M3 rangefinder calibration (DIY)

[Puggie]

I've bought an M3 and if I'm honest it could do with a service, but that isn't going to happen for a couple of months due to finances. The shutter speeds seem reasonable but I reckon the rangefinder may be a bit out. So I've found the PDF on how to adjust the 10m and 1m points, but do I go on the lens markings or what?

I can see a nice crisp antenna about 75m away and I'm using this as my 'infinity' because its a very think silhouette on the sky so easy to focus on. The other adjustments are for 10m and 1m distances, do I just bring these up on the lens distance scale and then remove the lens and tweek the adjustments until they are in agreement with the rangefinder? The lens is a Voigtlander Nokton 50mm f1.5 on the voigtlander type II M>LTM bayonet adapter (if that makes any difference).

Grateful of any advice,

Thanks

 

[Shutterspark]

The lens markings aren't all that accurate most of the time. You're better off using a bit of ground glass on the film plane.

You might want to test the camera before adjusting the close up distances, since the infinity adjustment is the one that is usually out.

 

[Sparrow]

... yep, I'd use it first too ... and see if it's OK in the real world

 

[Puggie]

I know the lens markings on the canon 17-40L i borrowed were massively out but I assumed this would be a bit closer to the mark.

Thanks for the advice, I may as well be worth poking a bit of cheap B&W through first and checking the 1m on the rangefinder and on the lens to see with is more accurate compare to a measured distance.

 

[Sparrow]

Once one starts looking for faults it's easy to find them ... personally I've not checked alignment at infinity in 40-odd years using these things

 

[rxmd]

I know the lens markings on the canon 17-40L i borrowed were massively out but I assumed this would be a bit closer to the mark.

Thanks for the advice, I may as well be worth poking a bit of cheap B&W through first and checking the 1m on the rangefinder and on the lens to see with is more accurate compare to a measured distance.

I wouldn't start messing around with it unless you know it's wrong. The M3 rangefinder mechanism is pretty rugged. Rather spend that B&W roll for shooting something more meaningful than focus targets and only start worrying about RF alignment if you find out it's seriously off.

 

[Benjamin Marks]

Also: I would use something CONSIDERABLY further away than 75 m for infinity. Try two miles.

Ben

 

[Puggie]

right... poked a roll of Adox CHS25 and shot a dozen frames over lunch, will chop the half roll out and soup it after work.

 

[SolaresLarrave]

Usually, the RF gets out of alignment in only the vertical or the horizontal line, not in both. Your M3 may have a misaligned RF but you still can focus and shoot very sharp images. I had that problem with one of my M6TTL bodies and with my Nikon S2. As long as I was able to line up the vertical lines (horizontal was a bit off) my shots were as sharp as the proverbial pin.

In any case, wait some time, use the camera, see if your photos suffer from this problem and have it repaired by a technician. It's a good tool, you don't want to wreck it. Take care!

 

[rxmd]

right... poked a roll of Adox CHS25 and shot a dozen frames over lunch, will chop the half roll out and soup it after work.

You use CHS25 for this kind of experiment? 😱

 

[Puggie]

You use CHS25 for this kind of experiment? 😱

What I had to hand, Its about 3 years OOD so it really should have been used by now anyway! There is a real lack of half decent cheap B&W film in the UK. If anyone knows where I can get a 100ft roll of some cheap and reasonable B&W film I'm all ears 😉

 

[Jockos]

What I had to hand, Its about 3 years OOD so it really should have been used by now anyway! There is a real lack of half decent cheap B&W film in the UK. If anyone knows where I can get a 100ft roll of some cheap and reasonable B&W film I'm all ears 😉

The Kentmere series is from England (Ilford), decent and very very economical. If you cannot find it in GB, try GeneralPhoto in Germany.

Would you like me to post a picture of my adjustment tool? I made one for the M3 myself by hand in aluminum a while back, just let me know!

 

[Puggie]

Love to see a pic of your adjustment tool, I'm assuming I need a good cranked flat blade screwdriver.

Well it looks like the rangefinder is out by about 10cm at 1m, but looks ok at infinity (I'll do a shot of the spinaker tower on my way home which is about 5 miles away to check that). I have found there is a light leak though as I'm getting dark bands between the sprocket holes and the 1000th setting the second curtain is catching the first so I'm only getting about 1/3 of an image.

thoughts?

 

[Sparrow]

It's beginning to sound like a job for someone who knows what they're doing, do you think?

 

[Jockos]

^ click for larger image.


She aint pretty, but works very well. It's a piece of 1mm thick aluminum, cut to a rough L shape. I found that it's easier to use if the holding part continues a little behind the "foot".
The "foot" end is filed to roughly one third the thickness, it's important that you don't file it to a sharp V-shaped edge, but rather like this: \_/, otherwise you may wear out the adjustment screw, and risk using to much pressure to keep the tool in the slit.
Be sure to not apply any excessive force upwards.

This can only be used for infinity adjustment, so unfortunately I don't think it will solve your problem 🙁

 

[rolfe]

What I had to hand, Its about 3 years OOD so it really should have been used by now anyway! There is a real lack of half decent cheap B&W film in the UK. If anyone knows where I can get a 100ft roll of some cheap and reasonable B&W film I'm all ears 😉

Check out:

http://www.macodirect.de

and look at the price of APX100.

Also, I'm not sure if the ORWO motion picture stocks are easily available there, but in the U.S. they are both cheap and available.

 

[Shutterspark]

I just used a flat screwdriver bit.

 

[Puggie]

It's beginning to sound like a job for someone who knows what they're doing, do you think?

Well its starting to look like a number of seperate jobs IMHO:

rangefinder tweeking, if my shots prove it needs it.

second shutter curtain closing too fast, surely that is just a tension tweek and measure the curtain speed, if anyone knows the curtain speed I'm listening but if not I'll slow it to the speed of the first

light leak, its an old camera, I kinda expected the light seals would need attention, my Pentax MX, and 67 both needed them replacing, it wasn't a big job.

I will get someone like malcom taylor to work their magic on this at some point but I'd rather actually use the thing for the couple of months if possible rather than sit it on a shelf waiting to find the cash for someone else to overhaul it. These issues strike me as small calibration tweeks not major faults.

its a mechanical camera not the Mir space station.

Check out:

http://www.macodirect.de

and look at the price of APX100.

Also, I'm not sure if the ORWO motion picture stocks are easily available there, but in the U.S. they are both cheap and available.

blimey, the kentmere and rollei is going to be worth a look at that price thanks.

 

[rxmd]

its a mechanical camera not the Mir space station.

No offense meant, but most people ruin the first cameras they start working on - best start with a Zorki rather than an M3.

Well its starting to look like a number of seperate jobs IMHO:

rangefinder tweeking, if my shots prove it needs it.

second shutter curtain closing too fast, surely that is just a tension tweek and measure the curtain speed, if anyone knows the curtain speed I'm listening but if not I'll slow it to the speed of the first

light leak, its an old camera, I kinda expected the light seals would need attention, my Pentax MX, and 67 both needed them replacing, it wasn't a big job.

I will get someone like malcom taylor to work their magic on this at some point but I'd rather actually use the thing for the couple of months if possible rather than sit it on a shelf waiting to find the cash for someone else to overhaul it. These issues strike me as small calibration tweeks not major faults.

If you start working on this yourself, just remember:
* re/the shutter capping issue: Leicas are finicky with over-tensioning the shutter; you will probably need less than 1/4 or 1/3 turn of the tensioning screw.
* re/light seals: there are a number of places where light can creep in - through the back door, around the shutter curtain, from the top - so I'd check where it's coming from. This includes test shooting a roll of colour film to check whether the light is coming from the front or the back, you don't see that with B&W film. There are some seals that are tricky to replace, such as the ones in the slit where the curtain runs (you can't take just any material).
* re/adjusting the 10m and 1m points: it helps to have a known good lens and adapter and some way to check accurate focus on a ground glass with a strong loupe. You obviously need a target exactly 10m and 1m away (or an adjustment stand with the respective optics). For 1m you can shine a laser pointer through the back of the RF window and adjust until you get the points to align (of course for 10m you can do the same if your laser pointer is powerful enough and you have enough free space). And 75m is not far away enough for infinity focus, 5 miles would be OK, but the easiest is to use the moon or a star.

 

[funkydog]

Even if you currently consider this M3 as your one and only forever camera, please - for the benefit of future users - either spend the money to fix it or sell to fund one in working condition.

In the past, I've bought a M2 and M4-2 off Ebay touted as "CLA'd". Turns out the self CLA involved crude adjustment of the rf roller. The screw threads were damaged by someone going in at an angle with a non specialized tool.