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10-21-2015, 11:29 AM   #16
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QuoteOriginally posted by UncleVanya Quote
it would be cost prohibitive for most people
Not to anyone shooting a 645z who might consider picking up a k-2 body as back up. Seems like a no brainer to me.

10-21-2015, 12:26 PM   #17
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QuoteOriginally posted by UncleVanya Quote
I'm not sure what such an item might cost but I suspect it would be cost prohibitive for most people and only really appeal to those with a stable of lenses for their 645.
QuoteOriginally posted by rangercarp Quote
Not to anyone shooting a 645z who might consider picking up a k-2 body as back up. Seems like a no brainer to me.
I'm confused. How is that not what I said, you only copied part of what I said. 645 in my quote was intended to cover all 645 users, digital and film alike.
10-22-2015, 04:49 AM   #18
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QuoteOriginally posted by UncleVanya Quote
I'm confused. How is that not what I said, you only copied part of what I said. 645 in my quote was intended to cover all 645 users, digital and film alike.
My point was not to twist what you said, but to emphasize this particular high spending group of Pentax users. You certainly acknowledge that this group exists, but downplayed their importance.
10-22-2015, 10:47 AM   #19
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QuoteOriginally posted by RuiC Quote
120 times 1.5 = 180 !!!
That's the crop factor going between APS-C to 35mm, Rui. :-)

10-22-2015, 02:02 PM   #20
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QuoteOriginally posted by clackers Quote
That's the crop factor going between APS-C to 35mm, Rui. :-)
It is also very close to the ratio of 35mm FILM to 645 FILM if you use the horizontal measure (56mm / 36mm = 1.5666), the 645 digital format is smaller however as pointed out earlier.

---------- Post added 10-22-15 at 05:07 PM ----------

QuoteOriginally posted by rangercarp Quote
My point was not to twist what you said, but to emphasize this particular high spending group of Pentax users. You certainly acknowledge that this group exists, but downplayed their importance.
I think again you are putting a spin on interpretation of me. "Cost prohibitive for MOST people" doesn't imply a lack of people who may spend money - it does indicate that the appeal will only be to a smaller subset of users than the majority. I also would posit that a fractional number less than 100% of the 645z users would be interested in this solution.

Ultimately the marketing group within Ricoh has to determine if they can manufacture this for a cost that would appeal to enough people that would buy it to offset development of the product and make enough profit to be worth tying up capital. Since I don't know what it will cost to develop, nor do I know what the market numbers are - I give up - I no longer advocate a particular viewpoint on this...

Last edited by UncleVanya; 10-22-2015 at 02:08 PM.
10-23-2015, 02:59 PM   #21
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QuoteOriginally posted by clackers Quote
That's the crop factor going between APS-C to 35mm, Rui. :-)
Of course !!! I don't know why I guessed it was about aps-C ! I apologize !
10-23-2015, 04:49 PM   #22
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QuoteOriginally posted by clackers Quote
Pepperberry Farm is quite right, Sunshine.


The focal length will still be 120mm, the FoV will be about that of a 150mm lens.


There is a 645 to K-mount adaptor already, no?
Because they use a special 645 to K adapter the FOV stays the same!!! A 120mm 645 lens will have the very same FOV when used on a Kmount FF camera!

" Pentax 645 K-Mount Adapter?? - Photo.net Pentax Forum "

" The 300mm 645 lenses give you same FOV as the 300mm k mount versions. "

Last edited by RuiC; 10-24-2015 at 03:24 AM.
10-23-2015, 07:41 PM   #23
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QuoteOriginally posted by RuiC Quote
Because they use a special 645tok adapter the FOV stays the same!!! A 120mm 645 lens will have the very same FOV when used on a Kmount FF camera!

" Pentax 645 K-Mount Adapter?? - Photo.net Pentax Forum "

" The 300mm 645 lenses give you same FOV as the 300mm k mount versions. "
Uh... no. The FOV of a 300mm lens on any camera is the same without respect to which 300mm lens system the lens is from as long as the image circle covers the entire film or sensor.

So Take an 8x10 300mm and put it on a Sony A7 or a Pentax K3 or a Pentax Q - each system will show the same FOV it would show for a native 300mm mount. So the Sony will show the FF equivalent FOV, the K3 the APSC FOV, the Q the mega zoom fov that it does.

What doesn't happen is that you don't take a 300mm 645 lens and see the same FOV it offers on film or even digtal 645 on the K3 or the Sony or the Q. In each case the FOV seen on the camera is the same as a native 300mm lens - because focal length didn't change - just the part of the image you were able to capture.

SO when you put a 120mm 645 lens on the K3 - you see the same FOV you would normally see for a 120mm K mount but that FOV is nothing like what you see on the 645d or z or even a film 645.

10-24-2015, 12:42 AM   #24
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QuoteOriginally posted by RuiC Quote
Because they use a special 645tok adapter the FOV stays the same!!!
Without glass in it, this is impossible.

Even a superb teleconverter like the Pentax x1.4 will degrade an image to an extent.
10-24-2015, 03:54 AM   #25
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QuoteOriginally posted by clackers Quote
Without glass in it, this is impossible.

Even a superb teleconverter like the Pentax x1.4 will degrade an image to an extent.
We must bear in mind that the 645 adapter changes the register distance. When you use a K lens on an APS-C body the register is the same SO different FOV. With the 645 adapter the lens is moved outward by 25 mm!

The same for the 67 lenses with the 67 to K adapter.

---------- Post added 24-10-15 at 03:58 ----------

QuoteOriginally posted by UncleVanya Quote
Uh... no. The FOV of a 300mm lens on any camera is the same without respect to which 300mm lens system the lens is from as long as the image circle covers the entire film or sensor.

So Take an 8x10 300mm and put it on a Sony A7 or a Pentax K3 or a Pentax Q - each system will show the same FOV it would show for a native 300mm mount. So the Sony will show the FF equivalent FOV, the K3 the APSC FOV, the Q the mega zoom fov that it does.

What doesn't happen is that you don't take a 300mm 645 lens and see the same FOV it offers on film or even digtal 645 on the K3 or the Sony or the Q. In each case the FOV seen on the camera is the same as a native 300mm lens - because focal length didn't change - just the part of the image you were able to capture.

SO when you put a 120mm 645 lens on the K3 - you see the same FOV you would normally see for a 120mm K mount but that FOV is nothing like what you see on the 645d or z or even a film 645.
You are right BUT we are talking about FF not the K3 !!
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10-24-2015, 04:30 AM   #26
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QuoteOriginally posted by RuiC Quote
l
You are right BUT we are talking about FF not the K3 !!
Same effect just different fov.
10-24-2015, 06:33 AM   #27
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QuoteOriginally posted by UncleVanya Quote
Same effect just different fov.
??? ???
10-24-2015, 07:32 AM   #28
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QuoteOriginally posted by RuiC Quote
??? ???
Saying K3 or FF doesn't change anything I said - it just changed the math slightly.
10-24-2015, 08:31 AM   #29
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QuoteOriginally posted by UncleVanya Quote
Saying K3 or FF doesn't change anything I said - it just changed the math slightly.
Not at all !! A 645 lens with adapter to K will not crop on a FF camera. It will 1.5 on an APS-C camera !!
10-24-2015, 11:06 AM   #30
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QuoteOriginally posted by RuiC Quote
Not at all !! A 645 lens with adapter to K will not crop on a FF camera. It will 1.5 on an APS-C camera !!
And you base this on what? I think you are very confused about how cropping occurs and what the glassless adapter from Pentax does.

So. If we take a 50mm lens for 645 and put it on FF it will give the same field of view as the standard Takumar m42 lens mounted on the same FF camera. I think where the train is off the tracks is that you seem to think that the 645 lens will magically give the same field of view on both 645 and FF but on the 645 it will have a wider field of view.
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