Which Petzvals have the Dallmeyer modification?

[Mark Sawyer]

It's pretty well known that with their 1867 Patent Portrait lenses, Dallmeyer refined and reversed the Petzval's rear air-spaced group. I've heard some other manufacturers later did the same. The Vitax may be one; Wollensak called it "an improved Petzval formula" and "a modification of the Petzval formula", but they may have been referring to the diffusion dial or some other refinement.

Does anyone know of other Petzval's that were designed to have their rear group reversed, as Dallmeyer did?

[Steven Tribe]

A very good discussion to bring up.

I don't think there are any French or German lookalikes, although they may have the patent pair without the soft adjustment. A number of French makers had the extension/contraction of the main barrel as softness control (for instance, Darlot's Universal). Just as the B&L Portrait series rear adjustment moved moved the complete cell.

Patent protection was only granted for a limited period in the 19th century. Perhaps someone could illuminate this factor?

[CCHarrison]

The Hyatt Special Portrait Lens was a Dallmeyer copy, as was the Wollensak Royal portrait, Vitax, Ilex Acme Portrait (Vitax copy), Bausch & Lomb Portrait Series A and Series C, (not sure about Unar). I am sure there are many more.

Berliner should be able to help with this. He probably has all these and can check first hand :)

References : http://antiquecameras.net/softfocuslenses2.html http://antiquecameras.net/softfocuslenses3.html http://piercevaubel.com/cam/catalogs/1904b&lporrtraitlenses.htm

[Steven Tribe]

The unar is a classic dialyt type, I think. Probably the inspiration for the Graf Vaiable.
The B&L portrait series A may have the Dallmeyer rear cell, but soft adjustment is whole cell movement.

[CCHarrison]

I think Mark's question is which lenses have the Dallmeyer Petzval layout not necessarily the Dallmeyer diffusion method ?

[goamules]

Mark, I've seen very few with the "thick" in the rear, as the Dallmeyers. Like we're saying in this thread, it seems to be a few of the American companies, later (none of the early American Radial drives was this way). And since B&L or Wollensak made most of the F3.8 and F5 Portrait lenses in the early 1900s, it stands to reason a rebranded lens would be the same, whether labeled Hyatt or the dozen other big photographic resellers that bought their lenses.

My question to you is does your Gundlach Petzval Portrait lens have the Dallmeyer ordering? They are another US company that I think actually manufactured their own lenses.

Here are two interesting patents by Gundlach, one for a Petzval Mod (but not the Dallmeyer ordering).
https://www.google.com/patents/US212099
https://www.google.com/patents/US442251

[goamules]

duplicate....mod please delete...

[goamules]

Here's a diagram of the Unar, which is really a "pre-tessar" design. https://c2.staticflickr.com/2/1497/26300293666_be4af0ca91_o.jpg

[CCHarrison]

The 1890 Gundlach patent lens is seen here http://piercevaubel.com/cam/catalogs/1891gundlachlp303.htm

[Mark Sawyer]

Berliner should be able to help with this. He probably has all these and can check first hand :)



My question to you is does your Gundlach Petzval Portrait lens have the Dallmeyer ordering?

One problem is, over the years so many of these lenses have been disassembled for cleaning, then reassembled wrong. Some of us are probably re-configuring lenses with the Dallmeyer layout into the classic Petzval layout, if someone hasn't already beat us to it, so we can't really trust the assembly of the lenses as they are now. So really, the only way to be sure is to have a reliable list of which are assembled one way, and which are assembled the other way. Dan's list in post #3 is a good start.

Garrett, my Gundlach-Manhatten Series A Portrait No. 5, (15 inch Focus F:5) has the classic ordering, but I'm not sure if I trust that to be correct. My Vesta also has the classic order of assembly, but was Wollensak using both configurations (Dallmeyer's for the Vitax, classic for the Vesta) simultaneously?

On a connected side note, does a Petzval being marked for diffusion indicate it was of the Dallmeyer configuration?

[Steven Tribe]

Well, I have some news about this. In my newly acquired Le reve data booklet, I can see that from about 1875, Gasc & Charconnet, made a version of their Quick Acting Petzval, called B in their catalogues, which is described as " imite ceux de Dallmeyer". Now I happen to have a quick acting G&C Petzval sold by Bryant in the USA and I noted that the rear cell had the 2 lenses mounted separately - without giving a thought to what this might mean. It does, indeed, have the Dallmeyer rear layout. Adjustment can only be made by taking off the rear cell and screwing the inner cell.

These were made in 3 sizes:

13cm efl, lens diameter 54mm
16cm efl, lens diameter 70mm
25cm efl, lens diameter 81mm

It is last one I have.
It might be a good idea to check your Bryant/G & C lens!

[Steven Tribe]

And another one!

Again, I overlooked the logical meaning of a rear cell, where the two lenses are joined by a screw thread.
This is a large Derogy, with export engravings "London and Paris". Exactly the same system as with the above G & C and with no graduation marks inside. I image there are details in Le Reve booklet no. 16 which includes Derogy.

I now have this booklet which includes Derogy. There is no mention of "Ross" and "Dallmeyer" versions in the text.

[goamules]

Well good work detective! I'll have to check my G&C Quick Acting and see if it's that layout too.

[Mark Sawyer]

Just as a note, I'm cleaning up a couple of 14-inch Vesta lenses today and re-ordering them to the Dallmeyer layout. I've seen several notes in Wollensak catalogues that they are "built on a modified Petzval formula", built on a modification of the Petzval formula", and "an improvement of the Petzval formula". Wollensak used similar language in describing the Vitax, ("a modification of the Petzval", etc.), so I'm guessing both lenses use the Dallmeyer layout.

If anyone has information contradicting or confirming this, I'd love to hear it...

[Steven Tribe]

The modification may be the general redesign, initiated by Hermagis and Voigtlander, in the 1850's which moved the visual and chemical focus to the same plane.

[Mark Sawyer]

The modification may be the general redesign, initiated by Hermagis and Voigtlander, in the 1850's which moved the visual and chemical focus to the same plane.

The only re-design by Voigtlander that I know of is the 1878 modification wherein Voigtlander cemented the two rear elements, resulting in a less-sharp lens. (Obviously, that modification is pretty recognizable when you disassemble the rear, so it's not on any Petzvals I've seen.) Can you point me to any information on the 1850's redesign?

[Steven Tribe]

Here are two sources. Sorry about the quality.

The Voigtlander extract includes the number of turns necessary on the lens focussing knob. What a problem they must have had in the 50's!

[Mark Sawyer]

Interesting! I've had surprisingly little issue with chemical vs. optical focus with Petzvals on wet plate. But as far as I know, all my Petzvals are 1860 or later, so perhaps the modification was common to all Petzvals by then. I wonder what Hermagis' "modification" was, re-ordering the rear elements, different spacing, different curves to the lenses?

Perhaps I'll just have to shoot a Vitax and Vesta in both configurations and see how they compare. But that still may not tell me how the were assembled by Wollensak... :(

For those who don't read French, here's a translation of the first text from someone who reads it poorly:

PORTRAIT LENSES

LENSES OF ORDINARY MOUNTS

Petzval lenses (4 lenses in 3 groups) having blur due to residual chromatic aberration (anachromatic objectives), presence of a chemical focus different from the optical focus (image modification of the order of 2%, thus requiring focus correction. Hermagis was one of the first to greatly reduce these disadvantages.

(Meaning a focus correction of 2% was necessary before Hermagis' modification.)

[thafred]

Can someone explain to me why "chemical focus" was different to optical focus? Intriguing..
Is it because the lens doesn't focus all the colors on the same plane but the orthochromatic emulsion records only blue light? Since the human eye is least receptive of blue light we focus the other wavelengths more naturally so what looks sharp on the ground glass is blurry on emulsion?
That would mean that to get the sharpest focus out of my petzval I would have to use a color filter on panchromatic film?

Thanks for clarifying!

Back on topic. I bought a nice big (nondescript) petzval some time ago (somewhere there is a thread here) that had terrible picture quality until I reversed the configuration of the rear group, making it into a dallmayer effectively. I don't have a clue who made this lens but it was obvious that the previous owner had cleaned it and put it together the wrong way around.

[Mark Sawyer]

"Chemical focus" (aka "actinic focus") is only an issue with non-panchromatic processes. The old orthochromatic films and plates were sensitive to UV, violet, blue, and green light, which focuses at a closer distance from the lens than the visible spectrum, especially so with the older non-apo-chromatic lenses. So after focusing on the visible light, photographers would shorten the focus (usually by 1% to 2%) to get the UV-blue wavelengths that would actually be making the image in focus. Modern panchromatic emulsions match the human visible spectrum very closely, so no correction is necessary. A very strong filter at either end of the spectrum can affect the chemical focus; that's why there's a focus correction for infrared photography.

Hope that helps...

And yes, I've run into many Petzvals that were re-assembled in seemingly random order. I've always re-assembled them in the classic order, but with some (a few? most?) later Petzvals, they may have been designed for the Dallmeyer layout. I'm not sure which, hence this thread. I believe the Vitax and Vesta were Dallmeyer-style.

[Steven Tribe]

The swap of the order of the rear pair of "Petzvals" doesn't create a lookalike "Dallmeyer" patent Petzval! Both Dallmeyer rear cells are redesigned and so are the later clones.

Now the whole question of light (and near visual) wavelengths is a fantastic topic in Photography, viewing and registering on different media. I certainly don't have all the answers! Is is logical that if the early Petzvals needed a % change after viewing focus in order to focus the blue/uv wavelengths for ortho type, then most colour wavelengths would have been dramatically out of focus - even if not seen by the emulsions. Would panchromatic emulsions be unusable on these early Petzvals, would some wavelengths be always of out of focus?

[Mark Sawyer]

...Would panchromatic emulsions be unusable on these early Petzvals, would some wavelengths be always of out of focus?

Panchromatic would be the easiest to use on the old Petzvals. Because panchromatic film matches the human visual spectrum so closely, what you see is what you get for focus. No corrections at all.

I work a lot in wet plate, one of those very-orthochromatic processes, and I find only a slight correction is needed. When focusing, I just err on the short side of the acceptable range, and that does it pretty well.

[goamules]

The only re-design by Voigtlander that I know of is the 1878 modification wherein Voigtlander cemented the two rear elements, resulting in a less-sharp lens. (Obviously, that modification is pretty recognizable when you disassemble the rear, so it's not on any Petzvals I've seen.) Can you point me to any information on the 1850's redesign?

Actually Lerebours was the one that first corrected the actinic vs visual problem in Petzvals. Voigtlander, being the original Petzval, were guilty of the problem. Lerebours fixed it. Some sources here http://www.largeformatphotography.info/forum/showthread.php?51323-Lerebours-or-Voigtlander

Quickly, others adapted the Lerebours correction. Here is an ad for Ross' new "Orthographic Petzvals", which correct for the difference between actinic and visual light. Hard to read, but it's in the The Athenaeum, 1859
https://c1.staticflickr.com/5/4157/35228227670_d3bd5a91ef_o.jpg

[Mark Sawyer]

Actually Lerebours was the one that first corrected the actinic vs visual problem in Petzvals. Voigtlander, being the original Petzval, were guilty of the problem. Lerebours fixed it.

Hmm, maybe that's why I need so little correction compared with what was recommended in very early photography. Talk of actinic vs. visual focus seemed to die down after the mid- to late-1860's. Do you have a date on the Lerebours correction, and what it involved? (And I wonder if that's why Tony's very early Voigtlander was so soft?)

[Jody_S]

Well, I have some news about this. In my newly acquired Le reve data booklet, I can see that from about 1875, Gasc & Charconnet, made a version of their Quick Acting Petzval, called B in their catalogues, which is described as " imite ceux de Dallmeyer". Now I happen to have a quick acting G&C Petzval sold by Bryant in the USA and I noted that the rear cell had the 2 lenses mounted separately - without giving a thought to what this might mean. It does, indeed, have the Dallmeyer rear layout. Adjustment can only be made by taking off the rear cell and screwing the inner cell.

These were made in 3 sizes:

13cm efl, lens diameter 54mm
16cm efl, lens diameter 70mm
25cm efl, lens diameter 81mm

It is last one I have.
It might be a good idea to check your Bryant/G & C lens!

Does your lens resemble this (http://www.ebay.com/itm/MICROSCOPE-PART-VINTAGE-BRASS-CHARCONNET-GEO-BRYANT-OPTICS-AS-IS-BIN-AE-09/252969695601), by any chance? I swore I wouldn't buy any more but they're like potato chips.

[plaubel]

Talk of actinic vs. visual focus seemed to die down after the mid- to late-1860's.

In general - no.
Late cameras up to the 20century, with meniscus lenses, further have had the focus shift
Refocusing per formula (or following onboard tables), or using a yellow filter while focusing has been the trick.

[Steven Tribe]

Does your lens resemble this (http://www.ebay.com/itm/MICROSCOPE-PART-VINTAGE-BRASS-CHARCONNET-GEO-BRYANT-OPTICS-AS-IS-BIN-AE-09/252969695601), by any chance? I swore I wouldn't buy any more but they're like potato chips.

I have checked P et P and there are no visible differences between the "Ross" and "Dallmeyer" versions. Both were made in the size 13cm efl with total lens diameter of 54cm - which is the one you have bought, I think! The Ross ones were made in much larger sizes as well. This what the rear cell looks like on the Dallmeyer clone. Can only be unscrewed by taking out the lens.

I checked my similar clone - a Derogy- and it is built up in an identical way. P et P describe 4 series of plain Petzvals, but mine must belong to one of the first two series (serial number). But no information there about a Dallmeyer copy!

[Jody_S]

I have checked P et P and there are no visible differences between the "Ross" and "Dallmeyer" versions. Both were made in the size 13cm efl with total lens diameter of 54cm - which is the one you have bought, I think! The Ross ones were made in much larger sizes as well. This what the rear cell looks like on the Dallmeyer clone. Can only be unscrewed by taking out the lens.

I checked my similar clone - a Derogy- and it is built up in an identical way. P et P describe 4 series of plain Petzvals, but mine must belong to one of the first two series (serial number). But no information there about a Dallmeyer copy!

Thanks. I'll check when it arrives.

[Mark Sawyer]

In general - no.
Late cameras up to the 20century, with meniscus lenses, further have had the focus shift
Refocusing per formula (or following onboard tables), or using a yellow filter while focusing has been the trick.

Focus shift occurs on lenses (such as meniscus lenses) with significant spherical aberration. It's remedied by re-focusing after shutting down the aperture.

Using yellow filters while focusing on orthochromatic film would have an adverse effect; you'd be focusing on yellow light, while blue light would be making the actual exposure on a different focal plane. Yellow filters have quite a few uses historically. Kuhn furnished them with early Imagons because he was largely a landscape photographer, and liked the yellow filter's effect of darkening the sky and brightening foliage. It was also though to be a contrast enhancer on b&w films, and could negate some of the effects of chromatic aberration without causing much loss of light. Yellow filters were also used with isochromatic films to give them a more panchromatic effect. In portrait photography, yellow filters reduce freckles and blemishes, and supposedly improve skin tone.

[Steven Tribe]

I have been able to find the series from Derogy which included the "Dallmeyer" alternative.

The answer was in the diameter of the lenses. Derogy gave these as the physical size, not the visible size when mounted. Mine is 88mm which appeared in the second list of Petzvals - both these first two lists date from 1870. My serial puts it in the 1870's. Why should there be two, apparently identical Petzval series from the same date? Well, there is some difference in speed. But within the series there is also quite a lot of variation, especialy for no. 27 and no.28, which have identical focal lengths for lenses that are 88 and 108mm across.

Checking my lens, which I assumed must be no.27, with a focal length in the catalogue of 25cm, I find a figure of 30cm focal length from the WHS. Is this a back focal length in the catalogue? I think it must be, as the same three lenses appear in the later series with the "extra" focal lengths measured up to the WHS stops.

1870. 1890.

no.27 88mm lens fl 25cm. no.6. 88mm lens fl 30cm
no.28. 108mm lens fl 25cm. no.7. 108mm lens fl 31cm
no.29 135mm lens fl 35 cm. no. 8. 135mm lens fl 42cm

The increasing differences between 1870 and 1890 for the larger sizes is what you would expect from the longer barrels.
Anyway, here is the list which may contain ( or always, perhaps?) "Dallmeyer" Petzvals. Focal lengths are back measures.

[DrTang]

Question:

I have a Briggs Special Portrait lens 5x8 f5 which is a rebranded something.. and similar to a Hyatt Special Portrait??

anyway..in reading thru the forums..it seems my lens might be assembled backwards...it has two separate elements up front with the soft focus markings 1 thru 4, and the bigger cemented element in the rear

is this backwards? and if so..how would one adjust the softness w/o taking the lens off the camera since those elements would be on the back inside the camera

also.. who the heck really made it?

pix:

https://www.flickr.com/gp/11191083@N00/oV6U6a

and

https://www.flickr.com/gp/11191083@N00/7wpB4B

[tjuliuxue]

hugo meyer atelier petzval from Germany is also modified petzval

[ndavidson27]

Adding to this thread, Ross made a "Universal" line of petzvals, which had the Dallmeyer designed flipped rear grouping. They seem to be quite scarce and I can't find any historical information on it. My example is 10" at f5.

[Steven Tribe]

It has been written in another thread, but deserves to be repeated here-

Ross's later Cabinet series adopted the Dallmeyer rear lens arrangement!

[Mark Sawyer]

My Ross No. 3 Cabinet Petzval (serial no. 56993, putting it 1890-95, according to Wilkinson and Glanfield) has the classical layout.

I've taken to classifying the two layouts by the shape of the rear positive lens. The illustration below, taken from Kingslake's History of the Photographic Lens, shows the Petzval element to be slightly bi-concave, while the Dallmeyer is slightly meniscus, (though both are close to plano-convex.) I'd be interested whether others think this is a reliable method, as I'm unsure whether the curves changed on either design through the years...

[Steven Tribe]

My Ross No. 3 Cabinet Petzval (serial no. 56993, putting it 1890-95, according to Wilkinson and Glanfield) has the classical layout.........

When I wrote "later Cabinet series", I meant sometime in the 20th Century! This is from the Professional Kodak Catalogue of 1934. Of course, sales of Portrait Petzvals were pretty low by then as the number of numbers of Studios were stable - or already falling. This would also explain why we see virtually none of the additional Dallmeyer Patent Petzval sizes that were offer in the same 1934 Catelogue.

[Steven Tribe]

Just to add another known convert to the Dallmeyer rear cell design in the 20th Century.

The late series 1a Petzval from Voigtæander also had it. This is the series that mostly had smaller sizes and managed F2.3

[Mark Sawyer]

Just to add another...

Interesting! Looks like they also reduced the diameter of the rear cell, which would of course be magnified by the front cell. Half-way between t5he Petzval Portrait and the Petzval View, (Orthoskop).

BTW, I just noticed the drawing above, taken from Kingslake's History of Photographic Lenses, refers to it as the Orthostigmat. An obvious mistake, as anastigmats didn't appear til nearly 50 years after the Orthoskop was designed.