rangefinder adjustment on a film M - how to check focus?

[menos]

I do adjust my R-D1 and M8.2 by myself.
They are spot on and work great with fast lenses - especially the M8.2, which also is spot on with the longest M lenses.

I too have a M6 and M7, which work ok for film.

I have captured a f1 lens, which works spot on with my M8.2.
Of course, I die after using the f1 lens on the film bodies.
I am now looking after some tips of the mechanics here, how do you check focussing precision with the film bodies, other than shooting, developing, checking.

I have seen a specially tweaked IIIf body at one of the second hand lens dealers around, he uses with a loupe, to check focus alignment - didn't inspect the fixture though.
So - how do you do it - a special screen with loupe over the film rails while focussing?
If so, which materials, which loupes do you prefer?

[Ezzie]

A piece of semi-transparent tape across the film gate, mark a cross on the side most in plane with the emulsion side of your film. With camera back open towards a window or light source, set lens to infinity (or preferably focus first on a subject at infinity - in case lens focuses past infinity) and use your D300 with 300mm lens, also set to infinity, pointed down your M-lens (as close as possible). If cross is in focus you're OK. If not, try to adjust focus on M-lens until OK. If you can't get perfect focus, you might be able to adjust RF cam with copper tape. If adjusting focus closer to home works, lens can be shimmed.

Look up on lens collimation.

[menos]

Thanks Ezzie for the tip - looks like a major project for a weekend!

So film body alignment has to wait a bit - maybe I get lucky and see, the bodies work bliss on the new lens after I catch up with developing the film, that waits in the fridge form the last 6 months (I am one lazy person regarding developing, I suppose)!

I had a bit of an easier theory in mind:
I imagined, I could fix a screen to the film rails, where the lens projects any image from focussing at all times, so I can directly compare the image being sharply focussed or not, when the range finder signals good focus on the subject !?

I had the impression, this was, what the nice old gentleman did with his hacked IIIf body ?

I am fantasizing?

[mooge]

uh, that's lens collimation... maybe the RF's just off.

I assume the body and lens are collimated/aligned alright (usually a safe bet...) and then...
1. set the lens to infinity.
2. check the RF agrees, if not, adjust.
3. set the camera on a tripod, remove the back.
4. focus on something ~1m away through RF
5. set a focusing screen (I got one from a Canon F-1) on the film rails, use a loupe or something to check to see if it's in focus.

That seemed to work for me. hope it helps... ish...

[bwcolor]

Where do we find information on adjusting focus on M lenses and or adjusting the rangefinder on Leica rangefinders? Don't have a clue as you can tell by the general nature of the question.

[mooge]

pow!



a few notes: That's the infinity adjustment, not the 10m adjustment.

Everything can be accessed without disassembly!

all screws are at an angle, be careful not to strip them! use as big of a screw bit as you can get away with- it will 'grab' the screw better and is less likely to destroy the screw head.

Be as gentle as you can- you don't want to break this stuff.

for the 1m adjustment, put a focusing screen (or a bit of tape) on the film rails. Look through the RF, focus on something close to 1m. check the image on the focusing screen with a loupe. If it's not in focus, change the 1m adjustment.

For vertical alignment, check against lettering, if you have posters on your wall. Align the RF... then move it out a touch. You should easily be able to see if the RF is too high or too low. a little light works well too- my radio has a little LED that shines when it's off.

links for more professional info:
http://www.pentax-manuals.com/manual...c%20repair.pdf
http://leica.nemeng.com/034b.shtml

good luck!

[Pirate]

I adjusted the focus on my M4 with just the eccentric cam and it all came into focus at infinity and the 1m mark. I measured out an exact 1m mark and used a film box, then used the moon for the infinity. a few tweaks and it was good to go.

[bwcolor]

Thanks...That is very instructive.

When a lens gets adjusted for back, or front focusing, what is being adjusted and how does that work?

[mooge]

back or front focusing would probably mean that the optical stuff is not aligned with the focusing stuff, so you'd have to put shims between the optical module and the focusing module to get the lens calibrated right. to get the distance scale to agree with the RF and the actual focus of the lens.

something like that.

cheers.

[Pirate]

See that screw circled in Red? That's an oblong cam. You can't unscrew it, it will keep going 'round and 'round. That's the first and simplest way I have found to check the focus.

Pick a place to adjust the camera like across a table or counter top. Use an edge at one end, this is where you will set the camera. Make sure you can hold the camera at the edge and still look through the viewfinder and even adjust the focus without moving the camera.

Use a lens with a 1 meter minimum focus point. Measure out an exact 1 meter = 39.3 inches, and mark that across the table/counter top. I use masking tape to make my marks on.

Find something square like a Pop-Tart box, preferably with a flat face and big writing that you can see easily - like opposite colours on top of each other (black and white work great). I've used the Pop-Tarts and even a box of Film. With the camera at the edge, you want to be able to see your target at the 1 meter mark clearly in the center of the viewfinder.

Bring the lens down all the way to 1 meter, check to see how far out of focus it is, take the lens off, use a screw driver to adjust the oblong cam just a little at a time until you get the 1 meter mark in focus. This may take a while.

Once you complete that, you will check the Infinity focus next. The moon on a clear night works the best. I had to wait a week to get a couple nights with a clear moon. Repeat process.

Tips: Using a small L-shaped screw driver works best. Don't press too hard as you don't want to bend any of the armature assembly, and it's tricky to get a screw driver to work the first time, but once you get it, you're good. Take your time. If you're going to do it yourself, you can't afford to rush it or you'll be paying someone else a lot more than you would have in the first place. It's a doable job, just relax with it.

This link may help a little:

http://nemeng.com/leica/034b.shtml

Good luck

[Frankie]

I also use a lens with 1m minimum focus as a tool...the lens barrel markings are too ambiguous. However, I verify that by placing a thin Nikon FM focusing screen on the film rails and observe with a 12X loupe.

I set out a "bench" on a table by marking on masking tape a distance of 97.2cm...the M flange to image plane depth is 28mm (27.95mm). On the camera side, I tape a short piece of wood molding as a stop for the camera body front. On the target side, I use a bookend with a newspaper square taped to it.

Checking 1m RF accuracy this way is positive. For my ZI and R-D1, I also use a Nikon DG2 viewfinder magnifier (2X) with the same thread as the eyepiece. My desk [bench] is over a window which makes it easy to also check infinity at a distant scene.

The lens I use is a 90mm/f4 Rokkor M, which has a hyper-focal distance of 68m wide open. I won't have to wait for the moon to appear, and even if there were any error, you will never know it.

If the 1m focus is off, move the bookend back and forth a little to determine how much. Don't worry if the error is under 2cm...even a 40mm/f.14 lens at 0.7m closest focal distance will have a fore/aft DoF of 2.5cm anyway.

[M4-I-Love]

Question for Mr. dragunov,

You have taken the RF unit off the camera? I assume you have to unscrew the bolt that hold the eccentric cam? The roller bearing and the arm with the limit stopper also comes off? My question is there is a spring with the roller bearing and arm. Will things fly off if I remove the machine bolt completely? Is it easy to put back?

Reason is I stripped to bolt slightly while doing adjustment and I'm trying to find a replacement.

[mooge]

four screws need to be removed- the two screws under the VF, the screw with the brass eccentric on it, and the screw holding the RF cam on it.

no springs will fly out at you when you do this.

this might help:



you DO NOT need to take off the screw 'holding' onto the RF roller! That's the infinity RF adjustment, and will just turn in circles.

hope this helped...

[mooge]

yeah, my instructions for the first pic are vague. to get all the RF arm stuff out, you just need to remove the screw on the pivot.

and you'll need to re-align the RF once you put it back.

[M4-I-Love]

Thank you for the fast reply with the very clear pictures. Very helpful indeed. For the moment I would just like to remove the roller arm pivot screw. I stripped the pivot screw slightly. I still works, but its no longer pretty . (Actually my pivot screw looks like the one in your picture you posted. Mangled slightly. )

There is a spring which pushes the arm against the lens cam. So I assume this spring is inside the rangefinder i.e. above the top plate?

Once the arm is removed, how do you get it back to the old position? Is there some kind of notch or groove that will mate it to the upper part?

[mooge]

yes, the spring is inside the RF, safe and sound. it's not going to fall off.

yeah, the arm has a slot that fits on the axle. You'll see.

try using a bigger screwdriver- large diameter grip, and a head that will fit very snugly into the screw. that will really grip the screw head well and make it easier for you.

good luck!

[M4-I-Love]

Thanks for the reply. Gives me confidence to unscrew it all the way. The only thing now is if I can source a replacement screw. If I can't find a replacement, I'll just let it be.

Anybody know if there's a similar screw from Tamiya or Kyosho that will do the job?

[maddoc]

To the OP ... I had sent my Noctilux and M4-P to Leica to get both calibrated and since then never a focus problem with this combination due to adjustment problems. From my experience with aligning of optical components under laboratory conditions I would not want to try it with a Leica and or Noctilux ...

[mooge]

if your screw is just ugly like mine, leave it be. it still works fine...

[M4-I-Love]

What is OP?

[maddoc]

Originally Posted by M4-I-Love

What is OP?

OP = original post(er)

[M4-I-Love]

Ok, thanks. Myself, I bought my camera from ebay. Camera is probably second or third hand.

So I don't think I got any kind of warranty from Leica. Sending the camera back to Leica will probably cost me maybe 2/3 of what I paid for my M body.

[Frankie]

Originally Posted by M4-I-Love

Thanks for the reply. Gives me confidence to unscrew it all the way. The only thing now is if I can source a replacement screw. If I can't find a replacement, I'll just let it be.

Anybody know if there's a similar screw from Tamiya or Kyosho that will do the job?

Try http://www.mcmaster.com; my trusty supplier for decades. Screw head type, thread size [likely metric] material type would be your selection criteria.

I have an exploded drawing for the entire mechanism [from a US Army KS-15 service manual] which labels the screw as an articulate "machine screw". I would post that drawing to share if I have a handy .pdf to .jpeg converter. Or I could email that drawing...

[M4-I-Love]

Yup. I think I have a pdf of that service manual too. No mention of the size and length . I will check out the website you mentioned. Thank you.

[Frankie]

Originally Posted by M4-I-Love

Yup. I think I have a pdf of that service manual too. No mention of the size and length . I will check out the website you mentioned. Thank you.

That machine screw can be unscrewed and removed. If you have a caliper...even a digital one is cheap, ~$50...you can measure the head size, total length, thread length, thread size and pitch...then go through the McMaster catalog.

Searching on-line is easy these days [I used to go through telephone book size hardcopy to look for machine parts!]

Try:
http://www.mcmaster.com/#machine-screws/=87ajcg