[Leica] Re:Noctilux abberations?

[horsts at iinet.net.au (A.H.Schmidt)]

Hi, I am not quite sure, why anybody would want to worry about  any 
abberations of the Noctilux.

1. it is a Leitz lens, This means to me, it is just about as good as its 
gets.
2. The lens has been around for some time now, and if  there where 
better F1 lens, then, I am quite sure,
Leica would release a somewhat updated lens.

I have the F1 Noxtilux now  some years. I sold all my screw Leica stuff 
and bought this lens from the proceeds.
I never looked back. 

What one can do with available light and even  with normal lighting with 
this Lens, is exceptional.

Why worry, if you Photograph a Jazz band in a Jazz club full of smoke 
and half dark , and you get a bit of lost sharpness on the edges or a 
bit of vignetting.
On the contrary,  I believe, it  enhances the important parts of the 
picture. I dont really care if the bloke behind the band on the upper 
left corner is not super sharp. I rather wish he wasn't there at all. 
Even on a nice sunny day,  if I take a landscape or a bunch of trees or 
something to this effect, then I am rally not worried if the edges are 
not as sharp the the centre. As long as they are not fuzzy or actually 
distorted. The Noctilux is just perfect for this.
I really havent worked out why  people are so  worried about the edge 
sharpness in photographs.  If it was so importand, the I am sure our 
eyes would also be super sharp right up to the edges.

However if I had to do some architectural  jobs or something  technical 
shots, I suppose I would select another type of lens.

Lastly, I would have to be crazy,  after spending 4 Grand or so on a 
lens , to worry if it here are the slightest type of any abberations. 
Who cares. As long as you have a bit of an idea,  what the particular 
(any Lens)  can do wide open  the you'll
propably find you'll like the special charm of available light 
photographie with this type of lens.. Just about any modern lens can to 
really great things at  F5.6 or so.     I am glad  I have a Noctilux
Of all the pictures (quite a few) which I think are not worth while 
keeping,  none was the fault of this lens. It was always me.

Regards, Horst Schmidt






>
>Hi, 
>
>Ted wrote: 
>  
>
>>I've used a Noctilux since it was available in Canada, '72-73? And at 
>>times it was - is my main lens indoor and out. 
>>However I was never aware of this condition. Is this something I've missed 
>>all these years that's good, bad or ugly? 
>>Serious question. 
>>    
>>
>
>I love my Nocti.  I've shot a hundred or so rolls through mine since I 
>bought it from George Lottermoser in January 2005.  it's the same version 
>as yours Ted, the 58mm filter thread one that came with a separate hood.
>
>You've raised something interesting here Ted - all lenses have aberrations, 
>it's just a physical fact of optics.  Even the Leica M asph lenses 
>(probably better corrected for aberrations as a family than any other group 
>of lenses current manufactured for cameras) and the 50/2 Summicron (a very 
>well-designed lens with conservative specifications)  have them, you just 
>have to know what to look for.  With these lenses, most of the time most of 
>these aberrations hardly matter (in a well-designed, adequately constructed 
>lens) and are completely invisible to most viewers (who don't know what 
>they're looking for).
>
>The Noctilux is another story.  As Erwin Puts points out, wide open, the 
>Noctilux displays coma, spherical aberation and chromatic aberrations from 
>an image height of 9mm outwards at full aperture. He also notes 'some 
>inward bending curvilinear distortion' in addition to the vignetting or 
>light falloff that is quite pronounced.  These are, to some extent, 
>inevitable when designing a lens this fast.
>
>But what does all that mean? 
>
>Coma, 
>http://hyperphysics.phy-astr.gsu.edu/Hbase/geoopt/coma.html 
>http://en.wikipedia.org/wiki/Lens_(optics)#Coma 
>otherwise known as oblique spherical aberration, makes bright sources near 
>the edge of the field look like a comet with a tail rather than a single 
>spot.
>
>Spherical aberration 
>http://hyperphysics.phy-astr.gsu.edu/Hbase/geoopt/aber.html 
>http://en.wikipedia.org/wiki/Spherical_aberration 
>occurs because spheres are not the ideal optical surfaces (this is why 
>aspherical lenses perform better if properly designed) and results in 
>softness or blurring.  If you take a photo of a sheet of newspaper under a 
>sheet of glass with a Nocti (actually somewhat more instructive than it may 
>seem at first), it will be softer at the edges than in the centre.
>
>Chromatic aberration 
>There are several kinds of this.  The most common and the one the Nocti 
>suffers most from is described here: 
>http://hyperphysics.phy-astr.gsu.edu/hbase/geoopt/aber2.html 
>http://en.wikipedia.org/wiki/Chromatic_aberration 
>where the lens bends different colours of light to differing degrees.  It 
>results in strange colour effects with colour films and a loss of sharpness 
>in B&W.
>
>'Inward bending curvilinerar distortion' simply means that if you take a 
>picture of a brick wall square on with a Nocti at f1, the bricks at the top 
>and the bottom will look like they're curving in towards the centre of the 
>image rather than as straight lines.  This is often called 'barrel 
>distortion' presumably from the corresponding outward bending aberration's 
>propensity for making things that are composed of straight lines look like 
>a barrel - fatter in the middle and thinner at the edges.
>
>The vignetting or light falloff is an optical inevitability of the speed of 
>the lens.  Despite the extremely high refractive index of some of the glass 
>used in the Nocti (the higher the index the more the glass can bend light) 
>the edges of the lens simply can't transmit the same amount of light from 
>the edges of the field to the edges of the film frame.  In the case of the 
>Nocti it is definitely optical vignetting (of this type) as opposed to 
>physical vignetting where the barrel or lens hood gets in the way of the 
>edges of the field.
>
>The Noctilux is a truly magnificent design.  There are fewer aberrations 
>wide open in the 55/1.2 asph breechblock lens for the Canon FD cameras, in 
>the 58/1.2 Noct-Nikkor and of course in the 50/1.4 asph leica-M lens.  Wide 
>open, even the original 1.2 aspherical Nocti performs better in some 
>respects.  All these lenses are, of course, also a half to a whole stop 
>slower.  Any lenses as fast or faster than the Nocti that have been 
>manufactured are inferior.  The Canon EF 50/1 is the closest in 
>performance, but it still lags behind in many areas.  it's also about the 
>size of a piece of telegraph pole (well, maybe not, but if you think the 
>Nocti is big, the Canon is huge).
>
>It would be possible for Leica to design an asph version of the f1 Nocti 
>that would improve the performance relative to the current version.  While 
>the current Nocti is astoundingly good, lens design, glass manufacture and 
>(especially) methods for making aspherical elements have improved 
>enormously in the last 20 years.  Such a lens would probably be entirely 
>unaffordable and anyone hoping for a 50mm lens with the least number of 
>aberrations should buy a 50/1.4 asph.
>
>That ended up way longer than I intended . . . hope it was useful. 
>
>Marty 
>
>
>  
>
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