Schneider Kreuznach Center Lens Filter III

[jerome_ibanes]

<p>How should one adjust its exposure when using a Schneider Kreuznach Center Lens Filter III?</p>

[leicaglow]

The 3 is equivalent to the number od a neutral density filter, so you must add another

one and a half stops. So a reading of f/22 on your meter, should be set at f/11 and a

half .... halfway between f11 and f16.

[q.g._de_bakker]

The three is a size indicator, but yes, the III has a maximum (centre) density that requires 1.5 stops.

[jerome_ibanes]

<p>Oh thanks, I was afraid III meant the number of stops to compensate, which would be quite significant.</p>

[jerome_ibanes]

<p>Few more questions about this filter.<br>

<br />* Which size of cap does it takes, I measured 82mm, but it might as well be 83, not trivial to tell.<br>

* Would adding a polarization filter be possible on the Schneider center filter, or would it be visible on film? (if so, again, which size should be ordered).<br>

Thank you.</p>

 

[q.g._de_bakker]

If it is the III, it takes a 90 mm push on cap.<br><br>The center filter must be the first you put on the lens. The center filter's front thread is 86 mm. Oversized (the III filter is made for two 67 mm front thread wide angle lenses) to avoid vignetting when using more filters. So you can use a 86 mm thread mount polarizer. But t will also depend on how deep that polarizer is, so try before you buy.

[jerome_ibanes]

<p>86mm or 90mm looks like the diameter of the outer ring, but the diameter of the threaded, recessed female thread really looks more like either a 82 or 83mm, and in this same notch, the lens caps (which is currently broken) is placed.<br>

Is there a document that describes this?</p>

[q.g._de_bakker]

Well, you could always use Google and try to find Schneider and what they have to say.<br><br>90 mm is indeed the diameter of the outer ring. That's why a 90 mm push on cap, as supplied by Schneider, is recommended by Schneider. If you want to use a cap that fits in the filter thread, you must find a 86 mm cap.<br>Which takes us to your measurements: screw threads mesh, have two diameters. Measuring the diameter of the 'female' mount, you're measuring the minimal diameter. The thread that will fit that will have to be larger, have a maximum diameter that is a bit larger than that.<br>It's 86 mm thread.<br><br>What lens are you putting this filter on?

[jerome_ibanes]

<p>I see, thank you.</p>