Re: [Leica] New Newsletter

[Dante Stella <dante@umich.edu>]

So is the problem the RF calibration?  That's not as bad.


On Fri, 20 Jul 2001, Erwin Puts wrote:

> In the past two months, while silent on the Lug (for obvious reasons), I
> have produced a newsletter for a small group of people, who have a keen
> interest in the optics, mechanics, engineering, secrets and use of
> mechanical precision engineered 35mm camera systems. With these
> afficionados I discussed topics like: a indepth test of the new Hexanon
> 2/35 lens, the philosophical and ergonomical differences between the M6
> and the Hexar RF, the essence of the SLR and RF viewing systems, the
> engineering arguments behind the Hexar/Leica incompatibility, the
> artistic differences between Provia100, Kchrome 64, the issue of film
> flatness, the concept of depth of focus, and so on. Find below an
> excerpt from the latest newsletter.
> If you are interested in receiving the newsletter, send me an email with
> your address and topics you may wish to have discussed in the future. It
> is free, no $18 fee for this service.
>
>
> ###
> Having established in previous newsletters that there is more to
> Konica/Leica lens compatibility than the simple measurement of the
> distance from flange to pressure plate, I did some further research, now
> testing in real life with 100 ISO slide film all leica lenses from 24 to
> 135mm on a calibrated M6 and a factory provided Hexar, which had the
> distance from pressure plate to flange of 27.95mm, thus identical to
> Leica but differing from the Konica specs.
> As you recall, the Lug was very quick to some simple checks, which in my
> view were done not to find the truth, but to 'prove' that nothing is
> wrong. This view has been canonized in Nemeng's FAQ.
> My results are different. I used a tripod, a high resolution test chart
> and a measured distance of 4 meters. All Leica lenses on Leica body were
> focused manually several times and the average setting on the distance
> ring calculated. All lenses were within 3% of the factual distance and
> the slides showed accurate focus under the microscope at the 40X
> enlargement. The Leica lenses on the Konica body showed on average a
> misalignent of close to 10% and that consistently over all lenses.
> I did a special study of the 75mm lens, but not at the allegedly
> critical setting of 1 meter (which is not that critical if you study the
> shape of the curve). The 3 meter setting is more critical. I first set
> the Leica body and the 75mm on the tripod etc. Made a series of pictures
> and then I kept this distance setting carefully when using the lens on
> the Hexar. Results (microscope) showed a loss of micro contrast, a drop
> in edge sharpness and a loss of the very fine detail, including closely
> spaced lines. Then I refocused the 75mm using the Hear RF system.
> Results were truly bad: slides were unsharp and only the gross outlines
> of the test patterns could be detected. I also used the 75mm/hexar at 1
> meter distance. Results were much more acceptable, but not really good,
> but not knowing the other results could mislead you in assuming  that
> the focus was within range.
>
> I did this test three times on several days, using several films and
> creating every time a new setting and so tried to eliminate any specific
> bias. Of course this test is not conclusive, but it does indicate that
> the Lug has been too quick to bury the subject. But as Bob Dylan used to
> sing: sleep well, Mr President.
>
> The monster test of the BW films is underway.
> I had some old rolls of Panatomic-X (20 years old), the film that
> introduced high resolution acutance photography to 35mm users. I also
> used the Maco UP25, 64 and 100, which are all versions of the classical
> Adox high actance series of KB films. And an ortho 25, APX25, APX100 and
> previous tests included PanF, TM100 and D100.
> To keep it manageable I used one developer (the famous CG512) and tried
> to develop to the same CI value. You need to do this as otherwise the
> steeper curve of the APX25 may lead you think this film is sharper than
> as example a D100, while in fact both are as sharp (seen as recording
> the same information from the object) but the 25 has higher contrast so
> the pictures have more punch, which could be sen as more sharpness.
> All pictures were enlarged 14x. which in my view is the minimum to
> differentiate  meaningfully between films.
> The shots were of a model in an old desolated factory, giving ample fine
> details, tonal scale and   resolution possibilities.
> The Pan-X showed outstanding sharpness and acutance, but its grain
> pattern was a bit rough but very tight. It resembled the grain pattern
> of the APX100, which is a bit finer, and indeed the two films are close.
> Finest details however were suppressed by the grain pattern. The tonal
> scale   showed quite subtle grey values, again till the threshold of the
> granularity noise. The whole atmosphere is an image of very pleasing
> tonality, gritty sharpness and details painted with broad strokes.
> The UP100 (Adox KB21) has surprisingly fine grain, but on inspection the
> grain is clumpier but the edge sharpness is low so the fineness is
> bought at the expense of definition. Overall quality is still
> commendable and while not up to todays standards, in its day it
> certainly was a winner.   The Pan-X and KB21 images indicate the
> progress realized in 20 years of emulsion technology.  In itself of
> amazing quality, these films lag in all significant areas when compared
> to todays super stars. But the differences are on the other hand more
> evolutionary that revolution.
> The APX100 gives images that suit the reportage style of location
> photography very well. These images have a fine realistic imprint: some
> what gritty, but with a smooth tonality and sufficient fine detail to
> make the scene interesting.
> The APX25 has a higher inherent contrast and so small details are
> recorded somewhat more forcefully. Grain is absent, which adds a creamy
> tonality to the scene, but on close inspection the recording
> capabilities are just a small edge compared to the APX100 or PanX. The
> finer grain  does record the faintest shades of grey values, which adds
> to the 3D impression of the scene.
> The UP25 (KB14) is very close to the APX25. Grain is slightly more
> pronounced, but much less so than PAnX or APX100. The tonal scale is
> identical to the APX25. The intriguing characteristic of this older thin
> layered, thick silvered emulsion is the edgy grain clumps, which, being
> very fine, also roughen up the image structure. It makes the picture
> very lively and especially for model photography and architectural
> photography adds an effect that can be described as  underscoring the
> main story.
> Compared to the PanF as example the KB14 is definitely less smooth and
> its finer details lack the stark micro contrast of the PanF, but all
> said, this film is a worthy emulsion, that deserves a try. On a normal
> viewing distance, the main subjects literally jump from the picture.
> The Ortho25 is a trouvaille: I had some films and asked myself: why not?
> In the same setting, the  prints proved excellent. The skin of the model
> came out very realistic and I did not notice any  strange grey values. f
> course there was no red in he scene, so all  other gray values are more
> or less 'natural".  Sharpness is excellent and grain very fine. The film
> has a clear base and so  looks very contrasty, even if the values are
> close to normal. Not a film for every topic, but I am inclined to use it
> more often and when using some filters can even add some additional
> tonal scale.
> Definitely a film to try and use for portraits, glamour etc. Take care
> of red of course. But more versatile than mostly thought of.
>
> As a preliminary conclusion I have to say that the UP25 and Ortho 25 are
> very potent films with a  potential for intriguing results that need to
> be explored. They are not as good as current  top performers, but the
> distance from a TP as example is less than often imagined. So it is as
> easy to note that there is hardly any progress in BW emulsions in the
> last decades or to state that we have advanced a big stride to deliver
> superior results.
>
> If you habitually use enlargements below 10X, the difference are even
> smaller.
>
> The lesson: try more film than you use now: it will add to your toolkit
> and visual awareness.
>
> Next:
> the PanF, D100, TM100, D400 (new).
>
>
> Erwin
>
>
>
>
>