Minolta Leica Thread Mount lenses are uncommon, very little written about them. I started picking them up ~2 years ago, the 5cm F2 "Summitar" formula lens, then the 8.5cm F2.8, 4.5cm F2.8, and 11cm F5.6- a "Japanese Mountain Elmar" of sorts. Today I added the 5cm F2.8- also a 3-1-1 formula lens. This one uses 40.5mm accessories, is much longer than the 4.5cm F2.8. Minolta held to the 32x24 standard much longer than Nikon, Canon, and most other Japanese camera companies. The 45 made sense for that format. Once they pushed out to the 36x24 frame, the 50 seems to have replaced the earlier lens.
The 45/2.8, 50/2.8, and 85/2.8 are as far as I know, reading Neblette and Kingslake- the only "3-1-1" configurations made. I took a 45/2.8 apart: the front two groups are stamped in a single metal fixture, the rear element is a positive element that forms an image on its own. The front two groups combined have a negative focal length, like a Cooke Triplet and a Tessar.
The Minolta Super-Rokkor F2.8 lenses started with a Cooke Triplet (1-1-1, "positive/Negative/Positive focal lengths) and split the front element into a cemented Triplet, providing a much faster F2.8 than is commonly seen. Most F2.8 Tessars of that day are quite soft when used wide-open, to the point that the F3.5 Zeiss Tessar has a much better reputation than the faster F2.8. The front element of the F2.8 Tessar is a thick piece of glass, "strong power" optic. I believe the optical engineers for Minolta decided to split the strong front element into the triplet, using elements of lesser power, making aberrations easier to correct. Manufacturing a triplet is expensive, doing so for "just" an F2.8 lens- maybe that's why this formula was not used by others.
The Super-Rokkors are quite good when used wide-open, edge to edge. The Super-Rokkors are not as plentiful in the US, and often the asking price on Ebay is too high. But with some patience, can be found at reasonable prices. In my opinion, they are the best F2.8 Triplets out there- better than the vintage 1-1-2 (4 elements in 3 groups, the rear element of the Cooke triplet made into a doublet) Tessars and Xenars. I will be doing some more informal tests, have an original Contax mount 5cm F2.8 Tessar, slightly later version- both Contax mount, in adapters; A Xenar Special 5 element in 4 group 5cm F2.8 adapted to Leica mount, and a good I26m. Will be an interesting shoot-out of the Moderate speed lenses.
The 5cm F2.8 Super-Rokkor, wide-open on the M9:
Minolta 5cm F2.8, wide-open by fiftyonepointsix, on Flickr
Minolta 5cm F2.8, wide-open by fiftyonepointsix, on Flickr
Minolta 5cm F2.8, wide-open by fiftyonepointsix, on Flickr
Minolta 5cm F2.8, wide-open by fiftyonepointsix, on Flickr
Above are quick tests- was late in the day. More coming in the next few weeks.
The 45/2.8, 50/2.8, and 85/2.8 are as far as I know, reading Neblette and Kingslake- the only "3-1-1" configurations made. I took a 45/2.8 apart: the front two groups are stamped in a single metal fixture, the rear element is a positive element that forms an image on its own. The front two groups combined have a negative focal length, like a Cooke Triplet and a Tessar.
The Minolta Super-Rokkor F2.8 lenses started with a Cooke Triplet (1-1-1, "positive/Negative/Positive focal lengths) and split the front element into a cemented Triplet, providing a much faster F2.8 than is commonly seen. Most F2.8 Tessars of that day are quite soft when used wide-open, to the point that the F3.5 Zeiss Tessar has a much better reputation than the faster F2.8. The front element of the F2.8 Tessar is a thick piece of glass, "strong power" optic. I believe the optical engineers for Minolta decided to split the strong front element into the triplet, using elements of lesser power, making aberrations easier to correct. Manufacturing a triplet is expensive, doing so for "just" an F2.8 lens- maybe that's why this formula was not used by others.
The Super-Rokkors are quite good when used wide-open, edge to edge. The Super-Rokkors are not as plentiful in the US, and often the asking price on Ebay is too high. But with some patience, can be found at reasonable prices. In my opinion, they are the best F2.8 Triplets out there- better than the vintage 1-1-2 (4 elements in 3 groups, the rear element of the Cooke triplet made into a doublet) Tessars and Xenars. I will be doing some more informal tests, have an original Contax mount 5cm F2.8 Tessar, slightly later version- both Contax mount, in adapters; A Xenar Special 5 element in 4 group 5cm F2.8 adapted to Leica mount, and a good I26m. Will be an interesting shoot-out of the Moderate speed lenses.
The 5cm F2.8 Super-Rokkor, wide-open on the M9:
Above are quick tests- was late in the day. More coming in the next few weeks.