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08-14-2019, 09:26 PM   #91
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QuoteOriginally posted by K1N8 Quote
Hmmm, I have a Mamiya Sekor C 80mm /1.9 for 645 and there are adapters to PK. Would that work with a K-1? Covers the full frame? What focal length would that translate to?
Your Maniya 80mm C series will cover the full frame. Adapters are slightly more than they are for aps-c to 35mm full frame remounting. Imported, they are inexpensive. You lose electrical contacts and have to meter in the green mode. Look up some of Northrup's detailed expository photo technology teaching on You Tube to figure focal length. From the hip, I think it stays 80mm, but could be slightly longer. I don' really know.

08-14-2019, 10:42 PM   #92
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A lens mm is defined by the distance from the lens to the focal plane at infinity. A lens with multiple groups can have it's theoretical center at any place so the lens size won't actually be that many mms long. A telephoto has a rear element that makes the focus closer than the mm distance. Most 500mm lenses are telephoto because 500mm long lenses are unweildy, put a telephoto element on and it can be 200mm in actual size because this changes the theoretical center of the "lens" which is many lenses combined such as a lens with 8 elements in 5 groups. The center isn't from the front element but where the center of these groups affecting each other is. That can end up being in front or behind all the lenses or somewhere between.
No matter what you focus on, be it a 8x10 film or a 2mm micro film a 50mm lens needs to be 50mm from it's center to the focal plane at infinity.
08-18-2019, 02:47 AM - 1 Like   #93
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K-5 IIs with Mamiya Sekor 35mm f2.8

and back to the point of this thread:






08-18-2019, 02:48 AM - 2 Likes   #94
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K-5 IIs with Mamiya Sekor 35mm f2.8





09-06-2019, 07:44 PM - 1 Like   #95
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K-5 IIs with Mamiya Macro Sekor 60mm f2.8

09-26-2019, 04:59 PM - 2 Likes   #96
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A soft focus approach

Here are a couple of soft focus shots with the K-1 and Mamiya 645 C 145mm f 4.0 soft focus, I believe one of the best soft focus lenses out there.
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1 Day Ago - 1 Like   #97
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Adapter for medium format Mamiya lenses

I have seen adapters to use Mamiya medium format lenses on K-mount cameras listed on eBay by Kippon and Fotodiox. These two adapters both appear to be of good quality, well machined, etc. I have the Fotodiox adapter, and photos of this adapter are attached. Prices on the Fotodiox adapters seem to be significantly lower than for the Kippon adapters. Why I cannot say. Both adapters seem to perform identically in fitting medium format M645 Mamiya lenses to Pentax K-mount cameras. With either adapter, the camera can be used in only Manual or Aperture Priority modes because neither adapter provides the electronic connection to the camera that would be needed for other modes.

There are fairly complete lines of M645 lenses in both the original C configuration as well as the N configuration. These lenses tend to be quite similar except for improved coatings on the N line. Both the C and N lenses tend to be very well built with all-metal construction, and generally lighter and more compact than their Pentax 645 counterparts. They are pleasing to use from a tactile standpoint, and I have found them easy to focus, though the focussing rings turn opposite from the Pentax direction. With Mamiya, your turn the ring to the left for infinity and to the right for closeup shots. Prices tend to be quite competitive, particularly for the C line, and I have found no problems with flare with the C coatings. For the same price, of course, the N line is to be preferred.

I have acquired nine of these lenses--including 45mm, 55mm, 70mm LS, 80mm.1.9, 80mm macro, 145mm soft focus, 150mm, 210mm, and 300mm. Generally speaking, these lenses tend to be a little lower in price than the A version of the Pentax medium format lenses and sometimes one stop slower than their Pentax counterparts, which may be why they can be produced in lighter and less bulky configurations than the Pentax lenses. Mostly these lenses offer no particular advantages over their Pentax counterparts although there are a few standouts. I particularly like the uber-fast Mamiya 645 C 80mm f 1.9, said to be the fastest medium format lens ever produced. The 145mm soft focus lens is the best soft focus lens I have ever used; though the soft focus lenses are no longer much in vogue I still like playing around with them. At the long end, the 150mm and the 210mm are quite sharp and offer a lot of reach for the money for K-1, K-3 cameras. There are some super long lenses (500mm) as well as several zooms that I have not tried and cannot comment upon.

Overall, this exercise in adapting Mamiya medium format lenses to the K-mount cameras has not produced any startling results, though you certainly can get some quality glass for low prices. Corner performance should be excellent since on K-mount cameras you are using the sweetest part of the image circle. I should point out in closing that it is not possible to adapt these lenses to the Pentax 645 line of cameras owing to incompatible registry distances which would necessitate including corrective glass in the adapter, and so far as I am aware no such adapter has been built.
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1 Day Ago   #98
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QuoteOriginally posted by ivanvernon Quote
I have acquired nine of these lenses--including 45mm, 55mm, 70mm LS, 80mm.1.9, 80mm macro, 145mm soft focus, 150mm, 210mm, and 300mm. Generally speaking, these lenses tend to be a little lower in price than the A version of the Pentax medium format lenses and sometimes one stop slower than their Pentax counterparts, which may be why they can be produced in lighter and less bulky configurations than the Pentax lenses. Mostly these lenses offer no particular advantages over their Pentax counterparts although there are a few standouts. I particularly like the uber-fast Mamiya 645 C 80mm f 1.9
That's quite the collection. Even if there isn't really an advantage in quality, i do like the certain "charm" in the results. I only have the 80mm f1.9 though.

1 Day Ago - 1 Like   #99
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QuoteOriginally posted by K1N8 Quote
That's quite the collection. Even if there isn't really an advantage in quality, i do like the certain "charm" in the results. I only have the 80mm f1.9 though.
That's true. As a retiree, it at least gives me something to do! I sometimes get out the same focal length in Mamiya C, P645, and P67 to try them on the same subject for the sake of comparison. The results are inconclusive.
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Some flower shots with Mamiya

Here are a few shot with the K-1 and the Mamiya 645 C80mm f 4.0 macro (medium format lens).
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