Pre asph Summicron-M 90; E49 vs E55 ?

[cbretteville]

Anyone care to elaborate on the differences between the E49 and E55 versions of the pre-ASPH 90mm Summicron - apart from the obvious that the filter size differs by 6mm and the telescopic hood covering the aperture ring on the E49. The E55 is reported as being shorter, but by how much?

Thanks,
- Carl

[luigi bertolotti]

Shorter in length, you say ? By memory (no docs in my hands at this moment) I'd say isn't so... obviously, is much shorter than the 1st type with 6 lenses and removable head... but seem to remember that the only difference is filter thread and hood shape... even the declared weight I seem is unchanged. Stand to be corrected, anyway.

[cbretteville]

7th ed. Leica Pocket book states that the overall length was shortened when the diameter was increased. That could just be another one of the inaccuracies in the book. Impossible to tell, I guess, without a comparison shot.

- Carl

[luigi bertolotti]

Damn, Carl, you've intrigued me about this question... I inspected my Cron 90 E49, looked some pics of the E55 and my personal findings are:

A) The glass assembly in itself HASN'T CHANGED : I take this as a basic assumption.
B) So the distance lens flange - top of front lens HASN'T CHANGED (and the bayonet, of course, IS the same)
C) The E49 has the filter thread on the inner face of the Leitz-engraved ring surrounding the front lens: its depth (caliper) is 3 mm
D) The hood, fully retracted, protrudes (caliper) 1mm from the above ring: so we have 4mm total from outer limit of the front lens.
E) In the E55 the inner face of the above ring isn't threaded... in the pics (Lager) it looks a little less "deep" than the 3mm I measured for the threaded version... I'd say more than 1mm but less than 3mm... say 2 ?
F) The E55 thread is on the inner face of top of the barrel... that protrudes over the usual ring... how much ? I see no reason for it isn't 3mm... this seems to be the std. for filter threads (I verified 4-5 lenses of similar age)
G) The hood, retracted, seems (Lager) NOT to protrude over the barrel itself, so we have probably 5mm total from outer limit of the front lens (this is uncertain, given my analisys partially based on pics, but I'd say it could maybe be 6, or, less probable, 4)

Conclusion : the E55 version IS NOT shorter than the E49: it maybe has the same length, or probably 1 mm longer, or even 2.

Sorry for the pedantry... blame is yours, Carl... I like too much these kind of issues...

And, above all... LET'S HOPE THAT A PERSON NAMED JC READ THIS THREAD !!!

[cbretteville]

Luigi,
I knew I could count on you to come up with the information! Honestly, I don't find this pedantic at all, just an attempt to thoroughly answer my question. This is exactly the kind of information I was looking for.

It makes sense that the length difference if any is negligible as the optical cell is the same in both. Seems a lot of the info in the Pocket book has to be taken with a grain of salt.

Thanks!
- Carl

[luigi bertolotti]

... and complients to you for the Metadata project... interesting a lot and very well written... 2 questions (unrelated at all between them)

1) In general, which useful and/or funny results can one achieve using an EXIF/DNG editor to alter the DNG files ? I played a little with PhotoME, altered semi-randomly the linearization table... rough variations in the "shadow" zone...saved the modified DNG, imported in LR... ok notable differences in shadow detail...didn't make other trials, but seems to me an interesting tool. Is unclear, to me, if you can really EXTRACT from the original file something you'll never achieve using LR and other DNG developers.

2) I read you are a security expert... do you have some inside info about (Hungarian ?) AVAST solution & company ? They proposed my company a partnership....

[cbretteville]

Luigi,
I honestly don't know enough of how the image data is encoded in DNG and what the tables control to answer your question. Sandy should be able to though.

Alwil (the makers of Avast) is from the Czech republic. And yes, I know of the company and have met some of their people (although that was almost 10 years ago).

This is however very off topic, lets take this off list. Why don't you email me?

- Carl

[jc_braconi]

The lenght for the very first model, 6 element, E48 including the mount and without the filter is 110 mm
the third model, 5 elements, E55, including the mount and without the filter is 84 mm, 78 extruding from the camera.

Rogliatti wrote page 92 of his first issue Leica & leicaflex lenses that the E49 is 63,7 mm !?...

Luigi, I do not have the one you got so please measure it.

[luigi bertolotti]

Just measured my E49... and my caliper says 78mm, flange to hood border (retracted).
The same as E55, one of my suppositions... as always, you were needed for the LAST word...

[jc_braconi]

Thank you Luigi, I just try to do my best.
Have you seen the pictures I posted about the F1 Maserati in the Tech. & indus. section ?

[luigi bertolotti]

Originally Posted by jc_braconi

Thank you Luigi, I just try to do my best.
Have you seen the pictures I posted about the F1 Maserati in the Tech. & indus. section ?

WOW !!! Thanks for the input... is a section I often don't open... fantastic shots and... what a car !!! And its'going HERE (Brescia, my town)... TOMORROW, you say ? You too with it ? PM to me something about, in case of...

[luigi bertolotti]

... confusion of dates... you spoke of "tomorrow" in a post of yesterday... oh well make me know...