keytarjunkie
no longer addicted
This thread is about the Komura 105mm f/2.8 for Nikon RF. This lens was made as a presumably less expensive alternative to the Nikkor-S 10.5cm f/2.5 lens. It was also made in a variety of other mounts, including Leica LTM and M42 SLR mount (with a double/preset aperture ring).
This image is taken from a Komura brochure (likely from the early or mid 60's, as I believe they were selling SLR lenses concurrently with RF lenses). The lens has five elements in four groups, someone mentioned this was an ernostar-type lens (as are many Komura telephotos) but I thought it looked more like a planar-type. What do you think?
Komura was an early 3rd-party lens manufacturer making large format and enlarging lenses. In the late 50's and early 60's they made lenses for Leica LTM and Nikon/Contax RF. Then they transitioned to SLR mounts such as Nikon F, M42, and Konica mostly using preset-type irises which soon fell out of fashion. They also produced some medium format lenses for the Bronica system. I believe they went out of business during the 1970's. Komura produced lenses for use under other brands including Soligor, Tanar, Atco, Acall, Honor, Bittco, Astra, etc. There is a good thread on Komura here.
For Nikon rangefinder, Komura also produced a 35mm f/2.8, 85mm f/1.8, 105mm f/2.0, and likely 135mm f/3.5 (at least, under other brands). It appears these lenses were made only for a few years in the early 60's, possibly beginning in the late 50's, at the tail end of the Nikon RF era. The famous Komura 36mm f/1.8 LTM was never made in Nikon RF mount, unfortunately.
A few months ago, I happened upon a 105mm f/2.8 for peanuts. The 3rd optical group was ruined, so the lens was sold for scrap. Fortunately the rest of the lens is in good condition and it came with some accessories.
Pictured is the Komura 105mm f/2.8 for Nikon RF, with original bakelite cap and lens hood. I'm not sure if the rear cap is original, it's unmarked. The lens has a 48mm filter thread, a whopping 16 (!) aperture blades, and click stops at each full aperture stop with half-stop markings. It focuses to just under five feet. The lens hood is in two parts, to hold some Series filter, not sure which type.
Unlike some other Komura-produced lenses, there is no indication that this lens is for Nikon RF mount versus Contax RF mount. It's possible that they had stopped producing Contax lenses at this point so they stopped labeling it. Often you may find a 'N' or 'C' on the rear of the mount, or on the barrel.
I also uploaded the images here for those not logged in or for future-proofing.
I tried improving the 3rd optical group with solvents and alcohol but it's beyond repair, so my next step is sourcing another broken lens with a good 3rd group to swap in. Anyway, if anyone else has information or some samples with this lens, please post them here (please only post photos taken with this lens).
This image is taken from a Komura brochure (likely from the early or mid 60's, as I believe they were selling SLR lenses concurrently with RF lenses). The lens has five elements in four groups, someone mentioned this was an ernostar-type lens (as are many Komura telephotos) but I thought it looked more like a planar-type. What do you think?
Komura was an early 3rd-party lens manufacturer making large format and enlarging lenses. In the late 50's and early 60's they made lenses for Leica LTM and Nikon/Contax RF. Then they transitioned to SLR mounts such as Nikon F, M42, and Konica mostly using preset-type irises which soon fell out of fashion. They also produced some medium format lenses for the Bronica system. I believe they went out of business during the 1970's. Komura produced lenses for use under other brands including Soligor, Tanar, Atco, Acall, Honor, Bittco, Astra, etc. There is a good thread on Komura here.
For Nikon rangefinder, Komura also produced a 35mm f/2.8, 85mm f/1.8, 105mm f/2.0, and likely 135mm f/3.5 (at least, under other brands). It appears these lenses were made only for a few years in the early 60's, possibly beginning in the late 50's, at the tail end of the Nikon RF era. The famous Komura 36mm f/1.8 LTM was never made in Nikon RF mount, unfortunately.
A few months ago, I happened upon a 105mm f/2.8 for peanuts. The 3rd optical group was ruined, so the lens was sold for scrap. Fortunately the rest of the lens is in good condition and it came with some accessories.
Pictured is the Komura 105mm f/2.8 for Nikon RF, with original bakelite cap and lens hood. I'm not sure if the rear cap is original, it's unmarked. The lens has a 48mm filter thread, a whopping 16 (!) aperture blades, and click stops at each full aperture stop with half-stop markings. It focuses to just under five feet. The lens hood is in two parts, to hold some Series filter, not sure which type.
Unlike some other Komura-produced lenses, there is no indication that this lens is for Nikon RF mount versus Contax RF mount. It's possible that they had stopped producing Contax lenses at this point so they stopped labeling it. Often you may find a 'N' or 'C' on the rear of the mount, or on the barrel.
I also uploaded the images here for those not logged in or for future-proofing.
I tried improving the 3rd optical group with solvents and alcohol but it's beyond repair, so my next step is sourcing another broken lens with a good 3rd group to swap in. Anyway, if anyone else has information or some samples with this lens, please post them here (please only post photos taken with this lens).
keytarjunkie
no longer addicted
A little update, I found the same lens in LTM in decent shape but when I took it apart, I discovered that the 3rd optical group was slightly larger that the one in my Nikon-mount lens! What a bummer. The coatings are yellow on the LTM mount lens and blue on the Nikon mount. The rear element was the same size, it's just the second one in from the back that they changed at some point, it still appears to have the same optical properties. I am having trouble taking the helicoids apart on both models, the outer focus ring can be removed but I am not sure how to proceed from there.
David Murphy
Mentor
Beautiful lens. I wonder how this compares to the Nikon 10.5 cm F2.5 in Contax mount.