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11-27-2010, 04:35 PM   #46
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QuoteOriginally posted by Pål Jensen Quote
For a cropped 645 format DOF is no problem unless one wants to exlore some really extreme near/far relationships. For digital most if not all the effects of tilt/shift can be achieved with cheaper means. Hence, the market for a Pentax tilt/shift lens is very small indeed....
I agree that tilt/shift lenses are specialised and only cater for a very small part of the lens market, but people that are in that field have specialised needs for a reason, there are some things that you can do with tilt shift lenses that are impossible with ordinary ones. I know with 40Mp it will be easy to crop and adjust for perspective distortion, but I prefer to do all that stuff in camera - which means actually using a tilt shift lens. but correcting perspective distortion isn't the only thing T/S lenses are good for, there is the scheimpflug and anti-scheimpflug* techniques that have applications in architecture, landscape and portraiture and fashion photography.

*anti-scheimpflug - while based on the scheimpflug principle it is used to give the illusion DOF which is far shallower than a conventional fast lens.

11-28-2010, 10:44 AM   #47
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To my way of thinking every camera we use is a crippled version of a technical camera since it lacks the geometric possibilities. Being able to shoot with my FA43 at an excruciatingly sharp f/4 or f/5.6 while getting an entire landscape in focus is some sort of a holy grail in APS-C. If I was investing ten grand I'd see it as an essential feature. Especially as architecture is also a favourite subject of mine.

Few people use tilt/shift not because it wouldn't make their shots better but because a) the lenses are not available, b) they don't know what it can do for them. Pentax should see this as a market waiting to happen. Not to mention all the pro shooters who compromise on Canon FF just because they can easily get the correct perspective shots they require. I am thinking a good number would move to a larger sensor to differentiate themselves. Yes, it's a small market but one willing to pay.
11-28-2010, 05:14 PM   #48
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Robin...Your observations are the main reason why I went into large format. My Chamonix is a little short of a technical camera, but it can deliver definition on the same order as the 645D and also has full movements. Of course, this comes with a huge usability penalty


Steve
11-28-2010, 08:19 PM   #49
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Exactly so, Steve. I am absolutely convinced that the portable, ergonomically brilliant and high IQ 645D combined with an excellent wide tilt/shift lens might win "many" converts... where "many" is defined relative to the MF marketplace. ;-)

Better yet, given that the sensor is cropped, a tilt/shift adapter that takes any and all existing 645 and 67 lenses would be a brilliant coup. That's the route Hassy took.

11-29-2010, 11:43 AM   #50
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Hello,

years ago build the small munich based company ZOERK an 645/67 Shift adaptor. As the 645 System was cancelld in Germany, they stopped Production. I have at the Photokina a nice talk with Mr. Zoerk, if there are enough customers he will build again the adaptor (360° rotation, shift over 20mm). In the moment he has only one, i could try it with the 645D and an 67 45mm at the Pentax stand, works fine. 45 is not really wide on the 645D, but better then nothing.. and the rest of 67 lensen can also be used, but only shift, NO tilt.

regards

Frank
11-29-2010, 04:17 PM   #51
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QuoteOriginally posted by Pål Jensen Quote
For large format tilt/shift function is a necessity in order to get anything resembling DOF.
My 90mm for my 4x5 has f64 and it really gets good DOF without the need of any tilt unless something is really close.

I think too a tilt/shift lens for the 645D would be a good move. Landscape, architecture and creative selective focus would be that camera's strong point.

Last edited by tuco; 11-29-2010 at 04:54 PM.
11-29-2010, 05:06 PM   #52
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First of all geometric perspective is controlled at the film plane i.e. the camera back, not at the lens.

Second you can't have the whole landscape in focus. What sheimpflug does is change the shape of the field of focus into a wedge, that's three dimensional of course. With the critical plane of focus running through the wedge. You still place the critical plane of focus as with a fixed body/lens, but it's not at hyperfocal anymore.

Third using scheimpfug allows one to not use f 64 to attain depth of field and use the aperture that yields the very noticeably sharper image and print. Something more like f 22 is more common as an optimal f stop. Not to mention the reduction in exposure time which can be critical in the wind, to stop water movement, etc. Wider angle lenses like a 90 have more depth of field and field of view and require even less tilt.

Claude Fiddler
Linhof 4 with Rodenstock 150mm. The only camera I owned or used for 30 years
11-29-2010, 05:10 PM   #53
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QuoteOriginally posted by claudefiddler Quote
First of all geometric perspective is controlled at the film plane i.e. the camera back, not at the lens.
You can also correct convergence by raising/lowering (shifting) the front standard too without the need of moving the camera's rear standard and hence the film plane.


Last edited by tuco; 11-29-2010 at 05:17 PM.
11-29-2010, 05:19 PM   #54
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One is not correcting a building or anything else's convergence by shifting the front standard. This type of shift assumes that the camera back (the geometric perspective) is parallel to the subject. Shift allows top and bottom of a tall subject, like a building, to be included in the picture frame. It does not change geometric perspective. That's done at the film plane.

Last edited by claudefiddler; 11-29-2010 at 05:45 PM.
10-22-2011, 10:11 AM   #55
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Did you try your 800 mm lens on the 645 digital??
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