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Pentax 645Z Image Quality Comparison

Below are crops comparing the Pentax 645Z with the Pentax 645D, Nikon D810 and Sony A7R. Given the massive 51.4MP, it's difficult to find competing cameras that match this resolution, however we've matched the new 645Z up against it's predecessor -- naturally -- and also the two latest, highest-resolution full-frame cameras currently available -- the Nikon D810 and Sony A7R, which have 36.3 and 36.4 megapixel resolutions, respectively. We've also decided to change up our typical IQ Comparison layout to offer larger crops -- the 250 x 250-pixel square crops normally seen in our IQ tables just don't show much with a 51.4MP image at 100%.

NOTE: These images are best quality JPEGs straight out of the camera, at default settings including noise reduction and using the camera's actual base ISO (not extended ISO settings). All cameras in this comparison were shot with our very sharp reference lenses. Clicking any crop will take you to a carrier page where you can click once again to access the full resolution image as delivered straight from the camera. And remember, you can always go to our world-renowned Comparometer to compare the Pentax 645Z to any camera we've ever tested.

Pentax 645Z versus Pentax 645D at Base ISO

Pentax 645Z at ISO 100
Pentax 645D at ISO 200
Pentax 645Z at ISO 100
Pentax 645D at ISO 200
Pentax 645Z at ISO 100
Pentax 645D at ISO 200

The 51.4MP 645Z brings a new standard for pure image resolution and detail. Compared to the 40MP 645D, which in its own right is astounding at base ISO, the new 645Z outdoes it with sheer fine detail performance. As expected, both display virtually zero noise at this low ISO sensitivity.


Pentax 645Z versus Nikon D810 at Base ISO

Pentax 645Z at ISO 100
Nikon D810 at ISO 64
Pentax 645Z at ISO 100
Nikon D810 at ISO 64
Pentax 645Z at ISO 100
Nikon D810 at ISO 64

Obviously, there's a notable difference in resolution between 51 and 36 megapixels. Barring that however, the Nikon D810 holds its own compared to the 645Z in fine detail and noise. Interestingly, the base ISO of the D810 is actually 64 thanks to the new sensor and processor in this camera. The primary difference in these crops, from an IQ standpoint, is the slight appearance of moiré in the fine red fabric pattern that's not visible in the 645Z image.

Pentax 645Z versus Sony A7R at Base ISO

Pentax 645Z at ISO 100
Sony A7R at ISO 100
Pentax 645Z at ISO 100
Sony A7R at ISO 100
Pentax 645Z at ISO 100
Sony A7R at ISO 100

This comparison is very similar to the previous one with the D810. The A7R uses a similar 36MP full-frame sensor, and at base ISO, it shows very clean, crisp fine detail compared to the 645Z, despite the stark resolution disparity. We see again a slight hint of moiré artifacts with the red fabric that's not visible in the 645Z image.

Most digital SLRs and CSCs will produce an excellent ISO 100 shot, so we like to push them and see what they can do compared to other cameras at ISO 1,600, and 3,200, and 6,400. Recent advances in sensor technology have made ISO 1,600 look a lot more like ISO 100, but there are still cameras whose quality starts to fall apart at this setting. We also choose 1,600 as a baseline of comparison because we like to be able to shoot at least at this level when indoors and at night.

Pentax 645Z versus Pentax 645D at ISO 1600

Pentax 645Z at ISO 1600
Pentax 645D at ISO 1600
Pentax 645Z at ISO 1600
Pentax 645D at ISO 1600
Pentax 645Z at ISO 1600
Pentax 645D at ISO 1600

Thanks to the new CMOS sensor, as opposed to the older CCD chip in the 645D, the noise performance at higher ISOs (and the simple ability to go to higher ISOs in the first place) is improved in the 645Z. Noise in the shadows is much less visible in the new model, yet fine detail is still excellent. Interestingly, we found that the 645D shows more fine detail in the red fabric pattern (along with some moiré still), whereas the 645Z's handling of the red fabric is a bit "smeary" and less detailed.

Pentax 645Z versus Nikon D810 at ISO 1600

Pentax 645Z at ISO 1600
Nikon D810 at ISO 1600
Pentax 645Z at ISO 1600
Nikon D810 at ISO 1600
Pentax 645Z at ISO 1600
Nikon D810 at ISO 1600

At ISO 1600, both the Pentax 645Z and Nikon D810 display similar low levels of noise in the shadow areas, and the fine detail remains very high from both cameras. Apart from the resolution, both cameras are quite similar in terms of noise and fine detail at this ISO. As with the 645D comparison above, the D810 displays a slightly better rendering of the red fabric pattern at this ISO level.

Pentax 645Z versus Sony A7R at ISO 1600

Pentax 645Z at ISO 1600
Sony A7R at ISO 1600
Pentax 645Z at ISO 1600
Sony A7R at ISO 1600
Pentax 645Z at ISO 1600
Sony A7R at ISO 1600

Compared to the other two ISO 1600 comparisons, it's easier to notice the noise reduction processing in the Sony images. It does a great job of reducing grain while still leaving lots of fine detail. Overall, both cameras still display lots of fine detail at this ISO level, but similarl to the previous comparison at this ISO, the 645Z struggles with the red fabric compared to the A7R.


Today's ISO 3,200 is yesterday's ISO 1,600, so below are the same crops at ISO 3,200.

Pentax 645Z versus Pentax 645D at ISO 3200



Pentax 645Z versus Nikon D810 at ISO 3200

Pentax 645Z at ISO 3200
Nikon D810 at ISO 3200
Pentax 645Z at ISO 3200
Nikon D810 at ISO 3200
Pentax 645Z at ISO 3200
Nikon D810 at ISO 3200

The higher ISO capabilities of the 645Z undoubtedly trumps that of its predecessor, which couldn't shoot past ISO 1600. Compared to the Nikon D810, however, the full-frame DSLR displays less shadow noise than the Pentax. On the other hand, the amount of fine detail present in the 645Z photo at ISO 3200 is very impressive nonetheless -- and in some areas, particularly the fine detail in the various fabric patterns such as the orange fabric behind the bottle or the pink fabric. And the mosaic tile area is incredible for this ISO.

Pentax 645Z versus Sony A7R at ISO 3200

Pentax 645Z at ISO 3200
Sony A7R at ISO 3200
Pentax 645Z at ISO 3200
Sony A7R at ISO 3200
Pentax 645Z at ISO 3200
Sony A7R at ISO 3200

The noise reduction is a little more apparent on the A7R image at this ISO. You can see it show minor artifacts on finer-detailed areas such as the mosaic and pink fabric. It also makes the red leaf pattern less distinguishable, however, the 645Z still struggles with this area more. Fine detail from the 645Z is impressive, with the mosaic tile looking more natural at this ISO compared to the Sony.

Detail: Pentax 645Z versus Pentax 645D, Nikon D810 and Sony A7R.

 
Base ISO
ISO 12800
ISO 25600
Pentax 645Z
Base ISO: 100
Nikon D810
Base ISO: 64
Sony A7R
Base ISO: 100

Pentax 645D

Base ISO: 200

Detail comparison. High-contrast detail is also important, pushing the camera in different ways, so we like to look at it, too. Overall all four cameras have outstanding performance on high contrast detail at base ISO, which is far from surprising. At ISO 3200 and 6400 -- the normal high ISOs we use for these detail crops -- on the 645Z, the D810 and the A7R all look very good with crisp, sharp detail and very little noise. So good, in fact, that we felt the need to show even higher ISOs for this crop just to demonstrate a larger difference between cameras for high contrast detail.

At ISO 12,800, we start to see some differences between the 645Z and the two full-frame cameras. The contrast fades slightly due to noise on the 645Z image and the crispness of the detail is lessened as well. Meanwhile, the two full-frame cameras look relatively the same as base ISO in terms of contrast. There's still some reduction in fine detail from both the Nikon and Sony at this ISO level though, and the Sony in particular starts to show some artifacts from noise reduction processing. Bumping up to ISO 25,600, more noise is apparent in the 645Z image, despite these shots using the default level of in-camera NR processing, the Pentax image is devoid of any NR artifacting, unlike the Sony image at this ISO. The Nikon shows less artifacts from NR, but there's a noticeable drop in fine detail overall and even the appearance of faint chroma noise.

These are very high ISOs for typical shooting however, and the detail present is really incredible for all of these.

 

Pentax 645Z Print Quality

ISO 100/200/400 prints look terrific at 30 x 40 inches and higher* with excellent detail and vibrant colors. Print sizes at these three lower ISO's are only constrained by the 645Z's massive resolution -- the highest we've tested thus far.

ISO 800 yields a stunning 24 x 36 inch print: super crisp with excellent colors and virtually no apparent noise. 30 x 40's are fine here for less critical applications as well.

ISO 1,600 produces 20 x 30 inch prints that have amazing detail in the mosaic tile area of our test target. The only hint that you're going up in ISO is a slight loss of contrast detail in the tricky red fabric swatch of our target, but this is typical of virtually all cameras (except for a few higher-end Nikons, which tend to handle that area better than the others as ISO rises).

ISO 3,200 prints a very good 16 x 20 inch print, and this is still quite an impressive feat at this ISO, and very few cameras we've tested can make this claim (the 645D didn't even go to ISO 3200). There is minor noise in flatter areas of our target, like in the shadows behind the bottles, and most all detail is gone from our red fabric swatch, but otherwise a solid print.

ISO 6,400 is where the 645Z touches back down to earth, allowing for a good 11 x 14 inch print. There are only minor issues similar to the ones found on the 16 x 20 at ISO 3200, but yet again still a nice size for this ISO. And the 8 x 10 really pops here and is excellent.

ISO 12,800 yields a very nice 8 x 10 inch print. Detail is now gone from our target red swatch but this is quite common at this ISO and higher. The print retains full color saturation and crisp detail in all other areas and, in fact, is one of the best 8 x 10's we've seen at this ISO to date.

ISO 25,600 yields an 8 x 10 that almost makes our "good" standard, and that would have put it into rare company indeed, as only two other cameras have been awarded with "good" 8 x 10's from our lab (the Nikon D4S and D800E). The 5 x 7 inch print here is excellent though, with great color and detail for such a high ISO.

ISO 51,200 produces a good 4 x 6 inch print. Only a few cameras we've tested have gone higher than this.

ISO 102,400/204,800 do not yield good prints and these settings are best avoided for any applications.

As we've said on rare occasions with only a few other cameras that have come through our lab, your printer will love you for having a Pentax 645Z. Stunning images at ISO 100-400 are limited only by resolution, a very nice 20 x 30 inch print at ISO 1600 (the highest ISO the 645D will allow) and even a really good 8 x 10 inch print at ISO 12,800. This is what you'd call "getting the job done" in the print quality department, and we weren't at all surprised by these results given how much we love the 645D. A solid upgrade, and well-done Pentax.

*[Note: we no longer provide print quality ratings for sizes larger than 30 x 40 inches, as we felt this wasn't particularly meaningful. At low ISOs, print sizes from high-quality cameras are pretty much limited only by their resolution, vs noise and noise-reduction processing. Going forward, we'll simply note "30x40 or larger" for cameras that achieve that level. As we see it, the real challenge comes at higher ISOs, where noise and noise-reduction processing become bigger factors, and maximum sizes would be more representative of sizes a majority of users would actually print at.]

 

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