[Leica] lens report 24/2,8 M and R

[Erwin Puts <imxputs@knoware.nl>]

I used two exemplars of the Elmarit-M 2.8/24 ASPH (# 3782523 and #3844221)
and compared it to the Elmarit-R 2,8/24.  Specs can be found everywhere.
The E-M is without any doubt a masterpiece of optical engineering and
within the Leica M range a landmark design.
At full aperture the lens exhibits a very high contrast image from center
across the whole field. Only the far corners drop in contrast and produce
soft details. Over an image circle with a diameter of 12 mm the outlines of
subject shapes and  details are delineated with superb edge contrast and
extremely fine details are crisply and clearly rendered. In the rest of the
field the very fine details are crisply atched in the emulsion with
extremely fine details visibly rendered but with softer edges. Exceedingly
fine  detail  is just rendered above the threshold of visibility, but with
slightly lower contrast.
Going from center to corner the contrast of the extremely fine details
drops a bit, but while a bit soft these details are still clearly visible.
Stopping down to f/4,0 the contrast of very fine detail improves and the
exceedingly fine detail now is clearly visible. Corners still lag a bit but
center performance (12 mm image circle) is at its optimum. This aperture
can be called the optimum. Stopping down to 5.6 we see that the finest
possible detail crispens a bit, but the outlines of shapes and details
starts to soften faintly. Overall contrast thus is a bit lower. It is a
matter of priorities which aperture is optimum. I would say that at f4.
this lens is at its best.
At f/8,0 corners continue to improve where the center now drops in
contrast. At f/16 the overall image contrast  is lower and very fine detail
suffers as diffraction sets in.
At close range (± 70cm) this excellent performance is preserved. A wide
angle lens like a 24 is worthless if the close up performane would not
equal the infinity setting. Due to aberrations we need to stop down to 5,6
to get the best of performance in the close up range.

Flare suppression is perfect. Night pictures with Kodachrome 64 show
excellent gradation in strong highlight sources and distance point sources
are clear and without any halo.

Of course some light fall off is visible at full aperture, but in most
picture taking situations you can forget abot it.

On the bench a faint trace of decentring could be observed. On the other
hand flatness of field is absent and astigmatism very well controlled. Coma
could not be observed.

Distortion is also hardly observable. Of course when you intentionally take
pictures in oblique postion the perspective is out of line. Used in  a
level position this lens is distortion free.

Its view is quite fascinating. I used it in reportage style picture taking
situations and could get very interesting pictures at close range. The
trick in using this lens is the selection of subject matter  at about 1 and
2 meters.
If this is interesting, the whole image will be. Some users might be
tempted to go for the grand view. In most instances you will be
disappointed as details are samll and foreground is excessive.

The R-version.
At full aperture the lens exhibits a medium to high contrast in the center,
dropping rapidly when going to the corners. Very fine detail is visible
with soft edges and a strong presence of astigmatism will wash out the
rendition of very fine detail. Also colour fringing will soften the edges
of the subject outlines. Going to the corners we notice a rapid drop in
contrast  and fine detail is clearly visible, if with soft edges, Atf/ 4
contrast improves and  fine detail now is crisply rendered. Optimum is
reached at f/8,0 where very fine details are just visible in the center and
barely make it in the field.
Close up performance is very good. In the field however the image quality
is quite below the one in the center at full aperture and we need to stop
doen to f/8 to get a decent performance.

Generally speaking the R version performs adequately  in most picture
taking situations. Some years ago I tested the R version against the Nikon
2.8/24 and I found the outcome a draw.
At optimum aperture of f/8.0 the R-version is not as good as the M-version
at full aperture. That is quite a statement, but it is unavoidable after
examining transparancies,  b&W prints, mtf graphs and bench results.

Many users could make a small mistake whencomparing lenses. If you would
use a Summicron-M 50mm and a Elmarit-M 24 mm side by side and take pictures
of the same object at the same distance the Summicron will win. Simply a
matter of magnification. As the focal lenght of the E is half the one of
the S any small detail that is reproduced by the E is also reduced twice in
comparison to the S. So detail rendition of the S is invariably better. The
meaningfull comparison would be to take pictures at 100x the focal lenght
and then you will notice that the E is almost equal to the S.

Conclusion.
The M version of the 24 is a lens that is a quantum leap forward in
comparison to the Rversion. It gives the user imaging quality potential
that is a challenge to materialize. Where the R version is quite capable,
the M version is just phenomenal.
At full aperture the M version is already almost at its optimum, realising
a long standing goal of the Leica optical designers: best quality at full
aperture ove the whole image field. This lens is quite demanding on the
capabilities of film emulsions. Pictures 0n 400ISO transparancy  film
proved that this lens will show its qualities even when relatively grainy
films are being used.
Within the Leica lens range this lens has a premium position. Its angle of
view produces fresh views of interesting objects in this world at close
range and its optical capabilities add a novel impact to pictures taken
with fairly wide angle lenses.
No Leica M user should be without this lens. The M style of photography
demands intimate close range photography and the 24 is one of the best
lenses to explore this area. It delivers unsurpassable quality in the 24
focal length.


Erwin