Weitwinke euryscop VII no7 confusion??

[Heiskis]

Hello,
I purchased weitwinkel euruscop vii no7 - and looking catalog (from 1890 I think), it should be 25 inch focal lenght..

After I got it - its about 13,5 inch - and based on same catalog - its most likely suplementary weitwinkel euryscop no7.

Any explanation available - confused because serie number 41 xxx gives year 1891 - about the same year as the catalog..

Not complaining -great lens - but would be nice to know why the difference or atleast confused at higher level..

Ps. Sorry - but Adding foto of the lens is too comlicated for me (or interface is...)

[Heiskis]

[gypsydog]

You are missing the "l" in Weitwinkel, meaning wide. this is a wide angle lens, the non weitwinkel VII Euryscope #7 would have been the approximate focal length of 25 inches you mention.

[mhayashi]

This lens was made in Aug. 17th 1891, Series VIII.
Your sample is listed as 14 linien oeffnung, which is about 31mm lens opening diameter.
But your sample is engraved as VII, which could be a typo supposedly, rarely seeen imo.
Or the Thiele’s book may list it as typo but I observe Series VIII all over the pages in this period.
Since you measure the FL as 343mm, the series VII No.7 FL is just 342mm.
Series VII comes with the rotating aperture disk except for No.7.
I think now the series VIII printing of the Thiele’s book is typo….

Just to identify your lens further, measure the front lens opening diameter.
Is it 31mm?

Unfortunately I couldn’t find the complete list of Series VIII, which was made for reproduction and is narrower field of view than Series VII.

Here is a sample catalog that doesn’t list yours but there were No.1 to No.7 too.


And for your reference, here is the Series VII.

[Steven Tribe]

These are the two Series tables for the Series VIII in the Prochnow volume 3.
He has done his usual conversion to “French” metric measures.

[mhayashi]

Good evening Steven. The lower list of VIII in Prochnow seems to be compiled from the Thiele’s book,
Which I now suspect the VIII annotations in the serial number tables are mostly typo of VII,
Based on the poster’s sample fact.

[Heiskis]

Now confused at higher level - thanks!
Most simple solusion is most likely (occami something...)..
As remeasurement gives about 36cm focal lenght and diameter of lens 30mm - giving f12..
I would go with writing typo on the lens...

[Heiskis]

Auts, it actually seems that my (english) prochure gives different info about euryscop vii than the German one...

[mhayashi]

I think your lens is Series VII No.7.
Always refer to German catalogs for consistency to avoid misunderstanding and wrong conversions from old Austrian units to English units.

The focal length depends on how you measure.

[Heiskis]

I think your lens is Series VII No.7.
Always refer to German catalogs for consistency to avoid misunderstanding and wrong conversions from old Austrian units to English units.

The focal length depends on how you measure.

I do agree !! Thanks..