[Rondec]

For studio photographers then yes resolution is better with the 645 series. 40 or 51 Mp vs 36 Mp, and the 645 got sharper lenses, resulting in sharper images. Not by a huge amount but I'm sure it will be notable. Its a huge price premium for a relatively little gain in resolution.

For landscape photographers its a bit more tricky. In situations where pixel shift resolution is useful the K-1 probably produces comparable detail level to the 645Z. In other situations its still a (small) advantage for both digital 645 models.

For ISO and DR I'm not sure the 645D actually are less noisy and have higher DR then K-1. I guess 645Z have a small advantage on DR and a larger advantage on ISO. But the 645Z is generally limited to f/2,8 primes and f/4 zooms (or around those apertures). The K-1 might be fitted with 1-2 stops larger apertures and remove the noise advantage completely.

The K-1 would also be lighter to carry to the best landscape sites, and the photographer will be less dependent on a tripod both because of weight/size and SR.

All in all, I still struggle to see that the 645 system offers any significant advantages over K-1. Slightly better resolution in some cases yes, but I think few will rationally think that alone is worth the price difference and disadvantages following the change (losing SR, availability of faster lenses and so on)

It is really tough to compare the 645D to current full frame cameras. The 645D was released in 2010 meaning that it is ancient with regard to its sensor and its specifications. In a way it would be like bringing up the D700 and saying that it is hard to see what people see in full frame. The question is whether current gen medium format sensors and cameras have something to offer versus current gen full frame sensors and cameras and I think the answer is still a qualified yes.

In the end, it really is about the glass and medium format glass does render exceptionally well and seems to be a notch above most full frame glass (of course it should be for the price).

[Simen1]

@D1N0: Yes, in some cases (like studio) its an advatage that 645Z don't need pixel shift to reach its level of sharpness. In other situations where pixel shift is usable, its not longer an advantage over K-1, but more or less equal.

No, a bigger sensor don’t mean you can shoot in another perspective. You select perspective by selecting lenses.

Rondec: I haven’t seen ISO and DR comparizons between 645D and modern FF cameras, but since it had CCD and other 33x44 CCD cameras show they was behind FF cameras on both DR and ISO in 2010 I suspect also the 645D is somewhat in the same area. I cant be sure, but I suspect. Going over to the CMOS sensor in 645Z its far better then its older CCD predecessor, and according to the DXO withdrawn results somewhat better then Sonys best FF cameras. But the difference isn’t large enough to compensate for the much larger apertures available in FF lenses. So a photograper wanting less noise would be better of using a Sony FF with f/1,4 and ISO 400 in stead of a 645Z with F/2,8 and ISO 1600 and the same shutter speed. 645Z doesn’t have a 2 stop advantage.

[wkraus]

So a photograper wanting less noise would be better of using a Sony FF with f/1,4 and ISO 400 in stead of a 645Z with F/2,8 and ISO 1600 and the same shutter speed. 645Z doesn’t have a 2 stop advantage.

In theory perhaps yes. But I assume those who choose to haul around a 645Z do so for a reason and not just out of stupidity.

[Simen1]

Sure, me too. Thats why I'm asking someone to elaborate the reasons I struggle to see myself. I already started to learn some of those reasons: high resolution single exposures of moving subjects, and lens sharpness.

[Nicolas06]

I don't think people that choose MF do it for the noise handling. The application were high iso is legitimate like birding/wildlife/sport/nightclub are not occasions were MF are used that much. Likely because they miss the fast AF lenses and fast AF system in body. Likely because also the lenses that would provide the reach would be huge. Imagine if you need a 1200mm lens... Not practical.

It seems to me that MF is more used for studio, fashion, advertisement, landscapes, picture of antiquities and art... So at base iso most of the time.

The equivalency of focal length and deph of field is a simplification. The deph of field is always the same for a given focal length and focus distance regardless of the system, but a larger format will use another focal length and narrower appertures. And that change the rendering. It change the background blur and bokeh and it change the in focus / out of focus transition.

One could say a good share of the interrest to go for a larger format is the ability to use longer focal length and still keep a wide field of view.

This is not really about dynamic range, this is not at all about isos. The goal is not to try to salvage a picture with too much noise or to salvage a picture with harsh light. Photography is not really about that and if anything canon being worldwide leader with sensor that have less impressive figure should give an hint of that.

This is not neither about extremely shallow deph of field. Many fashion and studio shoot have quite some deph, the background is usually perfectly controlled and so there no need to use this trick of large apperture neither to shoot in low light or to avoid the distraction from background.

This is also that anyway if you do high end work for a very high price, the price of the gear, even an MF phase-one and the lenses are just a detail. After all, this is still less money than what a taxi need in France to work and far less than most shops incure at a cost for renting their brick and mortar store.

But it make no sense of course for somebody that is not rich and don't make a living out of that. There no more reason to buy an MF digital if you just take few pictures while on vacations and at Christmass than to rent a store in the center of the city if you sell 2-3 used things a year on ebay. And well even as a pro photographer I got that many "pro" don't make much money, arround 25K$ a year and they have to find a flat for themselve, buy food and whatever. There no much money to spend on high end gear. But not everybody in that sitatuion. Some photographers make more than 100K$/year and here spending 30K$ every 5-10 years seems very reasonnable.

[Rondec]

@D1N0: Yes, in some cases (like studio) its an advatage that 645Z don't need pixel shift to reach its level of sharpness. In other situations where pixel shift is usable, its not longer an advantage over K-1, but more or less equal.

No, a bigger sensor don’t mean you can shoot in another perspective. You select perspective by selecting lenses.

Rondec: I haven’t seen ISO and DR comparizons between 645D and modern FF cameras, but since it had CCD and other 33x44 CCD cameras show they was behind FF cameras on both DR and ISO in 2010 I suspect also the 645D is somewhat in the same area. I cant be sure, but I suspect. Going over to the CMOS sensor in 645Z its far better then its older CCD predecessor, and according to the DXO withdrawn results somewhat better then Sonys best FF cameras. But the difference isn’t large enough to compensate for the much larger apertures available in FF lenses. So a photograper wanting less noise would be better of using a Sony FF with f/1,4 and ISO 400 in stead of a 645Z with F/2,8 and ISO 1600 and the same shutter speed. 645Z doesn’t have a 2 stop advantage.

There are very few situations where f1.4 on full frame would actually be a good idea. Even with sharp lenses, the depth of field is often narrow enough that this is pretty unusable.

As to the 645D, DXO Mark did test it and it isn't near the top of the lists either with regard to high iso performance or to dynamic range. But certainly based on images on the forum, it does a great job, even now.

Anyway, I can't afford a 645Z or even 645D, but can afford a K-1. In a perfect world, I would still love to get a 645Z and a 28-45 zoom and use it basically for landscape photography. I think those who can afford it will still gravitate in that direction.

[biz-engineer]

It seems to me that MF is more used for studio, fashion, advertisement, landscapes, picture of antiquities and art... So at base iso most of the time.

Like Raymond Depardon of magnum photo , using large format camera on a wooden tripod. I'm not sure if he is looking at DXO mark figures, but he once said that Nikon FF wasn't about art, but this kind of camera was for people in hurry, not his style he said ;-)

[Simen1]

There are very few situations where f1.4 on full frame would actually be a good idea. Even with sharp lenses, the depth of field is often narrow enough that this is pretty unusable.

If you stop it down to f/2,0 and use ISO 800 you would get equal depth of field and noise levels as the 645Z with f/2,8 and ISO1600. Since its equal its not an advantage or reason to pay a lot more for the 645Z.

But if you use the 645Z at ISO100, there is no ISO50 to push the K-1 into. Then the 645Z would in theory make cleaner images. Cleaner then very very clean is not necessarily visibly cleaner.

In a perfect (or utopic) world, I would have a medium format camera with f/1,4 primes and f/2,8 zooms, all light weight and affordable priced.

biz-engineer: Film are quite interesting, but its severely hindered by its film "sensor" technology. So it needs a huge area to compensate for the per area shortcomings. Large format are more then large enough to compensate for shortcomings in noise and detail that would be common with FF film vs FF digital. In the right hands, large format film cameras can produce stunning results that are impossible to imitate with current digital cameras, even medium format. In a perfect/utopic world we would have large format CMOS sensors.. Even with astronomic budgets its currently not feasible. The worlds largest telescopes in space and on ground uses multiple medium format* sensors side by side with a gap in between. (*I guess 10x5 cm can be called medium format)

[Rondec]

If you stop it down to f/2,0 and use ISO 800 you would get equal depth of field and noise levels as the 645Z with f/2,8 and ISO1600. Since its equal its not an advantage or reason to pay a lot more for the 645Z.

But if you use the 645Z at ISO100, there is no ISO50 to push the K-1 into. Then the 645Z would in theory make cleaner images. Cleaner then very very clean is not necessarily visibly cleaner.

In a perfect (or utopic) world, I would have a medium format camera with f/1,4 primes and f/2,8 zooms, all light weight and affordable priced.

biz-engineer: Film are quite interesting, but its severely hindered by its film "sensor" technology. So it needs a huge area to compensate for the per area shortcomings. Large format are more then large enough to compensate for shortcomings in noise and detail that would be common with FF film vs FF digital. In the right hands, large format film cameras can produce stunning results that are difficult or impossible to imitate with current digital cameras, even medium format.

Even f2 isn't particularly usable in many situations. I get frustrated with the ignoring depth of field issues. I have seen a lot of good photos spoiled by too little depth of field. If you are a long way away from your subject, then probably f1.4 or 2 is usable, but even with portraits on APS-C I tend to stop down a little.

Be that as it may, there are a lot of cameras out there now that are "good enough" for the average photographer and you could make similar arguments about APS-C versus full frame as you would make full frame versus medium format. But for most of us, it is a question more of (a) Can I afford it? and (b) Do I want it? I think people will be more likely to answer yes to both those questions with regard to the K-1 than with a 645Z -- particularly once you factor in lenses.

[Nicolas06]

If you stop it down to f/2,0 and use ISO 800 you would get equal depth of field and noise levels as the 645Z with f/2,8 and ISO1600. Since its equal its not an advantage or reason to pay a lot more for the 645Z.

But if you use the 645Z at ISO100, there is no ISO50 to push the K-1 into. Then the 645Z would in theory make cleaner images. Cleaner then very very clean is not necessarily visibly cleaner.

In a perfect (or utopic) world, I would have a medium format camera with f/1,4 primes and f/2,8 zooms, all light weight and affordable priced.

But that would not improve your pictures one bit, quite the contrary if you abuse of very large apperture on very large sensor. People always assume that more is better, it can be only if used wisely.

Thinking 1cm of deph of field is not narrow enough and that you need to have 1mm or less to achieve anything is not the goal of theses MF bodies. And on purpose there not that many lenses that follow.

Personnally for a perfect or utopic world, I'll give up all the MF or even FF photographic gear in exchange of no more wars, enough food for everybody... But that's just me. Unfortunately, it is more likely we get what you ask for a perfect world that what I ask.

Anyway what is arround the corner is that in a few years, you'll get the OOF rendering of your dream in software without much work, almost all automatic so people would be able to choose render like a large format camera with an f/0.7 lens and be done a bit like today we get tons of picture with sepia old look from instagram, you'll get that on every post processing software. Once the 13 year old kit will get better shallow deph of field picture effect with his iphone 12 or 13 than you get with your 50000$ MF, it will not be that fashionnable anamore for "serious" photographer, ahem, gear heads.

[Kunzite]

If you stop it down to f/2,0 and use ISO 800 you would get equal depth of field and noise levels as the 645Z with f/2,8 and ISO1600. Since its equal its not an advantage or reason to pay a lot more for the 645Z.

But if you use the 645Z at ISO100, there is no ISO50 to push the K-1 into. Then the 645Z would in theory make cleaner images. Cleaner then very very clean is not necessarily visibly cleaner.

In a perfect (or utopic) world, I would have a medium format camera with f/1,4 primes and f/2,8 zooms, all light weight and affordable priced.

If you are interested in a forum-level theoretical comparisons between formats, look no further: the small format (which somehow is now called "full frame", I don't quite get why) is the best. Period.
Actually every such discussion should start with "hey, in theory, which format..." responded with "OK, say no further, "full frame" is for you"

OTOH, I saw large medium format prints which were truly jaw dropping. Perhaps a K-1 with its pixel shift resolution can reach a similar level.
But that's not theoretically, thus it's uninteresting.

[Simen1]

Even f2 isn't particularly usable in many situations. I get frustrated with the ignoring depth of field issues. I have seen a lot of good photos spoiled by too little depth of field. If you are a long way away from your subject, then probably f1.4 or 2 is usable, but even with portraits on APS-C I tend to stop down a little.

If you prefer a certain DoF in portraits, then all of the situation under will give you the same DoF and noise levels (as in DXO print, not screen), assuming you use lenses with the same field of view and same camera-subject distance.

APS-C with f/4 ISO 400, 1/200s
FF with f/5,6 ISO 800, 1/200s
MF with f/8 ISO 1600, 1/200s

So even with the restraint of having the same DoF, you will get the same low noise levels with FF as you do with MF. The sensor size related noise difference is compensated by the aperture number.

Be that as it may, there are a lot of cameras out there now that are "good enough" for the average photographer and you could make similar arguments about APS-C versus full frame as you would make full frame versus medium format. But for most of us, it is a question more of (a) Can I afford it? and (b) Do I want it? I think people will be more likely to answer yes to both those questions with regard to the K-1 than with a 645Z -- particularly once you factor in lenses.

Yes, I have heard that argument about good enough for sizing down formats and lens apertures, but that is not the case here between MF and FF. As said above you get the same noise levels with both formats (given the restraints mentioned). Its generally not the same situation between APS-C and FF because both formats usually scales to f/1,4 primes and f/2,8 zooms. The same aperture numbers. If there was many f/0,7 APS-C primes and many f/1,4 APS-C zooms the situation would be similar to the FF vs MF, but thats not the case. In other words, A selection of f/1,4 primes and f/2,8 zooms for MF would change the situation to be similar to the APS-C vs FF situation. Today MF simply lacks those lenses. And I must add, I agree it wouldn't be much useful for portraits due to the thin DoF. Maybe that is what holds lens makers back.

[Nicolas06]

If you prefer a certain DoF in portraits, then all of the situation under will give you the same DoF and noise levels (as in DXO print, not screen), assuming you use lenses with the same field of view and same camera-subject distance.

APS-C with f/4 ISO 400, 1/200s
FF with f/5,6 ISO 800, 1/200s
MF with f/8 ISO 1600, 1/200s

So even with the restraint of having the same DoF, you will get the same low noise levels with FF as you do with MF. The sensor size related noise difference is compensated by the aperture number.

APSC crop factor is 1.5 (and it depend a bit if you choose Canon or Pentax for example). now for MF it depend what MF format you speak of? 6x4.5 is 1.66 time FF 645Z more like 1.3 and 6x9 is 2.5 time more difference than m4/3 vs 24x36.

So f/4, iso400, 1/200s 50mm on APSC is like f/6 (not f/5.6) 1/200, 75mm on FF.

f/5.6, 1/200, 50mm on FF is like f/7.3 1/200 65mm on 645Z but on 6x4.5"it is f/9.3, 83mm... in 6x9 this give us f/14, 125mm...

For the iso part, this assume same sensor technology/performance. There 1 stop difference between 5D-II and A7R-II or even 0.7 EV between 5D-III. Even for same generation same brand, there 0.5 EV between A7R-II and A7-II. Until now, I didn't see an APSC camera that match what the math would say for high iso perf of A7R-II. An APSC body should give 1800 score for high iso in DxO mark, a full 0.5EV gain but there no APSC camera that does that to my knowledge. Nikon made Sony design a specific sensor for them, with iso 50 support and there sensor like A7-S that are not impressive for most, but shine at iso high iso only.

But there more than iso equivalence because most of the time picture are taken at base iso so iso 100 or for some cameras, iso 50. People will simply shoot at 1/100 or 1/50 if necessary, or add more power to the flash. They may even have 2 minutes shutter speed for what we now (astrophotography, long exposure of water...).

And of course there more than dof equivalent as the bokeh and rendering will be quite different too even of dof the same.

To go back to your wonderfull orange vs clementine metaphor, you compare orange with clementines.

[Nicolas06]

to f/1,4 primes and f/2,8 zooms. The same aperture numbers. If there was many f/0,7 APS-C primes and many f/1,4 APS-C zooms the situation would be similar to the FF vs MF

You don't need f/0.7 APSC-primes and f/1.4 zooms to match, 1.4/1.5 = 0.93 so that f/0.93, you can round it to f/1.

f2.8 / 1.5 = 1.86, so f/1.8 or f/1.9 is enough and now with sigma there 2 f/1.8 zooms: 18-35 and 50-100. This narrow the gap.

Question is if you really need f/1... of even f/1.8... for most shots.

The worst is that changing the f number doesn't change the dof that much, there almost no different between f/1.2 and f/1.4 for both light gathering and dof, but some pay huge money for that tiny change.

Even f/1.4 vs f/1.8 is not that noticable 23% less dof like 1.5cm dof instead of 2... and say iso 160 vs iso 100... It is enough to have an A7-RII instead of A7II to eat the difference. But often manufacturer ask more than twice money for the difference. Chance are the guy with the f/1.8 if he is only a tiny better photographer, this would make much greater difference in the end.

[D1N0]

28-50 and 75-150 aren't really long zooms compare to 24-70 and 70-200. There is a trade of for going 1.8 on a zoom. You also loose your size advantage.