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Thread: Pentax 645Z Review with Samples

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    Pentax 645Z Review with Samples

    Dear GetDPI'ers, after waxing lyrical about this camera in a couple of posts and posting links to my May Iceland portfolio, I finally completed my review so you can see why I have been so impressed. Pentax 645Z Review & Opinion: Part 1

    Its quite lengthy, not very technical and very much orientated towards the camera as a practical proposition for scenic and landscape type shooters. I have also included some full resolution horizontal slices through frames and lots of crops from the Pentax 28-45mm DA lens (and 75mm FA plus 80-160mm A) because I know there are very few examples online (I tried to find them myself).

    While the Sony A7R II will sway some, I really don't think the Sony will fully compete on outright image quality (on a number of levels) and believe that there are other compelling reasons to give this camera serious consideration if you aim to make very large, high resolution prints that will tand up to The Print Sniffers
    Last edited by turtle; 25th June 2015 at 12:25.
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    Re: Pentax 645Z Review with Samples

    Tom, thanks so much for a great review. The more I use my 645z, the more I am liking it too.
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    Re: Pentax 645Z Review with Samples

    Thanks, if only to basically confirm what I think about the 645Z too.

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    Re: Pentax 645Z Review with Samples

    Thanks for the review! It seems like a very nice camera. I would consider it myself except for the lens selection and the max flash sync speed.

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    Re: Pentax 645Z Review with Samples

    I want to comment on these bits from the review:

    The new DA lenses are expensive and this caused me to pause, until I realised they were no more expensive than the Hasselblad and Phase One offerings and just as good. I also noted, with an uncomfortable shuffle of my bottom, that they are priced the same as average Leica optics and not as expensive as Leica’s fastest lenses. The problem here is that there are not very many of them and nothing over 90mm (75mm in FF terms)! I also did not want to jump in with both feet and pony up the money for a full set of their newest optics, so acknowledged that legacy lenses would have to feature.
    The DA lenses are actually significantly less expensive than Phase and Hasselblad variants, the 28-45 doesn't have a direct equivalent in the other systems, but their wide zooms are roughly $8000 a piece, namely the Phase 40-80mm and Hasselblad 35-90mm. Except the 28-45 is even better because it's a constant aperture zoom and is stabilized, at the cost of a lack of central shutter. Additionally, the HCD 120mm macro is $5,500 vs the $4,500 for the Pentax 90 macro, and the Phase/Mamiya macro is priced somewhere between the two. (note that I'm going by B&H new prices, often you can get many of these lenses for less, the 90mm macro is like $3,300 or less direct from Japan)

    As for the "average Leica lens price" quote, I actually recently added together and divided the price of every lens in the S system, and ended up a few dollars short of $7000... the Pentax glass is nowhere near that; very few systems are.

    SMC Pentax DFA 645 55mm f2.8 AL (IF) SDM AW: Nice and compact, very sharp on centre, but with that darned field curvature issue at the edges and corners plaguing subjects at long distance. I saw some samples that made me think ‘you are better off with 35mm cameras by a mile’. Frankly, this lens stinks at infinity at the edges, unless stopped down to f11 or more at which point it is no better than ‘OK’. Closer in it looks amazing, but I am not aiming to shoot portraits. I also noted that lots of people sent copies back due to edge performance only to find their replacements were the same i.e. it was by design. Quality control seemed fine. 450g.
    I must have gotten an amazing copy myself, because I have nothing but praise for this lens. I did shoot a test chart when I first got it, and it's corners are somewhat soft in the extreme edges, but looking back over my images, there is almost no situation where I could complain about corner quality.

    Here's an image I shot hand-held at f/9 and a crop of the top-left corner:




    ...Moire on the AC block is better than "ok" in my book!

    120mm Macro (A and FA): 9 (10) 10

    Brilliant. Everyone says the same thing: ‘one of the best lenses I have ever used regardless of label’. Eyeball slicing on the 645Z and also very good at infinity. I am always of suspicious of this, as most Macro lenses need plenty of stopping down at infinity and perform poorly until f11 or more. Almost no sample variation. All seem great. 650g or so. 200+ (A series). 690g (A) 740g (FA).
    I must have gotten my lenses from bizzaro land, as unlike the 55mm, the 120mm is my softest lens, and at infinity @ f/8 the 150mm 2.8 runs circles around it and is sharp edge-to-edge. Sample variation is very much there, and I will almost certainly one day be replacing it with the 90mm 2.8.

    The 150mm 2.8 is soft-ish from f/2.8 to f/4, sharpens up at f/5.6 and is razor sharp at f/8~11, this is somewhat convenient as portraits don't end up overly sharp, and for regular distance shots it's incredibly sharp. As with all legacy Pentax lenses, it's plagued by LoCA though...

    With that said... start pumping iron and enjoy

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    Re: Pentax 645Z Review with Samples

    There are bad samples around alright. I have yet to really use my second hand 120mm, but know it has a substantial focus error so will need to test with live view first and then sort calibration issues out. The same goes for my 35mm A, tho I have live view tested that one and its laser sharp right to the corners. I also think a lot of people talk about their wonderful 120mm Macro at infinity then post an example of it being shot at 50m or so, which is nowhere near infinity for a 120mm lens! I am not convinced it is the infinity lens some claim and will find out in a few months at least how my sample works, once back in the UK. My 80-160mm A may not be perfect, but covers 120mm nicely, so I am not bothered either way.

    Regarding the 55mm, I have no doubt it is a great performer closer in (and this is well recognised). Your photo is relatively close in and field curvature would actually help hold good edges, if it curves back towards the photographer at the edges. Unfortunately in all the samples I have seen where distant vistas are photographed, the performance drops off substantially at the edges in a way that would be clearly visible in, say, a 40" print. As we know there can be a huge difference between 10-20m and infinity performance. I know some users have returned multiple copies for the same issue (concluding its a design fact, not assembly error), whereas others are happy with theirs for landscape, so go figure! I have seen samples at f11 that at fairly convincing, but not wholly so and have decided to try a Hassy 60mm Distagon instead, which will neatly plug the gap between 45mm at the long end of the 28-45mm and the 75mm FA I have in any case. Your 55mm is obviously working for you very nicely, but I felt it was too expensive to take such a chance in the face of the evidence I had seen (which may not be representative of course). I should be able to pick up the Zeiss Distagon for about 250-300, whereas a used 55mm DA seems to be over double this.

    When I dabble with Hasselblad glass, I will write it up, because although there is some opinion out there (consensus being that Hassy V glass is superior in most cases to legacy A and FA lenses), there are few comparison samples and I like to see things with my own eyes.

    Re Leica glass, should have been more explicit: I was referring to M glass, as I have an M system and have merrily (and not so merrily) paid the very high prices for these lenses over the years. But on the subject of Pentax 645 glass, there are of course relatively few of the new DA lenses so comparing them to S glass is a little apples to oranges I think. Leica glass always commands a premium and of course all S glass is brand new and recognised as performing at 'top of class'

    I totally agree about the 28-45mm. This was the lens upon which I made a decision and took a huge gamble, which has thankfully paid off! I am happy to invest in the better Pentax lenses because.... its a great investment. There will be a 645Z successor and probably one after that and I have no doubt that they will remain staggeringly good compared to the competition and retain their price point. I have total faith in the kit I have to get the job done and I'm really excited about the new adventures awaiting me and the 645z. I just hope and pray they introduce some tilt and shift lenses. That would be HUGE!

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    Re: Pentax 645Z Review with Samples

    Thank you, Tom –

    I really appreciated the thoroughness of your review and especially that it's a user review, not just charts/measurements.

    Two points stood out for me, somewhat as surprises:

    1. It can be handled without barbell training. I'd seen it at CameraWest, but didn't dare pick it up. I would never have imagined it being handy to hold.

    2. For me, the decisive factor: You mentioned that unless one were printing as large as 30", the gain in image quality over 810e or A7r (or its anticipated successor) is not particularly impressive.

    My main concern in considering the 645Z was improved IQ in the size of print I make, usually 14x21" or 15x22.5" (from MM, usually 2 or more files stitched). In this regard you've given me confidence that I needn't bear either the expense of the Pentax or the burden of carrying it. Whew!

    While I'm relieved by your review, I hope others who make larger prints are encouraged to follow you.

    Kirk

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    Re: Pentax 645Z Review with Samples

    Quote Originally Posted by thompsonkirk View Post
    1. It can be handled without barbell training. I'd seen it at CameraWest, but didn't dare pick it up. I would never have imagined it being handy to hold.
    Well it is fairly balanced, I'll say that... not especially different than carrying any pro DSLR with a zoom attached, if that's a point of reference that makes sense.

    2. For me, the decisive factor: You mentioned that unless one were printing as large as 30", the gain in image quality over 810e or A7r (or its anticipated successor) is not particularly impressive.
    I would say you would even have to go as wide as 60"+ to see the benefits in full color, but that's only as far as the resolution is concerned, the 645Z still has an extra stop of DR/noise advantage at any equivalent sensitivity level.

    Plus the noise at ISO12,800 is like an instant film grain filter, it even looks better than what I get out of Silver Efex!

    My main concern in considering the 645Z was improved IQ in the size of print I make, usually 14x21" or 15x22.5" (from MM, usually 2 or more files stitched). In this regard you've given me confidence that I needn't bear either the expense of the Pentax or the burden of carrying it. Whew!
    Except you won't have to stitch! HDR is something that I just haven't been able to take advantage of since moving to the Z (every shot is an HDR), but I do still stitch every now and then, simply because I lack a wide angle lens... two shots vertical and I'm at 8k x 8k pixels, two shots horizontal and I'm at over 14k pixels wide, that's just wayyy too much and my ol' iMac is crying.
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    Re: Pentax 645Z Review with Samples

    It all depends on viewing distance and expectations and everyone has different opinions here.

    60" from the A7R is only 120 PPI. The output from most cameras will have long since fallen apart to my eyes, if looking for truly fine detail at close viewing distance. IMHO the differences between a 645Z and A7R will be quite clearly visible well before then.... especially if you include lens factors. If one can see obvious differences on a retina screen at 1:1, its going be clearly on print in the 30-40" range and in most cases the 645Z files look comfortably ahead. If you view the prints from a distance, of course not, but when inspected, the differences will be there if fine detail is critical.

    I'd say the 645Z with a comparable weight lens handles and grips quite a bit better than a Pro DSLR with built in grip, simply because the grip offers much deeper wrap around of the fingers. Your fingers hook inside in a way that they don't on less boxy cameras.

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    Re: Pentax 645Z Review with Samples

    Other advantages of Z files are the PP flexibility where up to 5 stops can be salvaged and where 14 bit files versus 8+3 are best to have, nit to mention true DNG files versus some cooked ARW files. Also since I often like to crop, sometimes crop extensively, I can still have a 40MP image after cropping. With my P45+ they would often be around 30MP after cropping and with an A7r they would be down around 20MP. Sure stitching works well and as we all know there is often plenty of waste with stitched images where larger file sizes come into play again and again.

    Why have a MF camera? Larger photo sites than any FF camera, period. Z sensors versus FF are about 70% larger. That's a lot!

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    Re: Pentax 645Z Review with Samples

    would love to see sample comparison with IQ back.

    Thanks

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    Re: Pentax 645Z Review with Samples

    Quote Originally Posted by Dan Santoso View Post
    would love to see sample comparison with IQ back.

    Thanks
    Which IQ back do you mean? The IQ250 and the Pentax 645Z share the same sensor pretty much so it comes down to what lens you put on the front. If you are talking about the IQ180 vs Pentax 645Z, I've owned both. If you can get the exposure and focus perfect with the former - with the limitations inherent in the CCD sensor - the files will give you more resolution. You may have trouble post-processing them as much as the Pentax though because of the inability to pull out shadow detail as much and the 'tiling' effect. In the end, the prints when the size exceeds 30" on the long side you may notice a slight difference viewed up close but that's about it.

    I have done that and in the end, it is about how much bang for the buck you get and how easy/difficult a product is to use. If you want the ultimate in quality then the IQ180 with a technical camera and really good glass in front will get you the best results there is no doubt of that. With the old DF645+ body and standard SK lenses, the difference with less than 30" prints was not obvious, at least to my eyes.

    Pradeep
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