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11-30-2009, 09:50 PM   #61
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still ugly, not as slick as the H3D..

11-30-2009, 11:59 PM   #62
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QuoteOriginally posted by Asahiflex Quote
Ytterbium, you have just proposed a new AF system
It's not new, a Contax had it in the late eighties.
12-01-2009, 01:45 AM   #63
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QuoteOriginally posted by eurostar Quote
It's not new, a Contax had it in the late eighties.
Indeed; I should have added "for Pentax". Mamiya also had this focusing method in their Mamiya Six folders (moving the film plane instead of the lens for focusing).
12-01-2009, 03:16 AM   #64
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Indeed. Allowing the sensor to move forward by some 25.41mm (after a MLU) and perpendicular to the optical axis would theoretically allow to use 35mm legacy lenses with CDAF in live view mode. Moving the sensor forward in any way other than perpendicular would even bring a poor man's alternative to TSE lenses. Mmmh...

12-01-2009, 08:10 AM   #65
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PENTAX 645D FX and DX mode - Part I

QuoteOriginally posted by Samsungian Quote
Wouldn't the K Mount lens rear element interfere with 645D Mirror and its function?

Now if there were no mirror then I think you could stuff an adapted K Mount lens into bigger 645D lensmount hole, though controlling manual aperture on lens would be next obstacle.

Well indeed. That large mirror when flipping up and down would severely interfere with the back flange of a K-mount and would go kaput. Then we have to find a way to overcome that. This because I still want Pentaxians to use this 645 body with the gorgeous SMC DFA lenses. DFA? And what about the FAs? Well if you cannot make everyone happy then let's do our best.
On the picture attached you find the 645 mirror box. As you see the mirror(31 in picture, 32 being an optical filter) is hinged on the ceiling of the MB, that hinge being on the back, closer to the sensor, swinging from a 45degree inclination to a horizontal position blocking the light to the viewfinder. OK, that everyone knows already! What then? To cover the 6x4.5 format the mirror dimensions would be, at least, 4.5cm wide and 6cm depth because on a 120 film roll the 6cm is the height of the frame and 4.5cm the width. With a sensor size 36.7x49 (as per thibs) and with the longest side in a horizontal position the mirror had to be 37mm depth, saving a little more room. It's not enough for a K-adapter? Ok, let's do it, in part II of this post.

Rui
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12-01-2009, 08:36 AM   #66
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PENTAX 645D FX and DX mode - Part II

QuoteOriginally posted by eurostar Quote
And will work only as a macro lens.
QuoteOriginally posted by thibs Quote
Mmm in theory, since the 'hole' of the mount is a lot bigger on 645 than on FF, an adapter may be made so the lens would get recessed into the 645mount at the proper register distance.
I doubt it, though, specially, on a practical usage point of view. But why not..
QuoteOriginally posted by Samsungian Quote
Wouldn't the K Mount lens rear element interfere with 645D Mirror and its function?

Now if there were no mirror then I think you could stuff an adapted K Mount lens into bigger 645D lensmount hole, though controlling manual aperture on lens would be next obstacle.
QuoteOriginally posted by eurostar Quote
Well, the FF lenses would need a mirror at least large as an LX one, but a 645 lens, even on a cropped 44x33 sensor, would need a larger mirror, and thus no space for the register of 35mm lenses.
QuoteOriginally posted by jeffkrol Quote
lens would have to extend into the body about a full inch.
25.41mm
mounts.htm
Part II-

Well we have now a shorter mirror, and a little more room. To make it more practical and effective let's do a little(huge) modification on the way the mirror works.
Now we have an optical filter in upright position behind the mirror in its 45 inclination. This mirror is only a half mirror (semi-transparent) in a way that only half of the light is reflected to the viewfinder and the other half goes through it, through the optical filter(91A) reaching the sensor that is blocked by the shutter curtains. Opposite to the previous mirror box, this mirror is not hinged on the ceiling but on the floor of the box(91C). On the photographing action, the mirror swings to a vertical position, vertical that is, perpendicular to the optical path, letting half the light go through it to the sensor through the filter. You can see this on the picture being S the direction of the mirror movement. The mirror no longer blocks the viewfinder path. To avoid light entering via the VF, a shutter(92A) is installed on the eyepiece which closes when the shutter is fired, blocking the light from above.
This movement allows far greater room on the front making the use of DFA lenses a vary easy one via the adapter. This adapter must guarantee light tightness so lenses with aperture ring are voided on this design allowing only DAs and DFAs lenses. With this you can use FX and DX modes.
Thank you for listening. Any questions should be directed to Hoya_Pentax Support,
Thanks
Rui
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Last edited by RuiC; 12-01-2009 at 12:57 PM.
12-01-2009, 08:59 AM   #67
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QuoteOriginally posted by turbosaturn Quote
I sure hope that the camera would be fast enough using SD cards.
Actually, I think SD cards are potentially superior to CF cards, and future specs are impressive. Check this out: SDXC - SD Card Association
12-01-2009, 08:59 AM   #68
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Interesting..
So since the swing of the mirror is at the sensor side, it wont hit a lens that protrudes deeper.

I wonder what lenses can you actually stick in the 645 mount when some space for adapter is allowed. M's and A's i guess can be used at some fixed aperture setting, but the ring is not accessible when the lens is mounted.

The looking patent like makes them quite creditable. May you happen to have a link to the patent itself, somewhere online? Has this idea been used already before in any film MF cam?

12-01-2009, 12:54 PM   #69
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QuoteOriginally posted by ytterbium Quote
Interesting..
So since the swing of the mirror is at the sensor side, it wont hit a lens that protrudes deeper.

I wonder what lenses can you actually stick in the 645 mount when some space for adapter is allowed. M's and A's i guess can be used at some fixed aperture setting, but the ring is not accessible when the lens is mounted.

The looking patent like makes them quite creditable. May you happen to have a link to the patent itself, somewhere online? Has this idea been used already before in any film MF cam?
Mirror box:

United States Patent: 7334949


Lens adapter:

" [0026]In an embodiment, a camera system is provided, including an interchangeable lens including a lens-side mount ring and an annular packing made of a resilient material; a packing-incompatible camera body including a second mount ring to which the lens-side mount ring can be coupled, an inner peripheral surface of a rear end of the annular packing being positioned radially outside of the second mount ring in a state where the lens-side mount ring is coupled to the second mount ring; a packing-compatible camera body including a first mount ring to which the lens-side mount ring can be coupled. The first mount ring includes an annular portion identical in size and shape to a corresponding the second mount ring, and an annular contacting portion provided on an outer periphery of the annular portion of the first mount ring, an outer diameter of the first mount ring being greater than an inner diameter of a rear end of the annular packing in a free state.

[0027]According to the present invention, the relative position between the interchangeable lens and the camera body to which the interchangeable lens is mounted in the optical axis direction becomes appropriate in either case where the interchangeable lens is mounted to the first-type camera body (packing-compatible camera body) or the second-type camera body (packing-incompatible camera body). Therefore, in the case where the user buys the new interchangeable lens with the annular packing, a lens optical performance in accordance with the lens design thereof can be achieved even if this interchangeable lens is utilized with the packing incompatible camera body already owned by the user. "

United States Patent Application: 0080075454

" 9. A camera system comprising: an interchangeable lens including a lens-side mount ring and an annular packing made of a resilient material; a packing-incompatible camera body including a second mount ring to which said lens-side mount ring can be coupled, an inner peripheral surface of a rear end of said annular packing being positioned radially outside of said second mount ring in a state where said lens-side mount ring is coupled to said second mount ring; a packing-compatible camera body including a first mount ring to which said lens-side mount ring can be coupled,wherein said first mount ring includes an annular portion identical in size and shape to a corresponding said second mount ring; and an annular contacting portion provided on an outer periphery of said annular portion of said first mount ring, an outer diameter of said first mount ring being greater than an inner diameter of a rear end of said annular packing in a free state. "

This maintains fully auto operation of the lens.

Regards
Rui

Last edited by RuiC; 12-01-2009 at 01:01 PM.
12-01-2009, 12:56 PM   #70
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QuoteOriginally posted by RuiC Quote
Mirror box:

United States Patent: 7334949


Lens adapter:

" [0026]In an embodiment, a camera system is provided, including an interchangeable lens including a lens-side mount ring and an annular packing made of a resilient material; a packing-incompatible camera body including a second mount ring to which the lens-side mount ring can be coupled, an inner peripheral surface of a rear end of the annular packing being positioned radially outside of the second mount ring in a state where the lens-side mount ring is coupled to the second mount ring; a packing-compatible camera body including a first mount ring to which the lens-side mount ring can be coupled. The first mount ring includes an annular portion identical in size and shape to a corresponding the second mount ring, and an annular contacting portion provided on an outer periphery of the annular portion of the first mount ring, an outer diameter of the first mount ring being greater than an inner diameter of a rear end of the annular packing in a free state.

[0027]According to the present invention, the relative position between the interchangeable lens and the camera body to which the interchangeable lens is mounted in the optical axis direction becomes appropriate in either case where the interchangeable lens is mounted to the first-type camera body (packing-compatible camera body) or the second-type camera body (packing-incompatible camera body). Therefore, in the case where the user buys the new interchangeable lens with the annular packing, a lens optical performance in accordance with the lens design thereof can be achieved even if this interchangeable lens is utilized with the packing incompatible camera body already owned by the user. "

United States Patent Application: 0080075454


Regards
Rui
That one was rumored by some to be no other than WRed DA bayonet. That kind of technical vocabulary is way beyond my skills so, really I may be completely off here.
12-01-2009, 01:05 PM   #71
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QuoteOriginally posted by thibs Quote
That one was rumored by some to be no other than WRed DA bayonet. That kind of technical vocabulary is way beyond my skills so, really I may be completely off here.
Thibault, they talk of two incompatible bodies that share the same lens via the adapter. It is WRed because the 645D is also WRed


Rui
12-01-2009, 01:20 PM   #72
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QuoteOriginally posted by RuiC Quote
Thibault, they talk of two incompatible bodies that share the same lens via the adapter.
Interesting =)

QuoteOriginally posted by RuiC Quote
It is WRed because the 645D is also WRed
Rui
Well I suspected that for quite a time, I wouldn't be surprised at all if the 645 was announced to be WRed, indeed.
12-01-2009, 05:05 PM   #73
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QuoteOriginally posted by RuiC Quote
"..... wherein said first mount ring includes an annular portion identical in size and shape to a corresponding said second mount ring; and an annular contacting portion provided on an outer periphery of said annular portion of said first mount ring, an outer diameter of said first mount ring being greater than an inner diameter of a rear end of said annular packing in a free state. "
I'm trying to visualise this and what I keep getting is the old 6x7 inner/outer bayonet, except that the register distance is the same for both on the 6x7. Technically I suppose you could put a new mount outside the 645 bayonet but I can't imagine why you would do that.
12-01-2009, 05:21 PM   #74
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QuoteOriginally posted by Paul Ewins Quote
I'm trying to visualise this and what I keep getting is the old 6x7 inner/outer bayonet, except that the register distance is the same for both on the 6x7. Technically I suppose you could put a new mount outside the 645 bayonet but I can't imagine why you would do that.
That's a valid opinion. If the 645 exists for a long time (???) and that 6x7 to 645 adapter exists since then, why would Pentax submit a patent request as late as Sept, 2007 for that?
I admit I could be wrong on my guess. I just try to interpret the patents submitted.

Rui
12-02-2009, 04:00 AM   #75
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SNIP...

QuoteOriginally posted by RuiC Quote
Part II-

Rui
One small problem, how is the mirror box blacked out during exposure to prevent extraneous light entering from the Prism box.
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