[Leica] UC-Hexanon 35/2 review by Erwin Puts? Anyone have it?

[philippe.orlent at pandora.be (Philippe Orlent)]

Fascinating to read the accurateness of the measurements. It is  
almost incredible to believe that these tiny variations would make  
such a difference.
Erwin is a real apostle :-)

But at some stage, I was thinking he was talking of this camera:
<http://home.earthlink.net/~dannygoodwin/22.html>
or was it this one?
<http://warandgame.wordpress.com/2007/11/08/hythe-gun-camera/>

Philippe



Op 13-nov-07, om 20:36 heeft Thinkofcole@aol.com het volgende  
geschreven:

>
> from Erwin Puts     _http://www.imx.nl/photo/faq/_
> (http://www.imx.nl/photo/faq/)
> I hope this helps, G.  Medina...(Hexar is listed under Leica)....  
> regards,
> bob cole
>
>
> Konica Hexar and register
>
>
> I am currently using the Hexar RF for several  reasons. To test the  
> new
> Hexanon 2/35mm, to check on Hexar body - Leica lens  compatibility  
> and get a
> feeling for the Hexar system.
>
> To start with the body: the specs are well  known, so I can jump to  
> the more
> philosophical topics. The body appears to be a  very high  
> engineering quality,
> has a very solid feeling and is really easy to  use. The electronic
> shutter-motordrive unit is a sealed box and can not be  separated.  
> It is the same as
> used in the Contax G/2 series. As an aside: if  Leica were to use  
> this unit, the
> manual advance lever would have to go. The  viewfinder is slightly  
> lower in
> contrast than the Leica and the Hexar  rangefinder patch has a  
> distinct yellow
> tint, that will lower contrast and makes  it more difficult to  
> focus at
> objects at 10 meter or more distance. While the  body has almost  
> identical
> dimensions to the Leica, the look and feel is  distinctly  
> different. The rounded body
> contours of the Leica and the clean top  cover make it look more  
> elegant,
> compared to the squarish and somewhat boxy  character of the Hexar.
>
> In use the Hexar is quite simple and its  controls are well laid  
> out and
> generally useful to the photographer. The  exposure compensation  
> feature is nice,
> but with the leica a simple half click  stop of the aperture ring  
> will do the
> job as fast and easy.
>
> Biggest drawback of the hexar is the small time  delay between  
> pressing the
> shutterknob and the actual firing of the shutter.  This delay and  
> the instant
> of wait and thus insecurity is most annoying and you  can not use  
> the Leica
> technique of prefocusing and fire when the object is sharp  in the  
> finderpatch.
>
> When you close your eyes and pick up the Leica  and the Hexar  
> several times,
> the difference in feeling and haptics emerges. When  you hold the  
> Leica, your
> thumb slides behind the advance lever and your finger  lays on the  
> shutter
> release button, which is sharp as a trigger. This simple and   
> intuitive act
> signifies to the brain a state of alert attention and you fall   
> into the mood of a
> hunter or an active sportsperson anticipating the moves of  the  
> other players.
>
> When holding the Hexar, both hands hold the body  and wen your  
> finger touches
> the release button, there is no trigger effect. The  finger just  
> rests there
> and you do not get any feedback from the body. So you  switch almost
> automatically into a more passive state of mind and allow the   
> camera to work for you.
> That is easy to do as the automatic functions of the  camera  
> (exposure, film
> transport, motorwinder) are so well executed that you  start to  
> rely on them
> and even transfer control to them. In fact you are  starting to  
> become an
> operator of the camera, adjusting the wheels and not the  driver  
> who forces the
> camera to do as he wants it to act.
>
> The transfer of controls to the camera and the  mood of becoming  
> more passive
> in the photographic act is in my view the fine  distinction between  
> the Hexar
> and the Leica. Photographing the same objects with  a leica and a  
> Hexar in
> quick succession underscores this difference: with the  Leica the  
> work is harder
> (more to think and act), but your act blends in with  the subject  
> and you are
> part of it. With the Hexar your work is easier, but the  remoteness  
> of the
> controls acts as a filter between the object and yourself. Let  me  
> say, that you
> become a bit lazier when using the hexar and that shows in the   
> pictures.
>
> Technically there is nothing wrong with the  Hexar pictures, well  
> exposed,
> sharply focused etc. The Hexar then is for  photographers who avoid
> technicalities and want good imagery with a minimum of  technical  
> and manual control and
> who feel that the visual involvement with the  object has to be  
> separated, even
> detached from the tool they use. In this sense  the Hexar is close  
> to the
> Contax G. The family resemblance goes a step farther.  My test of  
> the Hexanon
> 2/35 indicates that Hexanon imagery is in character very  close to  
> the Zeiss
> philosphy of correction. The Hexanon is an 8 element lens  (with  
> the now familiar
> negatively curved front lens, pioneered by Leica and  quickly  
> adopted by
> Konica and Voigtlander). The Summicron has 7 elements, but  has one  
> aspherical
> surface, and one such a surface equals two spherical  surfaces). At  
> full aperture
> the lens exhibits a medium contrast (less than the  leica lens),  
> has visible
> flare in the bright areas and small detail rendition.  The  
> performance on axis
> till an image height of 6mm (image circle of 12 mm  diameter) is  
> excellent
> with a very good definition of very small detail. In the  outer  
> zones the image
> quality drops significantly and now we see small detail  with quite  
> blurred
> edges. Astigmatism is very well controlled, but there is some   
> curvature of
> field. The lateral chromatic error is quite large, and may add in   
> the bokeh
> preservation. The corners are very weak. At 2.8 the flare is gone  
> and  the image
> crispens a bit, the central disk of excellent quality now extends  
> to a  image
> height of 8 mm, with the corners still bad and the outer zones  
> hardly  improving.
> At 4 we find an overall improvement, but the chromatic error still   
> softens
> the edges of very small and tiny detail. At this aperture the  
> quality is
> comparable to the Leica, that shows better reduction of the  
> chromatic error and
> thus a crisper and cleaner image. If resolution figures were  
> relevant, I had to
> note that the
> Konica has the edge here. But these are bench  mark figures (large  
> scale
> projection test) and in actual photography the small  advantage  
> would be lost.
> This sideline indicates that differences in resolution  of 10 line  
> pairs/mm are
> not indicative of superior image quality. Optimum  aperture is at  
> 8, and after
> that contrast and resolution drop due to diffraction  effects.  
> Close up
> performance at 1 meter is identical to the tested distance  which  
> is at 100 times
> the focal length.
>
> The inevitable question of course is how this  Hexar lens compares  
> to the
> last non aspherical Summicron. In my view the Hexanon  is the  
> better lens
> overall.
>
> But you cannot use the Hexanon lens on a Leica  body: a collimator  
> check
> showed that the Hexanon lens has a focus plane that  differs from  
> the Leica lens
> by 0.09mm. Is that important? The discussion on the  Lug about the  
> Hexar
> body/Leica lens compatibility dismissed small differenes in  the  
> area of less that
> half a mm as irrelevant, because some uses could not  detect any  
> difference
> when comparing different lens/body combinations. The truth  is  
> this: a did a test
> on the bench and focussed carefully on maximum image  quality. Then  
> I used a
> micrometer to defocus by 0.03mm (which is quite small).  In the  
> image the loss
> of contrast was very evident, but resolution at least at  the lower
> frequencies (around 40 lp/mm) did not suffer. What did suffer was  
> the  edge sharpness.
> If you were to do your own testing and looking at the negatives   
> with an
> 8-times magnifier, you would not se any drop in resolution (beyond  
> the  detection
> capability of the eye at that magnification). But at a larger   
> magnification
> you begin to see it quite
> clearly.
>
> Now the continuing saga of the Hexar/Leica lens  compatibility.  
> First a few
> remarks: You can not measure the actual distance from  bayonet  
> flange to
> pressure plate by using the pressure plate itself as a  reference.  
> The slightest and
> unnoted pressure from the instrument itself on the  pressure plate  
> will give
> errors and the pressure plate itself is hardly ever a  plane  
> itself. So
> additional errors. The only way to do it is to remove the  pressure  
> plate and insert
> a device that is calibrated to be at the same distance  where the  
> pressure
> plate ideally has to be. To start from here. The distance  from the  
> bayonet
> flange to the pressure plate or more accurate the top of the  outer  
> film guide
> rails ( pressure plate rails) in the Leica M is 27.95mm. This   
> distance is also
> (but wrongly referred to as register. But this distance and   
> measurement is
> used to check if the guide rails and the bayonet flange are   
> parallel to each
> other
> and have the correct distance. The second  important measure is the  
> distance
> from the film rail (the innermost film guide  rails) to the bayonet  
> flange. In
> the Leica this is 27.75mm. The film gate then  has a distance of  
> 0.2mm. In
> every Leica book I know of there is a reference to  the filmplane/ 
> flange of
> 27.80mm.
>
> What is this. Rogliatti, Roger Hicks, Collectors  Checklist,  
> Hasbrouck you
> name them, all refer to flange to film plane distance  or flange to  
> film
> register. Now in German the word is "Auflagemass". This can be   
> correctly translated
> as "flange focal length" or "flange focal distance". But  this  
> measurement is
> done for the lens itself on a collimator where the lens is   
> adjusted such that
> the distance from the lens bayonet flange to the true optical   
> focal plane
> (focal point) is indeed exact 27.80mm. First lesson: NEVER believe   
> what is
> written about Leica in books that are focussed on history or  
> collecting:  these
> persons are no engineers. In every other book, check, double check,  
> triple
> check to make sure the person knows what he talking about.
>
> To sum up: we have an optical measurement done  on the lens to  
> adjust the
> flange focal distance and that distance should be  27.80mm. We have  
> a mechanical
> measurement on the Leica body, which is the  distance from bayonet  
> flange and
> the pressure plate rails which is 27.95mm. The  film gate is 0.2mm.  
> If we now
> use a film with a total thickness (emulsion plus  base) of 0.13mm  
> (APX25 as
> example) the thickness of the film will not fit into  the film  
> gate. There is
> some play and therefore the film will curl and curve  inwardly  
> (away from the
> lens). By using a focal distance of 27.80mm, Leica will  ensure  
> that the film
> when bowed a little, still will be correctly aligned in  relation  
> to the focal
> plane. It is intriguing to note that thick colour neg  films of  
> about 0.27mm
> will fill the
> film gate completely and the pressure plate will  press the film to  
> a plane
> position, instead of the curved position with thin  film emulsions.
> Theoretically a thick film would have a better flatness than a   
> thin film. Of course more
> research is needed, but these investigations do show  that the  
> information in
> the public domain is at best scanty or at worst  misleading.
>
> Now for the Konica Hexar. Here I have only one  official fact: that  
> is the
> bayonet flange to the pressure plate rails of  28.00mm. But I do  
> not have
> official info about the flange distance to the film  rails (or film  
> gate distance).
> Nor about the lens flange focal length. My own  measurements on one  
> Hexar body
> and lens showed that the film gate had a  thickness of .24mm and  
> the lens a
> flange focal length distance of 27.71. On the  basis of these  
> measurements the
> flange to film rail distance is 27.76mm. These  results are however no
> reliable enough to draw firm conclusions. What I do know  from  
> discussions with
> konica people is that their tolerances are wider than with  leica  
> and are choosen
> such that the best fit of Hexar body to hexar lenses is  assured.  
> The many
> inconclusive reports about problems or the lack of problems  with  
> fitting a leica
> lens on a Hexar body is partly to be explained by these  tolerances  
> and partly
> by the unreliability of the reports themselves. The Konica  people  
> at the
> factory told me that the Hexar is designed for use with the   
> Hexanon lenses and t
> hat all dimensions inside the Hexar are based on that fact.  If a  
> hexar user
> fits a leica lens and he has problems, than it is caused by  these  
> different
> dimensions and/or the chain of tolerances add up unfavorably. If   
> he has no
> problems: than he is plain lucky as the tolerances are such that  
> they  are close
> to what is expected for leica bodies and/or his demands are such  
> that  they are
> below the visibility threshold for the mismatch to show up.
>
> This is not the end of the story. People would  expect quick  
> solutions and
> fast answers and move on to the next topic. That is  living in the  
> fast and
> superficial lane of user group discussions. Serious  research takes  
> time and
> experience and dedication: scarce resources in a hasty  world.
>
>
>
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