New 35 Lux bokeh, foliage - and focus

[tashley]

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Curvature of field would be the technical term; the image surface isn’t planar but curved, resulting in a similarly curved plane of maximum sharpness.

 

I assume that lenses are corrected for the fact that we don't place our lenses at the centre of patterned spheres and that therefore this odd focus effect might have something to do with correction for our largely planar pictorial world. That means that the lens needs to be able to focus the centre of the frame, which is nearer to it than the elements on the edge, which are slightly further from it but which also need to be in focus... so it might in effect be designed to focus the centre of it's FOV at slightly closer distances than the edges. However, the math that dictates that design has to also take account of changes in distance of focus and in aperture and maybe the phenomenon I am observing is merely the upshot of a complex series of compromises needed to make this all hang together?

 

Like I say, no engineer here!

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[tashley]

Here's my little experiment. The results are less obvious than on the London skyline shots because a) we are seeing the effect shown across top to bottom of the frame rather than left to right, i.e. using less of the FOV and the subject distance is only three metres and as I have observed the effect appears to me to be larger at middle and longer distances.

 

Frame one show the entire frame just for reference.

 

The following two frames show 90% quality JPEGs at 100% crop of the entire height of the frame. Tripod mounted, levelled, F4, developed in C1 from DNG at defaults. The first crop shows the frame with focus pulled a bit closer than the RF indicates and the second frame shows the frame focussed exactly as per the rangefinder. It is subtly clear that the second frame shows the frame sharper at then ends and softer in the middle, whereas the first frame is the opposite. I think!

 

At this subject distance it is really 'angels on pinheads' but as the skyline shots showed, at greater subject distances this effect would make a difference visible in medium o large sized prints, on certain types of subjects.

 

 

[DFV]

Interesting, but not as interesting as the other two shots of the roofline. As you well point out you can't appreciate the near and far effect, which ultimately is the thing that is most intriguing.

[tashley]

Interesting, but not as interesting as the other two shots of the roofline. As you well point out you can't appreciate the near and far effect, which ultimately is the thing that is most intriguing.

 

I agree - but I think there are several effects going on and each anal experiment is part of piecing together the puzzle!

[mjh]

I assume that lenses are corrected for the fact that we don't place our lenses at the centre of patterned spheres

Curvature of field (see Petzval field curvature - Wikipedia, the free encyclopedia is an optical aberration that, like all the standard aberrations of lenses such as chromatic aberration, spherical aberration, distortion etc., is generally corrected for to some degree. The question is how much of it remains.

[Mauribix]

For those who may be interested, I had the opportunity to check both my "old" 35lux ASPH and the new one.

 

There's IMHO a certain difference in the way the two lenses render the OOF area, especially when subject in focus is at the closest (or nearly) focus distance.

 

With a slight degree I prefer the "old" 35lux ASPH for that, while I have no doubt in preferring the new one for what is concerning flare resistance (dunno if it's a different coating or simply the new hood design).

 

new 35lux (full frame):

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"old" 35lux (full frame)

 

new 35lux (crop)

 

"old" 35lux (crop)

[Mauribix]

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And here the shots for the flare (veiling one?)...

See that there's some more vignetting with the "old" 35lux because I didn't set the correction for that as to distinguish the frames later.

 

 

Old 35lux ASPH:

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New 35lux ASPH:

[tashley]

I'm finding pretty much exactly the same Maurizio - the bokeh is not quite as nice but the flare resistance is much better and not having to deal with focus shift is a blessing!

[elviskennedy]

All very interesting and helpful. For all-around excellent image quality he 35 'cron asph is the best lens I've ever owned. I suspect it would remain so even if I ever stumble across an affordable 1.4 to compare it to.

[chris_tribble]

And here the shots for the flare (veiling one?)...

See that there's some more vignetting with the "old" 35lux because I didn't set the correction for that as to distinguish the frames later.

Maurizio - do I see red edge in the bottom of these frames?

[Mauribix]

Maurizio - do I see red edge in the bottom of these frames?

 

Chris it may be... dunno if it's a WB problem then. There are different lights and temperature in those shelves... I have to check once again 'cause I can't actually see it with the "old" lens shots.

[schnapshot]

Thank you very much, Mauribix. Most interesting.

 

For me one very important aspect of a fast leica lens is the OOF rendering.

I really was curious about the OOF of both lenses compared.

 

The new lens seems to offer more "pop" in general. This seems also to be visible in the bokeh: it seems also to have more "pop" (e.g. colours and contrast)

 

But let’s wait for more direct comparison shots....

[newtoleica]

Very interesting. it reinforces what I've observed from looking at images on Flickr and this site. FOR ME the bokeh on the older version is much better and Ill trade that against the flare any day. Not noticed and focus shift in my shooting so far with my V 1.

[edlaurpic]

I might have already posted this, but haven't seen a response from anybody.

 

All of this is purely academic unless the new 35/1.4 ASPH (11663) is actually available for sale somewhere. So far, in the US at least, I have not been able to find any for sale. Anybody know where one could be purchased? If you respond to this post, please also PM me, as I might otherwise miss it. Thanks in advance for your help if you know where one can be purchased.

 

Ed

[MP3]

Tim

 

Thanks for your post and findings on the new 11663.

From the pics and your description, I believe your copy of 11663 was calibrated slight back focused at f1,4 when it comes out of Leica factory. Most Leica fast lens got a spherically curved field of view, not planar. When you are facing your subject, the 'sphere' of maximum sharpness is like a bowl with opening facing you. For Noctilux, the sphere is even more deep. So when you find the in-camera RF is perfectly aligned but still the edge of resulting image is sharper than the centre, and you need to pull a bit near, that is quite a sign of back focus calibration in f1,4.

 

If you try hard to source some more copies of 11663, you will find some tack sharp at the centre wide open, some like yours and some is simply off too far.

 

Personally, I have encountered a lot of Leica lenses exhibiting this 'phenomenon'. I understand it is very hard to believe a factory or brand like Leica can have this kind of calibration standard. But that is it, they take a person to do it. Like you, I like Leica and been fascinating with all it offers. But nothing is perfect as we all know. Let's enjoy taking pics.

 

My 2 cents =)

[lars_bergquist]

Would it have bothered HCB – or any other practical photograher of note? Even if he/they had worked in colour?

 

The old man from the Age of the 3.5cm Elmar

[lct]

35mm lenses were not HCB's cup of tea and his favorite Summicron 50 reversible has quite a smooth bokeh already.

He was not caught by the sharpness mania either. You know what he said about that:

"Je m'amuse toujours de l'idée que certaines personnes se font de la technique en photographie, et qui se traduit par un goût immodéré pour la netteté de l'image ; est-ce la passion du minutieux, du fignolé, ou espèrent-elles par ce trompe l'oeil serrer la réalité de plus près ?" (Le Photographe n° 1607, page 28).

Free (poor) translation: I always make fun of the way certain people imagine the technique in photography and which results in an immoderate taste for sharpness in the image; is this some passion of meticulousness or finickyness, or do they hope by this trompe l'oeil coming up closer to reality?

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