Tag Archives: Pentax

Pentax KP vs. Nikon D500: white balance

16 Mar

Continuing my series on the Pentax KP, and possibly starting a sub-series comparing the Nikon D500 against it, today my attention was drawn to ephotozine’s Pentax KP sample photos, particularly the colour section:

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Pentax KP (top) vs. Nikon D500 – ISO 200 (left) to ISO 819,200.

Particularly the ISO 819,200 sample from Nikon seems to be soaked in yellow, although the ISO 409,600 sample also seems affected. Here’s the 819,200 comparison, with two attempts to fix the Nikon’s white balance in post:

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Pentax KP (left) vs. Nikon D500 OOC, Nikon D500 with my own special WB procedure, and finally Nikon D500 after “color->auto->white balance” from Gimp

If “fluorescent” white balance is used in the Pentax, it gets even further ahead of the Nikon – an unfair comparison perhaps, but it’s only a single step of configuration and straight out of camera:

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With even more prodding, I eventually got the Nikon image to behave. I managed to keep noise levels on par, but keep in mind that it’s a fair amount of work, and you really have to know what you’re doing in Photoshop or Gimp to get this kind of result – remember the one button fix is the image on the far right, and it improves things, but doesn’t really “fix” the problem. Cutting to the chase, here’s that final result:

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Even using the Pentax’ default white balance, it does impressively well, keeping in mind we had to massage the Nikon image for several minutes to get it into decent shape:

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The bottom line is that in terms of colour, the Pentax produces reasonable JPEG output even at very high ISO, while the Nikon D500 takes considerable time in post-processing to achieve a competitive result. The Nikon is not usable as a JPEG camera at this high ISO and I would instead recommend, if using the D500 at all, to shoot raw and use a raw converter, in which case it’s the raw converter’s job to give you a reasonable-looking image (this will be the next part in this series, if time allows).

Pentax’ PLM and DC lenses explained

2 Mar

DC (“direct current”) is a kind of focus motor that has been used in Pentax lenses for some time. While it is quiet, it’s not entirely silent. Pentax’ most recent 55-300mm lens features a new type of motor branded as PLM. Here is what Pentax representatives had to say about it in an interview:

The PLM design can quickly activate and allow for faster focusing, but the lens element must be low weight due to limited power (torque).

The DC motor can generate high power (torque) with deceleration mechanisms, which is better for lenses with larger focusing elements. A DC motor can be driven at high speed, but there is an issue that a little sound is generated.

Generally, we use the what we feel is the best focusing mechanism for each specific lens design.

It would be reasonable to suspect that the 55-300mm’s new optical formula and narrower aperture were needed to allow the faster, silent motor to be used, although it should be noted that, like the recent 18-50mm kit and non-kit zoom lenses, the new 55-300mm lens is collapsible to a somewhat smaller size, with the difference between collapsed and uncollapsed size being more pronounced in the 18-50mm.

In the interview, the representatives went on to explain that they do not expect to see PLM in a large aperture lens any time soon, instead putting their money on researching other kinds of motors as well as algorithms to improve autofocus.

Pentax KP better at high ISO than K-70, especially after DxO PRIME treatment

11 Feb

Imaging Resource have published RAW samples from the Pentax KP. Since I was able to cheat DxO 11 into processing an ISO 102,400 file, I thought I would post the results of performing PRIME noise reduction on a pair of these at ISO 102,400 – one from the KP and one from a K-70 – click on the image for a 1:1 view of the striking difference (KP on left, K-70 on right):

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Compare with the out-of-camera JPEG result (KP on left, default in-camera noise reduction on both):

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The out-of-camera JPEGs retain a little more detail, along with some more noise – probably a matter of personal taste, but I would go with processed raws here.

The Pentax KP features saturation compensation, to stop colours looking washed out at higher sensitivities. The in-camera processing deals with this gracefully, so that no luminance detail is lost (KP on left, K-70 on right, both with default in-camera noise reduction):

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The current version of DxO OpticsPro does not include a Pentax KP profile, and some loss of luminance detail could be seen in the PRIME processed image. As explained by a commenter over on Imaging Resource, this may be due to the KP using a different white point in its raw output compared to previous Pentax cameras. That being the case, it would be true to say that this will not be an issue once the DxO software is updated to support the Pentax KP.

Pentax cameras offer a lot of configurability of the output, and it’s therefore likely that the saturation compensation can be turned off or on as needed.

Overall, one can’t help but conclude that the KP is a huge advance over the K-70, a remarkable camera in its own right. And after initial reserve over the design of the camera, many now seem to be swayed by its rich features, performance and customisability.

Feel free to head over to Imaging Resource for more samples, or take a look at a comparison of the K-70 and Nikon D500 at ISO 102,400, or the post-processed ISO 800k result from a night-time Pentax KP out-of-camera JPEG. Alternatively, read my overall thoughts on the Pentax KP.

Pentax 645 shutter sounds

9 Feb

I couldn’t fit them all into the previous post, so here they are now:

1) Pentax 645Z

2) Pentax 645D

3) Pentax 645Z vs. 5Ds, D810, OM-D E-M5 II, a6000

And the classic:

4) Pentax 645

Pentax K-70 vs. Nikon D500: high ISO raw IQ

7 Feb

In trying to get a glimpse of how the Pentax KP might compete with the D500, I looked at test scene samples on DPReview. Keep in mind that the D500 retails at about three times the cost of the K-70, or a difference of 1300 to 1350 Eurodollars. That is, choosing the K-70, for the same budget, you could get at least four nice lenses, two great lenses, or one truly stellar lens in addition to the camera – or three bodies instead of one. Or two bodies and two nice lenses.

So is that price difference reflected in the raw output? Are images from the D500 three times as good? Let’s take a look:

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The K-70 has slightly higher resolution – 24 megapixels rather than 20. Differences in pixel dimensions are difficult to compensate for in image quality comparisons. However, I think we can see that at sensitivities of ISO 51200 and 102400, chroma noise is very similar. It seems finer grained and less luminous in the Pentax, but the D500 looks like it has had more sharpening and contrast applied to it – hard to say if this was in-camera and, if not, owed to the default settings of Adobe Camera Raw, which DPR use to generate the above “raw” views.

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Time and again, I found the image quality to be very similar, and I could not decide which camera I would prefer on that basis. Having said that, a camera is more than its image quality, and the D500’s buffer depth, to name just one aspect, far exceeds that of the K-70, but this is useful in a narrow range of shooting situations, primarily in wildlife and sports. Both cameras may be outdated in two years, and there’s no obvious reason to expect the depreciation on the D500 to be less than three times that experienced in choosing the K-70. So to continue our budget thinking, you could pick up a K-70 and two nice lenses now, and save the rest for an upgrade to the next mid-level camera from Pentax in 2019, all for the price of one D500 and a kit lens. If you’re anything but a pro who absolutely needs the capabilities of the D500 for sports or wildlife, or a wealthy amateur, that reasoning is hard to argue with.

By the way, if you’re worried about the disk space raw images will take, the 24 megapixel image from the K-70 was the same size at ISO 104200 as the D500 (20 megapixels), and slightly smaller at ISO 51,200, in spite of having the same bit depth (14 bits). At lower ISOs, the K-70 files are consistently about 20-25% smaller. So if you prefer resolution over other considerations, the K-70 has a slight edge without obvious disadvantages.

For an additional test, I passed both images through DxO’s PRIME noise reduction engine (click through for 1:1 view):

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As before, the Nikon image has more contrast and looks more graded; in terms of noise and detail, after DxO PRIME treatment, both images have edge artefacts at this ISO. It is no surprise that the Pentax retains more detail in black and white areas. In textured areas, the winner is less obvious, and the Pentax image has grainier noise and shows the DxO artefacts more strongly.

Finally, comparing a pixel shift Pentax image with a normal Nikon capture, controlled for total exposure, shows no clear advantage, either:

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The pixel shift image shows more detail as expected, but having, in the interest of a fair comparison, controlled for total exposure and thus compared Pentax at ISO 102400 to Nikon at 25600, the Nikon shows less noise.

In conclusion, at a technical level we can say that the Nikon D500’s slightly greater resistance to noise justifies its slightly lower resolving power, at 20 megapixels rather than the now ubiquitous 24 megapixels. However, justifying the price differential is an entirely different exercise, and the Pentax K-70 looks an extremely strong challenger. The Pentax KP is expected to build on the low light capabilities of the K-70 and exceed it, and at little over half the price of the Nikon, adds another strong option for the budget-conscious.

Strikingly, having compared the K-70 to Nikon’s other recent APS-C releases, it is obvious that the D500 is currently the only Nikon APS-C camera that’s still competitive with Pentax on image quality, other Nikons having been left in the dust.

And the successor of the Pentax K-3 II is only months away, with an announcement date around September, and will challenge the D500 on a broader set of features, including buffer depth.

Update: I added a comparison of the Pentax KP and K-70 at high ISO.

Did DigitalRev TV foreshadow the KP?

6 Feb

I may have more to say on what’s recently happened to DigitalRev TV on another occasion, but here’s a soundbite from Kai in May 2011, a good five and a half years prior to the announcement of the Pentax KP:

I think if they made something which looked kind of retro and cool, that would be really good. I think I’m jizzing my pants if they made this kind of a silver and black, made it look a bit like your OM-1, that would be great.

That’s a reference to Lok’s father’s OM-1, which Lok showed off in the preceding segment of the video. In a mock charity donation video for Pentax, Kai’s presumably scripted voice-over continues:

help Pentax be a pioneer again … help them think different and create a create a retro cool DSLR that will make the world a better photographic place

They added this photoshopped image:

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And this is what Pentax came out with:

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And here is an actual OM-1:

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Released under CC-BY-2.0 license by Flickr user E Magnuson

Design similarities:

  • Pyramid prism housing, rather than various other shapes used by Pentax over the years
  • Protruding strap attachment points (rather than recessed as used on Pentax’ mid-range models); Ricoh left off the triangular piece for the photo, but it is usually included in the box
  • Control elements on the front and top plate in almost exactly the same places

Oh, and it comes in silver, with all the same parts in silver that would be so on a traditional SLR like the OM-1:

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Well, what do you make of it? Coincidence? Inevitability? Inspiration?

And would this have been a better design to release in February 2012, less than a year after DRtv’s video, instead of the K-01?

Sigma brings back the moiré

3 Feb

I believe I’ve written on this subject before. DPReview just exclusively announced the results of DxOMark testing of the Sigma 85mm f/1.4 “Art” lens, announcing it to have achieved a perfect 36 “perceptual megapixels” on the Nikon D810’s 36 megapixel sensor. It therefore sort-of-ties with the Sony FE 90mm f/2.8 macro lens, which achieved 42 perceptual megapixels on a 42 megapixel sensor.

Discussion immediately broke out on whether the Zeiss Otus 85/1.4 or Nikon 105/1.4 provided nicer bokeh and whether this was, in fact, more important than sharpness. The Zeiss, in particular, is almost tied with the Sigma for sharpness, and like it excels in many other technically measurable characteristics. The Nikon may be half a step behind, and in fact has a focal length of 94.8mm vs. the Sigma’s 79.9mm, so is more comparable than it sounds at first.

But back to my original point, which is the following:

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Excerpt from DPReview sample image no. 30, of the Sigma 85mm samples.

That’s right, moiré. It is a physical certainty that if the sensor has no anti-aliasing filter on it, and the lens outresolves the sensor, you will see moiré on certain subjects (you can find technical details of moiré and aliasing on the Wikipedia pages, moiré pattern and Nyquist frequency). Many manufacturers have dropped the anti-aliasing filter to squeeze more resolution out of their images and as a small cost-saving, or installed a second filter that cancels the first (slight cost increase). Wisely, Canon added the 5Ds without the R to their line-up, which cuts back on moiré much better than the 5Ds R.

In Nikonland, it seems the highest resolving lenses and highest resolving sensors do not make a good pair. That being so, should we buy high resolution cameras at all, and what other choices do we have? Both the Nikon D600 and D610 have weak AA filters (link in Polish) – a bad idea for a lower-resovling camera as the range of lenses that outresolve it will be greater.

Pentax now releases its cameras with an AA filter that works up to shutter speeds of 1/1000s – presumably adequate for most portrait work, and hopeful that anything you’ll want to shoot above that shutter speed will be moving so fast that aliasing is not likely.

In spite of this, Pentax remains, as of this writing, a stalwart of compact lenses that value bokeh over resolution – partly, perhaps, owing to the fact that some of its lenses have been available for quite some time.

It’s well known that Tamron and Pentax have been sitting in a tree lately, and so it is fitting that Tamron somewhat recently launched a line of f/1.8 primes – more compact than the competition’s f/1.4 standard. DxOMark allows comparing Tamron’s 85mm lens with Zeiss’ Otus and Milvus, for instance, and there’s hardly a hair between them. Most surprising perhaps is the performance of the Milvus at less than half the price of the Otus.

Incidentally, while the three aforementioned lenses max out the D800E’s sensor at 36 perceptual megapixels, Sony’s new Gold Master 85mm lens reaches no more than the same value – 36 P-Mpix on an AA-filterless 42 megapixel sensor.

It’s worth asking therefore whether the trend for the second half of this decade is going to continue with lenses increasing in size, resolving power, and price, as exemplified by the Art and Otus, or a reconsideration of traditional values.* If the former, I hope consumers will be asking for strong anti-aliasing filters, and that camera makers, in spite of mobile phone cameras nipping at their heels, will grant that gift.

*An opportunity, perhaps, for Chinese lens makers trying to push into the market.

Update 7 February 2017: For differences between the Art and Otus, check out Roger Cicala’s blog post.