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10-30-2011, 11:57 AM   #1
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645D pro's besides other MF digital cameras?

I don't own a pentax 645D but I was reading some info about it and what I understood is that the advantages of the camera in comparaison with other MF digital camera (mamiya, hasselblad) are:

- Price
- Autofocus dots
- size
-weather sealed

And the cons are:

- There's no leaf shutter
- Lens availability: I mean the new ones, the ones that are build for this camera. i.e: if you want a 35mm equivalent lens you must go with the old 45mm because the 55mm will behave more like a 40mm, because of the 1.3 factor, right????

10-30-2011, 03:03 PM   #2
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There are two leaf shutter lenses for the Pentax 645 system. The 75mm and 135mm LS lenses.

There are a wide range of manual and auto focus lenses available for the 645 system, both new and second hand.

If you want a lens with the field of view equivalent to a 35mm lens on 135 Full Frame you would need a 55mm for 645 film or a 45mm for the 645D.

The 645 55mm lens will behave like a 75mm 645 lens on 645 film camera, with the same field of view of a 50mm lens on 135 full frame.

Regards

Chris Stone
10-30-2011, 03:30 PM   #3
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Original Poster
Thanks Chris for this info, I did not know that pentas has LS lens for 645. Also could you point a good reputated autofocus 45mm lens for 645?
10-30-2011, 04:29 PM   #4
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From what I understand, the FA 45-85mm zoom is better than the 45mm prime (manual focus or AF), which has not impressed many people on the 645D. There is also a 33-55mm zoom and one member here uses it on his 645D. The 55mm is the normal on this sensor. I really like my D-FA 55mm. The 35mm manual focus and AF versions are nice lenses on the 645D and similar to a 28mm lens on a 35mm camera--I have the 35mm manual focus version and really like it.

10-31-2011, 05:32 AM   #5
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Pentax made in 645 mount since 1984:

A series, manual focus: 35 45 55 75, 75LS, 120M, 135LS, 150, 200, 300, 400, 600, 1.4X, 2X, 45-85, 80-160

FA series, auto focus: 35, 45, 75, 120M, 150, 200, 300, 400, 33-55, 45-85, 55-110, 80-160, 150-300.

D-FA series: 55, 25.

I have used both the 45/2.8 in A and FA and find the sharpness nest on the 45-85 at 45 setting.
I hvae also used the 75LS on a 645D with full leaf shutter function.
10-31-2011, 06:53 AM   #6
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QuoteOriginally posted by Yamanobori Quote
From what I understand, the FA 45-85mm zoom is better than the 45mm prime (manual focus or AF), which has not impressed many people on the 645D. There is also a 33-55mm zoom and one member here uses it on his 645D. The 55mm is the normal on this sensor. I really like my D-FA 55mm. The 35mm manual focus and AF versions are nice lenses on the 645D and similar to a 28mm lens on a 35mm camera--I have the 35mm manual focus version and really like it.
I'm the guilty part as far as the FA33-55 is concerned and I find it pretty sharp between f/11 and f/16. I got a well priced FA 45 prime which is pretty good but haven't used it all that much. Finding a well priced 45 - 85 is more challenging. I have the FA 55-110 which is sharp at f/11 - f/16 but pretty soft after that particularly above f/22 (it goes up to f/45). The FA 75 is a very sharp lens in my experience and the A200 is also sharp
12-08-2011, 04:34 AM   #7
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Quick quesiton about the filter size on the 35mm lens - is the A version 77mm and the FA version 82mm? Thanks...
12-08-2011, 04:43 AM   #8
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QuoteOriginally posted by Tim Ernst Quote
Quick quesiton about the filter size on the 35mm lens - is the A version 77mm and the FA version 82mm? Thanks...
Don't know about the A lens but the FA is definitely 82mm

12-08-2011, 05:56 AM   #9
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OK, thanks!
12-08-2011, 08:50 AM   #10
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With a the focus system in the H4D cameras, is more focus dots really an advantage?
12-08-2011, 12:39 PM   #11
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QuoteOriginally posted by tuco Quote
With a the focus system in the H4D cameras, is more focus dots really an advantage?
considering the price difference, I would say so.
12-08-2011, 02:05 PM   #12
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Neither would i, but for the AF speed using a group of focus-dots with 645D, definitely, to the cost of accuracy.

I tried a few months ago the Hassy H4D, Leica S2, Phase One P40 and found the Pentax AF definitely faster than the 3 others, be it with SDM or FA lenses, using single central spot.
The Hassy has just got the interesting "true-focus" function that can make the difference in terms of AF accuracy when re-framing subjects.

Last edited by Zygonyx; 12-08-2011 at 02:10 PM.
12-08-2011, 03:47 PM   #13
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QuoteOriginally posted by Tim Ernst Quote
Quick quesiton about the filter size on the 35mm lens - is the A version 77mm and the FA version 82mm? Thanks...
The A version is 77mm.
12-08-2011, 11:03 PM   #14
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Thanks Yamanobori.
12-09-2011, 06:39 AM   #15
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About the lenses.
In an interview Pentax said that the wide angle lenses will be the first ones to be replaced.
With a digital sensor the lights need to hit the sensor at an as straight possible angle to increase the image quality and since the angle is already quite straight with the longer lenses they are given a lower priority.
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