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#1
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135-mm Oxyplast lens
I inherited a large format lens marked as follows:
Oxyplast 1:4.5 f-135 mm L. O. Bittnet A.G. Munchen Doppel-Anastigmat It's mounted in a dial-set Compur shutter, Serial Number 522465 Limited testing indicates it isn't very sharp. Does anyone have any further information about this lens? Gerry Ashton |
#2
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135-mm Oxyplast lens
"A" wrote in message ... I inherited a large format lens marked as follows: Oxyplast 1:4.5 f-135 mm L. O. Bittnet A.G. Munchen Doppel-Anastigmat It's mounted in a dial-set Compur shutter, Serial Number 522465 Limited testing indicates it isn't very sharp. Does anyone have any further information about this lens? Gerry Ashton The dial set shutter is a very rough indication of age. These were replaced with the "rim-set" Compur about 1930. I'm sorry to say I have never heard of the manufacturer or the lens before. You may be able to discover its construction by looking at the reflections of a small light source like a pencil flashlight. Uncoated glass-air surfaces are very bright, cemented surfaces are quite dim but visible. Look at each cell from both sides. The name dopple anastigmat suggests that it is a symmetrical lens, i.e., both cells the same. The flashlight, with the aid of a magnifier will also show up problems with any cemented surfaces. Shine the light through the cells and look for any haziness, etc. Sometimes apparent lack of sharpness is due to internal haze or defective cement. There appear to have been a number of lens makers in Munich in the 1920's and before. Among them are Steinheil, Rietzchel (became Agfa), Rodenstock, and Staeble. Staeble used lens names similar to the above, that is, ending in -plast, but not an Oxyplast, at least that I can find. -- --- Richard Knoppow Los Angeles, CA, USA |
#3
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135-mm Oxyplast lens
Gerry Ashton wrote:
I inherited a large format lens marked as follows: Oxyplast 1:4.5 f-135 mm L. O. Bittnet A.G. Munchen Doppel-Anastigmat It's mounted in a dial-set Compur shutter, Serial Number 522465 Limited testing indicates it isn't very sharp. Does anyone have any further information about this lens? Actually, the lens maker is L.O. Bittner of Munich. The dates of manufacture for three designs of lenses they marketed range from 1919 to 1922, so the company wasn't around very long. The Oxyplast is a 4/4 double anastigmat design, manufactured around 1922. The coverage is 70 degrees, so it should provide moderate movement on 4x5. The reference I have indicates that the lens may have been supplied by Staeble. If it isn't "sharp", the elements may require cleaning. Also, these lenses are best when stopped way down. |
#4
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135-mm Oxyplast lens
Michael, what is your source for the info? you seem to have data on
some pretty rare lenses (I was going to say obscure lenses but I don't mean the pun). By 4/4 do you mean 4 elements in each cell? Is this a variation of the double Protar? The Protar patents would have been long expired in 1920. f/4.5 is very fast for this type of lens. If it is a cemented meniscus it probably suffers from the excessive zonal spherical aberration typical of the type. At f/4.5 this would likely be quite exagerated. Dagors and conertible Protars are sharp at around f/22 for moderate coverage. If it isn't reasonably sharp stopped down I would look for cement damage. A little oxidation around the edges doesn't make a lot of difference but if the cement has become cloudy it would make a mess of the image. -- Richard Knoppow |
#5
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135-mm Oxyplast lens
Richard Knoppow wrote:
Michael, what is your source for the info? you seem to have data on some pretty rare lenses (I was going to say obscure lenses but I don't mean the pun). By 4/4 do you mean 4 elements in each cell? Is this a variation of the double Protar? The Protar patents would have been long expired in 1920. f/4.5 is very fast for this type of lens. If it is a cemented meniscus it probably suffers from the excessive zonal spherical aberration typical of the type. At f/4.5 this would likely be quite exagerated. Dagors and conertible Protars are sharp at around f/22 for moderate coverage. If it isn't reasonably sharp stopped down I would look for cement damage. A little oxidation around the edges doesn't make a lot of difference but if the cement has become cloudy it would make a mess of the image. Hi! The source was Hartmut Thiele's "150 Jahre Kameraoptik in Deutschland", a trove of once obscure information. By 4/4 I mean 4 elements in 4 groups, which was more or less of a simple approach to wide angle lenses that most makers tweaked. The Oxyplast is listed as a f/6.3 lens, however, the focal lengths range from 135 to 195 mm. A shutter for f/6.3 195 would give a speed of around 4.4 with the shorter focal length if one assumes the shutter and not the cells limit the aperture. Bittner made other 4/4 lenses with similar specs that are listed as f/4.8, f/5.4, f/6.3 with the same model name (Orthoklinar), focal length and year of manufacture (1922), but suggested that the f/4.8 lens covered 75 deg and the 6.3 covered 70 deg. My guess is they used different shutters, and got less vignetting with the fast shutter, and "improved" specs. In 1919 they made their other model (LOB Ananstigmat; 4/4) with f/4.5 and f/5.5 apertures. By the 1920's, designs were improving and without a presence in the marketplace or R&D (can't find any lens patents for Bittner), they probably faded away quickly. I have a similar Hekla 90mm f/6.8 4/4 doppel-anastigmat in a dial-set Compur that was on an Ica folder. After cleaning it up, it covered 4x5 past the movements of my Wista. The same lens is going on ebay for $0.77 (dagor77; item 7591597266). Unlike the Bittner, these are common and perhaps worth a couple of dollars if someone's looking for an antique uncoated very flare-prone design. A Dagor or Protar easily outperforms this lens. |
#6
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135-mm Oxyplast lens
"Michael Gudzinowicz" wrote in message news:vykKf.3053$p13.2051@trnddc08... Richard Knoppow wrote: Michael, what is your source for the info? you seem to have data on some pretty rare lenses (I was going to say obscure lenses but I don't mean the pun). By 4/4 do you mean 4 elements in each cell? Is this a variation of the double Protar? The Protar patents would have been long expired in 1920. f/4.5 is very fast for this type of lens. If it is a cemented meniscus it probably suffers from the excessive zonal spherical aberration typical of the type. At f/4.5 this would likely be quite exagerated. Dagors and conertible Protars are sharp at around f/22 for moderate coverage. If it isn't reasonably sharp stopped down I would look for cement damage. A little oxidation around the edges doesn't make a lot of difference but if the cement has become cloudy it would make a mess of the image. Hi! The source was Hartmut Thiele's "150 Jahre Kameraoptik in Deutschland", a trove of once obscure information. By 4/4 I mean 4 elements in 4 groups, which was more or less of a simple approach to wide angle lenses that most makers tweaked. The Oxyplast is listed as a f/6.3 lens, however, the focal lengths range from 135 to 195 mm. A shutter for f/6.3 195 would give a speed of around 4.4 with the shorter focal length if one assumes the shutter and not the cells limit the aperture. Bittner made other 4/4 lenses with similar specs that are listed as f/4.8, f/5.4, f/6.3 with the same model name (Orthoklinar), focal length and year of manufacture (1922), but suggested that the f/4.8 lens covered 75 deg and the 6.3 covered 70 deg. My guess is they used different shutters, and got less vignetting with the fast shutter, and "improved" specs. In 1919 they made their other model (LOB Ananstigmat; 4/4) with f/4.5 and f/5.5 apertures. By the 1920's, designs were improving and without a presence in the marketplace or R&D (can't find any lens patents for Bittner), they probably faded away quickly. I have a similar Hekla 90mm f/6.8 4/4 doppel-anastigmat in a dial-set Compur that was on an Ica folder. After cleaning it up, it covered 4x5 past the movements of my Wista. The same lens is going on ebay for $0.77 (dagor77; item 7591597266). Unlike the Bittner, these are common and perhaps worth a couple of dollars if someone's looking for an antique uncoated very flare-prone design. A Dagor or Protar easily outperforms this lens. For some reason, probably because it was 3AM, I didn't recognize the standard nomenclature for lens construction. Oh, dear. The lens soulds like the common double Gauss type often used for wide angle lenses, for instance the Kodak Wide Field Ektar. It may be that the particular lens is just not a good example of the type, they are capable of very good sharpness. I looked up Hartmut Thiele, it looks like he has written a number of interesting looking books, mostly on Zeiss cameras and lenses. My German is sparce but I can make it out with the aid of a dictionary. I think I will have to aquire this book. -- --- Richard Knoppow Los Angeles, CA, USA |
#7
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135-mm Oxyplast lens
"Michael Gudzinowicz" wrote in message news:MJ9Kf.1680$0z.343@trnddc01... Actually, the lens maker is L.O. Bittner of Munich. The dates of manufacture for three designs of lenses they marketed range from 1919 to 1922, so the company wasn't around very long. The Oxyplast is a 4/4 double anastigmat design, manufactured around 1922. The coverage is 70 degrees, so it should provide moderate movement on 4x5. The reference I have indicates that the lens may have been supplied by Staeble. If it isn't "sharp", the elements may require cleaning. Also, these lenses are best when stopped way down. Thanks to Michael and Richard for the information. Indeed, I hit the wrong key and the maker really is Bittner. The elements look good, and it's good to know it should be a decent lens if stopped down enough. |
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