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08-21-2013, 06:03 AM   #1
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Mirrorless K-Mount Camera

Sorry in advance if this has been asked already, in advance. So, I was just casually thinking about the K-Mount, and it came to me. Would it be possible for Pentax/Ricoh to release a M4/3 mirrorless that uses a K-mount in which the register distance is reduced in order to keep the same FOV of a APS.C Pentax DSLR such as the K-01 or K-5? Would there be any disadvantages/advantages from a set up like this, such as DOV of image quality degradation?

08-21-2013, 06:08 AM   #2
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The K-01 is a mirrorless K mount camera, not a DSLR. I would also be surprised if Ricoh released a Pentax 4/3 camera because it would compete agains the Q and the Pentax DSLRs.
08-21-2013, 06:11 AM   #3
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Sorry, the point about the K-01 was just a little slip of the tongue, was just wondering because mathematically, this is entirely possible.
08-21-2013, 06:22 AM   #4
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Also, about a K-Mount mirrorless competing with the Q range, I personal believe that the target audience of the Q is actually quite niche, until the image quality can be improved, whereas an improved(smaller) K-Mount mirrorless would may demand a larger audience due to the much smaller volume compared with a DSLR. Also, building two separate no interchangeable systems can be quite expensive, especially seeing that each new Q camera seems much more desirable compared with the previous Q camera.


Last edited by Joshua A; 08-21-2013 at 06:23 AM. Reason: Wording Error
08-21-2013, 06:50 AM   #5
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Pentax does have an official adapter to use K mount lenses on the Q, and from the image quality standpoint it's quite surprising what it can do.

While doing somethign like this may be possible, the greater issue is development costs, or lack of them. Also, they wouldn't want a 3rd system in their ICL lineup to compete with what they currently have.
08-21-2013, 06:53 AM   #6
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QuoteOriginally posted by Joshua A Quote
.....a M4/3 mirrorless that uses a K-mount in which the register distance is reduced in order to keep the same FOV of a APS.C Pentax DSLR
Why retain the K-mount if the register distance is reduced and you still want the same FOV. That would render existing K-mount lenses usless unless you introduce a telecompressor-like adapter, would it not?
08-21-2013, 07:06 AM   #7
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QuoteOriginally posted by Joshua A Quote
Sorry in advance if this has been asked already, in advance. So, I was just casually thinking about the K-Mount, and it came to me. Would it be possible for Pentax/Ricoh to release a M4/3 mirrorless that uses a K-mount in which the register distance is reduced in order to keep the same FOV of a APS.C Pentax DSLR such as the K-01 or K-5? Would there be any disadvantages/advantages from a set up like this, such as DOV of image quality degradation?
You could only reduce the register distance with optics. The K mount lenses have an innate register distance/flange focal distance, which, in order for them to widen out the field of view to what we see on an APS-C, the camera would need a focal reducer. It's possible, for sure. Will they make a camera like this? Like Voice of Reason said, I don't think so.

What would be more practical is to make a K to Q adapter that's also a focal reducer/speed booster/telecompressor. The flange focal distance of the Q is 9.2mm; on the K mount it's 45.46. So, it's theoretically possible to go much wider than what an APS-C sensor would normally show. You could probably go full frame and gain a couple of stops of speed. Unlike a normal adapter (K to Q, F to E, or 645 to EF), an adapter that's also a telecompressor reduces the register distance of a lens, which would make the whole getup smaller. Anytime you add glass, though, you run the risk of image degradation.
08-21-2013, 06:39 PM   #8
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So, just to explain the maths, it is possible to have a shorter register distance if a smaller sensor was used. Also, like joel_tauzin mentioned, you can adapt a Q camera to use a K-Mount lens. But, because of the significantly smaller sensor and factoring in crop size, the FOV of these adapted lenses is much more narrow. Now, I do realise that this would be a most unlikely design, but compared with the K-01, which is an amazing camera when based just on picture quality, would have a significant advantage when it comes to the total volume of the camera.

08-21-2013, 06:42 PM   #9
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QuoteOriginally posted by Stone G. Quote
Why retain the K-mount if the register distance is reduced and you still want the same FOV. That would render existing K-mount lenses usless unless you introduce a telecompressor-like adapter, would it not?
I might of possibly made some errors when it comes to calculations, but as long as the incident angle on the sensor is equal between sensors, wouldn't that mean that the field of view between the two cameras would be equivalent.
08-21-2013, 06:46 PM   #10
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QuoteOriginally posted by VoiceOfReason Quote
Pentax does have an official adapter to use K mount lenses on the Q, and from the image quality standpoint it's quite surprising what it can do.

While doing somethign like this may be possible, the greater issue is development costs, or lack of them. Also, they wouldn't want a 3rd system in their ICL lineup to compete with what they currently have.
Well, from a financial point of view, that is entirely true. Ricoh would most probably not invest a large sum of money into a project such as this. But, seeing I don't own a Q system camera, I really am not in a position to make a judgement on image quality, but I can assume that it is not equivalent to other larger sensor MILC cameras. Plus, you could say that the K-50 competes with the K-5, seeing that both cameras share most of their features, so I would assume that your saying that if they dropped out of low end cameras, the sales of the K-5 would improve?
08-22-2013, 01:09 AM   #11
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QuoteOriginally posted by Joshua A Quote
I might of possibly made some errors when it comes to calculations, but as long as the incident angle on the sensor is equal between sensors, wouldn't that mean that the field of view between the two cameras would be equivalent.
Specific types of lenses - such as Pentax K-Mount and Asahi Takumar - are designed to fit one, single registration distance. In our case 45.46mm ( Flange focal distance - Wikipedia, the free encyclopedia ). Mounting such on a slimmer body with a smaller mount-sensor distance while still achieving focus will require either:

A. an adpater (hollow, "passive" tube) that adds to the lens mount-sensor distance. It does not change the focal lenght, but the smaller the sensor, the more you will crop the image that the lens produces. You will not retain the FOV in that case.

B. a telecompressor/focal reducer that reduces the focal length of the lens and reduces the registration distance, not for the lens itself but for the lens+telecompressor combination as a whole. Within certain physical limits you might design a telecompressor that would give you about the same FOV on a smaller sensor.

Designing new lenses with a smaller registration distance for smaller sensors (and most likely also smaller image circle to reduce dimensions and weight) is "easily" done, but making such with K-mount and calling them K-mount lenses would create havoc......
08-22-2013, 03:48 AM   #12
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QuoteOriginally posted by Joshua A Quote
Sorry in advance if this has been asked already, in advance. So, I was just casually thinking about the K-Mount, and it came to me. Would it be possible for Pentax/Ricoh to release a M4/3 mirrorless that uses a K-mount in which the register distance is reduced in order to keep the same FOV of a APS.C Pentax DSLR such as the K-01 or K-5? Would there be any disadvantages/advantages from a set up like this, such as DOV of image quality degradation?
No, this is not possible. What you change by moving the lens closer to the sensor is focus, not FOV. If it would be possible to set focus on a K-mount lens with much shorter register distance than on K-mount, the FOV would still be the same.

Edit: It might be possible to set focus on infinity using macro lenses with focus set on shortest focus distance with shorter register distance, but on other lenses it would not be possible to set focus with much shorter register distance.

Last edited by Fogel70; 08-22-2013 at 04:01 AM.
08-22-2013, 04:28 AM   #13
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QuoteOriginally posted by Joshua A Quote
Well, from a financial point of view, that is entirely true. Ricoh would most probably not invest a large sum of money into a project such as this. But, seeing I don't own a Q system camera, I really am not in a position to make a judgement on image quality, but I can assume that it is not equivalent to other larger sensor MILC cameras. Plus, you could say that the K-50 competes with the K-5, seeing that both cameras share most of their features, so I would assume that your saying that if they dropped out of low end cameras, the sales of the K-5 would improve?
Nope. The feature set is different between the two. One is a midrange camera, the other is a top of the line (though it's getting dated) camera.
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