Bosun Higgs
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Now here is a lens you don't see every day.
The Corfield 95mm Lumar with 39mm LTM mount.
This is the 95mm f2.8 Lumar intended for use with the Periflex camera made by the British manufacturer, K.G Corfield.
The rear and front of the Lumar. Note, this image was taken after internal blackening.
All of the example images in this post (apart from the aperture set) are full frame unsharpened, shot at f2.8.
Advisory - Below is some background on the strange Corfield cameras and their lenses, if photographic history bores you rigid, just skip down to "The Lens" to avoid this nerd fest.
The Corfield Periflex.
A PeriFlex 1 in black leather. The arrow shows the eyepiece of the periscope.
The Periflex camera is a kind of halfway house between rangefinders and SLRs. The Periflex body style is very similar to early Leica rangefinders and had a 39mm Leica Screw mount, but there is no built-in rangefinder.
Instead there is a spring-loaded inverted periscope tube on the camera's top plate. When the tube is depressed it lowers a mirror into the light path behind the lens and the image can be viewed through an eyepiece built into the tube to allow focusing. The mirror only covers a 4x4mm area near the centre of the frame, so the periscope is for focusing only, a regular top mounted viewfinder unit is used to compose the whole frame.
The internal mirror of the periscope lowered in focusing position. Note finger on top plate keeping the spring-loaded mechanism in the down position.
Once focused, the periscope is retracted and the exposure made. In early cameras the periscope was spring-loaded and had to be manually depressed and held for focusing, but later cameras had an internal periscope that was viewed through a second viewfinder window and was automatically deployed and retracted.
Corfield Lenses.
In the beginning Corfield had lenses designed, and elements made, by the British Optical Lens Company (BOLC). Corfield produced the lens tubes and mountings and fitted the elements in their factories, but eventually BOLC actually manufactured some lenses completely.
Corfield followed the same path with the German manufacturer Enna Werk. Initially Enna produced elements only and Corfield made the bodies, and fitted the elements in the UK, but from about 1961 Enna were making completed lenses for Corfield.
My 95mm Lumar is one of these later Enna made lenses.
The "standard" 45 and 50mm Corfield lenses were called "Lumax", the shorter 28 and 35mm lenses, "RetroLumax" and the 85mm to 400mm lenses, "TeleLumax". For some reason one 50mm, and one 95mm lens (mine) were named "Lumar".
Some of the later lenses were also made with M42 and Exakta mounts.
The lens.
A product of the heavy metal era, the construction is all aluminium, not so much as a rubber grip ring in sight, consequently it is very light. To put this in context, my 100mm Meyer Trioplan weighs in at 430g, and the 95mm Corfield from the same era is a mere 210g.
The tube is finished with a rather fetching black and silver zebra-stripe design. There is a 52mm front filter thread and the obligatory 39mm LTM at the rear.
The aperture runs to f22 and is clicked in whole stops, oddly there are two copies of the aperture scale engraved into the ring, complete with two index marks on the lens tube. The iris has 12 blades, is deliciously smooth, and is circular at all settings.
A long focus throw turning in the Nikon direction allows focusing down to a very useful 86cm with my Sonys.
My lens came with a contemporaneous Heliopan metal hood, which I really like.
The Lumar ready to rock with the snazzy Heliopan hood and LTM-E-mount adaptor.
The Optics.
The lens is a triplet!
Published layout of the 95mm Lumar.
The above diagram is a published layout, my lens was so clean when I received it that I could find no excuse to take it apart :O(
The elements are coated and mine has a nice purple/blue colouration. My lens has a 35.5mm diameter front element which suggests a maximum possible aperture of f2.68.
The IQ.
OK, there is a serious problem with the stock lens - contrast.
Triplets typically have a long back focus, so there is a lot of empty tube between the optical block and the mount, at MFD there is a whopping 65mm. The interior of the Lumar is black, but shiny anodised aluminium black, combine this with the huge coverage also typical of triplets, and you have large amount of light splashing around in what is essentially, a Kaleidoscope.
Yeah, the contrast was absolutely awful.
Painting with Black 4.0 throughout cured this problem, and with the coated optics, contrast became good.
Much better contrast after painting.
The next problem is that the lens is not very sharp wide open.
Although appearing sharp at full frame here, even modest cropping would reveal the underlying softness.
Another apparently sharp subject, but only when viewed unmagnified.
Having said that, it is also one of those lenses where the image looks acceptably sharp at lower magnifications. All of the sample images here are unsharpened and some do look quite sharp, but when you view actual pixel level, they are anything but.
It may not be super fast or sharp, but it can still draw your attention to the IF subject.
Highish contrast edges show colourless fringing, which almost looks like double imaging at times.
[ATTACH alt="The background bokeh here is mirroring the "double edge" fringing seen on focused objects."]3770282[/ATTACH]
The background bokeh here is mirroring the "double edge" fringing seen on focused objects.
Using unsharp mask does not really help with sharpness as it emphasises the "double edges" produced by the fringing.
Despite the above limitations, because of the deceivingly sharp appearance, very reasonable images can still be had.
Predictably for a triplet, there is no field curvature, and vignetting is extremely slight.
The mannequin is lifesize, so the background blur is what you would get with a portrait.
Perhaps due to the lack of sharpness and the small maximum aperture, getting optimal focus can take a while, even using magnify.
Disappointed by the sharpness wide open I decided to see if it could be improved, so in a huge departure for me, I actually stopped the lens down:-
Pixel level crops from frame centre.
Predictably, sharpness improves on stopping down, and f5.6 looks to be a good compromise. Bear in mind that these are central crops, it is probably not a good idea to say anything about the corner sharpness - at any stop.
The Bokeh.
The bokeh bubbles are large and unusually for triplet, very soft edged.
The closest I got to sharp-edged or outlined bokeh bubbles.
OK, the lens is a triplet, is f2.8 and very near to 100mm, so the first word springing into most bokeholic's minds will be - Trioplan!
Just to answer the inevitable questions, here is a comparison:-
Lumar left, Trioplan right. Both lenses focused at the same distance.
The Lumar's bokeh bubbles show almost none of the outlining that the Trioplan is famous for. Not only that, but they are very soft edged. Both lenses show very little catseyeing, and then, only in the extreme corners.
Looking at the comparison, it appeared to me that the Lumar bubbles were bigger than those from the Trioplan and measurement confirms this. The Lumar bubbles are 20% larger diameter despite the 5mm shorter FL and similar maximum f stop.
The Lumar produces very smooth OOF backgrounds at close focus, there is almost no texturing or patterning to speak of, and certainly none of the horrible "porridge" bokeh I regularly see with triplets.
The closest I got to getting bokeh texture, and even here, the results are on the smooth side.
In fact the Lumar bokeh reminds me strongly of that produced by Rodenstock triplet projection lenses such as the Splendar and Trinar, but the bokeh from the Corfield lens is much smoother, in fact it is hard to get it to produce any outlined bokeh bubbles at all.
The Lumax can occasionally darken backgrounds on close focused shots (the rose shots), I have seen this before, mainly with large format lenses used on smaller formats, and it can give an attractive almost "studio lit" appearance in some situations.
The Bottom Line.
Focus was on the central flask.
The Lumar can produce very nice pictures and the lens itself looks stunning mounted on camera.
The images appear sharper than they really are, especially viewed in small size. When viewed near pixel level, the feet of clay become apparent, this is not a lens that will stand a lot of cropping. The images also respond very badly to sharpening in post.
Impressively smooth bokeh for a triplet, but the rose is not truly sharp.
Although the bokeh is stunningly smooth for a triplet, the lens is after all, only an f2.8. The lenses I normally use are f2 and faster so I was continually disappointed by the lack of background blur at medium foci.
Of course, I am a bokeholic, and crave the max blur, so the bokeh of the Corfield may well be ample for other snappers.
This is one of the "fast" Corfields, there is also a 90mm f2.8 and an 85mm f1.5, but these two are much rarer. Despite being more plentiful, the 95mm is still a relatively rare lens, and on average you will have to pay around £250 for a 95mm in good condition.
To put this in perspective you can probably get a reasonable example of the much more famous triplet, the Meyer Trioplan, for about half this price.
I have always been curious about the 95mm Lumar and there are very few example images from the lens online, so I was prepared to wait a long while for one to appear at a low price to slake my curiosity.
There are big problems with the Lumar, contrast with digital bodies will be terrible due to internal reflection in the tube, but this can be fixed. The lack of sharpness can only be remedied by stopping down, and as that effective destroys the bokeh, it is not an acceptable solution for bokeholics such as myself.
After reading this post and looking at the images, I suspect the lens will only really appeal to collectors, given its usually steep price. If you are looking for a vintage lens around this FL from the same age, there are several other options with better IQ and a lower price, the 100mm Meyer Orestor springs to mind.
The Corfield 95mm Lumar with 39mm LTM mount.
This is the 95mm f2.8 Lumar intended for use with the Periflex camera made by the British manufacturer, K.G Corfield.
The rear and front of the Lumar. Note, this image was taken after internal blackening.
All of the example images in this post (apart from the aperture set) are full frame unsharpened, shot at f2.8.
Advisory - Below is some background on the strange Corfield cameras and their lenses, if photographic history bores you rigid, just skip down to "The Lens" to avoid this nerd fest.
The Corfield Periflex.
A PeriFlex 1 in black leather. The arrow shows the eyepiece of the periscope.
The Periflex camera is a kind of halfway house between rangefinders and SLRs. The Periflex body style is very similar to early Leica rangefinders and had a 39mm Leica Screw mount, but there is no built-in rangefinder.
Instead there is a spring-loaded inverted periscope tube on the camera's top plate. When the tube is depressed it lowers a mirror into the light path behind the lens and the image can be viewed through an eyepiece built into the tube to allow focusing. The mirror only covers a 4x4mm area near the centre of the frame, so the periscope is for focusing only, a regular top mounted viewfinder unit is used to compose the whole frame.
The internal mirror of the periscope lowered in focusing position. Note finger on top plate keeping the spring-loaded mechanism in the down position.
Once focused, the periscope is retracted and the exposure made. In early cameras the periscope was spring-loaded and had to be manually depressed and held for focusing, but later cameras had an internal periscope that was viewed through a second viewfinder window and was automatically deployed and retracted.
Corfield Lenses.
In the beginning Corfield had lenses designed, and elements made, by the British Optical Lens Company (BOLC). Corfield produced the lens tubes and mountings and fitted the elements in their factories, but eventually BOLC actually manufactured some lenses completely.
Corfield followed the same path with the German manufacturer Enna Werk. Initially Enna produced elements only and Corfield made the bodies, and fitted the elements in the UK, but from about 1961 Enna were making completed lenses for Corfield.
My 95mm Lumar is one of these later Enna made lenses.
The "standard" 45 and 50mm Corfield lenses were called "Lumax", the shorter 28 and 35mm lenses, "RetroLumax" and the 85mm to 400mm lenses, "TeleLumax". For some reason one 50mm, and one 95mm lens (mine) were named "Lumar".
Some of the later lenses were also made with M42 and Exakta mounts.
The lens.
A product of the heavy metal era, the construction is all aluminium, not so much as a rubber grip ring in sight, consequently it is very light. To put this in context, my 100mm Meyer Trioplan weighs in at 430g, and the 95mm Corfield from the same era is a mere 210g.
The tube is finished with a rather fetching black and silver zebra-stripe design. There is a 52mm front filter thread and the obligatory 39mm LTM at the rear.
The aperture runs to f22 and is clicked in whole stops, oddly there are two copies of the aperture scale engraved into the ring, complete with two index marks on the lens tube. The iris has 12 blades, is deliciously smooth, and is circular at all settings.
A long focus throw turning in the Nikon direction allows focusing down to a very useful 86cm with my Sonys.
My lens came with a contemporaneous Heliopan metal hood, which I really like.
The Lumar ready to rock with the snazzy Heliopan hood and LTM-E-mount adaptor.
The Optics.
The lens is a triplet!
Published layout of the 95mm Lumar.
The above diagram is a published layout, my lens was so clean when I received it that I could find no excuse to take it apart :O(
The elements are coated and mine has a nice purple/blue colouration. My lens has a 35.5mm diameter front element which suggests a maximum possible aperture of f2.68.
The IQ.
OK, there is a serious problem with the stock lens - contrast.
Triplets typically have a long back focus, so there is a lot of empty tube between the optical block and the mount, at MFD there is a whopping 65mm. The interior of the Lumar is black, but shiny anodised aluminium black, combine this with the huge coverage also typical of triplets, and you have large amount of light splashing around in what is essentially, a Kaleidoscope.
Yeah, the contrast was absolutely awful.
Painting with Black 4.0 throughout cured this problem, and with the coated optics, contrast became good.
Much better contrast after painting.
The next problem is that the lens is not very sharp wide open.
Although appearing sharp at full frame here, even modest cropping would reveal the underlying softness.
Another apparently sharp subject, but only when viewed unmagnified.
Having said that, it is also one of those lenses where the image looks acceptably sharp at lower magnifications. All of the sample images here are unsharpened and some do look quite sharp, but when you view actual pixel level, they are anything but.
It may not be super fast or sharp, but it can still draw your attention to the IF subject.
Highish contrast edges show colourless fringing, which almost looks like double imaging at times.
[ATTACH alt="The background bokeh here is mirroring the "double edge" fringing seen on focused objects."]3770282[/ATTACH]
The background bokeh here is mirroring the "double edge" fringing seen on focused objects.
Using unsharp mask does not really help with sharpness as it emphasises the "double edges" produced by the fringing.
Despite the above limitations, because of the deceivingly sharp appearance, very reasonable images can still be had.
Predictably for a triplet, there is no field curvature, and vignetting is extremely slight.
The mannequin is lifesize, so the background blur is what you would get with a portrait.
Perhaps due to the lack of sharpness and the small maximum aperture, getting optimal focus can take a while, even using magnify.
Disappointed by the sharpness wide open I decided to see if it could be improved, so in a huge departure for me, I actually stopped the lens down:-
Pixel level crops from frame centre.
Predictably, sharpness improves on stopping down, and f5.6 looks to be a good compromise. Bear in mind that these are central crops, it is probably not a good idea to say anything about the corner sharpness - at any stop.
The Bokeh.
The bokeh bubbles are large and unusually for triplet, very soft edged.
The closest I got to sharp-edged or outlined bokeh bubbles.
OK, the lens is a triplet, is f2.8 and very near to 100mm, so the first word springing into most bokeholic's minds will be - Trioplan!
Just to answer the inevitable questions, here is a comparison:-
Lumar left, Trioplan right. Both lenses focused at the same distance.
The Lumar's bokeh bubbles show almost none of the outlining that the Trioplan is famous for. Not only that, but they are very soft edged. Both lenses show very little catseyeing, and then, only in the extreme corners.
Looking at the comparison, it appeared to me that the Lumar bubbles were bigger than those from the Trioplan and measurement confirms this. The Lumar bubbles are 20% larger diameter despite the 5mm shorter FL and similar maximum f stop.
The Lumar produces very smooth OOF backgrounds at close focus, there is almost no texturing or patterning to speak of, and certainly none of the horrible "porridge" bokeh I regularly see with triplets.
The closest I got to getting bokeh texture, and even here, the results are on the smooth side.
In fact the Lumar bokeh reminds me strongly of that produced by Rodenstock triplet projection lenses such as the Splendar and Trinar, but the bokeh from the Corfield lens is much smoother, in fact it is hard to get it to produce any outlined bokeh bubbles at all.
The Lumax can occasionally darken backgrounds on close focused shots (the rose shots), I have seen this before, mainly with large format lenses used on smaller formats, and it can give an attractive almost "studio lit" appearance in some situations.
The Bottom Line.
Focus was on the central flask.
The Lumar can produce very nice pictures and the lens itself looks stunning mounted on camera.
The images appear sharper than they really are, especially viewed in small size. When viewed near pixel level, the feet of clay become apparent, this is not a lens that will stand a lot of cropping. The images also respond very badly to sharpening in post.
Impressively smooth bokeh for a triplet, but the rose is not truly sharp.
Although the bokeh is stunningly smooth for a triplet, the lens is after all, only an f2.8. The lenses I normally use are f2 and faster so I was continually disappointed by the lack of background blur at medium foci.
Of course, I am a bokeholic, and crave the max blur, so the bokeh of the Corfield may well be ample for other snappers.
This is one of the "fast" Corfields, there is also a 90mm f2.8 and an 85mm f1.5, but these two are much rarer. Despite being more plentiful, the 95mm is still a relatively rare lens, and on average you will have to pay around £250 for a 95mm in good condition.
To put this in perspective you can probably get a reasonable example of the much more famous triplet, the Meyer Trioplan, for about half this price.
I have always been curious about the 95mm Lumar and there are very few example images from the lens online, so I was prepared to wait a long while for one to appear at a low price to slake my curiosity.
There are big problems with the Lumar, contrast with digital bodies will be terrible due to internal reflection in the tube, but this can be fixed. The lack of sharpness can only be remedied by stopping down, and as that effective destroys the bokeh, it is not an acceptable solution for bokeholics such as myself.
After reading this post and looking at the images, I suspect the lens will only really appeal to collectors, given its usually steep price. If you are looking for a vintage lens around this FL from the same age, there are several other options with better IQ and a lower price, the 100mm Meyer Orestor springs to mind.
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