Plasmat-lens??

[seawolf66]

I have been reading to darn much on this site : you have dagor-lens- you have amatar-lens, you have tessars-lens, you have many other types of lens and I know each was made for a specific reason by their manufacture! But was is a Plasmat lens???? I have put that word in here on the search colum and had some good reading but still no answer as to what it is, and please Keep It Simple Sir's:: thanks

[Eric Leppanen]

http://photo.net/bboard/q-and-a-fetch-msg?msg_id=00IXw8

http://www.apug.org/forums/forum44/15673-what-does-all-these-lens-lerms-mean.html (in particular see Jim Galli's post)

[Ron Marshall]

http://www.largeformatphotography.info/forum/showthread.php?t=9070

[Ernest Purdum]

"Plasmat" originally was a tradename for a Hugo Meyer lens. The history goes back to 1903, although the name came along later. Each cell has three elements, like a Dagor, but there is an airspace between the inner two. This lets the designer play more games to optimize the performance.

Before WWII, the type was fairly well regarded, but since there are eight air-to-glass surfaces, there were some problems. Coating, and particularly multi-coating, has reduced the potential of these problems so much that the Plasmat type is now by far the most popular basic design for large format lenses.

[Glenn Thoreson]

Too many people worry about lens and design names. I just put the thing on the camera and shoot some film. If I like it, it stays. If I don't, it goes. I could care less if it's name is George.

[ifer]

its true... there are alot of lingo for lenses and for me, the price and size is more important... shen hao user here.

[Glenn Thoreson]

It kind of baffles me at how many folks spend so much time and energy trying to get opinions on this lens stuff. I often wonder if they ever shoot a picture, to find out. Any decent old Anastigmat will give you a good negative when properly used, as will Aplanats, Rectilinears and even meniscus "landscape" lenses. It's more the person using it than the lens.

[JOSEPH ANDERSON]

Glenn you hit the nail on the head, Twice.
Joe A

[seawolf66]

Gentlemen: Forgive me for try-ing to understand something that I am learning about and do ask weird question such as what is a Plasmat lens was: I just like to know things: as for Lens'es go , I have a rodenstock Sinaror 150mm F5.6 also have a Carl zeiss [London] F4.5 150mm tessar and a Ilex wide angle F16 Focus 4" which is 100mm and on top of that I have a Kodak anastigmat F5.6 130mm Shutter =Diomatic # 1
T-B 10 to 100 So as far as lens go I have what I want but still like to learn about lens and their habits ::Thats all not to start Moan and groan about a quesstion: Mr. Lauren MacIntosh
Glenn Thoreson and JOSEPH ANDERSON
and if you wish to bar me fine!!

[Dan Fromm]

Lauren, there are books. Buy one. You'll learn more, and more quickly, than by asking questions.

[Michael Alpert]

Lauren,

Ernest Purdum answered your question quite well, but perhaps a bit more information would be helpful. The heavier "normal" lenses are Plasmats, like the Schneider Symmar and Rodenstock Sironar lenses, in all their many versions. These six-element lenses have good coverage and are usually very sharp at the edges of the image circle, as well at the center, with only moderate stopping-down (assuming that you have a modern multicoated lens from one of the major lens-makers). Smaller lenses, such as Tessars and other four-element designs, usually need a greater amount of stopping-down to acheive sharpness toward the edge of the image-circle. Since Plasmat lenses in longer focal lengths, such as the 240mm Sironar-S, are large and heavy, they perhaps are not so good for hiking. Plasmats of 210mm or shorter are not nearly as heavy and are found in smaller shutters.

Plasmats are not wide-angle lenses, nor are they telephoto lenses. They are used most often at the mid-range lengths for a format: about 135mm to 180mm in 4x5, with 150mm considered "normal."

[Michael Alpert]

Joseph,

Was Glenn's nail worth hitting? And what, pray tell, did he hit it with? Maybe just answering a sincere question in a straight-forward way would be more to the point (so to speak).

[seawolf66]

Michael: Ithank you and ennest Purdum did give a good answer: all I needed was to be told that its different others since its 6 group lens!
And based on what your saying is they are better at the edges than others[I:E]
such as instead of hav-ing to use F16 you might be able to use F8 or lower maybe !
Thas what I have gotten from your note:
Thank for your time and helpfull answer :
Mr.Lauren MacIntosh

[Gordon Moat]

In general, one reason to use smaller apertures is for the greater freedom of movement from a larger image circle coverage. Near wide open, some lenses barely leave room for movements.

I tend to shoot near wide open, or quite often in the f11 to f22 range. I have a Symmar-S 135mm that I need to be careful about in the corners when near wide open. On my longer 180mm Nikkor-W (6 elements in 4 groups), I have much more room to try unusual movements closer to wide open (which is f5.6).

In practice it is something you need to try. It is also something that you might consider an additional creative choice. Many large format photographers just don't shoot at or near widest aperture.

Ciao!

Gordon Moat
A G Studio (http://www.allgstudio.com)

[cobalt]

Gentlemen: Forgive me for try-ing to understand something that I am learning about and do ask weird question such as what is a Plasmat lens was: I just like to know things: as for Lens'es go , I have a rodenstock Sinaror 150mm F5.6 also have a Carl zeiss [London] F4.5 150mm tessar and a Ilex wide angle F16 Focus 4" which is 100mm and on top of that I have a Kodak anastigmat F5.6 130mm Shutter =Diomatic # 1
T-B 10 to 100 So as far as lens go I have what I want but still like to learn about lens and their habits ::Thats all not to start Moan and groan about a quesstion: Mr. Lauren MacIntosh
Glenn Thoreson and JOSEPH ANDERSON
and if you wish to bar me fine!!

I've learned from experience that there tends to be a "piling on" mentality on this forum. I asked a question a few months ago that ended up being DELETED, simply because some took offense--why, I do not know.

Glad to see the question posted, as I wondered about the same thing. Good day to you, sir.

[Ole Tjugen]

One day when I get really bored I'll sit down and write a short article about the different "basic" lens types - meniscus, achromat, periskop, aplanat, triplet, "Protars", dagor, reverse dagor, tessar, plasmat, dialyte, double Gauss and so on.

I'll even shoot a couple of sheets of film with each type. :)

[Ernest Purdum]

Ole, I hope you'll get really bored quite soon.

[Dan Fromm]

Ole, surely you have better things to do, and the need isn't pressing. Think of the books on the subject in english: Cox, who barely uses the word Plasmat; Brandt; Henney & Dudley; Kingslake; Kingslake; and, in case I forgot to mention him, Kingslake. I'm sure I missed a few. And then there are books in other languages too.

To top it off, the question at the top of this thread isn't new at all. A number of the replies to it are little more than pointers to answers that had already been posted. This is a bad sign. It makes me suspect that if you wrote a short article, no matter what you do some of the people who want to know will manage not to find it.

But if you insist on writing it, please give at least as much attention to differences in performance between lenses of the same design types as to differences in performance between lenses of different types. I ask for this because I've noticed that not all of my double Gauss types -- they have different coverages and maximum apertures -- shoot equally well. The same goes for my dialytes and the heap of plasmats and tessars in the corner.

And if you insist on writing, I'd really appreciate verbal descriptions of what you see as differences in lenses' "signatures" that point to differences that can be discerned in the images that accompany the text. I ask for this because I'm an insensitive clod and really do need to be told where to look and what to see ... And even then I don't always see the really subtle differences.

Cheers,

Dan

[GhoSStrider]

I second that Ole. I think that would be a fascinating read. May boredom come your way soon! ;)

[seawolf66]

Mr.D.Fromm: I found Kingslake and is on order: thank you:

[JOSEPH ANDERSON]

Lauren, Perhaps some of us misunderstood your question. I did. You were not asking for opinions. But attempting to collect some knowledge on a specific lens design. and that's a good thing. Had I taken my time reading your question the first time around I would have
understood this. So please accept my apology.

Joe A

[Ole Tjugen]

Ole, surely you have better things to do, and the need isn't pressing. Think of the books on the subject in english: Cox, who barely uses the word Plasmat; Brandt; Henney & Dudley; Kingslake; Kingslake; and, in case I forgot to mention him, Kingslake. I'm sure I missed a few. And then there are books in other languages too.

To top it off, the question at the top of this thread isn't new at all. A number of the replies to it are little more than pointers to answers that had already been posted. This is a bad sign. It makes me suspect that if you wrote a short article, no matter what you do some of the people who want to know will manage not to find it.

But if you insist on writing it, please give at least as much attention to differences in performance between lenses of the same design types as to differences in performance between lenses of different types. I ask for this because I've noticed that not all of my double Gauss types -- they have different coverages and maximum apertures -- shoot equally well. The same goes for my dialytes and the heap of plasmats and tessars in the corner.

And if you insist on writing, I'd really appreciate verbal descriptions of what you see as differences in lenses' "signatures" that point to differences that can be discerned in the images that accompany the text. I ask for this because I'm an insensitive clod and really do need to be told where to look and what to see ... And even then I don't always see the really subtle differences.

Cheers,

Dan

Dan,
somehow I missed seeing your post until now. At the moment I'm more concerned with the big hole in my garden which is only half the size it should be - it's the beginning of a new drainage ditch that should be finished before heavy rain sets in, which of course it did yesterday.

You forgot Beck in your literature list; and at least one Kingslake, I believe. And Neumann in German, and...

If I do eventually write an article I expect people to miss it, as evidenced by all the questions on coverage and weight of this-and-that old lens - most of which are listed in the articles referenced on the largeformatphotography.info front page. That doesn't really worry me, since it would provide an opportunity to write "read xxxx, on the front page" in reply to even more questions. :)

Different versions of the same design - ah yes. That's a difficult one. The miniscule tweaks to a lens design that changes it from a super-sharp 35mm lens to a smooth-focus (not "soft", "smooth") LF portrait lens are an entirely different subject. Whole books could be written (I'm not saying they should be written) on the differences between triplets; or even on the sample-to-sample variability on one type of triplet from one factory in one year. So if you'll excuse me I think I'll just ignore that potential nest of vipers - and concentrate on what I can actually see from the samples I happen to own. I don't intend to buy any more lenses for this, as I already have more lenses than film holders and will need to reaload on the fly. On the other hand I intend to include the 150mm f:3.5 Schneider Xenar Typ D; none of the descriptions of this that I've found match the lens I have. If I feel really adventurous I might even include the 500mm f:5.5 Schneider-Göttingen Aerotar; from all I can find, mine is the only existing sample. :cool: