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Using M lenses


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It depends on your lighting conditions - however - you can turn off the real time setting and it will stay at a consistent brightness in manual mode. and won't adjust based on your exposure settings. I leave this setting on to reflect it real time unless I'm in fairly dim settings

 

Michael

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You can see well enough to focus at most apertures thanks to brightness auto adjustment. No problem to focus at f/8 or even f/11 with image magnification. Those pics have been focused at f/8 this way for instance (CL, Tele-Elmarit "thin" 90/2.8 and Elmar-C 90/4):

 

 

i-FcnZHm7-L.jpg

 

i-dZQTJ3B-L.jpg

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Thinking of getting a CL to use with my M lenses.  How dark does the EVF and LCD get when at f8 and above.  Can you still see well enough to focus manually, or do you have to focus wide open and then stop down

BTW, while it is sometimes cumbersome, focusing wide open is always more (or equally) precise as focusing with closed aperture. I have problems using MF with any aperture but wide open.

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You shouldn't do that. Focusing wide open and stopping down is less precise than using working aperture on an EVF camera. It does not take focus shift into account and you are bound to move the camera when operating the focus ring. The EVF at full magnification gives a clear view of the plane of focus at all apertures.

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+1. I wonder why so many people go repeating that focusing at full aperture is the way to go. This snap has been focused at f/16 :o for example. Not the best setting to say the least but just to show what it is possible to do. Needs focus magnification though.

(CL, CV 21/4, f/16)

 

i-q6nB9sb-L.jpg

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BTW, while it is sometimes cumbersome, focusing wide open is always more (or equally) precise as focusing with closed aperture. I have problems using MF with any aperture but wide open.

 

 

It's easier but not as precise, due largely to focus shift which varies on a lens by lens basis.

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If many lenses had significant focus shift then the leica rangefinder system could never have worked.

I have focussed at full aperture for 60 years on ground glass screens, slr cameras and now evf. There are far more errors to be had from the increased depth of focus at smaller apertures than from lenses with focus shift.

 

Gerry

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You're certainly entitled to your opinion. I've been working with cameras for a similar time and always focus stopped down or as close as I can manage. 

 

Most SLR lenses are very tight on focus shift due to the necessity of an auto-diaphragm mechanism for a "bright enough" viewfinder, but many RF lenses have more focus shift than you might think. 

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Remember the little button below/near the lens of our SLRs in the past folks. Was made to focus stop down but microprism or split image focus screens became difficult to use then due to VF darkening. We have not this problem with EVFs anymore now. As for RFs they don't focus stop down of course hence focusing issues in case of focus shift and/or field curvature we did not notice much with film but becoming more obvious with digital. This is not a problem with EVFs anymore either, which does not alter the cons of RFs especially speed when nailing focus is not requested.

Edited by lct
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I've not noticed any problems with my (relatively modest) lenses on a III, an M3 and an M6ttl in the past, nor with evf so far, but I will keep a closer eye on things with the Fuji.

 

Gerry

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Then how do you achieve any consistent focus with a rangefinder camera? It cannot possibly take any notice of such things.

 

Gerry

 

 

I've not noticed any problems with my (relatively modest) lenses on a III, an M3 and an M6ttl in the past, nor with evf so far, but I will keep a closer eye on things with the Fuji.

 

Gerry

 

 

Consistency is not the issue, but critical accuracy is. Most RF shooters get used to the characteristics of their lenses and accept a certain amount of focus variability as part of the lens's charm or imaging character. They also learn how to 'fudge' the rangefinder's focusing indicator for the lens they are using for the most part, depending on what aperture they're using. This isn't as hard as it might seem because most RF shooters generally work with only three or four prime lenses most of the time, rather than the SLR/EVF camera users working with both more lenses and zooms more of the time.

 

Most Leica RF lenses are pretty good, but some have quite noticeable focus shift. The ones I know about for sure are the Voigtländer Ultron 28/2, the Zeiss C-Sonnar T* 50/1.5, the older Leica Summilux 75/1.4 (circa 1980-1982), Summilux 35/1.4 v2 (mine is circa 1972), the Voigtländer Nokton 50/1.5 ASPH(LTM), and Nokton 40/1.4MC. With all of these (of them, the only one I still have and will never sell is the 'Lux 35 v2), I always found myself focusing with the rangefinder and then tweaking the focus setting a little bit based on what aperture I was working with. Nearly all were perfectly consistent with the rangefinder indication when set to f/4 or smaller lens openings... and most I could not tell the focus difference easily on film but saw it easily on digital capture. 

 

My WATE, Summicron-M 50, Summarit-M 75, M-Rokkor 90, Color Skopar 28, Color Skopar 50, and Hektor 135 all show insignificant focus shift, film or digital capture: It takes a very tight test and careful examination of the results to see it, and it's simply not an issue that changes how the lenses image worth worrying about. 

Edited by ramarren
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I've not noticed any problems with my (relatively modest) lenses on a III, an M3 and an M6ttl in the past, nor with evf so far, but I will keep a closer eye on things with the Fuji.

 

Gerry

Film does not really count, the focus tolerances are far more forgiving than a sensor.

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Thanks for the list, I don't have any of those. The older 28/1.9 voigtlander is supposed to be better and I haven't noticed any problems with mine so far.

 

Gerry

 

 

The Voigtländer Ultron 28mm f/1.9 exhibits less focus shift but has more flare and lower contrast than the f/2 model does. It's a trade-off. I'd forgotten about that lens... The one I had wasn't mine, it was loaned to me for a couple of months about a decade ago, when I got the Ricoh GXR and its M-mount camera unit. 

 

Of the Voigtländer 28mm lenses, the one I loved and have kept is the Color Skopar 28mm f/3.5. It is a fantastic little lens, but sadly is a poor match for the M-D sensor, exhibiting a lot of color shifting. It does nicely when used with CornerFix as a processing step, or with B&W rendering, however. 

 

42373887105_60bb916620_o.jpg

Leica M-D typ 262 + Color Skopar 28mm f/3.5

ISO 200 @ f/8 @ 1/500
 
... This image is best printed to 13x19 inch or larger; the detail that the 28mm lens resolves is hard to see on a digital display. Here's a small detail capture:
 
42559477634_2642ac9c70_o.png
Edited by ramarren
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I bought the 1.9 Voigtlander about 14 yrs ago, to'fill in the gap' between 35 and 21 with something faster than the 21 Elmarit asph. I have never liked the 28mm fov on full frame much, but it was occasionally useful. At the time I bought it the Summicron asph 28 had just been anounced, Puts reckoned the Voigtlander better than anything Leica had before that.

It has proved much more useful to me on aps-c, on nex 6 and Fuji, and even proved good on the Sony A7 on the odd occasion I used it.

I didn't see any reason to change it for the f/2.

 

Gerry

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I bought the 1.9 Voigtlander about 14 yrs ago, to'fill in the gap' between 35 and 21 with something faster than the 21 Elmarit asph. I have never liked the 28mm fov on full frame much, but it was occasionally useful. At the time I bought it the Summicron asph 28 had just been anounced, Puts reckoned the Voigtlander better than anything Leica had before that.

It has proved much more useful to me on aps-c, on nex 6 and Fuji, and even proved good on the Sony A7 on the odd occasion I used it.

I didn't see any reason to change it for the f/2.

 

 

That's fine; I found I didn't like the Ultron 28mm f/2 model very much either.

 

The Color Skopar 28mm, on the other hand, is a very different thing and is the sweetest 28mm lens I've owned. It's unfortunate that the lens design isn't particularly friendly to digital sensors, but CornerFix takes care of that without any problems for the M-D. 28mm on APS-C format nets the equivalent FoV of a 42mm on FF, which was always a favorite of mine, and the APS-C format eliminates most of the Color Skopar 28 corner problems and color shifting with its smaller format. It was one of my favorite lenses on the Ricoh GXR with M-mount camera unit. 

 

8258596436_d4859202b5_o.jpg

Ricoh GXR-M + Color Skopar 28mm f/2.5

ISO 566 @ f/3.5 @ 1/60
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For Gerry:

 

It should be noted that focus-shift comes from Spherical Aberration - the light rays from the edges of a lens wide-open focus in a different place than the light rays passing through the center. At full aperture, there is a spread of focused images, with a point or zone of "best focus" (circle of least confusion) somewhere in the middle.

 

https://en.wikipedia.org/wiki/Spherical_aberration

 

As the lens is stopped down, the aberrant edge rays get cropped off by the aperture blades, tightening and changing the location of the circle of least confusion until it is, for practical purposes, a single point in a single plane, but a different plane than the "average" best focus wide-open.

 

It is mostly a problem with larger apertures (≥ f/2), longer lenses with less DoF/Fo, and older designs (or reproductions of an older look) with lots of SA - as ramarren's list shows. SA does tend to contribute to soft, smoothly-transitioning bokeh, at the expense of focus-shift and reduced total resolution at wide apertures. A trade-off many accept for a certain look.

 

(The underlying problem is that, ideally, lens and mirror surfaces should be parabolic, not spherical, for correct focus. But parabolic surfaces are really hard and expensive to make, while simple constant-radius segments of a glass sphere are easy and cheap to calculate, grind and polish. ASPH surfaces are not necessarily parabolic either, but can correct SA already produced by spherical elements. Floating elements - E.G. 35 f/1.4 ASPH II - can also compensate for focus shift)

 

Personally, with rangefinder focusing, I've usually preferred longer, faster lenses to have some SA (90 f/2 non-APOs, 75 Summilux) - because it gives some "windage" in hitting the extended range of "least confusion" wide-open. Better "pretty sharp" even if my eye, or the lens, or the RF are a tad out of calibration, than "really sharp" - with no room for error. (The true inventor of the rangefinder camera was not Oscar Barnack, but Marge Innovera. ;) )

 

I don't worry overmuch about focus shift, since I usually skip the apertures f/2, f/2.8, f/4 when using an f/1.4 lens - either it is wide open for greatest background blur, or dim light - or I want some serious DoF anyway, with a much smaller aperture. With such habits, I almost never see focus shift.

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Thanks Adan, I know the theory, I did my City & Guilds Advanced in the days when Cox's Optics and Langford's Advanced Photography were required reading.

I've only used three lenses faster than f/2 as far as I can remember, and they only served to confirm my feelings that for what I do I don't need anything so exotic, let alone even more so.

I have heard tales of questionable focus shift with, for instance, one or two Zeiss lenses but rather assumed that Leica stuff would be better, i.e. any focus shift was maked by depth of field/focus. If it isn't then I am glad I haven't felt a need to use these lenses. It seems to fly in the face of sense to take such a precise mechanical focusing system as the M rangefinder and then have to 'tweak' what it does.

It has become obvious that the digital 'revolution' has meant a fundamental rethink of optical design, not only that the sensors are far less forgiving of optical aberrations considered acceptable on film, but also that the sensor stack means that design configurations of short focal length lenses need to be reconsidered. I spent a while trying to get old favourites to work, but have come to the conclusion that its probably better to start again with newer designs intended for and fit for digital purpose.

And as far as cameras are concerned, hooray for evf, no more coping with the vagaries of mechanical systems, both in design and maintenance. I like optical finders, but my Nikon required a return to Nikon for adjustment from brand new. So the Xpro2 suits me fine. Optical finder, and evf focussing.

 

Gerry

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