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08-29-2018, 08:54 PM   #16
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QuoteOriginally posted by SunnyG. Quote
The size of 645 film is 56 x 42! But the current generation of medium format sensors are 44 x 33. Why is this? The current generation of medium format cameras are mostly mirrorless. This means, they have a much smaller footprint. My question is, if cameras can shoot at speeds in excess of 20 fps, why can't they integrate a real 645 sensor ?
Medium format dimensions have always been approximate. 645=not 60x45mm but 56x42mm; 6x6=not 60x60mm but 56x56mm; 6x7=not 60x70mm but 56x67mm.

Why? I know 120/220 film is 61mm in width, and that limits and prevents anything more than 56mm if you're going to have edge numbers. But of course, "they" could have made it 45x60mm but then have less exposures per 120/220.

So why isn't it called 5642? Or 4433? And if 35mm film actually 24x36mm, why don't we just call all medium format 61mm?

And why isn't digital medium format 56x42mm? Probably because of cost vs. benefit.

08-29-2018, 09:16 PM   #17
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QuoteOriginally posted by serothis Quote
Thank you. I think that the smaller one is the size that the OP was thinking of. The Type 4.2 is the larger:
“Sony's plans include the launch of 100MP 44 x 33mm and 150MP 55 x 41mm medium-format sensors in 2018.”
08-30-2018, 04:14 AM   #18
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QuoteOriginally posted by serothis Quote
Holy shit! 150mp? That's an over kill 😂. If Pentax uses that in their camera! All hells gonna break loose! Cuz we all know it'll be priced cheaper than a leica! & Hasselblad might go out of business! 😂

---------- Post added 08-30-18 at 04:18 AM ----------

QuoteOriginally posted by Alex645 Quote
Medium format dimensions have always been approximate. 645=not 60x45mm but 56x42mm; 6x6=not 60x60mm but 56x56mm; 6x7=not 60x70mm but 56x67mm.

Why? I know 120/220 film is 61mm in width, and that limits and prevents anything more than 56mm if you're going to have edge numbers. But of course, "they" could have made it 45x60mm but then have less exposures per 120/220.

So why isn't it called 5642? Or 4433? And if 35mm film actually 24x36mm, why don't we just call all medium format 61mm?

And why isn't digital medium format 56x42mm? Probably because of cost vs. benefit.
I can understand the cost factor! But what do you mean by benefit? Are you indicating towards easier to pronounce names? Or what?

---------- Post added 08-30-18 at 04:19 AM ----------

QuoteOriginally posted by RobA_Oz Quote
Thank you. I think that the smaller one is the size that the OP was thinking of. The Type 4.2 is the larger:
“Sony's plans include the launch of 100MP 44 x 33mm and 150MP 55 x 41mm medium-format sensors in 2018.”
That's correct! I was referring to the crop format one!
08-30-2018, 04:40 AM   #19
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I doubt that a full frame pentax 645z II would cause much if any grief for hasselblad or phase one. People/companies buying those systems are in the world of hyper specialized.

08-30-2018, 04:46 AM   #20
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QuoteOriginally posted by serothis Quote
I doubt that a full frame pentax 645z II would cause much if any grief for hasselblad or phase one. People/companies buying those systems are in the world of hyper specialized.
Competition can hurt profits.

Hasselblad couldn't survive and is now owned by a Chinese drone manufacturer.

08-30-2018, 06:17 AM   #21
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QuoteOriginally posted by serothis Quote
I doubt that a full frame pentax 645z II would cause much if any grief for hasselblad or phase one. People/companies buying those systems are in the world of hyper specialized.
Let me be clear when I referred to Hasselblad that I was talking about the X1D, which, like the Fujifilm GFX50, is price competitive with the 645Z. The higher priced Hasselblad bodies, like the Phase One bodies, are in a completely different price range.
08-30-2018, 06:23 AM   #22
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I imagine that the full frame sensor would force the 645z into a higher price bracket than currently.

08-30-2018, 06:26 AM   #23
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QuoteOriginally posted by serothis Quote
I imagine that the full frame sensor would force the 645z into a higher price bracket than currently.
Probably so, but the 645Z is currently selling at quite a discount from its launch price.
08-30-2018, 06:34 AM - 1 Like   #24
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I would love to see features like SR and pixelshift in the 645z. That could give fuji and hasselblad some grief.
08-30-2018, 07:28 AM   #25
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QuoteOriginally posted by serothis Quote
I would love to see features like SR and pixelshift in the 645z. That could give fuji and hasselblad some grief.
Pixelshift exists already on large Hasselblad H family backs (called MS for multishot, so we know it is possible to do it). If Pentax was to introduce this feature on a 645 model, that would be a big problem for Hasselblad H MS product line.

Regarding sensor size, Pentax could have access to the current 100MP non BSI 54x40mm sensor probably at discounted price, because it is replaced now by the 150MP BSI one. But would Sony be interested in continuing the production ? And would people be interested in a potential 645 100MP full format but "old tech" vs mirrorless offers with small 100MP BSI up-to-date sensors ? I don't think the price would be much different between the 2 options, and in any case more expensive than actual offers.

It is quite difficult to guess what Pentax will do, and if they will continue the 645 line at all. All we kind of know is that Pentax signed a development agreement with Sony regarding 54x40mm sensors some time ago, so they have studied the question and probably built some prototypes just to see. That ended without serial product so far.
08-30-2018, 09:10 AM   #26
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QuoteOriginally posted by SunnyG. Quote
---------- Post added 08-30-18 at 04:18 AM ----------

[/COLOR]
I can understand the cost factor! But what do you mean by benefit? Are you indicating towards easier to pronounce names? Or what?[COLOR="Silver"]
I wasn't separating cost from benefit; cost vs. benefit. In other words, is the cost of actually producing 56x42mm sensor instead of 44x33mm worth the benefit of resolution and file size. In a different way the same is true with film; Pentax could make a true 60x45mm negative on 120 film, but to do so, instead of getting 15-16 exposures per roll, you'd get 12. Is that extra real estate in either analog or digital worth the cost to the photographer?

Although it does irk me that a 645 is not really 645, I understand and, for example, would not want to trek around town and country with a 6x7 just to get that larger size neg. I also would not want to only get 12 exposures per 120 roll. Not everyone would agree and, for example, many photographers love their 67. But then, are they bothered their negs are not 60x70mm??
08-30-2018, 02:36 PM   #27
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QuoteOriginally posted by aaacb Quote
There have been backs with larger sensors, just not for the "cheap" pentax 645, fuji etc. Check out Phase one P65+, it's quite old (found a review from 2009) and it has a sensor size of 53.9mm x 40.4mm. The recently announced IQ4 back is also "full frame medium format" and it costs just over 50k
I sold my 645Z in favour of the Phase One P65+ as the 28-45mm lens for the 645Z was too big to lug around. The P65+'s larger sensor means that the small and lightweight Phase One 35mm lens is as wide as the 28mm end of the 28-45mm. Perfect. No more aching shoulders!

Also, the Phase One 28mm on the P65+ is equivalent (in 35mm terms) to an 18mm lens!!

Yes, the P65+'s dynamic range isn't as good as the 645Z but it's close enough for my style of shooting. Horses for courses, I guess.

I live in hope that one day Pentax will release a TRUE full-frame '645X' with smaller and lighter lenses.
08-30-2018, 09:56 PM   #28
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If the prices for larger sensors come down, it would be worth to consider the feasibility of a digital 67. Sure, it's not on the agenda now, but I am curious if Ricoh would enter this segment, once sensors in this size become available and not too pricey.

In the meantime, an un-cropped 645 would be great, I think (although I am not really a potential customer).
08-31-2018, 02:37 AM   #29
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QuoteOriginally posted by serothis Quote
I doubt that a full frame pentax 645z II would cause much if any grief for hasselblad or phase one. People/companies buying those systems are in the world of hyper specialized.
I think it might! Because it'll be more affordable! Affordable = more sales. Why spend 17k on a crop format medium format when you can get a full frame for almost the same price! How about that?

---------- Post added 08-31-18 at 02:41 AM ----------

QuoteOriginally posted by RobA_Oz Quote
Let me be clear when I referred to Hasselblad that I was talking about the X1D, which, like the Fujifilm GFX50, is price competitive with the 645Z. The higher priced Hasselblad bodies, like the Phase One bodies, are in a completely different price range.
Different price range but same sensor!

---------- Post added 08-31-18 at 02:57 AM ----------

QuoteOriginally posted by SylvainB Quote
Pixelshift exists already on large Hasselblad H family backs (called MS for multishot, so we know it is possible to do it). If Pentax was to introduce this feature on a 645 model, that would be a big problem for Hasselblad H MS product line.

Regarding sensor size, Pentax could have access to the current 100MP non BSI 54x40mm sensor probably at discounted price, because it is replaced now by the 150MP BSI one. But would Sony be interested in continuing the production ? And would people be interested in a potential 645 100MP full format but "old tech" vs mirrorless offers with small 100MP BSI up-to-date sensors ? I don't think the price would be much different between the 2 options, and in any case more expensive than actual offers.

It is quite difficult to guess what Pentax will do, and if they will continue the 645 line at all. All we kind of know is that Pentax signed a development agreement with Sony regarding 54x40mm sensors some time ago, so they have studied the question and probably built some prototypes just to see. That ended without serial product so far.
I once read an article regarding Sony Sensors! Sony said customers can customize our sensors according to their needs. Let me elaborate, what this means you can take features of other sensors and put them all in a sensor of your choice. For example, if Pentax decided, they can choose to update their 36mp sensor. In theory Pentax could order a 36mp stacked sensor with 4k video out! I can't find the article, I can't prove if it's correct.

---------- Post added 08-31-18 at 03:05 AM ----------

QuoteOriginally posted by Alex645 Quote
I wasn't separating cost from benefit; cost vs. benefit. In other words, is the cost of actually producing 56x42mm sensor instead of 44x33mm worth the benefit of resolution and file size. In a different way the same is true with film; Pentax could make a true 60x45mm negative on 120 film, but to do so, instead of getting 15-16 exposures per roll, you'd get 12. Is that extra real estate in either analog or digital worth the cost to the photographer?

Although it does irk me that a 645 is not really 645, I understand and, for example, would not want to trek around town and country with a 6x7 just to get that larger size neg. I also would not want to only get 12 exposures per 120 roll. Not everyone would agree and, for example, many photographers love their 67. But then, are they bothered their negs are not 60x70mm??
Do you know what irks me more??? APS-C isn't APS-C at all, it's much more cropped than it should be. The real half format was 24mm x 18mm. While today's APS-C is 23.5 x 15.7!!! They have shrunk it from 24x16! This pisses me off!

---------- Post added 08-31-18 at 03:08 AM ----------

QuoteOriginally posted by yucafrita Quote
If the prices for larger sensors come down, it would be worth to consider the feasibility of a digital 67. Sure, it's not on the agenda now, but I am curious if Ricoh would enter this segment, once sensors in this size become available and not too pricey.

In the meantime, an un-cropped 645 would be great, I think (although I am not really a potential customer).
For that to happen, sensor tech needs to improve first! Like for example inclusion of graphene!

Last edited by SunnyG.; 08-31-2018 at 02:59 AM. Reason: I made typing errors.
08-31-2018, 03:33 AM   #30
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QuoteOriginally posted by SunnyG. Quote

[/COLOR]
Do you know what irks me more??? APS-C isn't APS-C at all, it's much more cropped than it should be. The real half format was 24mm x 18mm. While today's APS-C is 23.5 x 15.7!!! They have shrunk it from 24x16! This pisses me off![COLOR="Silver"]
Are you sure? 35mm "half-frame" was indeed 24x18mm, where as APS-C film was 25.1×16.7 mm. So actually larger in one dimension, but smaller in the other.

And then APS-C digital sensors are all different sizes (9 or more); most notably Canon (smaller) vs. everyone else (Sony, Toshiba, etc).

APS-C - Wikipedia

I guess we have to think of these not as precise standards, but rather as general categories.
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