#217. Should you buy a Pentax 645Z (implied: or a Sony A7R)?

By pascaljappy | Opinion

Apr 18

In late 2010, Pentax stunned the Medium Format photo world by releasing a 40Mpix camera at a price point that seriously undercut the competition’s. Using a 44x33mm CCD, it slightly outresolved the best full-frame DSLRs such as the D800e at base ISO, but crumbled rapidly after ISO 800 and suffered from lower dynamic range.


Today, Pentax is back with a 51.4Mpx CMOS sensor from Sony and an even “cheaper” retail price. Irresistible? Dunno …

Back in early 2011, the lure of larger sensors and larger pixels was strong. Today, things have changed quite a lot and cameras such as the Sony A7R provide amateurs and pros with all the technical quality required to create excellent 40 inch prints in a small and easy package.


So how do the two compare ?

In terms of absolute resolution, there’s not much in it. At 8256×6192 pixels (Pentax) vs 7360×4912 pixels (Sony), there’s only a 12% increase on the long side and 26% on the other. Hardly noticeable in most prints. And since the two sensors share similar technology, there won’t be difference in per-pixel quality. The 18% larger pixels on the Pentax won’t be the source of a quantum leap in quality either. Call it a *very* slight win for the Pentax, on paper.

What’s much more important to my eyes is the 4:3 format which is more pleasant and often requires less cropping. A clear win for Pentax.

Pentax wins because of its more extensive and reasonably priced range. Sony have now almost reached a point where they produce more full frame bodies than full frame lenses, so any reference to a range is laughing matter.

But, what Sony lenses have released are mostly excellent and significantly cheaper. The Sony/Zeiss FE 35 and FE 55 and absolutely stunning lenses that few other – regardless of price or format – can touch.

Contrast this with the more extensive Pentax SMC range, below:

  • SMC-FA 645 75MM f/2.8
  • SMC-FA 645 45MM f/2.8
  • SMCP-FA 645 150mm f/2.8 IF
  • SMC PENTAX-FA* 645 300MM f/5.6 ED IF
  • SMC-FA 645 400MM f/5.6 ED IF
  • SMC-FA 645 ZOOM 45-85 f/4.5
  • SMCP-FA 645 120mm f/4 MACRO
  • SMCP-FA 645 200MM f/4 IF
  • SMCP-FA 645 80-160 f/4.5
  • SMCP-FA 645 33-55 f/4.5 AL
  • SMCP-FA 645 ZOOM 150-300MM f/5.6 ED
  • SMCP-FA 645 35mm f/3.5 AL IF
  • SMCP-FA 645 55-110 f/5.6

And add the endless pile of older Pentax 645 lenses available very cheap in second-hand stores and on eBay and the possibilities are infinite.

However, these are much larger than the Sony’s and not always as bitingly sharp. Besides, the A7r can also count on a large variety of legacy glass, one I am particularly fond of being the very affordable Leica-R range. Because of the price, weight and sharpness advantage, I feel the A7r catches up with the Pentax here. Call it a draw.

It’s hard to fall in love with the Sony’s ill-conceived ergonomics. Very hard. But it’s small and nimble. It’s likely to be with you where the much larger and ponderous Pentax will not be able to follow.


Advantage Sony A7r.

That Medium Format look
This is where a larger sensor truly shines and where the Pentax should show its heals to the Sony.

(c) Ricoh Imaging - click to access original (full-size) file

(c) Ricoh Imaging – click to access original (ful-size) file

That look many of us were hoping for in our long wait for full-frame sensor is a combination of smooth tonal gradations and acute sharpness. While none of the samples released so far are really convincing in terms of sharpness, the tonal rendition is really lovely.

However, the A7r shouldn’t be discarded too quickly as it too can produce that look in spades and with the right lens, sharpness is second to none this side of 10 grand.


Bosphorus Palace (c) DearSusan.net (click for larger version)

A slight advantage to the Pentax 645Z.

High ISO
With a more recent sensor that’s also 68% larger, the Pentax should dust the Sony easily here. And the crazy max ISO specs of the Pentax also hint at amazing performance.

But none of the pictures I have seen so far have convinced me of this superiority. And if I tell you the A7r Bosphorus image above was shot at ISO 3200 and remains buttery smooth, you’ll probably agree there’s little lacking in the Sony’s performance.

The jury is still out on this one.

As impressive and laudable as Pentax’s achievement is, the Sony is still 60% cheaper and most of the excellent++ lenses also are.

Clear advantage to Sony.


If you already own a slew of Pentax lenses, your decision’s already made.

If, like me, you wake up at night dreaming of technical cameras, the Pentax is a step in the right direction, though probably not a tipping point.

For most photographers, and particularly of the Traveling Wilbury species, the Sony is the far more logical choice. Of course, I’ve yet to lay hands on a 645Z, but I strongly doubt I will feel sad when I do and hand it back to return to my A7r and it’s gorgeous glass.

So I guess the real verdict is that you must all petition Sony to release that rumoured (nudge nudge, Andrea) medium format RX2 and give the (leaf-shutter) fixed 45/2.5 Distagon (Sonnar?) all the love and know-how they can muster. If they do, the waiting lists will be huge. I’m in!

Email: subscribed: 4
  • Russian Photographer says:

    Did you intentionally avoided the fact that Sony has terrible electronic viewfinder that makes the camera almost unusable. Also ergonomically not everyone would agree on Sony being a better choice.

    • pascaljappy says:

      The Sony indeed has an electronic viewfinder, but few would agree it’s terrible. Having used Nikons all my life and switched from a D800e to the A7r, I can certainly tell you there is no feeling of loss. On the contrary, when I tried to focus a Zeiss OTUS on the D800e, not one of my shots were critically sharp. Whereas this is never an issue with the Sony. EVFs have evolved to the point that what they add largely compensates for what they rob you of. Yes, they’re a cultural and visual shock at first but, given how small and miserable optical viewfinders have become in most DSLRs, I’ll take the A7’s EVF *any day* over them.

      I have to agree with you about the Sony’s ergonomics, though … Someday, Sony will hire a photographer to actually use their cameras before release … But too many layers of corprate pride are still getting in the way. They will have to learn the hard way, presumably.

  • PhA says:

    Pascal, very interesting argument, but, in an ideal world, these two camera do not competed one with the other: they are just two different tools in the box of an enthusiast photographer.

    The A7r, assuming the vibration issue of the shutter is solved, is close to the ideal tool for light travelling photography, whilst a medium format can provide you with some magic when you really want to build (and take the time for that) a fantastic picture. In the pre-digital age, I had (and still have) a Leica M6 and a medium format Rolleiflex 6008 Integral. Two outstanding cameras, but different uses. Different pleasures.

    Great article anyhow.



    PS: as a light tool, the Ricoh GR is fantastic, with top ergonomics for a demanding photographer.

    • pascaljappy says:

      Hi PhA, thanks for the kind words.

      You’re probably right about the two cameras not competing that often in the real world. My point really is that the A7r captures a bit of that magic while being more convenient. If Sony does use this sensor with a great lens and leaf shutter in a RX2-style camera, I’ll be the happiest photographer in the galaxy 😉

      If the vibration issue is a real concern to you, let me reassure you. The pictures produced by my A7r are consistently the sharpest I’ve ever made. The whole vibration issue has been totally blown out of proportion. It’s probably there in certain conditions and with very long lenses, but I have *never* encountered it in any of my 8000 photographs with lenses up to 150mm. Critical focus, tripod quality … all these are an order of magnitude more important in real life shots than the lab rat vibes 😉

      I’d love to try a Ricoh GR myself. The previous versions were already remarkable cameras. Ricoh truly is an admirable company always pushing the conventional limits. I wish them well.

      All the best,

  • >