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01-13-2020, 04:10 AM - 1 Like   #16
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Pentax is clearly evaluating their options of how to differentiate future 645 cameras. They will do one of two things -- either go with a larger "full size" medium format sensor or they will add IBIS to the 645 camera. If they were able to add IBIS, they probably could add astro tracer, pixel shift tech, etc as well. That feels most likely, if they can up scale their current IBIS tech to move a bigger sensor and certainly their mount would accommodate a lot of sensor movement, as well/.

01-13-2020, 09:21 PM - 1 Like   #17
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Seems like the most likely move would be to port some of the K-1 features to the 645. IBIS and pixelshift being the most obvious. Seems like that could be done at less cost than a fullsize MF sensor. And having pixelshift would give many of the benefits of a higher MP sensor, without requiring one, and without always resulting in gigantic files.
This would keep the cost reasonable. Maybe also leave money for some new lenses.
01-13-2020, 09:44 PM   #18
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QuoteOriginally posted by SteveinSLC Quote
Seems like the most likely move would be to port some of the K-1 features to the 645. IBIS and pixelshift being the most obvious. Seems like that could be done at less cost than a fullsize MF sensor. And having pixelshift would give many of the benefits of a higher MP sensor, without requiring one, and without always resulting in gigantic files.
This would keep the cost reasonable. Maybe also leave money for some new lenses.
Fuji's GFX 100 already has IBIS, so I think they'll need something more than that to remain competitive. Maybe they'd be able to partner with someone for a whole new FF 645 chip...like they did with the 645D and Kodak...
01-16-2020, 08:09 PM   #19
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QuoteOriginally posted by Bassat Quote
The 645N is great for landscape work. All that is missing is a proper UWA lens.
The 35mm is pretty wide on 645 film - equivalent to about 21mm on 36x24. The A645 35/3.5 is pretty affordable.

01-18-2020, 01:17 PM - 1 Like   #20
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What are you talking about? You want a rectilinear wide that is under 24% of the frame diameter for any format? The only good lens on the market I can think of that does is the Canon 11-24 zoom, but it’s 25% of the format diameter, not 24%. And it’s a zoom, so it isn’t limited to just the extreme wide end of its range.

A fixed-focal lens at 18mm for 33x44 would be such a narrowly specialized lens, I don’t know how many they could sell.

And the 25 has a FAR better reputation than that Sigma 12-24 used on full frame (I bought the Sigma maybe 16-17 years ago—the Canon blows it away, but the Sigma was all there was in those days).

The widest really good lens in that focal range is the Rodenstock 23mm HR-Digaron, which is designed for a maximum sensor size of 36x49, but with a 90mm image circle it might go large enough to approach a quarter of the frame diameter at small apertures. It’s a double-gauss design with only 16mm sensor clearance at infinity. The Fuji 23 is more retrofocus, and it’s a good lens. Hasselblad’s widest for the Pentax-size sensor is 21, and it’s deeply retrofocus. It’s cheaper than I thought it would be, but still in the same price class as the Pentax 25 back before they lost the supplier who could make the front element.

But 18? For 58x44?

Rick “people complain that the 28-45 is too heavy” Denney
01-18-2020, 04:32 PM   #21
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Surely, some portion of the use cases that would support a sub 25 mm could be effected by stitching, whether stitching multiple images output from the Z sensor, or from scanned film images.

---------- Post added 18th Jan 2020 at 18:57 ----------

Some further contemplation of this quest reminds me that the Holy Grail of two-color IR threat warning sensors is to have fields of view exceeding 90 degrees, telecentric focusing on a flat field, fractional pixel chromatic aberration, high resolution, low f/#, etc., including low cost (in military wallet space). And for threat warning, the last piece of glass can be practically on top of the focal plane because there is no mirror volume. I fear that the large back focus required for the 645 would require something that looks like the Kiev Arsenal 30mm fisheye on steroids -- a giant lens assembly with a small effective aperture.

And hardly anyone would pay for it. Do I correctly vaguely remember that Ken Rockwell a few years ago put up for sale a massive lens of this type for 35mm at an eye-watering price?
01-18-2020, 10:31 PM - 1 Like   #22
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The issue underlying all these silly threads about what Pentax isn’t doing accuse Pentax of not doing what others (Fuji, Hasselblad) are doing. All the requests for this or that new feature are tinged with the color of Pentax Must Do This To Stay Relevant. Sorry I colored your post with that tint.

A request for a lens so short relative to the frame diameter that it doesn’t exist in any format just seemed a bit off the wall.

Now, I own the first version of that Sigma 12-24, and have owned and used it for a very long time. Even on my 5D Classic, it’s good in the center but not sharp at all in the corners. But I didn’t realize there was a Mk II before the Art, which was apparently improved over my Mk I. Maybe it’s the Mk II you are describing. I still use it on the very rare occasion when I want something that wide, but even interiors lose geometric relevance when the lens is that short.

But Roger Cicala, who does I think the best lens testing in the biz, thought very highly of the Canon lens, with enough testing to resist a fanboy accusation.

https://www.lensrentals.com/blog/2015/02/canon-11-24-f4-l-mtf-tests/

I don’t own it, and the latest 16-35 would be in front of it in line. But the shutter is dying on my 5DII and I haven’t been willing to buy its replacement, now that I have the 645z, so I haven’t been lens shopping for Canon EF in a long time.

Rick “who overdosed on ultrawides a decade or so back” Denney


Last edited by Sandy Hancock; 01-18-2020 at 11:47 PM. Reason: Keeping the eyes on the ball
01-18-2020, 11:19 PM - 1 Like   #23
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Settle down people. Play nicely.
01-19-2020, 05:19 AM   #24
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Only Pentax knows what camera line is or was successful in making money. GR1 and 360 win these days. APS-C camera is next to support/maintain the system. FF needs some lenses to keep momentum. 645 could need an update, but we do not know how well it sells right now. New features other than pixel count should trickle up from APS-C or FF. Currently Pentax is just slow. To become faster they probably need to consolidate lines. Only Pentax knows the numbers.
01-19-2020, 10:22 AM   #25
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Pentax may or may not produce a successor of the 645z, however I wish they did what they say were going to do: for years there have been a couple of lenses on the lens roadmap of the 645 system but they never materialised!
01-19-2020, 12:14 PM   #26
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QuoteOriginally posted by rdenney Quote

Rick “people complain that the 28-45 is too heavy” Denney
Snort. I'm not complaining about that lens...but it does feel like it needs a collar and foot. Just sayin'.
01-19-2020, 04:02 PM   #27
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QuoteOriginally posted by texandrews Quote
Snort. I'm not complaining about that lens...but it does feel like it needs a collar and foot. Just sayin'.


Not as much as the 300!

Rick “who implemented a solution for that lens, however” Denney
01-19-2020, 07:53 PM   #28
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I am not sure what it is about this particular subject, but do I detect a slight 'tetchiness' of tone in the discussion? One of the things I most value about this particular site is how well we interact with one another, even when we disagree...

Love to all :-)
01-19-2020, 10:46 PM - 1 Like   #29
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Do the DA MF lenses only cover a cropped sensor (like the DA APS-C lenses)? If so, I don't see Pentax rushing to update the 645Z to FF. That means even more new lenses to design and build. Plus Pentax would always be at a huge price disadvantage vs Fuji.

Sensor shift resolution would be more affordable to implement. Would it be possible to retool the 645 to have interchangeable digital backs? How about a camera than can be updated as opposed to Fuji's "buy a new camera" plan. How many 645 owners would buy into an upgradable system?

Thanks,
barondla
01-27-2020, 01:12 AM - 1 Like   #30
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QuoteOriginally posted by barondla Quote
Do the DA MF lenses only cover a cropped sensor (like the DA APS-C lenses)? If so, I don't see Pentax rushing to update the 645Z to FF. That means even more new lenses to design and build. Plus Pentax would always be at a huge price disadvantage vs Fuji.

Sensor shift resolution would be more affordable to implement. Would it be possible to retool the 645 to have interchangeable digital backs? How about a camera than can be updated as opposed to Fuji's "buy a new camera" plan. How many 645 owners would buy into an upgradable system?

Thanks,
barondla
As far as I know only the DA 28-45 mm covers the cropped sensor. All other lenses cover fully. Maybe the DA 25 mm is for a cropped sensor too or is it just a different lens hood?
As for retooling: I guess it would be much cheaper to bring out a FF 645; best would be with pixelshift or shake reduction and then we are set for the next 5-7 years. I would love to have either an updated AF with a much larger field of AF points or even better the nifty refocus system from Hasselblad.
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