[bkpix]

A case to be made for starting with a Pentax 645z medium format vs. the k mount system


I've always been intrigued by the Pentax medium format dslr's - or the medium format dslr's in general, it's just that I'm loyal to Pentax and it helps that they have the most affordable medium format camera(s)... The last dslr medium format, as far as I can tell, is the 645z, which a quick search on the auction site shows that a couple with low actuation counts sold for around $1500.00 recently.


For quite a while, as far as I can tell, Pentax held the position of having the only other medium format dslr other than the very expensive Hasselblad (correct me if wrong). Fujifilm recently, in the past 2 years that is, caught my eye as being another brand in the medium format dslr arena - someone explain to me why they call their versions, on their websites, as being large format cameras. Anyways, their cameras & lens, used on the auction site, still cost significantly more, to me, than the Pentax alternatives - the cameras being so probably because they are newer (the lens probably so also & I'm guessing their mount just hasn't been around as long, I dunno)...

Even for a 2014/2015 camera, the Pentax 645z certainly appeals to me for several reasons. One, I've always been intrigued by medium format & wanted to shoot with it. The medium format size coupled with a 50 megapixel sensor is certainly attractive to me when it comes to the detail one can capture. Of course, the size & weight of the 645z is something to consider as a downside (I haven't even looked up it's weight, but can see it's size is manageable & perhaps even desirable from videos I've seen).



Coupled with my desire to go medium format comes an added bonus, which is the lens. From a wikipedia read, the 645 lens system goes back to 1984 - while not nearly as far as the K mount (1975 I believe) but still quite a lot of lens are out there for it, IMO. I only have one new lens in my collection of K mount lens, so it goes without saying that the used 645 lens are certainly appealing to me. Most of my k mount lens are manual, so the used 645 manual lens certainly are appealing also for one very big reason. And that reason is, the price of the 645 lens are often 1/2 to even 1/3 the price of the same lens available in K mount. I can't tell you, and you've probably experienced the same, can't tell you how many times I've searched for used lens for the K mount to have my mouth water at the price, of the "same" lens, the same lens in 645 mount. Here's an example, a Pentax 645 A* Green Star 300mm lens can be bought right now for $169.99 and the similar Pentax Green Star 300mm lens even in M/manual will cost $300 and upward. I was recently looking at Pentax brand teleconverters and experienced a similar experience.

So, I think I've made the case for a person, interested/intrigued in medium format, to start off with the 645 system, or for myself, to even switch to the 645 system. My two main attractions are 1) it's medium format (higher mp to boot), and 2) the price of the lens/accessories are so sweet to a used equipment buyers. I am certainly playing with the idea of selling off my K mount K-S2, lens, & K accessories, and switching to the 645 system. It makes sense for me, but how long it would take to sell off my equipment and get to where I want to be, well that's another decision/topic all on it's own (but the journey to get there could be fun, smiles). I am just toying with the idea, right now. I do wander also, about the Pentax 645D system - all I know of it is that it has a different sensor and has 40 MP (I should post something in the medium format forum here asking about that). Oh, and an obvious differnce too is that the 645D recently sold for $1200 and another sold for $13000.


Well, that's my case for owning into the 645 dslr system vs. staying in the k mount system, for myself that is... Your thoughts/comments are more than welcome - even much desired !


Michael

Addendum: Download this full size 645z image & zoom in on what you can see reflected in her right eys. Pretty amazing detail...

https://www.ricoh-imaging.co.jp/english/products/645z/ex/img/ex-pic02.jpg


Addendum 2: I reduced the quality of the above image by 50% in Gimp & exported it, bringing the file size of the original of 30 MP to down below 4 MP & I'm surprised at how much detail is still left in the image (click center of image several times to zoom in on it):

I'd say you're an excellent candidate for renting a 645z. Treat yourself as a New Year's present!

[Michael Piziak]

I keep trying to convince myself of all that.
Then I take some images with the 645Z, and realise that it is all bollocks.
Size matters.

I'm not quite sure how to understand your comment, especially after calling the 645Z images as bollocks then saying size matters. Are you saying that small size matters if what you think is that the 645z doesn't have good enough pics?


I would disagree on the images being bollocks - from my comparisons of uncompressed images from the 645z.

[Sandy Hancock]

I'm not quite sure how to understand your comment, especially after calling the 645Z images as bollocks then saying size matters.

Sorry if my meaning wasn't clear. Every time I use my 645, I realise that an argument that the K-1 is just as good is not accurate.

So we agree

[Michael Piziak]

One thing I'd like to add to this is that I viewed a video about the 645Z yesterday, and after the reviewer listed off the positives, he listed off the price of the lens as being a negative. He was speaking of the price of new lens for the 645z as being expensive.

I have had the opposite experience, as I stated previously, in that when searching for lens for the K mount (as I think we've all experienced when doing so), is that when searching for k lens we often see a 645 lens pop up, and the 645 lens are often if not always less experience.

Both of these statements above, of course are true. I can certainly understand that new 645 lens would be more expensive, as it makes manufacturing sense, as the 645 lens (physically) are larger and thus require more material. What makes the statement about used 645 lens being more affordable than k lens is also true & understandable, in my opinion because there is less demand for those lens when compared to k lens. So it simply comes down to an economic principal of supply and demand cause the used medium format lens to sell for used in the used marketplace. One note is that I generally am looking at manual lens & I don't know if automatic 645 lens also cost less than K lens in the used market.

---------- Post added 01-03-23 at 02:42 PM ----------

Were I looking at medium format today, I'd be looking Fuji, although they don't have the reliability of Pentax MF cameras.

I see that a 50MP Fujifilm GFX camera sells for around $2,000 on the auction site; likewise, the Pentax 645z also costs about the same... I'm sure the GFX is a newer camera.

My questions are, though, are the used Fujifilm medium format lens affordable like the 645 lens are? What is that mount called when looking for lens, GFX lens?

Michael



ADDENDUM: I believe the Fuji mount is called the G mount and has only been available for their digital cameras. So the G mount hasn't been around long as compared to the Pentax 645 mount.... (?)


---------- Post added 01-03-23 at 02:47 PM ----------

Interestingly enough, despite there being years of difference between releases, the Pentax 645Z uses the same Sony sensor as Fuji's GFX 50 series cameras. Fuji's medium format lens lineup is also relatively thin. Using plentiful and quality Pentax glass is certainly an option with the caveat that you lose AF.

Carrying this a step further for Pentax 645 cameras. I would imagine that an upgrade for the 645, which people seem to be wanting/waiting for a 645 upgrade, a logical upgrade for Pentax would be to put the 100MP sensor in the Pentax line that the Fujifilm cameras have in their 100MP medium format camera(s)...

Thoughts anyone ?

Addendum: link to the 100MP Fujifilm for quick reference for folks:


https://en.wikipedia.org/wiki/Fujifilm_GFX100

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Last edited by Michael Piziak; 01-03-2023 at 02:51 PM.

[gatorguy]

I'd say you're an excellent candidate for renting a 645z. Treat yourself as a New Year's present!

Excellent advice, and that also applies to the Fuji MF before committing a few thousand to one.

[Michael Piziak]

Given my reliance on portability, the GFZ 100s would be my choice, although, reliability reports have not been favourable. I'd need to buy two, so as to have a back up. But simple fact, I have never used the full resolution of my K-1 except for one or two prints. I simply don't make full use of even my 36MP camera enough to justify buying it.

On images like this I can't tell the difference between my older prints made with the K-3 and the newer ones taken with the K-1, printed at 16x20.


IMHO, much of the MP craze is misplaced marketing nonsense. Sure if you view at 100% on computer screen from 8 inches away you can see difference, but it's a difference irrelevant to my typical viewing behaviour. I never view 16x20 images from a distance of 8 inches.

My attraction to the higher MP sensors is not to pixel peep, but the advantges of cropping photos, on occasion.

[mikesbike]

The medium format size coupled with a 50 megapixel sensor is certainly attractive to me when it comes to the detail one can capture. Of course, the size & weight of the 645z is something to consider as a downside (I haven't even looked up it's weight, but can see it's size is manageable & perhaps even desirable from videos I've seen).

I guess the traditional answer to this dilemma still applies, but now not nearly as much. It largely depends on what you shoot, what you will do with it, and how you go about your photography. With 35mm film vs. MF, traditionally the superiority of MF showed itself to advantage in large blowups, as the image would not need to be stretched as much to get the blowup. The same is still true- however, the resolution now attainable from a top-level FF model is so good, this difference won't begin to be demonstrable until that blowup is of very large size. And, as technology keeps advancing, that gap is narrowed even more. If you are not doing large blowups, whatever advantage there might be eludes detection.

Then there are the downsides of the MF technology. As long as you are shooting what MF has the potential with which to demonstrate superiority (now reduced by comparison to the latest FF products), you MIGHT at times be able to visualize this superiority. Of course, not all viewers will be viewing your full-size effort and zooming in on an eye. Additionally, your efforts will need to be confined to subject matter where FF can work to any advantage. The FOV range of WA to tele will be reduced, as the lenses for such coverage will become enormous and enormously expensive, yet still be reduced in range. And, forget thinking about action shooting, faster AF, etc. Flash sync will also be reduced. You could easily wind up with a less widely-capable system, while giving up those other practical and functional advantages, but can provide some image detail advantage at times which is difficult or impossible to visualize.

Finally, there is the manner in which you operate. Then size can matter in the opposite way- becoming an encumbrance. This can mean fewer shots that will be as easily doable.

Getting back to the issue of fine detail in images, again, technology keeps advancing, narrowing that gap. Now on the horizon will likely come the K-1 III. It will most likely employ the same 45.7 sensor as the Nikon D850 and the top Nikon mirrorless models. This essentially 48mp sensor is of about the same amount of pixels as the 51mp Pentax 645Z MF model, but is within the FF size format, creating greater pixel density, with the potential for capturing even finer detail!! Especially in tele shots, where it is often beyond reach of the MF model, even if it had its largest available lens. At most advantageously fair comparison for the MF setup against the latest FF, it would be like comparing the APS-C Pentax K-3 III, with all its advancements, to an older 24mp FF model, and thinking the older 24mp FF model will provide greater resolution because it is FF. But in that case, if you get the same framing of a subject either by getting closer with the FF camera, or by using a longer lens of the same quality from the same distance, you would still be getting no more than about the same MP in the frame between the two cameras! There "might" still be some advantage, but it would be minuscule at best. You would be stuck in having to get closer to your subject, or in having to use a larger, more expensive lens for a similar result. In the case of the 645Z against the latest FF setup, the 645Z would not have the FL range in lenses to compete in this manner.

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Last edited by mikesbike; 01-03-2023 at 04:24 PM.

[RICHARD L.]

My attraction to the higher MP sensors is not to pixel peep, but the advantges of cropping photos, on occasion.

You can easily find "pictures within pictures" in a 645Z image :

[Michael Piziak]

I guess the traditional answer to this dilemma still applies, but now not nearly as much. It largely depends on what you shoot, what you will do with it, and how you go about your photography. With 35mm film vs. MF, traditionally the superiority of MF showed itself to advantage in large blowups, as the image would not need to be stretched as much to get the blowup. The same is still true- however, the resolution now attainable from a top-level FF model is so good, this difference won't begin to be demonstrable until that blowup is of very large size. And, as technology keeps advancing, that gap is narrowed even more. If you are not doing large blowups, whatever advantage there might be eludes detection.

Then there are the downsides of the MF technology. As long as you are shooting what MF has the potential with which to demonstrate superiority (now reduced by comparison to the latest FF products), you MIGHT at times be able to visualize this superiority. Of course, not all viewers will be viewing your full-size effort and zooming in on an eye. Additionally, your efforts will need to be confined to subject matter where FF can work to any advantage. The FOV range of WA to tele will be reduced, as the lenses for such coverage will become enormous and enormously expensive, yet still be reduced in range. And, forget thinking about action shooting, faster AF, etc. Flash sync will also be reduced. You could easily wind up with a less widely-capable system, while giving up those other practical and functional advantages, but can provide some image detail advantage at times which is difficult or impossible to visualize.

Finally, there is the manner in which you operate. Then size can matter in the opposite way- becoming an encumbrance. This can mean fewer shots that will be as easily doable.

Getting back to the issue of fine detail in images, again, technology keeps advancing, narrowing that gap. Now on the horizon will likely come the K-1 III. It will most likely employ the same 45.7 sensor as the Nikon D850 and the top Nikon mirrorless models. This essentially 48mp sensor is of about the same amount of pixels as the 51mp Pentax 645Z MF model, but is within the FF size format, creating greater pixel density, with the potential for capturing even finer detail! In this regard, it would be like comparing the APS-C Pentax K-3 III, with all its advancements, to an older 24mp FF model, and thinking the older 24mp FF model will provide greater resolution because it is FF. But in that case, if you get the same framing of a subject either by getting closer with the FF camera, or by using a longer lens from the same distance, you would still be getting no more than about the same MP in the frame between the two cameras! There "might" still be some advantage, but it would be minuscule at best. You would be stuck in having to get closer to your subject, or in having to use a larger, more expensive lens for a similar result.

To mikesbike,

All valid points & wrote very well & understandable.

The only advantage to the 645 format, after reading & agreeing with what you wrote about technology and future MP sensors, is that the 645 used lens will still be 1/2 to 1/3 the price of used K lens. In saying this, though, at some point the size and certainly the weight of the medium format lens (and carrying around the body), will come into play/consideration.

One would have to wonder, when will the 45.7 MP sensors show up on Pentax FF cameras.

[mikesbike]

at some point the size and certainly the weight of the medium format lens (and carrying around the body), will come into play/consideration.

Yes, and their limitations in FOV too. As to when the new Pentax K-1 III will appear, probably not for at least a year or three- but it will come out on the expensive side. Just look at the cost of the BSI sensored APS-C K-3 III at arrival! Then eventually, this cost will drift downwards some- but not way down. The K-1 II is a bargain these days for what it is and can offer, yet it has come down not a whole lot since it appeared. This time frame , however, gives us a good opportunity to save up, then wait for the price to settle after it does come out. Some will not bother to wait, as history has proven, they will be pre-ordering! I like to wait and get some test reviews, sample images, etc. before deciding if the new one will be worth it for me. I am already ecstatic over what I get from my K-1 II with a good lens on it. So, I am patient.

Again, the differences between APS-C and FF demonstrate how each has its own advantage. It has been well demonstrated how the advantage these days goes to APS-C when using more recent models, for telephoto use. But short of that, and when not needing maximum compactness, what the K-1 II can bring to the table is very impressive, when set up for optimum performance. That closeness for APS-C in some areas has been narrowed due to advancements in APS-C models.

When the 645Z was introduced, Pentax FF had not yet arrived. The development of the 645Z made sense. The most advanced and recent Pentax flagship was the K-3. Of course, the 645Z can beat the sox off a K-3 in terms of low noise at higher ISO, for low light use , etc. but now all that has changed since the KP, and now the K-3 III, and of course the K-1 II. However, in the kind of comparison test I indicated in the above post, in obtaining the same framing, the K-1 II can still emerge victoriously over even the K-3 III. 36mp vs. 26mp. Already not far from MF capabilities in both noise and in IQ. I believe the next Pentax FF model most likely will be able to successfully produce imaging that can easily go up against MF results. I doubt that there will be a successor to the 645Z.

[normhead]

You can easily find "pictures within pictures" in a 645Z image :

I have a friend who finds "pictures within pictures" in every image.

[Aaron28]

I'll admit to being a benefactor of a $1500 645z.......n of course several hundred dollars on lenses and 67 to 645 adapter thereafter......to me all worth it.......just something about the experience shooting with it and the room in the image to really feel the dof in action and as close as i will ever get to a digital 6x7 'like' image instantly.....there's nothing better than shooting on 6X7 but damn if it ain't 15 bucks a roll if not more if i do not scan it myself....plus there are benefits of fancy flash options when shooting with the 645z......then again i am just a fool who mostly shoots his dogs

[biz-engineer]

Interestingly enough, despite there being years of difference between releases, the Pentax 645Z uses the same Sony sensor as Fuji's GFX 50 series cameras. Fuji's medium format lens lineup is also relatively thin.

Fuji MF limited choice of lenses is no issue if you don't need/want supertele on MF. If I'd be willing to spend ~5000 E/$ , I'd go for the GFX100s + GF20-35 + GF45-100, and keep shooting Pentax K1II + 100 macro + 70-200 + 150-450. Fuji GFX100s is you have a variety of crop modes in the VF which makes it a fantastic still image composition tool, directly in the viewfinder or live view display. That said, I've tried Fuji GFX and AF sucks (slower than K1) in good light, and sucks even more in low light (e.g blue hour, or at night), and touch screen UI lags a bit when the camera processor is busy doing something which can be annoying , and the build quality is the same as for their $1000 X mount cameras clearly not as rugged at a 645z, and no it's not like what Fuji fans say online, what I'm saying is from the experience of using it.

---------- Post added 04-01-23 at 07:46 ----------

However, my other major argument for a 645z (or 645d), is the price of similar Pentax lens gives it more than a slight advantage over k mount lens.

645z crop fact is 0.79, about 20% larger. 645 FA glass is cheap but old optics. I wonder if recent Pentax D-FA glass easily close the gap between K1 and 645z.

---------- Post added 04-01-23 at 08:25 ----------

One more thing: when comparing camera systems, we should not consider images zoomed-in 100% , but rather our final display size. For example, I've compared, side by side, A1 prints of the same test chart (images+details), from GFX100 and Pentax K1 pixel shift, optimal post-processing as it would be done from prints. Practically, adults can't tell the difference, maybe kid's eyes would be able to tell (side by side). People can't tell the difference between native 300ppi and 300ppi interpolated and sharpened from native 225ppi. For A0 and larger prints the difference will be visible, but not at A1.

[jslifoaw]

The K-1 is generally a much more versatile platform. You have a much wider selection of modern AF + WR/AW lenses, combined with relatively fast speed and resolution that in some cases approaches the 645Z especially with wider aspect ratios - the K-1 is only 1000 pixels short on the long end (about 8300 vs 7300px)

Also worth noting is that if your cropping is mostly for reach, you may be better off with K-mount because the 645Z pixel density is actually slightly lower than a K-1 (and also any K-3).

There is also a Pentax 645 to K adapter, so pretty much any inexpensive 645 lens can be used on a K-mount camera, though the sensor and FOV will be smaller and you lose AE (and AF if applicable). The only lenses that are hard to adapt are the expensive DA/DFA lenses without an aperture ring. You also gain SR by adapting to K-mount; the only way to get SR on the 645D/Z is to use one of two expensive lenses (the 28-45 or 90 macro). The crop factor may not be a big deal since the widest angle lenses are generally quite expensive; the widest inexpensive lens starts at 45mm (wide-ish on digital 645, normal on a K-1)

Shooting a 645Z (and especially a 645D) demands more patience and discipline, especially with manual lenses. I installed focusing screens with focusing aids to make it easier to use manual focus lenses. If you're paying for resolution, you need to make the most of it with a combination of good support and/or good light, especially with no SR to assist.

I find shooting 645 extremely fun with the unique combination of bodies and lenses, and the results are often beautiful (got one image printed 3-4' wide a couple of times), but a K-1 or K-3 can produce excellent results and can also be fun to use.

Among the more inexpensive Pentax 645 lenses are the A series 55mm, 120mm macro, 200mm, and 300mm. While they are all good, the macro and 300mm stand out. However, they would be equally excellent adapted to K-mount. The 45-85 and 80-160 are also inexpensive, but in my mind aren't worth obtaining a 645D/Z body for on their own.

Many other favourites in Pentax medium format are anywhere from somewhat more expensive to considerably more expensive, but are generally viewed to be worth the price of admission:

645:
DA 28-45mm f4.5
A 35mm f3.5
DFA 35mm f3.5
DFA 90mm f2.8 macro
FA 120mm f4 macro (AF version of the A series)
FA 150mm f2.8
FA 300mm f4

6x7:
45mm f4
55mm f4 (last version)
75mm f2.8
105mm f2.4
200mm f4 (last version)
300mm f4 EDIF
400mm f4 EDIF
55-100mm f4.5

[RICHARD L.]

There is also a Pentax 645 to K adapter, so pretty much any inexpensive 645 lens can be used on a K-mount camera, though the sensor and FOV will be smaller and you lose AE (and AF if applicable).

Thus the tremendous flexibility afforded by the interchangeability of Pentax lenses between various formats (67 to 645, 645 to K, etc). Below : K3 III + 645 FA* 300 mm f/4 @ f/11 on tripod.