PHz

At the time we graduated from the "Gymnnasium" it was usual to paint veteran cars red and use them for excursions. Nowadays my grandchildrens generation buy and paint buses while hiring permanent drivers with the right type of licence (especially important if festivities turn intoxicating) .

This snap was made by a friend using an almost equally old 6x9cm and some kind of Kodak B&W film (which i did not develop myself).

Later I have preferred much smaller formats, preferring sharp images (even in a short while when using shirt pocket sized Minoxes) , some time before diapositives disappeared I also found having a darkroom was too much.

When digital devices became competitive I only excercized very few analogue cameras sparingly, but stil keep a roll of Ilford XP in the fridge

absolutely the same screen picture here as EXpat shows. I expected a more detailed listing, Possibly "subsub" might be a more precise description ?

p

Possibly a result of my paranoid security progams, but when I today tried to use the option "All subcategories"to aid my quick overview it definitely did not list all the nooks and crannies of this forum.

Not a major shortcoming, but something that might keep impatient users away from some themes. Again, my programs might not allow this mechanism to work properly.

p.

the url is http//forum.mflenses.com. There it unfolds the locaciousness and lack of precision of statiical language models. only worth sampling, not reading.

p

yet another follow up: the post ad Noritsu a few steps up from here is abolutely well worth reading for adaptation enthusiasts and experimenters. Too bad that the time of finding such machines in skips is long past.

p.

CURIOUS SEARCH FUNCTION (caps lock!)

I tried to find post ad Taylor ,Taylor& Hobson and the Kapella design bureau in case someone had knowledge of the "Opic" genesis , but the search for TTH only tunrned up three names, stating that they had no posts.

So, the question is whether the search engine (very fast !) has some need of revision.

p.

iT IS WORTH NOTING (and entering once capslock is off) that there is a chabot "user", justifying itself on the "MFlenses" site

p.

Sirs,

To further extend this longish thread,

I noted a comment above that the Noflexars were good for UV. The measurements and positive conclusions I have seen apply to the two-glass varieties, not the T-noflexar with its rear field-flattening element.

To contine ad Novoflex, I recently aquired their 35mm variety.

Its snap-out focussing-extension-mechanism is certainly convenient (especially compared to extension rings), and except for choosing reproduction ratio accuracy (moving in stages, not a continuous process), it is a lttle bit faster than twiddling the very long helix of my Leitz close-up lens. BUT of course the short focal length is a disadvantage.

p.

The Thorlab thing has as precise distance-setting mechanism. One may change the operative ends between pointed and spade-shaped with the minuscule hex key that lives in the paper envelope.

It fufills all needs for both destructive and constructive work.

Exept for basket-cases of fogging and internal oil spills on glass and aperture, I do not recommend unscrewing anything on a reasonably heathy lens, even if the Thor lab device may encourage you.

p.

A far more recent Zeiss product modified today instead of going out in the snow. I mounted a "diskusionswürfel" on my Zeiss/Winkel junior.

I lit up a highly unauthorized ledl-ight to illuminate stronger than the original 220volt bulb, put he PHACO on a suitale setting and laid a Leitz 1/100mm scale slide on the table.While hoping for the upper combination of extension rings and bellows to suffice.

The beamsplitter worked fine once the cryptic incriptions had been understood, but so far, no reproducible snap of a 1/100mm scale has been produced, so i took a snap of the entire device. maximally shrunk from the original 15Mb or so to fit

problem solved, replacing the microswitch and cannibalizing a Nikon remote control switch (which only short circuits one of the usbC leads) plus soldeing in a jackplug which mates with the pigiff C. However the preicsion required made me call on my capable son to achieve the result. By now i need not have three arms to manage sutter release while focussing. Most satisfactory case of "fremder eingriff", as Leitz service people use to label unauthorized use of screwdrivers.

One supplementary tale while relating this; I once had a IIIc modified at the Hauser Torwerk in Wetzlar, the head man there told me that all the screws they had losened would have to be replaced according to company policy, since their fastening capacity had decreased by having been use once.

p.

Not an experiment, but a case of DIY:

Still difficult to insert images, i wanted to post a snap of the innards of the Novoflex pigriffC where I am trying to resuscicate its electrical release function. I have already shrunk and comprressed teh picture.

The site algorithm does not seem to provide any means other than linking to a websiteURL even if I have switched off all my paraanoiac safety programs.Possibly Firefox and the current incarnation of Microsoft 10 does not like this site. I am too lazy to leave my desk to fire up the Linux rig one floor below to try again, and give up until encouraaged to try an easier method-

Now my aged memory reminded me that the cryptic arrow symbol performs an upload, so all is well.

p.

it is years since my brief stint of physics studies, and optics was not regarded as important then, so my lack of deeper knowledge is monumental.

However, my computer aids in gathering info- a good source for early lenses is the french site dikoptrique where one of Steinheils early efforts on doublets are listed as: dioptrique.info/OBJECTIFS2/00063/00063.HTM.

Further listings af triplets before 1914 yields nothing from Steinheil, and this list of triplets after 1914 maily gives the names in the patent descriptions, not the factory, so you have to know where for example mr. Glatzel worked: dioptrique.info/base/f/f3-1914.HTM.

You may also try "perplexity.ai" as search engine its LLM will give you a view of the majority of web myths. As all "artificial imbecility" machines it is completely devoid of critical faculties, but very polished in its presentation of fake "facts" and irrelevant circumlocution. It does,however turn up good leads in the form of a short list of publkished mails while implicitly contradicting itself in subsequent sentences if pressed.

I keep supplementing this thread:
In this case not beacuse of the lack of response or to expand public knowledge, but to correct one of my less precise remarks ebove.

I wrote that I had aquired another Fraunhofer doublet; while strictly speaking, the original Fraunhofer achromat with a convex crown glass in front of a concave flint glass had a small air gap.

My Staeble and Leitz varieties are cementet, no air gap, so calling them Fraunhofer to distigusih them from the Steinheil variety of achromat is not entirely historically exact but should do to identify which shape and glass is in front.

p.

Further to the point above ad presuming Alpa quality control of the lenses they put their name on. I have som personal experience of this:

A long time before the Vallorbe plant closed, I had beeen on a job in Geneva and used the excellent Swiss train sevice to go there. I was curious as to how they went about testing their merchandise .

Mr Bourgeois showed me around (He was particularly proud of the roman road tracks outside and would like to sell me a 360degree rotating camera, while all needed was to have one of my Alpas looked after). The factory had a basement room with a pillar at one end for fastening lenses to be tested , and a large, colourful and detailed target at the far wall. (I did snap a few pictures of the factory and the test room with my Minox but no repro here. I have not seen them for years, also 8x11mm is not easily digitized)

He said that all lenses they received were tested there before the special Alpa/omega filter mount and front ring was attatched and some were rejected. The rejection policy is confirmed in the Thewes book where he states that Rolleis proposed contribution (ZIV designed lenses) did not make it. The two prototype(?) Rollei/Alpas (135 and 35mm) I have are optically sufficient but Pignons might not have liked their mechanics. Much later when they were on the brink of bankruptcy they started selling lenses labelled (made for Alpa) presumably not vetted in Switzerland (apart from the small batch of Kern Switars mounted in a japanese helix which I presume was mounted with permission and advice from Aarau.)

p.

Ad labelling stunts, see my thread below. A phenomenon that can have similarities was when Ford tried to flog one of their their entirely ordinary cars as a "Jaguar", with a bog standard diesel engine and not a heron-top overhead valve petrol one. They had bought the rights to the name. I thought it strange that Leitz would put their name on watches without any experience in manufacturing such. I was too polite to mention minolta, sigma and panasonic although their contributions do stand up to critical examination.

The 382page Puts Book is named "Leica lens Saga" and according to the Colophon page was published as a limited edition in september 2016 by Puts and imX . I boughty it from Puts at the time, but assue that well stocked antiquariats like Lindemanns might be able to provide a copy.

I have once more read Erwin Puts on the details of pursuing mechanical and optical perfection in developing Leica optics. ISBN 978-94-91089-12-1,

Most interesting details, starting with the improved triplets that became the quadruplet Elmar and moving on through the Hektor to how the summicrons were improved while discussing how to measure performance. A useful summary of lens design and production even if one does not use leitz products.

p.

Supplementing my comments above on Staeble and the Memmingen works utilizing their products; some time ago I was tempted to try another Fraunhofer doublet, so now I have the Leitz monster sitting on top of a tripod waiting for the weather to suit me.

p.