Re: [Leica] 21m comparison (long)

[Five Senses Productions <fls@5senses.com>]

Erwin:

Do you have reports of this detail on R lenses?

Francesco

At 09:47 PM 1/27/98 +0100, you wrote:
>Super Angular 4,0/21mm:
>At full aperture light fall off is quite noticable, so is curvature of
>field. Distortion is hardly visible.
>At full aperture the image field from center to a radius of 5mm gives good
>sharpness and medium contrast.  The object outlines are well defined, fine
>and very fine details are a little bit soft. Extremely fine details are
>very soft with low contrast. So in fact hardly visible. From 5 mm the image
>contrast drops rapidly and from 8mm vey fine detail ist just noticable and
>fine detail is visible with low contrast. From 11mm astigmatism begins to
>reduce the visibility of fine detail. Subject outlines are rendered softly
>and in the corners even these details are unsharp.
>Stopping down naturally improves the quality. Contrast however stays at a
>low to meduim level. Stopping down to f/8 enhances contrast a little,
>extremely fine details are visible, but not in the corners and the outer
>zones (in horizontal view: the long side of the negative). At f/11 the
>optimum is reached and from f/16 the performance drops. There is slight
>decentring.
>Generally speaking: this lens at full aperture gives a good performance in
>the center and if the clear rendition of very fne detail is not the prime
>objective this aperture is usable. Modern performance is not possible even
>at optimum aperture.
>
>Super Angulon 3.4/21mm:
>At full aperture distortion is negligable, light fall off is reduced and
>curvature of field well corrected.
>At full aperture the center image within a radius of 8mm gives a crisp
>rendition of subject outlines and fine details.,the corners being very
>soft. Very fine details are rendered with medium contrast from center to
>6mm and with lowish contrast from 6mm to the corners. Extremely fine detail
>is just visible, with veruy low contrast and soft edges from center to
>about 10mm radius, vanishing in the outer zones.
>At f/4 this lens is a marked improvement on the SA 4.0.
>AT f/5,6 contrast is improved and extremely fine details are now clearly
>visible till the outer zones, the crners still being soft.
>At f/8 the optimum is reached, the rendition of extremely fine details is
>good with a medium contrast.
>AT f/11 and smaller the performance drops.
>generally speaking: this lens is a very good performer. its fine qualities
>only restricted by the presence of astigmatism that reduces contrast and
>crisp rendition of very fine detail.
>There is slighrt decentring.
>
>Elmarit-M 2,8/21mm:
>At f/2,8 the light fall off is slightly below SA 34 levels. Flatness of
>field is less well corrected as is distortion.
>At full aperture the center image with a radius of 10mm gives a slightly
>crisper image than the SA34. The generally somewat higher contrast results
>in a more clear delineation of fine details. Outer zones and corners are
>soft.
>The general performance of the E is s little above that of the SA 34 wide
>open. This is partly due to the reduction of astigamtism, resulting in
>improved rendition of fine details.
>At f/4 extremely fine details are visible with good contrast from center to
>a radius of 6mm.  From there to the corners the image details become

>progressively softer, but fine details stay within detectable range,
>The optimum is reached at f/8 with a good reproduction of extremely fine
>details till the outer zones. The subject outlines, especially in the outer
>zones have slightly soft edges, giving an overall impression of a smooth
>but not brittle sharp image. Stopping down to f/11 and smaller reduces the
>quality. Decentring was not measurable.
>generally speaking: this lens is a commendable performer and a slight
>improvement on the SA 34. It does not bear the Leica badge with full honour.
>
>Elmarit-M 2,8/21 ASPH:
>At full aperture contrast is high and extremely fine detail is very crisply
>rendered from center over a raduis of 11 mm. From then the contrast of
>edges drops a little but is still vastly superior to all its predecessors.
>Astigmatism and curvature of field are almost fully corrected. Subject
>outlines and fine details are extremely sharp and clearly almost lucidly
>rendered. In the outer zones and the corners this superior performance
>drops naturally. The overall image quality is a quantum leap forwards in
>relation to all predecessors and I may add competitors.
>To set it in perspective: the performance at f/2.8 is better in all
>respects to the SA 34 at f/5.6.
>Or: the max resolution of the SA 4 at f/,0 is about 70lp/mm with very low
>contrast where the ASPH at f/2.8 has 125lp/mm at high contrast.
>AT f/4,0 contrast and the clear rendition of very fine details improves,
>with the corners still lagging behind.
>At f/5.6 the optimum is reached with exceptional performance including the
>far outer zones.
>From f/8.0 the performance drops ever so slighly and at f/16 is visibly
>below optimum.
>Decentring is not measurable.
>Overall: this lens gives outstanding image quality at full aperture and
>improves till f/8.0.
>It is by a great distance the best 21mm in the Leica stable and the only
>choice for the person who needs superior performance from a 21 starting at
>2.8.
>
>A full report giving more details about flare, close-up performance and the
>hot topic of performance at infinity will be published at my site in a week.
>Erwin
> 


Francesco Sanfilippo,
Five Senses Productions
webmaster@5senses.com

http://www.5senses.com/