Doppel conversion Lens test

[cliffmanley]

Someone was talking about the old convertable Doppel lenses, and I thought I

would show you an example of what to expect when you use the conversion from

135mm to 220mm. These scans are from edge to edge on the 9x12 film, showing the

film sheath on the edge. These were taken from a fixed camera location, about 7

feet from knot. Only the lens was changed. On this one, you need to remove the

rear lens. What I DID discover is that my bellows has developed a light leak

when streched out to 200mm! You can barely see it in the roofline of the first

shot. Something else to fix!

 

But anyway notice the Bokeh difference when converted. Makes a nice portrait

lens like this. This is the Ross Doppelanastigmat lens in a Maximar 207/7.

Pretty sharp at 135 a bit softer at 220.<div></div>

[cliffmanley]

Light leak Found! Just a moth hole in the velvet seal of that plate holder.

 

Cliff

[classcamera]

I have a nice Dopple Plasmat, that I have been using as a 6.5" on my 4x5, it gives very nice sharp images, with reduced flair (I shoot it at night), and has excellent coverage on 4x5. I have yet to try it on the converted to the 10.625 length, however, I am sure it will be softer, but with more contrast. One interesting thing about these lenses, they are actually three lenses in one, not two. Using the Front group is focal length A, using the rear is focal length B, and the two together is focal length C. Also, the Dr. Rudolph, patent is one of the most successful of all lens designs, as this is the basis for the Planar!

[dan_fromm2]

Um, Mark, that's a little unclear. IIRC the original 6/4 double Gauss type Planar's patent antedates the various Plasmats' patents. And plasmats aren't 6/4 double Gauss. Both types can, don't have to be, convertible.

[cliffmanley]

I thought the doppel plasmats were 3+3, the same front and back.

[patrick j dempsey]

Totally different lens construction, but I recently discovered that the 80mm lens for Mamiya TLR's can be converted into a macro lens by removing the front set of elements... I'm sure the image quality is pretty low, but it's pretty exciting stuff!

[colin carron]

Cliff, interesting experiment!

 

I can't read all the writing round the lens - can you post the full thing?

 

Ross had of course their own lens designs and, pre-WWI, licensed designs from Zeiss and Goerz.

[dan_fromm2]

Colin, many of the lenses that have double or doppel (same thing) in their names are separable. Also many, in particular double Gauss and plasmat types, that don't. Thing is, although the individual cells may form an image there's no guarantee that it will be a good one. The single cells are usually less well-corrected than the entire lens, if you see what I mean.

 

I find it telling that the old dagor type Symmar and its replacement, the plasmat type convertible Symmar, were about equally good while the Symmar-S, not designed for either cell to be used by itself, is much better. There's a hint.

 

Cheers,

 

Dan

[colin carron]

Dan, yes, I think I get the doppel / convertible thing. The subject lens of this thread is 'doppel' but I imagine not intended to be conertible in the instance we see it as otherwise it would have the dual aperture scales.

 

Do you think the case above is a Zeiss design? I couldn't identify it presisely from the Vade Mecum.

 

The case of the Scheider Symmar series is interestng. I agree the non-conertible Symmar-S is an improvement of its convertible predecessor butthe old conertible Symmar seems nonetheless to be a very good lens indeed. My 1958 example in this thread is a pleasure to use

 

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

 

Many of them however seem to have built up a haze / depost of some kind beteen the front cell elements which can be cleaned by removing the front bezel and extracting the front cell. I found my Symmar convertibles improved a lot once I had done that. I got that tip from Neil Wright one of the Vade Mecum authors.

[dan_fromm2]

Colin, Plasmat is a Meyer trade name. I'm away from home, have my wife's laptop which doesn't have the VM installed, so I can't check. But I think if you look in the Meyer section you'll find a little info on the Doppel-Plasmat.

 

I take your point on the need to clean old Symmars etc. It applies to many old Ektars, especially the tessar types. I have just one convertible Symmar, a 135; on 2x3 it is little, if any better, than a 127/4.7 Tominon. I suspect it would beat the Tominon handily towards the edges of 4x5, though.

 

Cheers,

 

Dan

[david_m]

I'd repeat the test with the light leak fixed.

[cliffmanley]

This lens is marked Konrad Ross Furth and I think Furth is in Germany. I don't think it is the same London Ross we know, but anyway it looks to be a Goerz design lens. I think that there were many lenses that were made, and made to be used this way, that are not marked with dual markings on the shutter. I think they finally figured out people were stupid and they needed to spell it out for them, and later put that stuff on there. The real photographers knew how to apply bellows factors and calculate f stops for focal lengths, so didn't need that extra stuff, that is hard to read anyway.

 

I fixed the light leak and will post a new set of pics soon.

[dan_fromm2]

Um, Cliff, where does Ross come into this? I ask because in your first post you said the lens was a Ross Doppelanastigmat on a Maximar. This combination is very strange.

 

Now you say it is engraved Konrad Ross Fuerth. This ain't Ross London, at one time a CZJ and Goerz licensee. Please count reflections and tell us what you see. If you see four strong reflections and no weak ones from the front cell, the lens is a dialyte type. If you see two strong and two weak, possibly hard to discern, the lens is a 6/2 double anastigmat like the Dagor.

 

Both design classes were made by many makers without, afaik, licenses from the original designers. I'm not sure, but I think there were dialytes long before Goerz started making them.

 

Cheers,

 

Dan

[cliffmanley]

The lens reads: Konrad Ross Furth Doppelanastigmat Rossar and I think it is a Goerz design.

 

It is indead a Ross lens on a Maximar 207/7, but like I said, I didn't think it was the Ross in England. I don't have to count reflections, it is a 4/4 lens.

 

Here are some more pictures. The first is at 135mm standard. The next two are at 220mm. Notice how it flattens out the perspective so you aren't on top of the subject. Perfect for portraits. "I think"

 

This is a bit better subject matter than the knot in the tree. Gives a new meaning to "folding table"<div></div>

[cliffmanley]

Dan, I believe you are right on with the dialyte. Here is what I found on that.

 

ARTAR

1904

W. Zschokke

Goerz After the failure of the Alethar, Walter Zschokke and F. Urban, designed a much simpler Artar. It is based on a 4 element air-spaced type lens called a "dialyte" (dialyte is a design by Emile Von Hoegh), so is sharp across entire field of illumination

The positive elements were a dense barium crown, and the negative elements were made of telescope flint glass. Designed to be apochromatic for use in three color graphics arts. It has a narrower field of coverage than Tessar. This lens was the regular Goerz process lens for almost seventy years. Current modern implementations of this design are the Nikkor M series LF lens and the Schneider G-Claron's.

 

So it is an Artar branded by Ross as a Rossar. Anyway it works great.

[colin carron]

Cliff, thanks for posting the full inscription. I also thought you were saying it was a Ross, London, lens but it clearly is not. Maybe a lesser known Greman lens manufacturer using the Ross name to gain a bit of prestige? Thr Ross, London convertibles all seem to be slower than f/4.5.

 

Of the dialyt types the Artars all seem to have a smaller max aperture but how about a Dogmar copy which was made in f4.5 and even f/3.5

 

Dan, you need to copy ythe VM onto your wife's laptop! I can't find 'Konrad' 'Furth' or Rossar' in the VM which is not saying much except that this maker was not common enough to feature in the VM list.

[cliffmanley]

The main reason for my post was to show "NEW" photographers, that sometimes all is not as it seems. A camera is not some strange unidentifiable creature, just because the lens or shutter combination is not what was normally offered. My Father had a studio when I was a boy, and I have been in and out of darkrooms all my life. I have had my own darkroom for over 40 years, and if I have learned anything, it is that all things in life are not in a manual or directory. Sometimes you just need to try something or "Use the Brain" that God gave you. For anyone reading this, I hope you learn to try different things, even if they are not in the manual. It is so important to the entire "creativity" process.

 

Colin, I suspect that You might be right about "just using" the Ross name. Another reason I think that, is because this one Maximar, unlike any other that I have, has an American focus scale in feet. I think it is the only Zeiss Ikon, of any type, that I own, that is not in meters. I suspect that this camera / lens setup was sold through New York, Goerz American Optical branch and contracted or licensed out the making of this lens in Germany. I don't really know. But also like you said, most were of small apetures with narrow fields. This one has exactly the same coverage angle as my other 207/7 with the old Huttig designed Dominar triplet. It is a very nice, interesting lens, and performs well on this camera as you can see, when I keep the light leaks away, Ha Ha !

[colin carron]

Cliff, thanks for posting your test hotss - they were very interesting and it is fun trying to identify as closely as possible any mystery item like your doppel lens even if it finally escapes us.

 

Now in the future if anyone searches for any info on doppel / convertble lenses they may well come across this thread so hopefully this may answer questions about this bit of photography history for a while to come.

 

Now, in your collection you don't have any casket or combinable lenses, do you? :-)

 

regards - Colin

[dan_fromm2]

Cliff, at even odds your Ross in Fuerth was a camera store that had house brand cameras made. Its been done.

 

That the lens is on a Maximar is interesting. I just checked with Charlie Barringer (Google him, guys), who tells me that Maximar was an ICA brand before the mergers that formed Zeiss Ikon. The Ross lens may not be original to the camera.

 

Dialytes aren't all good. I have a Doppel Anastigmat Goerz that supposedly came from Tenax. It is a dialyte, not a Dagor as the seller mistakenly believed, and is just awful.

 

Cheers,

 

Dan