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jean_christophe_barnoud1

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Posts posted by jean_christophe_barnoud1

    Name, source, price of adapter ring for 50mm 'cron lenshead to bayonet of 4leged copy stand?

    in Leica and Rangefinders

    Posted

    <p><a href="http://www.1839.org/hors/trucs/boowu/index.html?lang=en">Everything you want to know on the BOOWU.</a> Just take care if your camera is more recent than the M4, you will need to rotate the bayonet half a turn relative to the aluminium cast part of the BOOWU or it will not mount (blocked by the preview lever). To do this, you will need to loosen the 3 small screws on the side, rotate the bayonet and tighten the screws again.</p>

    Chasseur D'Image

    in Leica and Rangefinders

    Posted

    The past lens tests for the Leica M and R are sold separately in a folder. I do not know if the Konica, Cosina/Voigtlander are bundled with the Leica M's lens tests.

     

    As to their value, they are tests and worth only the protocols used which are heavily influenced by the magazine's editorial choices. Basically, you do not test lenses for amateur photography the same way as for highly specialized technical uses. What is more, the relative importance you give to different aspects of quality is not the same. Chasseur d'Image has its set of procedures and criterions which naturally differ from those from other magazines ...

     

    Now, if someone can name one test person or organization who tests a lot of lenses across brands and whose results are recognized as credible by a large consensus of this forum, I am interested ...

    Leitz Small Ball Head: Renovation

    in Leica and Rangefinders

    Posted

    I do understand that you do not want to lubricate the ball or the surface that comes in contact with it to lock the system in place. Yet, it looks like the ball is locked in place by a moving cylinder that comes to press (hopefully hard) against it, this cylinder itself slides in a tube (the lower part of the head body) under the action of the tightening screw. In this head's case, the movement is very restricted by gumming of some lubricant (it feels this way at least) and prevents real locking of the head. To clean what must be cleaned and grease what has to be greased, I still have to open it ...

    OT: Mailing Things From US to Destinations Overseas

    in Leica and Rangefinders

    Posted

    In some countries, France at least, the USPS partnered with companies (not the local Post Office) for delivery. These are generally well equipped to deal with delivering to offices or factories that are grouped in business districts and have a reception desk (they work monday-friday 8 to 6). It gets much worse when they have to deliver to people who are scattered in out of business areas, out working (mon-fri 8-6, remember), live in buildings protected by a digicode, and so on.

     

    Half of the time you get a paper slip in your letter box or a letter (slowest, cheapest rate) telling you they have a package for you and please call this (paying) phone number to arrange delivery (mon-fri 8-6, they give you a day, and may come the day after...). Often when dealing with uninsured parcels, you just get nothing. Anyhow, they never have an office in town where you could fetch your parcel in the evening or on a saturday morning ...

     

    Most of the time the parcel finally goes back to the sender after two months ...

     

    If you want to secure shipping from the US to France, and use USPS (I am not sure the other guys are much better at delivering to people), you have to : add digicode and any other useful information to get to the recipient on the address label, use a tracked / insured system, send the tracking number to the recipient, have him locate the delivery company in his country, have him check with the local delivering company as soon as the parcel is notified as arrived in his country on the USPS tracking web site.

     

    Obviously, as this has been going on for 3 years now, the USPS is not interested in delivery to people abroad. My experience with the others is less extensive but not significantly better.

    protecting your glasses from the m's viewfinder eyepiece

    in Leica and Rangefinders

    Posted

    I tried the faucet O-ring approach last year and did not like it as the rings often got lost in my bag. I also feared that there was often some grit adhering to the ring that could scratch my glasses.

     

    I now use the PTFE (teflon like) adhesive pads one sticks under furniture to help glide them around. These are light gray, 17mm in diameter, with a thickness of 1mm. I punch a 12mm diameter hole in the center. You have to clean the metal eyepiece vith alcohol so that the adhesive can hold properly.

     

    The surface that comes in contact with the glasses is very smooth and seems to stay clean by itself.

     

    I have had two of those on M4Ps for the last 4 months, including a month on the roads in Madagascar. They seem to hold properly in place and have been used with hardened plastic as well as glass lenses without problem.

    Third party filter holder

    in Leica and Rangefinders

    Posted

    <p>The FilterView I have is really very lightly build compared to Lutz Steps. The difference is immediately evident.</p>

     

    <p>The only difference in features is the brake system that is present on the FilterView and not on the Steps. The efficiency of this system is limited (from experience) and there is a (very cheap and cheap looking) workaround that works very well with Lutz's Steps <a href="http://www.1839.org/hors/trucs/polarsm/sec3-2.html?lang=en">here</a> (see the use of an office standard rubber band on the pictures at the top and 3.4.4.2. getting the arms out of the view.</p>

    <center><img src="http://www.1839.org/hors/trucs/polarsm/thinarmsjcb77xx-001.jpg?lang=en" alt="© Jean-Christophe Barnoud, all rights reserved"></center>

    Mystery lens...Leica M mount

    in Leica and Rangefinders

    Posted

    Sorry, make it two such wrenches : one on the adapter and one on the fixed part of the lens, as near as possible to the mount and NEVER further than the first moving part (that means between the screw mount and the focus helicoid in most rf lenses). DO use the second wrench so that your hand holding the lens does not slip and accidentally grip the focusing ring as this would risk serious damage to the lens.

    Polariser & Colour Saturation

    in Leica and Rangefinders

    Posted

    I have seen old (E36) Leitz polarizers acting almost like clear -yellowish- glass. If you want to check an old (linear) polarizer, look at a laptop or flat panel computer display through the filter while you rotate it progressively, it should become totally black. With circular polarizers, the front side of the filter should face the screen.

    Circular or Linear Polorizer for Rangefinder

    in Leica and Rangefinders

    Posted

    <p>There is no need to use a circular polariser on a Leica M, yet the slimmest, multicoated filters are often circular polarizers (BW or Heliopan for instance).<p>

     

    <p>You will need some special device however to use on a M camera, either by Leica (swing-out system) or after-market <a href="http://www.1839.org/hors/trucs/polarsm/index.html?lang=en">(see here)</a>. Most after market solutions involve an oversized filter (often 77mm) which may be used on another (slr) camera. This camera may require circular polarizers.</p>

    bokeh or flare or same? - Eddy Day

    in Leica and Rangefinders

    Posted

    Lutz, this is only a crazy hypothesis. As such I have no idea of the maths conditions that would limit the angle in which this could happen but a great number of images does not seem more impossible than one.

     

    What puzzles me in the picture is that almost all "ghosts" are round or almost and are often grouped in clusters. They all have the same size (diameter) but different densities.

     

    From this I believe that either these ghosts are images of something round and very bright or out of focus images of very small and very bright lights.

     

    In the first case, distance conditions being the same for all ghosts I believe they all should have the same size and densities proportional to the pinhole size (aperture). In the second case (out of focus images of bright lights) I do not understand why the ghosts should all be so exactly close to round and their sizes should all be the same when densities are not (and so the sizes and shapes of the bright light areas cannot be ?).

     

    Yet again I am in waters too deep for me.

    bokeh or flare or same? - Eddy Day

    in Leica and Rangefinders

    Posted

    Not at all sure of myself here but I wonder if it could be the "Plato cave effect" at work.

     

    Small holes in the foliage acting as pinholes can generate images of the sun on the ground if this ground is in a dark area (this is a real image). Pinhole images having no focus, they exist as "virtual" images at any distance of the hole and can be made "real" by using a sheet of paper, ground glass or ocular.

     

    Could we have pinholes in very dense foliage generating virtual images of the sun in the air of the dark area under the tree (in the cave ?) and the camera lens acting as some kind of ocular picking these virtual images and generating a real (though out of focus) image on the film of something that looks like the sun ?

     

    Looks like it is a bit far fetched though ...

    Which table top Tripod for M?

    in Leica and Rangefinders

    Posted

    Basically you are expecting that the head control(s) and locking feels right and that you can safely set your camera and longest lens for horizontal or vertical compositions on a table, go make a cup of coffee and be confident that you will find the lot as you left it when you come back.

     

    For table tripods (only) -due to their small footprint- I believe that the elevation of the camera base (relative to the table) should really be less than the (shortest) side of the triangle drawn by the tripod's feet on the table's surface.

     

    I use the Leica table tripod but cannot manage to really trust it's stability when left alone. I also tried a small Gitzo but that was much worse (higher with the same footprint).

    Can someone help ?

    in Leica and Rangefinders

    Posted

    <p>Here is a summary :</p>

    <ul><li>Telescopic lens (4 lenses in 4 groups)</li>

    <li>Maximum reproduction ratio 1:3 (with the macro adapter).</li>

    <li>Minimum focus 0.77m without, 0.50m with macro adapter.</li>

    <li>240g (black), 320g (chrome).</li>

    <li>41mm length (pushed in), 59mm (extended).</li>

    <li>Optical performance is nearly optimal at full aperture, increases only slightly when reducing aperture, vignetting is just noticeable at full aperture, pincushion distortion of only 1.3%. (Comment says optical performance is nearly on par with the R macro-elmarit 100mm)</li>

    <li>Available middle of october 2003.</li>

    <li>price is given as 1100 euros (before tax), 1300 euros (including VAT) for the lens and 700 / 830 euros for the adapter.</li></ul>

    <p>I give no guarantee regarding the distortion figure, that is what I understand from the web page linked by Henry, though I should not consider 1.3% a small figure.</p>

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