This actually works

[colyn]

A friend of mine burned a hole in his IIIc shutter curtain and talked me into replacing the curtain....while he looked over my shoulder.. 🙄

Once ready to adjust the speeds I thought I'd give it a try so I drug out an old Win 2k machine with CRT monitor and tried it out..

I then checked the speeds with a "real" tester and found all speeds within range. No other adjustment was required..

http://rick_oleson.tripod.com/index-135.html

 

[le vrai rdu]

great 😀

I love this kind of method 😀

 

[colyn]

great 😀

I love this kind of method 😀

I just checked my IIIf black dial using this method and the speeds looked good.

I shouldn't be surprised since Leitz set the shutter speeds of all new screw Leicas using the drum method. This works somewhat on the same principal..

 

[xwhatsit]

This must depend on scan rate? E.g. NTSC has a vertical frequency just under 60Hz, PAL has vert. freq. of 50Hz. CRTs (gosh, remember those?!) range from 60Hz up to near 85Hz or something.

 

[payasam]

Depends on being able to correctly judge the width of the slit at different speeds. I tried it with my FED-2 but didn't get it quite right.

 

[wolves3012]

This must depend on scan rate? E.g. NTSC has a vertical frequency just under 60Hz, PAL has vert. freq. of 50Hz. CRTs (gosh, remember those?!) range from 60Hz up to near 85Hz or something.

It does depend on the scan-rate. If you use a PC monitor, there's generally a choice of a few rates from which you can select one to use. Mine gives me 60/75/85Hz. I tend to use a white raster (like a blank document or browser window).

I've used this method to set shutters several times, to be honest I tend to look for parallel bands rather than trying to figure exact speeds - parallel bands mean an even exposure. With film latitude and likely metering errors I've never had a fluffed shot that wasn't more my fault than the camera's!

 

[nobbylon]

I use this method to get the speeds roughly on and then use my home made tester to tweak the speeds to within tolerance. Knowing what the slits look like at 1/1000, 1/500, 1/250 and 1/125 also helps when buying s/h. The main problem i've come across with M's is that the 1/1000 speed is too fast, slit too narrow. Once adjusted the others seem to fall into spec.

 

[Sparrow]

shoot 400 asa at f2, slower speeds can be done using a record player with a penny on the platter