Tag Archives: crop camera

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 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.

Craving full-frame? Read this first.

3 Jul

Reading this article might save you some money. No, I’m not sponsored to write this, so you may safely proceed. All you’ll get is technical insight and honest opinion.

Perhaps like many photographers, you’ve thought about going for a full frame camera. Perhaps you’ve heard about shallow depth of field, low light shooting and noise. Maybe you’ve heard that full frame is “one stop faster” or “one stop brighter”.

In this article, I’ll cover one of the reasons for going full frame – more light, and how much sense it makes, especially for your bank balance.

Frontal product photo of a black camera against blueish white background.

Ever wanted a Nikon D800E? Read on. (Image credit: Jastrow)

By going from APS-C to full frame – probably the most common move – you gain approximately one stop of light, i.e. you get twice as much light over the whole of your sensor. It would be approximately true to say that shooting ISO 200 on full frame, you get the same noise as shooting ISO 80 on APS-C. So you can shoot faster shutter speeds and, over the whole sensor, get the same noise. However, if you shoot 16 megapixels on APS-C, then shooting 36 megapixels full frame, you will get the same PER PIXEL noise, at the same ISO. So far, so good.

Small rectangle denoted APS-C next to larger rectangle denoted

Relative size of the two major DSLR sensor formats (Copyright breakfastographer / Chriusha (Хрюша) / CC-BY-SA-3.0)

So if we shoot the same apertures, we gain a stop of light. So we can ask the question, how much does it cost to gain a stop of light?

If you upgrade from an 18-55/3.5-5.6 APS-C kit lens to a 17-50/2.8 APS-C premium zoom, you gain 1-2 stops of light, and it might cost you 150 Eurodollars if you buy used. Or for about the same price, you could upgrade to a 17-70/2.8-4.5, which gives you almost exactly one stop advantage over the kit lens, and a bit of extra range.

If you further upgrade to an 18-35/1.8 zoom, you might pay about 600 Eurodollars used or a good offer new, and you would gain a stop over the 17-50/2.8 or over two stops vs. an 18-55/3.5-5.6 kit lens. But you shorten your range by about one stop of teleconversion. Don’t worry if that sounds technical – just remember that 35mm is 35mm and not 50, 55 or 70mm.

Black zoom lens pointing upwards with hood attached, and lens cap lying next to it, label up. Zoom ring indicates 17-24-35-50. White background.

Another possible upgrade path? The Tamron 17-50/2.8 (Image credit: Christian Fischer/CC-BY-SA-3.0 Unported)

If low light shooting, reduced noise or faster shutter speeds are what you’re after, and you’re still shooting with an APS-C camera and kit lens, you owe it to yourself to first invest the 150 to see if the extra light is worth it. This will put you in a much better position to judge whether you want to invest about ten times that amount (or more) to get to a full frame camera and appropriate lens. (Note that a full frame camera with an f/4 lens offers no light advantage over an APS-C camera with an f/2.8 lens!)

There are other points to consider, of course, some of which I’ll touch on briefly. A full frame camera generally offers greater sharpness due to both an increase in resolution and easier manufacture and assembly of appropriate glass. The full frame format is more resistant to diffraction, typically tolerating f/11 rather than f/8 (APS-C) or f/5.6 (Micro Four Thirds) – note that these assumptions only hold for certain pixel pitch, i.e. a 36 megapixel full frame camera is just as sensitive to diffraction at the pixel level as a 16 megapixel APS-C camera. (Other assumptions apply, such as having comparable filter stacks in front of the sensor.) However, over the entire frame, the full frame camera is more tolerant. The flip side is that you need to shoot at those smaller stops to reach the same depth of field, meaning that in landscape shooting, there is no full frame advantage in available light, for the same positioning and framing.

Furthermore, full frame has greater limitations when it comes to designing zoom lenses – you may notice that a common superzoom lens specification for full frame is the 28-300mm lens, whereas on APS-C, the limit has been pushed to 16-300mm – the same versatility in focal length as a 24-450mm on full frame!

Similarly, compare the Sigma 18-35/1.8 to its full frame sibling, the 24-35/2. The smaller lens is both faster and, depending on your point of view, slightly more versatile. (The comparison is hampered by the full frame lens being the equivalent of a 16-24mm on APS-C – not an easy comparison!)

So a full frame camera is best suited to the shooter who knows what situations they want to cover and what their preferred focal lengths are. If you prefer spontaneous shooting and versatility, it is likely that a full frame camera will not make you happy.

Arguments about achieving shallow depth of field more easily on a full frame camera deserve a separate article.

Update 2/2/2017: Also check out my newer article, Low light photography? Affordable? Look no further! for the latest development, or check out a sample image.