Hermagis ?

[gliderbee]

I managed to buy this lens today (see pictures below). It says:

"Eidoscope f/5 N° 3"
"Hermagis"
"OptN ... Paris N° 40653".

It came in what the seller thinks is the original box, and included was a pouch with 5 metal "aperture slides" (I don't know the correct word for these), numbered 0.25, 0.36, 0.50, 1 and 2.

Also included was the brass front cap (looks beautiful) and rear cap (less beautiful), and some kind of instrument that the seller nor I could define. It might not even belong to this lens.

I found some info about Hermagis lenses and I came to this conclusion (but I have a few questions at the end, and please correct me if I'm wrong):

- it's a lens designed for soft-focus portraiture from about 1907
- it has a focal length of about 275mm (about 10.8"), and the front and/or real element can be used separatly, doubling the focal length.
- max aperture is f/5
- covers 5x7 max

My questions are:

- how are these "aperture slides" used ? How can I calculate the resulting aperture ?
- what kind of shutter can I use ? Any suggestions and/or links ?
- what might be that "instrument" on the last picture ?

Is this lens considered any good ? Are they rare or do you find them at each antique market (I never looked around for this kind of lenses; I really stumbled on this one on a flea market today) ?

I intent to use it, but IF I would sell it, what would be a reasonable asking price ? Glass is in excellent condition.

Thanks for any information.
Stefan.

[Jim Galli]

A pretty lens. I don't know too many answers to your questions but will say that it is very likely a petzval type since in the time period it appears to have been made, and just general geometry, that was about all that was on the market.

Someone has inadvertently screwed the front group onto the back and vice versa. Easily remedied.

When you have it in hand, measure the diameter of the glass and let us know. ie. if you measure 30mm X f5 = 150mm lens.

The waterhouse slide go into the slot you see and effectively reduce the ratio of focal length to aperture. Once you know the focal length the math is easy.

No way to guess at a value until size has been more closely identified. A 150mm petzval is very different in value than a 400mm one.

[gliderbee]

A pretty lens. I don't know too many answers to your questions but will say that it is very likely a petzval type since in the time period it appears to have been made, and just general geometry, that was about all that was on the market.

Someone has inadvertently screwed the front group onto the back and vice versa. Easily remedied.

When you have it in hand, measure the diameter of the glass and let us know. ie. if you measure 30mm X f5 = 150mm lens.

The waterhouse slide go into the slot you see and effectively reduce the ratio of focal length to aperture. Once you know the focal length the math is easy.

No way to guess at a value until size has been more closely identified. A 150mm petzval is very different in value than a 400mm one.

Ok, thanks ! I changed the front group and back group to where they belong

As for the diameter, it's about 58mm (the hood is in the way to measur it exactly), so that would make it 58 x 5 = 290mm ?

Thanks,
Stefan.

[Jim Galli]

Ok, thanks ! I changed the front group and back group to where they belong

As for the diameter, it's about 58mm (the hood is in the way to measur it exactly), so that would make it 58 x 5 = 290mm ?

Thanks,
Stefan.

OK, now if you can verify that one group is cemented 2 lenses together and one group has 2 lenses with a spacer, it is certainly a petzval, and 11" is a good number for people in the market.

Beware of the Capitalists. Guys like me who buy lenses from guys like you, play with them for half a year, and sell them at profit. This is evil.

[gliderbee]

OK, now if you can verify that one group is cemented 2 lenses together and one group has 2 lenses with a spacer, it is certainly a petzval, and 11" is a good number for people in the market.

Beware of the Capitalists. Guys like me who buy lenses from guys like you, play with them for half a year, and sell them at profit. This is evil.

Well, it looks like it are indeed 2 lenses in each group (I think: am I correct in thinking that the number of reflections of a lightbulb I can see shows the number of lenses ?). As for the spacer, I'm not sure how I can see that ? I don't see a difference, or I'm looking at the wrong place.

Stefan.

[Jim Galli]

A small penlight is best. Or one of those laser diodes on a key chain. One group should give you a distinct bright dim bright. This is the cemented group. Also look for very slight yellowish coloring from the balsam cement or even a bubble or 2 at the very edges.

The other group should give you 4 brights. One for each air ~ glass interface.

[gliderbee]

A small penlight is best. Or one of those laser diodes on a key chain. One group should give you a distinct bright dim bright. This is the cemented group. Also look for very slight yellowish coloring from the balsam cement or even a bubble or 2 at the very edges.

The other group should give you 4 brights. One for each air ~ glass interface.

Hm, I certainly don't see 4 brights; in fact, I don't see a difference between the two groups, and they both ahve a very slight, very thin yellowish coloring at the edges. Could it be that both groups are cemented ?

I found this in a French publication: "Composé de deux groupes symétriques, et corrigé de l’aberration chromatique, il ressemble à un rectilinéaire." Translation: "Made of two symmetrical groups, and corrected for chromatic abberation, it looks like a "rectilinéaire" (I don't know how to translate that last word).

Since it says "symmetrical groups", it's maybe normal that I don't see a difference ?

Stefan.

[Steven Tribe]

Jim - the first post says this is an Eidoscope - that is, a modified RR for soft effects!!
Suggest the original poster checks through the search function.
You would get more response if this was posted in the "lens" thread.
You will find your way to CCHarrison's "acheived sales prices soft lens sales" there.

[Emil Schildt]

Jim - the first post says this is an Eidoscope - that is, a modified RR for soft effects!!
Suggest the original poster checks through the search function.
You would get more response if this was posted in the "lens" thread.
You will find your way to CCHarrison's "acheived sales prices soft lens sales" there.

..and be happy to own it!

Make images - it is highly addictive - and of more worth than using time to figure out how expensive it might be!!

You'll love the results!!

Have fun - I know I do!!

[gliderbee]

Jim - the first post says this is an Eidoscope - that is, a modified RR for soft effects!!
Suggest the original poster checks through the search function.
You would get more response if this was posted in the "lens" thread.
You will find your way to CCHarrison's "acheived sales prices soft lens sales" there.

Hm, I looked for the lens subforum before posting, and for some reason (probably some missing brain cells ..), I didn't see it. Now I do see it. Can a tread be moved to the correct forum ?

I did search the forum, and I did found some threads, but nothing that explains the aperture .. Anybody who knows how these aperture slides work ? E.g. if I insert the "1" slide, what's the resulting aperture then ?

@Gandolfi: It's my intention to use this lens; it's my only vintage lens, and I'm very curious to the performance, but for that, I need to know how I can determine the effective aperture with these slides.

Stefan.