[lytrytyr]

FYI, there's a detailed review (by Szymon Starczewski) of the 645Z now posted on the Polish site Optyczne:

Test Pentax 645Z - Wst

While the lens reviews from the Polish site appear in English on Lenstip,
the English site only has some jpeg samples:

Pentax 645Z - sample shots - Lenstip.com

Google translate should help with the full review.

It's mainly positive, although the tonal range and resolution are assessed as weaker than on the Nikon D810.
On the other hand, the noise at ISO 6400 is above 1 EV better than the D810 and A7R,
but just under 1 EV worse than on the Canon 5D Mark III.
The main criticism is leveled at the AF system.

[Kolor-Pikker]

It's mainly positive, although the tonal range and resolution are assessed as weaker than on the Nikon D810.

On the other hand, the noise at ISO 6400 is above 1 EV better than the D810 and A7R,
but just under 1 EV worse than on the Canon 5D Mark III.

The 645Z should be ~1EV better than every 35mm camera going by simple physics, the sensor is 80% bigger, thus 80% more light. DxO doesn't have results for the 645z yet, but here's an analog: Photographic Dynamic Range versus ISO

According to these charts, the only 35mm camera to match the 645Z at any equivalent ISO is the A7S between ISO2000 and 5000, a 12MP full-frame sensor.

The main criticism is leveled at the AF system.

It's pretty good IMO, with a -3EV sensitivity it should be about as good as the Canon 6D, although it does cover only a very small part of the center. Continuous AF isn't very good, but then you're probably using the wrong camera if you shoot continuously for any length of time.

[Thomas]

".................resolution are assessed as weaker than on the Nikon D810.
...........

I have to question those results; 36 MP out resolves 51, with both using a Sony sensor? Popular Photography reported 4425 lpph for the 645Z vs. 3325 for the D800 (approximately the same ratio as the number of pixels).

Camera Test: Pentax 645Z | Popular Photography

[normhead]

I have to question those results; 36 MP out resolves 51, with both using a Sony sensor? Popular Photography reported 4425 lpph for the 645Z vs. 3325 for the D800 (approximately the same ratio as the number of pixels).

Camera Test: Pentax 645Z | Popular Photography

I agree, those results don't match anyone else's. And in the IR images, D800 images don't even match the 645D, forget about the 645z.

[bladawiec]

I have read many Pentax camera reviews on Optyczne.pl and comments posted below these reviews. In many comments you can read that Canon/Nikon/Olympus cameras are generally better judged by them. In comments you can also read that several important advantages of Pentax cameras are ignored but cons (in many cases fictitious) are exaggerated - in comparison to reviews of other brands.

Generally you can get the impression that Optyczne.pl is not Pentax friendly.

So you must have some attention when you reading these reviews and when you reading final scores - especially when scores are compared to other cameras.

[gavincato]

So I'm not going to bother posting them because it was very unscientific but I have done a quick backyard shot of a friends d810 with 24-70mm versus my 645z with 35mm of a tree in my backyard, both at f/11. There was a clear resolution advantage to the pentax. It wasn't a mind blowing difference but it was easily noticeable zoomed in in photoshop.

These guys are on crack.

[batmobile]

Yep, they're bonkers. My 645Z clearly and easily out-resolves my A7R. It also has a significant amount more DR, but how much I cannot say.

[lytrytyr]

Yep, they're bonkers. My 645Z clearly and easily out-resolves my A7R.

I don't see the connection with the mental health of the Optyczne reviewers,
but in terms of line widths per picture height,
they give 3400 for the 645Z, and around 2950 for the A7R.

On the other hand, in terms of line pairs per mm.,
the A7R does outresolve the 645Z
(although my Q outresolves both of them! ).

---------- Post added 06-08-15 at 03:05 AM ----------

I have read many Pentax camera reviews on Optyczne.pl and comments posted below these reviews. In many comments you can read that Canon/Nikon/Olympus cameras are generally better judged by them. In comments you can also read that several important advantages of Pentax cameras are ignored but cons (in many cases fictitious) are exaggerated - in comparison to reviews of other brands.

Generally you can get the impression that Optyczne.pl is not Pentax friendly.

It helps if you distinguish between the careful scientific tests carried out by the Optyczne staff,
and the usual meaningless internet chatter that appears in the comments.

---------- Post added 06-08-15 at 03:25 AM ----------

I have to question those results; 36 MP out resolves 51, with both using a Sony sensor? Popular Photography reported 4425 lpph for the 645Z vs. 3325 for the D800

Unlike Optyczne, Popular Photography does not report the contrast at which they are measuring the resolution.

(approximately the same ratio as the number of pixels).

Picture heights scale by length, while pixel counts scale by area.

[rfkiii]

FYI, there's a detailed review (by Szymon Starczewski) of the 645Z now posted on the Polish site Optyczne:


It's mainly positive, although the tonal range and resolution are assessed as weaker than on the Nikon D810.

I haven't read the review but I assume you've accurately paraphrased the article. Do you recall what lenses were used for the testing? Perhaps this is how the D810 tested better in resolution?

[Kolor-Pikker]

I don't see the connection with the mental health of the Optyczne reviewers,
but in terms of line widths per picture height,
they give 3400 for the 645Z, and around 2950 for the A7R.

On the other hand, in terms of line pairs per mm.,
the A7R does outresolve the 645Z
(although my Q outresolves both of them! ).

This is because the 645Z sensor is larger than 35mm, so in terms of pixels per mm, the 645Z is equivalent to a 30.5MP full-frame sensor. This metric is useless for just about anything unless you're a bird shooter and higher pixel density equates to longer "reach".

It helps if you distinguish between the careful scientific tests carried out by the Optyczne staff,
and the usual meaningless internet chatter that appears in the comments.

When the results of one test contradict the rest of the internet and the userbase of these systems, something has to be called into question.

Unlike Optyczne, Popular Photography does not report the contrast at which they are measuring the resolution.

Contrast only matters for optics, assuming they shot a well-lit test chart using the sharpest lens available for the system, it shouldn't matter. Unlike film, which gradually loses contrast as it reaches nyquist frequency, digital sensors maintain nearly 100% contrast right up until the moment it reaches the limits of resolution, at which point contrast falls off dramatically.
This is part of why sensors are so demanding of optics compared to film, and why it is also perfectly fine to test lens sharpness on digital sensors, unless the lens out-resolves the sensor, the sensor itself will never be a bottleneck until 90~95% of the resolution limit.

[lytrytyr]

Do you recall what lenses were used for the testing?

They used the D FA 645 55 mm f/2.8 AL IF SDM AW, along with an FA 645 120mm f/4 Macro.

Perhaps this is how the D810 tested better in resolution?

Contrast only matters for optics, assuming they shot a well-lit test chart using the sharpest lens available for the system, it shouldn't matter.

These Imatest computations cover the combination of the lens and sensor used.
So sample variation in the lens (which may be up to 15% or more) is also a factor.

[bladawiec]

It helps if you distinguish between the careful scientific tests carried out by the Optyczne staff,
and the usual meaningless internet chatter that appears in the comments.

When the results of one test contradict the rest of the internet and the userbase of these systems, something has to be called into question.

If there is a feature that Pentax camera has but other brands no (upper LCD in low-end K200D, in-body stabilisation, sealed body, etc.) this feature are sometimes not indicated by Optyczne as extra advantage of Pentax camera. Instead of it authors often show flaws of these features (no backlight of upper LCD in K200D is cons section; but which camera form this level have had upper LCD at all?).

One example (one of many) of "impartial" assessment by Optyczne.pl: in Pentax K-x Review the viewfinder (magnification: x0.85, area: 96%, diopter correction -2.5 do +1.5) was rated as "small and dark". But in Nikon D5000 review the viewfinder (magnification: x0.78, area: 95%, diopter correction -1.7 do +0.5) was rated as "crisp and clear". Why?!

In some Pentax reviews, Pentax cameras are compared to models of competitive brands from higher level but not from this same level. What is the reason? As you can guess, Pentax camera is a loser such comparisons.

Please compare features/quality of Pentax vs Canon/Nikon/Olympus cameras with final scores for these cameras.

At the end one exemplary score comparison with Dpreview prepared by one of Optyczne.pl users:

Optyczne:
Pentax K-X 4.4
Nikon 5000D 4.9
Sony A380 4.6
Canon 500D 4.8

Dpreview:
Pentax K-X 9.0
Nikon 5000D 8.0
Sony A380 7.5
Canon 500D 8.0

[lytrytyr]

If there is a feature that Pentax camera has but other brands no (upper LCD in low-end K200D, in-body stabilisation, sealed body, etc.) this feature are sometimes not indicated by Optyczne as extra advantage of Pentax camera. Instead of it authors often show flaws of these features (no backlight of upper LCD in K200D is cons section; but which camera form this level have had upper LCD at all?).

One example (one of many) of "impartial" assessment by Optyczne.pl: in Pentax K-x Review the viewfinder (magnification: x0.85, area: 96%, diopter correction -2.5 do +1.5) was rated as "small and dark". But in Nikon D5000 review the viewfinder (magnification: x0.78, area: 95%, diopter correction -1.7 do +0.5) was rated as "crisp and clear". Why?!

In some Pentax reviews, Pentax cameras are compared to models of competitive brands from higher level but not from this same level. What is the reason? As you can guess, Pentax camera is a loser such comparisons.

Please compare features/quality of Pentax vs Canon/Nikon/Olympus cameras with final scores for these cameras.

At the end one exemplary score comparison with Dpreview prepared by one of Optyczne.pl users:

Optyczne:
Pentax K-X 4.4
Nikon 5000D 4.9
Sony A380 4.6
Canon 500D 4.8

Dpreview:
Pentax K-X 9.0
Nikon 5000D 8.0
Sony A380 7.5
Canon 500D 8.0

Get over it!

Pentax K-S2 on Optyczne: 60 points.
Canon 700D: 52 points.
Nikon D5500: 57 points.
Sony A58: 49 points.

Oh, and by the way, where's the DPReview review of the K-S2?