New arrived HERMAGIS casket lens

[seanwang]

The set lens has 4 elements, No.5,6,7 and last one with no number but has "HERMAGIS Opt'n Fab't Bte Paris Aplanastimatique 1:6.8 F=310m/m" on the rim.
Lens is very heavy! More than 1kg.

Shows following.

The seller told me that this HERMAGIS casket lens can cover 8x10 even lager, maybe above 11x14. That's ture? And I find the combination table in the internet, does it correct? --- but I'm not understand it...:(

[Ole Tjugen]

The last one is likely to be the same focal length as the No. 5, so that the two combined give a 310mm f:6.8. Cells 6 and 7 are shorter - if Hermagis were consistent in the numbering, the No. 7 should be a 360mm when used alone.

The combination table for my "Trousse No. 7" seems correct.

www.casket-set.com

[seanwang]

The last one is likely to be the same focal length as the No. 5, so that the two combined give a 310mm f:6.8. Cells 6 and 7 are shorter - if Hermagis were consistent in the numbering, the No. 7 should be a 360mm when used alone.

The combination table for my "Trousse No. 7" seems correct.

www.casket-set.com


Ole, thanks!
I can't post pictures in my office's computer. For single cell, it has three images in reflection(2 lighter, 1 darker), so I guess it contain two or three glass.

[seanwang]

find a computer.
here is picture and the combination table. Is that correct?

[Ole Tjugen]

It seems that the conversion table was made for a larger set, so it may not be correct for the one you have. That table also indicates that the focal lengths of the cells were NOT constant, since my No.7 cell is 360mm and the one in the table is 250mm.

As you might be able to see from the picture, my Hermagis Trousse Aplanatique has a kind of bayonet fitting - you only have to rotate the cell a fraction of a turn to screw it tight, the threads are removed in three sectors.

Mine also has three cells marked 7, 8 and 9, while the fourth cell is marked Somethingorother (I'm at work now) 210mm f:6.8.

[Sven Schroder]

Hi

Thats the conversion table from the set I sold to hollis on ebay which is an earlier set? not marked Aplanastimatique? I have a Hermagis catalogue with " trousse d' Aplanastigmat Hermagis " as a new edition this includes a conversion table for - Trousse No 7/6/5. I don't Know if it will help? I'll post it on this thread when I get a chance.
Thanks and Regards
Sven

[Hollis]

wait, what? I never got a conversion table.

[Sven Schroder]

Hi
Oop's, Sorry Hollis I now realise its the conversion chart from the set I kept (the E Francis trousse rectilinear multipules). Its still here in the casket so to speak.
Again apoligies to Hollis
Sven

[Hollis]

no worries. Do you have a chart for the set that I have? Just wondering.

[seanwang]

Hi

Thats the conversion table from the set I sold to hollis on ebay which is an earlier set? not marked Aplanastimatique? I have a Hermagis catalogue with " trousse d' Aplanastigmat Hermagis " as a new edition this includes a conversion table for - Trousse No 7/6/5. I don't Know if it will help? I'll post it on this thread when I get a chance.
Thanks and Regards
Sven


Trousse No 7/6/5, I think it should be correct table, on my lens it marked this number.
Thanks and Waiting......;)

[seanwang]

It seems that the conversion table was made for a larger set, so it may not be correct for the one you have. That table also indicates that the focal lengths of the cells were NOT constant, since my No.7 cell is 360mm and the one in the table is 250mm.

As you might be able to see from the picture, my Hermagis Trousse Aplanatique has a kind of bayonet fitting - you only have to rotate the cell a fraction of a turn to screw it tight, the threads are removed in three sectors.

Mine also has three cells marked 7, 8 and 9, while the fourth cell is marked Somethingorother (I'm at work now) 210mm f:6.8.

Yes, I mount it on my 810 camera, 4 elements can combine 6 combinations, from 210mm to 310mm.:p For single cell, how about quality when shoot photo? And is the No.8 and No.9 hard to find?

[Ole Tjugen]

All casket sets are hard to find and/or expensive. Finding single cells and incomplete sets is easier, but in my experience these never fit the barrel you have - and I have lots.

Hermagis seem to have produced casket sets over a period of more than 30 years, so both optical and mechanical changes are very likely - meaning that the chance of an orphan cell fitting another set is quite unlikely.

There also seems to have been at least two very different optical designs used, which means that the quality of a single cell from one set says very little about the same from another set.

[Sven Schroder]

Hi
Attached is the table from the Hermagis 1925 Catalogue so hope it helps.
Hollis, I don't think I have a table for your set, but with a berthiot set I found a
cheque stub with the focal lengths, and it showed the maths involved.
The focal lengths are added together Say 390+305=695 this is then divided by 4 which gives 173.75 it seem close enough.
Regards
Sven

[Ole Tjugen]

The correct maths is Ft= 1/( 1/F1 + 1/F2 + d/F1*F2), where the F1 and F2 are the focal lengths of the cells, Ft is total focal length, and d is a spacing correction factor. The last term has been written in very many different ways through the ages, depending on how and by whom the spacing d was measured.

Ft=(F1+F2)/4 is wrong, but will give an approximately correct answer for two very similar focal lengths with no spacing.

[Sven Schroder]

Hi Ole

Thanks for the correction, maths is not a strong point with me, I am sure I have number blindness as well as word blindness.
Thanks and Regards
Sven

[seanwang]

Sven Schroder, Ole, Thanks!
Already printed :D

[Ole Tjugen]

Mine also has three cells marked 7, 8 and 9, while the fourth cell is marked Somethingorother (I'm at work now) 210mm f:6.8.

for "somethingorother", read "Hermagis Paris Aplanastigmatit 1:6.8 F=210 m/m"

[Ole Tjugen]

And by the way: They are 3 elements to each cell, looks like a Dagor-type design at a casual glance. :)