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09-24-2011, 01:16 PM - 1 Like   #1
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Idea: Mirrorless K-mount with telescoping mount

Hi forum members,

Probably the main reason why making a mirrorless version of an existing D-SLR mount is the flange distance required between the sensor and the lens. The lens has to be so far away from the sensor, that the body can't be be much tinned than existing SLR bodies, negating the size advantage offered by getting rid of the mirror.

So, how about this idea: Pentax should make a thin mirrorless camera, that uses the standard k-mount and keeps the existing flange distance. It can do this by using a telescoping mechanism on the mount. The mount could retract when the camera is off, creating a really slim body for carrying the camera. Then, when you turn on the camera, the mount and attached lens could extend out the the proper distance, ready for taking the picture.

It would certainly take some clever engineering to get this kind of mechanism working nicely, but Pentax has some great engineers. I'm sure they could pull it off.

What do you think?

09-24-2011, 01:18 PM   #2
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Bad idea IMO, would take space, would be fragile and expensive.
09-24-2011, 03:32 PM   #3
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Leitz beat you to this one by about 80 years (the telescoping lens idea, that is). I've got one on my Leica IIIc, and it isn't fragile - all it takes is a little engineering, so it could be done to satisfy lightness (materials) and strength (design and materials). Personally, I like a little heft in a camera, so I'd stick with steel, rather than go to carbon fibre.

When you weigh up all the other factors, like designing a completely new lens range, I don't think the small extra cost is a consideration.
09-24-2011, 05:18 PM - 1 Like   #4
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The sony A mount to E mount adaptor with pellicle mirror and phase detection autofocus is a much better idea.

09-25-2011, 12:04 AM   #5
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Funny, I suggested the very same idea several days ago here:

https://www.pentaxforums.com/forums/pentax-news-rumors/159325-exclusive-ricoh...ml#post1652751

QuoteOriginally posted by Noam Quote
Here's an idea for a K-mount MILC, that is not totally alien to Ricoh's design philosophy (cf. GRX): use the same K-mount, but make the mount part movable between two positions:
1) far position as in the current K-mount, for current lens compatibility, and
2) close position for a new line of smaller/better lenses designed for this reduced distance, as well as collapsing the camera for compact transport and storage even with a traditional lens on it.

This could be the ultimate solution for keeping compatibility with the huge optical Pentax heritage (esp. keeping the appeal of Limiteds) while enjoying the benefits of mirrorless design.
Since it is just a short rigid movement along one dimension, I believe that it could be feasible while keeping low cost, weight, size and possibly even weather resistance.

Hmmm...
The idea was scoffed as "silly" several times in the the thread, so I gave up arguing...

The main criticism was that it will be "fragile". I don't think necessarily so - the telescoping mount (I termed it "collapsing") will basically be a ~6.5cm-diameter tube made of rigid light metal (e.g. aluminium), travelling a short distance of about 2-2.5cm forward/backward in a tight frame around it.

I don't think this should add much to cost and size either.

The potential benefits of this approach are huge: Both worlds will be enjoyed: Both perfect legacy K-mount compatibility will be attained, AND new very compact lenses designed for the reduced flange distance could be used.

And, of course, Ricoh could later introduce a lower-price ultra-compact "crippled" body that offers an unmovable mount at the short-distance position for those who do not need backward compatibility. As long as this is indeed physically feasible (as I wildly assume), there is nothing to lose here.
09-25-2011, 02:27 AM   #6
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It is not a good idea, it is an obvious idea.

Many range finders have this function and it works good for them! Also the MF Mamiya RBs and RZs which are professional SLR cameras use belows, not to mention almost all large format cameras.

There is no reason at all this could not work. If such a camera existed, I would not only want it, I would love it.

Btw people, look up the Plaubel Makina! Great MF rangefinder.
09-25-2011, 02:58 AM   #7
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There is still the problem that the old k mount lenses are not optically perfect for digital both in parallelism and internal reflections. The telescoping would only create a small saving in bulk. I am another one who likes a bit of bulk in a camera, it adds stability. The "surplus" size could be used for features other compacts do not have, eg additional battery and SD storage.
09-25-2011, 03:51 AM   #8
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QuoteOriginally posted by fisheye freak Quote
There is still the problem that the old k mount lenses are not optically perfect for digital both in parallelism and internal reflections. The telescoping would only create a small saving in bulk. I am another one who likes a bit of bulk in a camera, it adds stability. The "surplus" size could be used for features other compacts do not have, eg additional battery and SD storage.
this.
mirrorless camera with same size as k-5 and the resulting free space used to add something better or new.

twin image processor
twin af sensors
bigger, faster buffer


Last edited by befocus; 09-25-2011 at 03:59 AM.
09-25-2011, 07:33 AM   #9
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QuoteOriginally posted by befocus Quote
this.
mirrorless camera with same size as k-5 and the resulting free space used to add something better or new.

twin image processor
twin af sensors
bigger, faster buffer

Yes!!!! A mirrorless camera the size of a K-5 or maybe a K-r size would be great. One would have room to add a lot of enthusiast/pro features. More space for batteries, memory cards, processing power, built-in radio flash contoller and larger EVF.

Has anyone compare the Olympus EP-3 with the VF-2 attachded. It isn't really significately smaller than the K-r. There are a lot of people on the forms that always has the VF-2 attached to their Olympus camera. It makes me wonder why Olympus hasn't came out with a camera with a built-in EVF.

Anyhow several companies are doing small ICL cameras. Even Pentax is with their Q. No one except for Leica with their M-9 is doing a larger more enthusiast/pro level camera.

Dave
Dave
09-25-2011, 01:05 PM   #10
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I considered buying such a camera at an antique shop yesterday, an old Argus (I forget which model) with a Leica-style pull-out Cintar 50/3.5 lens. But I didn't feel like tossing US$30 for it.

I'm still awaiting a mirrorless digital folder. It could have a zoom lens mounted on a solenoid-pushed lensboard for full movement (tilt-shift-rise-fall-extend-etc) and a Polaroid-SX70-type ultrasonic focusing kit. I'll take the big version with the 6x9cm 300mpx sensor, thanks.
09-25-2011, 01:23 PM   #11
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09-25-2011, 09:15 PM   #12
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Removing the mirror and keeping the size doesn't give you more space for batteries or whatever. I hope you people realize that space has to be filled by NOTHING for light to pass right?

Also, a bellow will not give the camera any more "heft". Do you intend to hold the bellow like you were holding a lens barrel?
09-25-2011, 11:17 PM   #13
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QuoteOriginally posted by Spare Tire Quote
Removing the mirror and keeping the size doesn't give you more space for batteries or whatever. I hope you people realize that space has to be filled by NOTHING for light to pass right?

Also, a bellow will not give the camera any more "heft". Do you intend to hold the bellow like you were holding a lens barrel?
If somebody wants a mirrorless, I would guess most likely he wants something small, so he can really use it as a carry-around camera but has the potential to delivery APS-C level IQ. If I have such a small mirrorless (and I do want to buy one), I would need it to be as simple and small as possible: I do need good low ISO performance and good IQ as current K5. I can give up functions as shake reduction, SDM, high fps or OVF. I have big lens as 50-135, but I just want to have a camera small enough to carry around and matches to my Limits.
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