Pentax K-3 Mk III

Nikon championed the APS format prior to the introduction of the D3 but have never built a proper line of lenses for the format. They might build nice new DX format SLRs, but I have my doubts about APS.
Marty

Marty, I can understand your point of view. Thom Hogan has discussed that for about 15 years now, again and again :). He has always critizised Nikon for being not active enough in the special DX lens segment for their APS-C cameras.
And it looks like a correct assessment.

But interestingly the Nikon customers have probably seen that differently, as about 85-90% of all sold Nikon DSLRs have been crop-sensor APS-C models!

If Nikon customers would have considered the Nikon lens line as insufficient, Nikon APS-C cameras would not have been so successful.
And by the way, Canon wasn't more active in this lens segment, too.
But Pentax has been, with lots of (excellent) dedicated lenses for the APS-C format. So the new Pentax K3 Mark III can rely on a huge lens base, from 11 to 560mm focal length.
 
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So, is it a good viewfinder or not? You guys have confused me! ;)


There are already some initial reviews of the K3 Mark III out there.
Because Pentax has given several units (but without the final firmware, but with the final hardware = also final OVF) two months ago to several photographers.
They all report the same: This completely newly designed OVF is excellent, and probably the best of all APS-C cameras.
An OVF on FF OVF level. That is amazing.
 
Since the aspect ratio of the sensors is the same, the APS-C sensor is 0.69 smaller no matter the diagonal, horizontal or vertical.

So if you put a 35mm lens on K3iii (equivalent of 50mm), things will be x0.68 (as per dpreview states) smaller than what your eyes see. D850 for comparison has a 0.75x magnification factor and the D500 has a .67 FF equivalent magnification factor.

The sensor and the viewfinder are independent. If you measure the viewfinder characteristics, as opposed to accepting manufacturer data, you’ll find that the horizontal coverage is not the same as vertical, that is why it makes a lot of difference how it is measured. If it has been calculated by area, however, you can trust the measurement. But manufacturers and reviewers rarely tell you.

So, is it a good viewfinder or not? You guys have confused me! ;)

I am reliably told that K-3 III viewfinder is by far the best APS viewfinder in an SLR. But the details are important, and more factors than coverage will be relevant to its performance. Pentax claim excellent manual focus characteristics, generally a weak point of autofocus SLRs because their focus screens are a welded section of light piping fibre optic cables with their own microlenses on each end. It is also a problem with APS format viewfinders because they are smaller, but the K-3 III offers promise here because it is larger.

What I am saying is don’t believe numbers alone - the visual experience of looking through the viewfinder is very, very important and can’t be entirely characterised by a small range of numbers, and the numbers are increasingly misused and unreliably presented.

Marty

And I’m much too interested in this camera, and am jabbering like an idiot to divert my own interest . . .
 
The sensor and the viewfinder are independent. .

In mirrorless cameras yes, but in (D)SLRs of course not. The size of the mirror (that usually matches the sensor size) is what primarily determines the magnification of the viewfinder (measured with an equivalent FF 50mm FoV). The lenses before and after the pentaprism/pentamirror usually don't increase the magnification by a large degree as it can degrade the image, and are mostly there to optimize the eye relief.
Here is a link with the effective sizes of the viewfinders for different cameras:
https://www.neocamera.com/article/viewfinder_sizes

The numbers that Pentax states (1.05x magnification) and the ones DpReview mentions (.68x equivalent), are pretty close and I see no reason to doubt them.

But as you say, the quality of the OVF depends on other factors as well.
 
There are already some initial reviews of the K3 Mark III out there.
Because Pentax has given several units (but without the final firmware, but with the final hardware = also final OVF) two months ago to several photographers.
They all report the same: This completely newly designed OVF is excellent, and probably the best of all APS-C cameras.
An OVF on FF OVF level. That is amazing.

I was joking... but thank you.
 
In mirrorless cameras yes, but in (D)SLRs of course not. The size of the mirror (that usually matches the sensor size) is what primarily determines the magnification of the viewfinder (measured with an equivalent FF 50mm FoV). The lenses before and after the pentaprism/pentamirror usually don't increase the magnification by a large degree as it can degrade the image, and are mostly there to optimize the eye relief.
Here is a link with the effective sizes of the viewfinders for different cameras:
https://www.neocamera.com/article/viewfinder_sizes

The numbers that Pentax states (1.05x magnification) and the ones DpReview mentions (.68x equivalent), are pretty close and I see no reason to doubt them.

But as you say, the quality of the OVF depends on other factors as well.

The mirror determines coverage - the % measure that is the proportion of the full frame displayed in the viewfinder. This is why coverage can be greater in one axis than the other, and why linear, diagonal and area measures of coverage are rarely the same, because if you measure the mirror it often has different proportional measurements to the sensor or film frame. The mirror has nothing to do with magnification, which is the relative size of the visual image to the aereal image cast by the mirror. Magnification is controlled by the pentaprism and whatever else is in the optical path.

I’m going to leave this now. Goodnight/day.

Marty
 
Meanwhile the camera is available and out there in the shops.
And the first pictures and reviews from buyers / users are online.
Wow, the performance is really impressive! It looks like one of the best ILCs ever made so far:
- outstanding picture quality on current FF level (and that as an APS-C camera)
- impressive viewfinder on FF quality level
- excellent build quality
- excellent rear display
- perfect ergonomics
- significantly improved autofocus.
I have never been a big fan of the APS-C format. But with such a camera, I could get weak.........;).
Pentax is back!!
 
Meanwhile the camera is available and out there in the shops.
And the first pictures and reviews from buyers / users are online.
Wow, the performance is really impressive! It looks like one of the best ILCs ever made so far:
- outstanding picture quality on current FF level (and that as an APS-C camera)
- impressive viewfinder on FF quality level
- excellent build quality
- excellent rear display
- perfect ergonomics
- significantly improved autofocus.
I have never been a big fan of the APS-C format. But with such a camera, I could get weak.........;).
Pentax is back!!

My philosophy is that, if there's an APS-C DSLR that is worth being interested in, Pentax is the one, because of the small and unique DA Limited primes. My dislike of APS-C format is mostly due to the way lens focal lengths are still often stuck in FF terms, i.e. 24, 35, 50... lenses which make more sense on FF formats. Pentax has unique lenses like the 15, 21, 40, 70 limiteds which are unique focal lengths that work really well.
 
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