Several Leica M9/CV50 f1.1 Nokton Samples

[carstenw]

Just a quick response to comments made after my inital post (above). Yes, the rule generally observed for most lenses (years ago) was DOF fell 1/3 in front of subject focued on and 2/3rds behind.With modern optics and different design and optical parameters being part of the lens manufacturers's objective, I have found this observation to be less and less true for many lenses (but not all)...especially when wide open. This is clearly not the case with "some" of VC fast glass nor with certain Leica lenses. Just look at the Lux 35mm f1.4 ASPH...a properly adjusted sample front focuses quite a bit wide open where the subject is placed at the very back of the depth of field.... to compensate for the backward focus shift observed when the lens is stopped down.

Your observation of the 35 Lux ASPH is not due to a basic failure in physics, but rather due to your implicit assumption that the point focused on is chosen by the rangefinder. The *actual* point focused on (as opposed to where the rangefinder says it is, which is sometimes fudged by Leica, as you described, to minimize focus shift) should still follow the same basic laws of nature.

 

[carstenw]

Since image magnification is less for objects behind the subject plane, DOF naturally will appear to be greater behind the subject plane than in front.

I need to read up on this to confirm, but I am pretty sure that the cause is not image magnification, but rather the distance-squared nature of depth of field. The square of the distance doesn't differ as much from the linear up close as it does in the distance, hence the rule of thumb.

 

[fotografz]

Jono you ask a great question ... and probably the only question that matters after all of the quibbling about this and that. Bottom line is that I like lenses that I can't wait to put on the camera again and again ... lenses that surprise me over and over again because they reveal subtle nuances that make me smile (extremely unscientific and unmeasurable for sure).

I felt it as soon as I looked at my first images from the 75lux/combination ... but, am uncertain as to whether or not I feel it with the CV50. The lens is a fantastic bargain, sharp as can be wide open and stopped down. But, in some respects, I feel rather take-it-or-leave-it about the lens. I like my lenses to have a little more micro-contrast and saturation and the CV50 just leaves me a little cold.

Perhaps I have to spend more time with it, bump up the contrast and saturation to suit my taste in post processing ... or forget how my Noctilux images made me feel before I sold it several years ago.

I think your observations are spot on Kurt. This is a great low light lens to extend usage of a M8 or M9 into lower ambient light situations ... and as such is a terrific bargain ... more than worth the money.

Yet it feels like there is something missing ... and your micro contrast observation may well be it.

When I look at shots done either with the Nocti 1.0, 0.95 or 75/1.4 the OOF areas have some subtile shaped character to them ... and this is also true for the front OOF areas that can be just as important as what's going on behind the subject.

When I look at your VC shots (and those from the VC 35/1.2 I used to have), the OOF areas tend to feel a bit like Photoshop blur was used ... they appear a bit featureless. It's all quite subtile, but if subtlety is what shakes your tree, you'll instinctively know when it's missing. Personally, I doubt any processing technique is going to change that.

-Marc