidens@denver.infi.net), March 21, 2002.


Mike and I posted the last two responses simultaneously - he just did a more efficient job of expressing the same thing....=8^o

-- Andy Piper (apidens@denver.infi.net), March 21, 2002.

This issue is really starting to twist my brain! Chris - put that file down - right now! It was quite some time ago that I modified my own 35mm/2.8, and I sold it ( ! ) not long after. But the results looked good - maybe I was being saved by DOF? The easiest test would be to see if the RF patch lines up at infinity with the eyes on and off. I could have sworn this was so, but then again, I like to work in close. I was under the impression that the bugeyes change magnification only, while RF focus remaines unaffected. I could see where physically placing optics in front of the windows could change the effective geometry, and that maybe the lens cam would need consequent tweaking. Boy, is this ever going to keep me awake!

-- John Layton (john.layton@valley.net), March 21, 2002.


Yes, I understand the part about the difficulty trying to align a double image of the same object when they're different sizes; I understand how the eyes work in that way. Although aligning vertical lines contained in objects would be easier. I wasn't asking about removing one eye, but both.

I also understand about triangulation; did some in high school physics. The physical distance between the two rangefinder "eyes" do not change whether one puts on a magnifier or the opposite. Although, I understand it makes actual focusing easier or harder, respectively. I still don't see why taking the eyes off, again irrespective of frame lines, would not work, as the movement in the roller in the body would stay the same for any given distance; "TEN FEET IS TEN FEET", and infinity would still line up in the viewfinder when the lens is at infinity lock. I was just too afraid to ask until now because it was always an accepted piece of knowledge. Pardon my ignorance, and THANKS for your effort Mike and Andy.

-- chris chen (chrischen@msn.com), March 21, 2002.


I sould have added: The magnification of BOTH eyes in the goggles MUST be the SAME. So, removing both should have no effect (?).

Please see previous thread regarding focusing cams one lenses. As Andy noted: they SEEM fairly planar, and focusing transcription to the body is done mainly be the lens helical.

Help Martin Tai, give an equation that solves MY problem. ;*) (it's a wink not an oriental racial slur; I'm an ABC: American B

-- chris chen (chrischen@msn.com), March 21, 2002.


Gentlemen:

If I may call a time-out and set the record straight.

I have in my hands an M3 sn#863xxx, with a 353.5 RF Summaron sn#1565xxx mounted on it. The "goggles" are held on with one thumb screw on the top which allows the "goggles" to slide off. When you do this, you must depress a ball allowing the lens to focus. When I look at a bookcase with the goggles on, the lens shows 8 feet, and with the goggles off, it shows 5 feet. When I look towards the lake, an object at 55 feet shows 30 feet with the goggles off, and infinity is correct either way.

Why? Because that is the way the engineers at Leitz engineered it.

-- Mark A. Johnson (logical1@catholic.org), March 21, 2002.


Thank you! I wonder why Leitz would go to all the trouble to do the thumbscrew and ball detent on a lens that wasn't meant to be taken apart to be used? I would have welded it all together and called it a day. Any ideas?

-- Michael Darnton (mdarnton@hotmail.com), March 21, 2002.

First time I've heard of one with that arrangement.

One option here would be to see if Reinhold Mueller in Canada wants to buy the viewer and return the rest of the lens properly calibrated for M2 focusing. He's the fellow who scavenges 35mm eyes to convert the 21mm f/3.4 SA to work with the 28mm frameline.

-- Bob Fleischman (RFXMAIL@prodigy.net), March 21, 2002.


Michael:

With the finder off, the lens is much easier to throw at the terrorists. It feels more like a baseball and rolls off the hand better. They were ahead of their time in designing unobtrusive weapons.

Actually, they probably used the same lens case for both versions of the lens. This was an easy way to attach it, as they had already mounted goggles on the DR Summicron. The top attachment area is the same on both lenses. The 35 Summaron has an index hole for the thumbscrew. I can put the goggles from the DR on the Summaron and vice versa. The focus is off, but the physical mounts are similar enough.

Quien sabe?

-- Mark A. Johnson (logical1@catholic.org), March 21, 2002.


The real solution here is to actually BUY an M3 to use with the Summaron AND the eyes...I hear they're quite a pleasure to use. But all kidding aside, I've never thought modifications of this kind benefitted the owner (at least considering resale value) and the thought of files being taken to these great lenses, eyes or no eyes, makes me cringe a little. Just my .02...

-- Carlin (carlinm@abac.com), March 22, 2002.

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