Meniscus Lenses? Another question for Mr. Galli, and others...

[jb7]

I've seen meniscus lenses mentioned here a lot recently-
including Jim Galli's current favourite-

Now, I know what they are,
but in the context of old photographic lenses,
do they have a single element only?
Or is it a lens that contains a meniscus element, among others?
Can a meniscus lens be a cemented group?

And Jim, do you have any idea what is contributing to the qualities your current favourite is exhibiting?

I have a few in front of me now, and will have a look at putting one in a shutter....

I have done a search, but you know, Mohammed, and mountains, and all that...

[Jim Galli]

I've seen meniscus lenses mentioned here a lot recently-
including Jim Galli's current favourite-

Now, I know what they are,
but in the context of old photographic lenses,
do they have a single element only?
Or is it a lens that contains a meniscus element, among others?
Can a meniscus lens be a cemented group?

And Jim, do you have any idea what is contributing to the qualities your current favourite is exhibiting?

I have a few in front of me now, and will have a look at putting one in a shutter....

I have done a search, but you know, Mohammed, and mountains, and all that...

Landscape Meniscus lenses are always a cemented doublet. Even in 1850 they understood that a cemented pair caused the chromatic abberation to improve or vanish. So we call a doublet an achromatic meniscus.

As to quality, it's a crap shoot. Most of them are downright sharp at f 16. And most are throttled to about f12 by their builders. You have to "uncork" them to see what they're going to be like wide open. Wide open you see many different looks, some more subtle than others.

[eddie]

i have a nice jamin landscape lens. sucks in the coverage department.....what kind of coverage you getting jim? when i use the "water house stops" it gets worse. what gives? it is installed correctly i am sure.

e

[Jim Galli]

i have a nice jamin landscape lens. sucks in the coverage department.....what kind of coverage you getting jim? when i use the "water house stops" it gets worse. what gives? it is installed correctly i am sure.

e

Coverage is conservative because they get so wild out in the edges that usually they were vignetted mechanically by longish barrels to the stop. Take the lens out of the barrel and use it in a shutter maybe? You've gotta play with them to see what's going to work. I've got a 6 1/2" Lancaster that I simply popped the group into a wooden lens board and then protected the front a bit with an old Hollywood style flaring lens hood. So now it covers 5X7. Sort of.

[jb7]

Thanks for that Jim, very informative-
I've got the rear group out of a 6" Dallmeyer Enlarging Anastigmat-
it's a cemented doublet, about 75mm fl.

Going to see if I can mount it into my point and shoot plank...

[jnantz]

i have 2 meniscus lenses, they aren't very fancy.
one was harvested off of a box camera and the other off of a folder.
they both had a throttle as jim spoke and they are not doublets.

[jb7]

Sorry, getting mixed up in my nomenclature-
I'm not used to this-

Anyway, it's a cemented group, it goes into a copal 1 (gaffered up around the edge)
and it's around 75mm ƒ/2.5.
Nice and wild open, but seems to tame quickly with stopping down-

Unfortunately, it vignettes in the plank point and shoot, due to the small helical-
maybe I need to make a new camera for it, because it covers 4x5 with a lot of movement...

[Steven Tribe]

This is posted here as it is the latest that thread discussed landscape meniscus objectives and mentioned Jamin! There are the sad remains of a portraits/paysages Darlot/Jamin listed on the famous auction place. Not so sad if you want a landscape set from 1860. This has the original front lens (used at the back with the landscape set-up) and mounting for the washer stops and a single washer. EFL is 18".

I have no connection with the seller - except he used to be a bidding rival in the days when bidders' name were available!

[CCHarrison]

The history of the photographic lens usually begins with Wollaston's menicus lens (or "landscape lens") of 1812, which was an improvement over the bi-convex (double-covex) lens that was commonly used in Camera Obscuras. The bi-convex lens suffers from Chromatic aberration which causes poor sharpness and only direct, on-axis light rays to focus properly.

Wollaston's lens not only changed the shape of the lens to a meniscus type which allowed more light rays to come into proper focus, but by placing a diaphragm in front of the lens, the off-axis rays were prevented from smearing the image sharpness. The diaphragm moderated multiple types of optical aberrations and greatly extend the field of clarity and depth of focus, albeit at the expensive of lens speed. The key to this improvement was the use of the diaphragm to cut off light rays that would otherwise create significant loss of sharpness due to spherical aberrations.

In 1821, Charles Chevalier improved this lens by using a cementing a negative flint glass element with a positive crown element, which allowed the lens to focus visual and actinic light in the same plane - making it the first "achromatic" lens and about f/17 speed. This was the type of landscape lens fitted to Daguerre's original camera, made by Giroux. This type of lens would be used for the next 150 years or so, in simple fixed focus cameras as it was inexpensive to manufacture, provided good sharpness over a moderate field.

the first image on the left is Wollaston's Meniscus and Chevalier's "Landscape" Meniscus on the right..

Dan

[jb7]

Thank you Dan, appreciate that very useful and concise history and explanation-

I'm sure I'll have more questions soon...

joseph

[Glenn Thoreson]

An ordinary magnifying glass is a double convex lens. You can take pictures with it, too. As with anything else, some magnifying glasses are better than others. You'll either get an "art" photo or you'll get crap. It all depends on our point of view. I have a habit of saving lens elements out of all sorts of junk lenses. I save the ones that will form a usable image on the ground glass and toss the rest. Some of them make great meniscus lenses. Some make good magnifiers.

[renes]

Is Kodak a meniscus doublet achromatic lens too? Is it comparable to other meniscus?

I just bought 3 of them with Kodak No.1, No.2A and No.3A cameras. They are supposed to be f/11 but I found out they are close to f/6,8 when you take off the small lens hood which has much smaller hole diameter then the cell. I reamed it to have equal sizes and screwed in the hood back. I will test them soon on my 6x9.

[Ramiro Elena]

The front cemented pair in a Petzval is a meniscus then?

[jb7]

I think that might be a Landscape Meniscus, Ramiro, as described in Dan's post No.9 overleaf...

I have another little question- to which the answer seems obvious, which makes me believe it has to be wrong-

I want to use one half of an Aplanat to make a Landscape Meniscus. Since I have the lens, I can measure the position of the Waterhouse stop-

Will the spacing of the diaphragm be the same for one group as it is in a complete lens?

I remember reading somewhere, can't find the reference now, that the curvature of the concave surface facing the diaphragm will determine the position of the diaphragm, but this could only be calculated in relation to a fixed aperture, no?

I have assembled the parts necessary to mount this lens behind a Copal 3, but the assembly is too long by about 12-15mm compared to the Waterhouse stop slot position. I've ordered something to bring it closer to the original position, but it won't be here for a few weeks-

I'll try this out anyway, and it's very possible that I won't see a difference between the two setups- the focal length of the single group is about 750mm, the Aplanat itself is 450mm. Putting the single group behind the Copal 3 will give me a maximum aperture of about f/16.

I thought that if anyone had any ideas about this, I'd probably find them here-

[Jim Galli]

The front cemented pair in a Petzval is a meniscus then?

Yes.


I think that might be a Landscape Meniscus, Ramiro, as described in Dan's post No.9 overleaf...

I have another little question- to which the answer seems obvious, which makes me believe it has to be wrong-

I want to use one half of an Aplanat to make a Landscape Meniscus. Since I have the lens, I can measure the position of the Waterhouse stop-

Will the spacing of the diaphragm be the same for one group as it is in a complete lens?

I remember reading somewhere, can't find the reference now, that the curvature of the concave surface facing the diaphragm will determine the position of the diaphragm, but this could only be calculated in relation to a fixed aperture, no?

I have assembled the parts necessary to mount this lens behind a Copal 3, but the assembly is too long by about 12-15mm compared to the Waterhouse stop slot position. I've ordered something to bring it closer to the original position, but it won't be here for a few weeks-

I'll try this out anyway, and it's very possible that I won't see a difference between the two setups- the focal length of the single group is about 750mm, the Aplanat itself is 450mm. Putting the single group behind the Copal 3 will give me a maximum aperture of about f/16.

I thought that if anyone had any ideas about this, I'd probably find them here-

Good luck, I've always been disappointed with half aplanat's. Yes, they do form an image, but an unremarkable one. Your mileage may vary. They are different from a 'landscape meniscus'.

[jb7]

Thanks Jim-

A usable 750mm lens in a shutter will have a character I can't achieve any other way, so I'll be trying it out anyway...

[Dan Dozer]

Yes.



Good luck, I've always been disappointed with half aplanat's. Yes, they do form an image, but an unremarkable one. Your mileage may vary. They are different from a 'landscape meniscus'.

Jim - you may not remember the little Ilex projection Petzval that you sold me about 4 years ago. Image size was too small for the 8 x 10, but when using only the front element alone, it easily covers 8 x 10 with about a 9" focal length. It works beautifully for portrait type of work and I use it all the time. Don't worry about a shutter or diaphram - just shoot it wide open. One of the best buys I ever made.