Are all plasmats convertible?

[Drew Wiley]

Again, some of these lens names or categories have a quite a long history, and thus become a moving target in terms of making generalizations. For example, the alleged coverage of Dagors. Apples to apples, an old 14" f/7.7 would have come in a big 4 or 5 shutter simply with less mechanical vignetting than a post-60's version in a no.3. Some of that peripheral coverage was probably less than ideal, but contact printers didn't notice it. Then this lens design wasn't as critically corrected for strong tangential tilts etc than plasmats, once that category had itself evolved awhile. I used the very last two generations of Kern 14" Dagors, both the SC and MC versions, and can attest their are very sharp and well corrected from f/11 down. But you might well need much smaller stops for sake of movements or depth of field issues. The contrast and tonal rendition is remarkable, but apo correction not as good as other LF lenses I use. Sometimes a bit of mythology gets attached to "cult lenses" that outlives their comparative performance or wild asking prices.

Today it was too hot to either take a LF camera hike or work in the darkroom, so for awhile I played in the backyard peeping through some of my unorthodox barrel lenses with the 8x10.

[lassethomas]

Enough talk, lets see the results
I put my Angulon 6.8/90mm to some unscientific action.
Full lens, rear and front cell.
And my short comments but make up you own mind if it works.

Full lens as reference



The full lens, f22, Fomapan 200 on my Chamonix 45H-1.
Focused on the chain on the wall of the house.
Scaned on an Imacon Flextight and no added sharpening or processing.
Right click to download full res

Perheps not the sharpest of lenses, lacking a bit of contrast and bite, but reasonably even over the whole frame.
To me this is usable, considering the size and portability.

Back cell, about 1.5 times the focal length



Rear cell, f22, Fomapan 400 on my Chamonix 45H-1.
Focused on the chain on the wall of the house.
Scaned on an Imacon Flextight and no added sharpening or processing.
Right click to download full res

Not very impressive. Soft all over. Not even the center is sharp.
This would not withstand any larger magnifications.

Front cell, about 2 times the focal length



Front cell, f32, Fomapan 400 on my Chamonix 45H-1.
Focused on the chain on the wall of the house.
Scaned on an Imacon Flextight and no added sharpening or processing.
Right click to download full res

Nice center sharpness. Sharpest of all three. Corners are not that impressive.
Not for landscape but for portraits or still life this could work.

[Tin Can]

Thank you!

More proof, less babble!

Enough talk, lets see the results
I put my Angulon 6.8/90mm to some unscientific action.
Full lens, rear and front cell.
And my short comments but make up you own mind if it works.

Full lens as reference



The full lens, f22, Fomapan 200 on my Chamonix 45H-1.
Focused on the chain on the wall of the house.
Scaned on an Imacon Flextight and no added sharpening or processing.
Right click to download full res

Perheps not the sharpest of lenses, lacking a bit of contrast and bite, but reasonably even over the whole frame.
To me this is usable, considering the size and portability.

Back cell, about 1.5 times the focal length



Rear cell, f22, Fomapan 400 on my Chamonix 45H-1.
Focused on the chain on the wall of the house.
Scaned on an Imacon Flextight and no added sharpening or processing.
Right click to download full res

Not very impressive. Soft all over. Not even the center is sharp.
This would not withstand any larger magnifications.

Front cell, about 2 times the focal length



Front cell, f32, Fomapan 400 on my Chamonix 45H-1.
Focused on the chain on the wall of the house.
Scaned on an Imacon Flextight and no added sharpening or processing.
Right click to download full res

Nice center sharpness. Sharpest of all three. Corners are not that impressive.
Not for landscape but for portraits or still life this could work.

[Bernice Loui]

90mm f6.8 Angulon was intended for 4x5, image circle of 152mm @ f22 or image circle just enough for 4x5.
In later Schneider catalog literature, Schneider dropped the convertible lens marketing moniker.



IMO, would not consider using a 90mm f6.8 on 4x5 given there are so many easily available modern wide angle lenses that have better performance trading off weight/size. Lightweight field folder style images are not much of a consideration, putting out the idea or need for using this particular Angulon as a prime lens or far lesser as a convertible lens.

That said, do use a 165mm f6.8 Angulon in barrel (never converted) with Sinar shutter on the 5x7 Sinar Norma with good enough results.

Again, this thing about convertible lenses was significant in the early days of view camera when lenses were an absolute premium and the idea of owning one lens that offered more than one focal length was believing ya got "three" lenses for the cost of one.. The optical performance trade-offs were not discussed, but the photographers figured this out and the availability of GOOD view camera lenses increased with their cost dropping.


Bernice

Enough talk, lets see the results
I put my Angulon 6.8/90mm to some unscientific action.
Full lens, rear and front cell.
And my short comments but make up you own mind if it works.

Full lens as reference

Perheps not the sharpest of lenses, lacking a bit of contrast and bite, but reasonably even over the whole frame.
To me this is usable, considering the size and portability.



Back cell, about 1.5 times the focal length

Rear cell, f22, Fomapan 400 on my Chamonix 45H-1.
Focused on the chain on the wall of the house.
Scaned on an Imacon Flextight and no added sharpening or processing.
Right click to download full res

Not very impressive. Soft all over. Not even the center is sharp.
This would not withstand any larger magnifications.

Front cell, about 2 times the focal length

Front cell, f32, Fomapan 400 on my Chamonix 45H-1.
Focused on the chain on the wall of the house.
Scaned on an Imacon Flextight and no added sharpening or processing.
Right click to download full res

Nice center sharpness. Sharpest of all three. Corners are not that impressive.
Not for landscape but for portraits or still life this could work.

[lassethomas]

90mm f6.8 Angulon was intended for 4x5, image circle of 152mm @ f22 or image circle just enough for 4x5.
In later Schneider catalog literature, Schneider dropped the convertible lens marketing moniker.



IMO, would not consider using a 90mm f6.8 on 4x5 given there are so many easily available modern wide angle lenses that have better performance trading off weight/size. Lightweight field folder style images are not much of a consideration, putting out the idea or need for using this particular Angulon as a prime lens or far lesser as a convertible lens.

That said, do use a 165mm f6.8 Angulon in barrel (never converted) with Sinar shutter on the 5x7 Sinar Norma with good enough results.

Again, this thing about convertible lenses was significant in the early days of view camera when lenses were an absolute premium and the idea of owning one lens that offered more than one focal length was believing ya got "three" lenses for the cost of one.. The optical performance trade-offs were not discussed, but the photographers figured this out and the availability of GOOD view camera lenses increased with their cost dropping.


Bernice

I agree, for most situations and needs a modern better performing lens would be a more resonable choice.

And the Angulons are old, so there are a large copy variations. I've got two 90mm (both as part in a larger deal). Both are from the fifties, one is OK (the one used above) and the other one is a sure lemon.
I guess that goes for the 165mm too, even though they are more rare.

I wouldn't mind a good 6.8/165mm for my 4x10 back though.

[Vaughn]

To correct for the out of focus (no longer corrected) blue light when using only front or rear element, a yellow filter can sometimes be used to increase sharpness. It was recommended when using the TR convertibles.

[Bernice Loui]

Schneider Angulon was Schneider's answer to the wide angle Dagor which was NOT advertised as focal length convertible, while in theory the wide angle Dagor IS convertible. The folks at Goerz knew better and valued optical performance over perceived marketing value.

Based on real time experience, it is true testing the Angulon before accepting the Angulon is a very, very good idea as they varied lots in optical performance. Some were good others were absolute duds. Back when this 165mm Angulon happened, part of the deal was right of return, if it proved to be a dud, it went back to the seller. This 165mm Angulon proved to be ok enough for 5x7 _ 13x18cm. Compared to the 150mm f5.6 Super Symmar XL, the modern lens has significantly better optical performance. Higher contrast, much "snappier" image in every way and the image circle is larger with inherent light fall off baked into any wide angle lens. Compared to the 165mm f8 Super Angulon, it is also better than the Angulon at larger taking apertures, contrast (more elements yet better optically), much larger image circle, better resolution at the edges of the image circle which is HUGE and this is a HUGE lens.


Bernice

I agree, for most situations and needs a modern better performing lens would be a more resonable choice.

And the Angulons are old, so there are a large copy variations. I've got two 90mm (both as part in a larger deal). Both are from the fifties, one is OK (the one used above) and the other one is a sure lemon.
I guess that goes for the 165mm too, even though they are more rare.

I wouldn't mind a good 6.8/165mm for my 4x10 back though.

[J. Patric Dahlen]

Corners are not that impressive.
Not for landscape but for portraits or still life this could work.

Utmärkt test! While most people would agree that the blurry corners make the single lens cells not suitable for landscape, I feel that the optical faults contribute to the image in a positive way, making it less "boring" to look at. They add a pleasing quality to the bottom picture. A perfect lens shows exactly what's in front of it in an undistorted way, making it feel like the lens is out of equation as it adds no character to the photo.

[Drew Wiley]

Depends on what one is after. Sometimes what appears to be an acceptable nuanced flaw in a contact print resembles a gross hippopotamus wallowing in mud in a big enlargement.

[Bernice Loui]

Brings up the topic of audience and perception of what is "desirable" then why is any image "desirable".

About 3.8 Billion images and 750,000 hours of video is up-loaded to the internet world wide daily. Given this vast flood of images and the ease of image making, what makes any individual image "desirable" or have value in some way?

This brings up the question of why film, why view camera, why alternative process images (tin types to carbon to many others) to the current fashion of using "vintage" or optics from around 1900 to make images today, this included "sorta-focus" lenses, all with the idea and such these "items" will self produce images that are distinctly different than the ~3.8 Billion images and 750,000 hours of video~ in process daily. Does this mean this media is better, individual, distinct or such? or does it really mean greatly discounted media creation allowing anyone to proclaim a moment of public notoriety ?


Bernice