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Visoflex use on the 240


rafael_macia

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I have heard a Visoflex III, needs to be modified to focus properly on a 240. The modification (I think), involves shimming up the ground glass of the Visoflex.

The reason being; the sensor plane is flat, ... somewhat different than a film plane.

Is this so ?

If it is, could I be pointed in the direction where "how-to" instructions might be ? Or if anyone knows of a repair facility who can competently do the modification ?

Thanking in advance for any help

rafael

 

I have done a search on this subject and come up empty

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I can only say that mine work just fine on the Monochrom and M9.

Shimming is not easy nowadays, as it is not simple to find the appropriate shims. It is done best either on a Collimatotor or using the EVF on the 240. A pro job or a lot of trial and error (and parts donor Visoflexes for the shims)

 

Will van Manen told me he is using the M240/EVF for lens adjustments (and Viso adjusting) nowadays, as it is more precise than his 60 cm Collimator(!). A lot cheaper too, he added rather ruefully ;)

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I was told the flange to film distance is the same on film and digital M's.

Therefore, theoretically all of the Leitz lenses should also work perfectly on the M240.

but .......

As the sensor is super flat and has no thickness compared to the not-so-flat film with a bit of thickness Most of the Leitz (especially Leica) lenses would probably need fine adjusting in order to be used with 100% focussing accuracy, on the M240, ........even though in theory they should all focus perfectly, just like the VISO lll should.

for what it's worth,

I think the difference is super minute, and would only be noticed by those shooting wide open.

 

In short then, the use of Leica/Leitz lenses are not 100% seamless (regarding super critical focus) between film bodies, digital bodies, and Visoflexes.

 

This all may be a non-issue but I just wanted to mention it anyhow.

 

Rafael

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No doubt the digital sensor is less forgiving than film, and many lenses have been found to need adjustment, some more than others, and some not at all. My 135 T-E required the optical cell be moved approximately 1mm closer to the body, and my 11819 50 Summicron also needed adjustment. My 50 Lux is a smidgen off but I haven't bothered sending it in because frankly my own judgment of the rangefinder image coincidence seems to overshadow the lens' calibration error. The rest of my lenses, including 135 Elmar and Hektor (an LTM used with Leitz M adapter) are spot-on (luck of the draw I guess).

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I use a viso 111 on an m8. I had a severe back focus with the viso on the m8 and back focus at close distances with rangefinder lenses. After 3 trips to Leica NJ complaining of back focus with rangefinder coupled lenses Leica fixed the rangefinder and the viso started to work properly. I concluded that the rangefinder was in spec the 1st time. Leica must have moved the sensor. I am glad I did not shim the viso to compensate for the sensor. I really enjoy using an optical viewfinder.

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With a correctly adjusted Visoflex one can get sharp images like this one IMHO.

 

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There is even a moiré in the plumage. :D

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I was told the flange to film distance is the same on film and digital M's.

Therefore, theoretically all of the Leitz lenses should also work perfectly on the M240.

but .......

As the sensor is super flat and has no thickness compared to the not-so-flat film with a bit of thickness Most of the Leitz (especially Leica) lenses would probably need fine adjusting in order to be used with 100% focussing accuracy, on the M240, ........even though in theory they should all focus perfectly, just like the VISO lll should.

for what it's worth,

I think the difference is super minute, and would only be noticed by those shooting wide open.

 

In short then, the use of Leica/Leitz lenses are not 100% seamless (regarding super critical focus) between film bodies, digital bodies, and Visoflexes.

 

This all may be a non-issue but I just wanted to mention it anyhow.

 

Rafael

It is all a matter of tolerances needing to be smaller on digital bodies because of the reasons you mention. Another aspect is that users were not apt to blow up a film image to insane size and then inspecting it from 25 cm. When one views an image on a monitor at 100% or even 200 or 400, that is exactly what is happening nowadays.

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