tessar vs. plasmat for highest image quality

[nick_rowan]

I am interested in finding the highest quality lens within a focal length range

of 360mm to 480mm to shoot b/w portraits in an 8x10 format, as I hope to

make mural size enlargements (12x) from the negatives. For several years I

have been using Rodenstock Sironar S lenses (210mm mainly), which is a

PLASMAT design, to shoot 4x5 b/w portraits (making 24x enlargements), but

recently I tried out a Fuji 450C, which if I'm not mistaken, is a TESSAR design,

and felt there was a very different "feel" to the whole way space and volume

were conveyed, compared to the Plasmat-design Sironar.

My question is this: is the Tessar design inherently capable of making just as

high quality photographs as the Plasmat design? By "quality" I mean superior

sharpness, resolution, depth, luminosity, tonal gradation, and whatever other

categories photographic lenses are scientifically measured and judged by. Or is

the symmetrical Plasmat design considered to be the more "advanced" level in

the historical evolution of photograhic lens design?

I am aware of other current Tessar-design lenses, such as Schneider's Xenar

and Rodenstock's Geronar--but was under the impression (perhaps erroneously),

that although these are considered "good" lenses, they wouldn't be the best or

optimal choice for the most exacting requirements (Bob Salomon at Rodenstock,

for instance, has characterized their Geronar lens to me as a "student

lens")--especially in the case, for instance, where high degrees of enlargement

are involved, such as 12x or 24 in my situation. Am I right about that? Or would

the Fuji 450C or 300C, both "compact" designs, (or Nikon 450M or 300M for that

matter) deliver just as good results, used as a portrait lens in a studio setting,

at a 12x degree of enlargement, as say a Sironar S or Schneider Apo-Symmar

360mm or 300mm?

 

Thank you.

[michael_briggs2]

First, from the cross-section diagrams, the Fuji-C series are not Tessar designs. The Nikkor-M series does appear to be a Tessar type design, with four elements in three groups. The Fuji-C series uses an all air-spaced design of four elements in four groups. For the cross-section diagram, I guess that the Fuji-C might be an variation of the dialyte design, converted to an asymmetrical design for improved performance at infinity.

 

The classical dialyte design is exactly symmetrical, which implies optimum performance at unit magnification. The symmetry argument doesn't imply that the infinity performance must be poor, just the certain abberations are completely eliminated at 1:1. Lenses in this family include the Artars, Apo-Nikkors and Apo-Ronars.

 

The four element designs don't necessarily have poorer image quality compared to a six element Plasmat. What is almost always true is that the coverage of a four element design is smaller than the coverage of a Plasmat. Since you are using a modestly long lens, 360 to 480 mm compared to the format diagonal of 300 mm, and since your application (portraits) will probably not use movements, you probably don't need the coverage of a Plasmat design.

 

As to whether a Tessar or a Plasmat will have superior imaging qualities in the central field: I guess that this question can't be given a general answer. First, there are many ways to characterize imaging quality, so "superior" is ill-defined. Second, details in the design and manufacture of a lens will change the image quality, e.g., glass selection, optimizing for coverage vs central image quality, manufacturing accuracy, etc.

 

It might be possible for a Tessar design to have "superior" image quality over a smaller field than the wider coverage of a Plasmat. For uses that require a wider angle of coverage, the Plasmat would be a better choice. A Tessar design would be an economy choice when the focal length about equal to the format diagonal: the design would permit only modest movements.

 

Another note: most modern Plasmat designs are modestly asymmetric, for improved performance at infinity. Exceptions are the Fuji-A series and the Schneider G-Claron series. Rumor is that both of these are now out-of-production, so if you want a wide-field lens optimized for 1:1, you might want to buy one while new stock still exists.

[tim_hicks]

Within it's limitations of lesser coverage the Tessar type lenses - CZ Tessar, Xenar, Kodak Commercial Ektar etc. are as capable of giving a quality result as any Plasmat. Compare an old uncoated Tessar with and early uncoated Plasmat and the Tessar wins by a mile because the simpler design avoids flare but still achieves sharpness.

 

However the limitations of the Tessar type is the lesser coverage (typically around 55 degrees but it varies with the different makes and apertures). Perhaps this is one reason people assume Tessar type lenses are not as good - if you try a Speed Graphic with an old Ektar or similar Tessar type lens of 135mm or even 127mm then the corners may not be sharp because of the limited coverage. A 135 Symmar will have between 70 and 75 degrees coverage by comparison, enough for a little movement. I have a CZ Tessar 150/f6.3 from around 1913 and it is excellent within it's limitations. I have a Ross Xpres 8 1/2"/f4.5. from around 1950 that is superb.

 

Modern coated Plasmats are not necessarily better, they are just more versatile. The trade off is that they are bigger, heavier and more expensive to make.

 

One small correction, The Rodenstock Geronar is not a Tessar type but a Gauss type - the only similarity is that it is a simpler older and more compact design like the Tessar

[thomas_vaehrmann]

Hi Nick,

 

the Fujinon-C is a repro-lens and dialyte-type (4 air-spaced lenses), the Fuji-Tessar-type is called Fujinon-L. And the Rodenstock Geronar is a Triplet, the Rodenstock-Tessar-type is called Ysarex. I've both plus Xenar and can say they are as sharp as plasmats. Because they are old or budget lenses, they are single-coated except Nikon-M-series. The 4-lenses/3-elements-design will give brilliant images. Technically the main difference is covering: Tessar-types cover about 55 deg, Plasmats about 70 deg. If you look on mtf-curves Tessar-types give a better resolution in the center (spec. on 5 lines/mm) and go down towards the edges. If you don't need to tilt or shift, a Tessar-type will be as good as a Plasmat although some people think it's an "inferior" lens.

As you mention the "feel" may be different, depending on the grade of correction, but this effect is not limited to Tessar-types. Try it out and choose the lens that fits your taste.

[pete_andrews]

<i>"...is the Tessar design inherently capable of making just as high quality photographs as the Plasmat design?"</i><br>Over a limited field angle of around 45 degrees - Yes.<br>Over the 70 degree field offered by the 'plasmat' design - No, definitely not.<p>The Plasmat allows extensive camera movements to be used with a relatively short focal length, the Tessar doesn't.<br>In addition, the six separate glasses and 12 curved surfaces of the Plasmat allow the lens designer to make much better correction of chromatic errors and other far-field aberrations. The four glasses of the Tessar are quite restricting to the lens designer, unless exotic and expensive glasses are used to correct chromatic errors. In this form the lens becomes known as an 'Apo-Tessar', and is the basic design for most process lenses. These Apo-Tessars are a far cry from run-of-the-mill Tessars, which are ususally of only mediocre optical quality, even over their limited coverage angle.

[tim_hicks]

Peter,

I think you are underrating the Tessar type lenses, My Ross Xpres f4.5 has a quoted coverage of 58 degrees at f 4.5 for example and there is plenty of evidence that good condition f4.5/f4.7 Tessars and Xenars can be sharp to the corner with 55 degrees coverage. Nobody would claim these lenses cover anything more than 60 degrees. Your 45 degrees figure is more likely to be true for a f3.5 computation of the Tessar and a f2.8 version would be even less.

 

A battered old Tessar will not match a nice new Apo Symmar but an interesting article by Neill Wright for the MPP users Club magazine did a range of comparisons between used Symmars, Tessars Coated and uncoated, Xenars new and old. The results were revealing and by no means entirely in favour of Plasmats. Within their limitations the Tessar type held up very well. This matches my own experiences but to be fair I dont have a nice new Apo Symmar to compare with.

[colin carron]

Tim,

 

Dr Neill Wright's article should perhaps be placed in its context - it was entitled 'Standard Lenses for the MPP' and compared the performance of Schneider Xenars and Symmars which would have been original equipment on the (1950 - 1970 or so) MPP Microtechnical cameras. Neill's conclusion was originally that the Xenar (Tessar type) was sharper and had more contrast but he then noted a film of dirt on the internal surfaces of the Symmars he was testing. The article then goes on to explain how he cleaned the internal surfaces by dismantling the Symmar. (On reading this article I was prompted to check my own 150/5.6 Symmar and found a similar problem which seems to be common with this age and type of lens). However having cleaned the lens surfaces he found that it now '...matched a nice clean one in contrast and performance.' I found the same once I had cleaned mine following his excellent instructions.

 

I think it would be difficult to tell the difference between a shot taken with a good quality modern Tessar type and a similar Plasmat type. The main difference remains the increased coverage of the Plasmat type.

 

PS If you possess an older (convertible) Symmar which requires cleaning I do not recommend dismantling unless you know what you are doing as it is quite easy to have a major disaster!

[david_goldfarb]

Bear in mind that at most portrait distances, you don't need a huge image circle on an 8x10" (magnification ratio for a head and shoulders portrait is on the order of 1:3, therefore the actual image circle will be larger than the image circle at inifinity), so a Tessar might be just fine, since you are using the center of the image circle and you will have less bellows flare.

[jim_galli4]

I have been playing with 3 older Tessar's all of 127mm length. A Kodak Ektar, a Rodenstock Ysarex (sic?) and a Mamiya (Polaroid 600SE). I've shot pics with these on my 5X7. I know they are marginal on 4X5 but the 5X7 allows a close study of the Tessar's one main flaw. They are all excellent to superb in the very center, but they begin to degrade well before 4X5 area is reached let alone 5X7. The fall-off is subtle at first and finally drastic. A 360MM on 8X10 would likely be very suitable as you would still be MOSTLY in the center. The 450 dialyte should be stunning on 8X10. Plasmats are better for normal photography where you want to count on MOST of your full image circle to be sharp.

[kevin_kolosky]

Nick

 

I do not know alot about lens design, but I am going to jump in here and say that I do know something about buying inaccurate film holders and I think that as you pay attention to the lens you are going to choose you should buy all means also pay very close attention to the film holders you will use. they can make a huge difference as I am sure others might be able to attest.

 

Kevin

[kelly_flanigan1]

<img src="http://www.hevanet.com/cperez/cameras/images/450FujiC.jpg"><BR><BR><a href=" http://www.hevanet.com/cperez/cameras/nice_lenses.html"> Fuji 450 C f/12.5<br>

 

Resolution in lines per mm (f-stop/center/middle/edge)

 

<br>f/12.5 48 48 24

<br> f/16 48 48 34

<br> f/22 48 48 34

<br> f/32 42 48 34<br>

 

Notes:

 

Four element, four group airspaced 'Celor' design

Copal 1 shutter

Very Small and Light for it's focal length

As sharp as anything testing in this length

Covers at least 11x14, and perhaps 12x20 straight on

MultiCoated optics </a>

[alpshiker]

I suspect mine of being better than that! Could be too sharp for portraits but excellent when structures and fine details need be render. I'm not sure this serie was designed for repro? The A serie was.

[tito sobrinho]

Kelly is always thorough on her responses. Kudos to her!!! I need to add that the Apo-Lanthar is a Tessar design using "exotic" glasses (Wisner). The C is a dialyte type a la Artar, Apo-Ronar, Apo-Raptar etc. They all derived from the original von Hoegh's design in 1899 (double anastigmat Goerz type B) but in 1904 they labeled it Celor.

[david_goldfarb]

The Apo-Lanthar is a Heliar type using lanthanum glass, not a Tessar, if I'm not mistaken.

[tito sobrinho]

Yes you are. It is a Tessar type with lanthanum glass. See Wisner forum. I have the 150mm that I use on my Technical Horsemam. Very restricted movements on a 4x5. Fifteen years ago, I bought an entire camera for a song (4x5 Crown) just because of the lens that came with it i.e the 150mm f4.5 Apo-Lanthar.

[david_goldfarb]

Have you seen any other references to that effect? I think it may be a slip on Mr. Wisner's part. Voigtlander Tessar types were generally called Skopar, Color-Skopar, or Apo-Skopar. Neblette lists the Lanthar as a Heliar type, but Neblette is full of errors so I wouldn't take it as the last word. Anyone with a better reference like Kingslake handy?

[arne_croell]

Re Voigtländer lens types:

 

From the Focal Press Bessa Guide, London 1955:

 

"The Vaskar is athree-lens air-apaced anastigmat....

The Voigtar......and the Helomar...are of similar constriction to the Vaskar...

 

The Color-Skopar is a three-component lens with a cemented back element; that is, an unsymmetric anastigmat consisting of four lenses with six glass-to-air surfaces....

The Skopar...is of similar construction...

 

The Color-Heliar is a three-component anastigmat with cemented front and back elements. It consist in all of five lenses with six glass-to air surfaces....

The Heliar....is of similar construction...

 

The Apo-Lanthar is a three component lens with cemented front and back elements consisting in all of five lenses with six glass-to-air surfaces..... This most modern lens shows full correction in the three main colours of the spectrum...."

 

So the Apo-Lanthar is of the Heliar type, Voigtländers Tessar types were named Skopar, and the Vaskar, Voigtar, and Helomar were triplets.

[nick_rowan]

Thanks to all who have responded so far.

 

I apologize for misidentifying the Fujinon 450C--and Rodenstock Geronar too--as

a Tessar design; I was only going on information supplied to me by a major photo

retailer for the Fuji design, and perhaps another post on this website for the

Geronar one--as both being Tessar.

 

Be that as it may, the crux of my question really was whether the Plasmat

design represented the "pinnacle" in current large-format lens designs, or

whether other designs--such as whatever the Fujinon 450C is (which I now learn

from your contributions is a "dialyte" or some such variation thereof), or other

"similar" designs, such as the Tessar--would perform just as well as the

Plasmat, under all the ways by which lenses are scientifically evaluated and

judged--such as sharpness, resolution, MTF curves, contrast, tonal sensitivity,

etc--understanding, of course, that such "scientific" forms of measurement are

ultimately subjective, in that they must meet up with personal or aesthetic

preferences. Sharpness/resolution/edge sharpness--however you want to

"define" it--was the spec. I was most interested in ascertaining, as I will be

making approx 12x mural prints from an 8x10 b/w negative. It sounds from

your replies that the Plasmat design is NOT necessarily "the best" lens in terms

of sharpness and overall image quality, but only that it has a larger circle of

coverage than most other lenses in its class--and that, for instance, therefore

that the Fujinon 450C and 300C, or Nikon 450M and 300M by comparison--would

yield pictures just as "good" or sharp under all the relevant criteria.

 

For those who use or prefer older (Tessar-design) lenses, such as the Ektar or

Apo-Lanthar (if that's its correct design identification), or any OTHER smaller (4

or 3-element) design of lens, would you maintain that these lenses too are just

as sharp as a CONTEMPORARY Plasmat, such as the Rodenstock Sironar S or

Schneider Apo-Symmar?

 

Or has large-format lens sharpness INCREASED/IMPROVED in the last 50, 40, 30

years?

 

Thank you.

[jim_galli4]

Your question is awfully subjective. I'm going to stick my neck out and say that the Plasmats do more things well than most of the older designs. And some things they can do are simply stunning. However, if I were going to try what you're proposing, portraits/ 12X I think I would take a hard look at the dialyte types. That Fujinon may be very hard to beat. I'd also want to play with a 14" Heliar. Red dot Artars are common and not too pricey. Sharpness isn't everything. A normal viewing distance for an 8X10 foot picture would only require a 50lp lens to look very good. What film are you proposing. Most will have visible grain at 12X but again, when you step back to take a large picture all in, it disappears.

[nick_rowan]

Jim,

 

You seem to be advocating the Fuji 450 dialyte quite strongly. In your first reply you wrote that "the 450 dialyte should be stunning on 8X10"; in your second reply you wrote that "I think I would take a hard look at the dialyte types. That Fujinon may be very hard to beat."

 

I am very apt to believe you. I too was "stunned" by the Fujinon 450C when I tried it recently on 8X10; it was extremely sharp and brilliant. I almost preferred it to the Sironar S design or "look".

 

But can you elaborate on why you think that it--the dialyte in general, as well as the Fuji dialyte specifically--might be as good as you say it is and as good as I think it is, especially how it MIGHT be BETTER than the Plasmat for my purposes, 8X10 portraits, enlarged 12x?

 

For one thing, I am shooting with an 8X10 Deardorff--and do not want to use a 480mm Plasmat if I can help it. I think it's simply too large and heavy for that type of camera. I DO want to employ slight front tilt to increase depth of field, and it's harder to work the front with such a large and heavy lens. I have tried 3 different focal lengths of Schneider Artar: 305mm, 360mm, and 480mm--and feel that while they are all sharp, I am somewhat disturbed by what I feel is their apparent shallowness of--or "differently apportioned"--depth of field, due, I can only conclude, to their being flat-field lenses--but I am not completely sure about that yet. To be sure, I have had two large format lens specialists echo my sentiment. The Fuji 450C seemed to have greater depth of field FROM FRONT TO BACK, as opposed to from side to side. Contrary to many portrait photographers, I like capacious depth of field, at least in the photos I am currently making.

 

Secondly, in addition to its shallower depth of field, I felt the 360mm was not quite long enough for my tastes, and that the 480mm was perhaps too long--so I think ideally I would like a 450mm or 420mm focal length. It matches more closely the 210mm focal length, my favorite portrait length, in 4x5. I am going to try a 420mm Apo-Ronar soon, but have some trepidations that it might yield the same shortage of front-to-back depth of field as the Artar. (By the way, I also felt the Artar was too "smooth" and "refined" looking, in spite of its blazingly sharp rendering of detail, but that's another issue entirely...) That leaves only the Fuji 450C--or Nikon 450M-- in terms of contemporary multi-coated lenses, as the only other possibility, at least as much as I am aware. The only downside to the Fuji, however, is that it is a f/12.5 lens, making it somewhat difficult to focus--at least quickly and easily--which is what I need to do in a portrait situation, although I often have my subjects planted in a stationery position.

 

Finally, I agree wholeheartedly that grain--and to some extent, shortfalls in sharpness--"disappears" at normal viewing distances of prints the size I am making. But I still would like the prints to be as sharp as possible; I do see differences, even at such long viewing distances--although they are admittedly smaller, less noticeable than viewing smaller, "regular" lap-size prints, for instance, one or two feet away.

[nick_rowan]

Kelly,

 

Can you please tell me where you got the lines-per-mm resolution figures for the Fuji 450C? (Do you also have it for apertures f/45 and f/64 on the Fuji 450C?)

 

Also, do you have such figures for the Rodenstock Sironar S lens line--as well as other Fuji lenses, such as the 300C and possibly its Plasmat line?

 

What a rapid, easy, and concise way of comparing "sharpness" of lenses! Just the kind of shorthand method (albeit admittedly incomplete by itself alone) I am looking for.

[nick_rowan]

Jim,

 

Sorry, I neglected to answer your question.

 

I am currently using 8X10 Tri-X, and will try HP5+ as well.

 

I preferred the Tri-X to "t-grain" Ilford Delta 100, in terms of edge-effect, overall apparent sharpness, and tonality.

[jim_galli4]

Hi Nick,

I could get in over my head and embarass myself rather quickly. The reason I surmised what I have is just my own personal experience and taste. Very seat-of-the-pants. I don't do portraits at all but I do have a passion for old machines that are roughly the same magnification and sometimes even closer in than portraits. I use Schneider Repro-Clarons for most of those (dialyte like Artars and Ronars) and I just like the look and feel. Can't give a good scientific explanation. When I do landscapes looking out over the big expanses, I gravitate to plasmats and wide angles. Good luck to you and I hope you'll continue to post what you learn in your project here.

[sal_santamaura]

The Fuji 450C has a design focal length of 439mm; not 420 but less than 450 anyway. In addition to the data Kelly provided above (and the site linked to) you can get another set of resolution figures at:

 

http://www.thalmann.com/largeformat/300-450.htm

 

Kerry's site is full of useful lens information. Finally, a rapid, concise way of comparing "sharpness" would be via MTF graphs. Unfortunately, Fuji doesn't provide them, and most folks have trouble interpreting them. Absent such tools, the empirical approach you're taking is very reasonable.

[nick_rowan]

Sal,

 

Thanks for that useful info.

 

If you get this post, I have another question to ask (or anybody else can chime in too): do you know if, in general, shorter focal length lenses render a higher number of lines of resolution per millimeter than longer focal length lenses?

 

I was doing some research on the Ektar lens today and found on the website www.hevanet.com/cperez/cameras/ektar_list.html resolution figures for 4 Ektar lenses, ranging from 80mm to 207mm, all of which had significantly higher resolution figures than the ones Kelly Flanigan cited for the Fuji 450C. For example, the 207mm Kodak Ektar f/7.7 is quoted as having at f/16 and f/22 60/60/54 lines per mm (center/middle/edge). Kelly cites the Fuji 450C as having "only" 48/48/34 at f/16 and f/22. I would have thought just the opposite would be the case, given all that I have been told about lens performance getting "better" in the last 30 or 40 years. Or is the large difference in lines/mm between these two lenses attributable merely to the difference in focal lengths? I mean Kelly does mention after citing her numbers that they would indicate that the Fuji 450C is "as sharp as anything testing in this length", suggesting that focal length is possibly an extenuating factor with regard to resolution figures in general. If it's NOT a factor, then I am going to stop believing what people tell me about contemporary glass, and consider getting an Ektar!

 

I'm sorry if I may be dwelling all too heavily on lines/mm figures as criteria for evaluating lenses, but unfortunately I am one of those for whom interpreting MTF graphs is still an impossibility.

 

Anything you (or anybody else) could add to this would be greatly appreciated.

 

Thanks.