Leica 1 Model A, some questions

[laffertyphotography]

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Thanks everyone I think the answer is its good enough. We shall see.

 

John

[jc_braconi]

Think about :

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[thomas_schertel]

With any viewfinder you have difficulties:

either the comensation of parallax (solved in M-cameras, the VIOOH, the IIIg)

or the smaller angle of view (solved by the VIOOH; it has a second, smaller index-mark for short distances), every lens has at nearer distances a smaller angle of view than at infinity.

The best solution is, to leave some centimetres distance between the motive and the viewing field of the finder. Enlarging the film you can easily correct this.

 

Yours sincerely

Thomas

 

Remember the Barnack-Challenge

[laffertyphotography]

Sorry if I missed the answer but I wonder what the minimum focusing distance (I mean in focus) will be with the lens set to infinity for the Elmar at f/18.5. For the Summitar at f16 it is approx. 5m. Any suggestions very welcome

 

John

[thomas_schertel]

Here you are helped:

Online Depth of Field Calculator

 

You can insert the camera. Either Leica M 9 or Film 35 mm, the focal length (50 mm or exactly 51,5 mm), the f stop and the distance set on the lens.

 

Yours sincerely

Thomas

[laffertyphotography]

Thomas

 

I have looked at this. I am not sure this is what I am asking and the figures seem somewhat generic ie 35mm film. I apologise if I have misunderstood....

 

Can anyone give me an approx. figure of at what distance focus is achieved at f18.5 on an Elmar 50cm lens when it is set to infinity.

 

With my summitar the lens markings tell me f/16 at infinity is 5m but there are no such markings on the Elmar

 

John

[giordano]

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Depth of field is an artificial construct. There's a smooth transition from sharp (at the exact distance focused on) to blurred, and "depth of field" is simply the zone of acceptable sharpness before and beyond the distance of sharpest focus.

 

With 35mm film cameras the customary definition of acceptable sharpness is "a circle of confusion of 1/30 mm" (a web search will give you the details). That's the definition used by the 35mm film setting on the online calculator Thomas pointed you to, and also on the depth of field scales on all Leitz and Leica lenses.

 

Apart from that, with ordinary lenses at ordinary distances, depth of field depends only on

1) focal length

2) f/number (aperture setting).

 

So the 5cm Elmar at f/16 gives the same depth of field as the 5cm Summitar at f/16. Focused on infinity, the closest focus is 5.1m, according to the calculator I use. At f/18, it's 4.6m.

[laffertyphotography]

At f/18, it's 4.6m.

 

Thank you!