Review: Pentax K-S2

Introduction and features

Ricoh/Pentax introduced its new K-S2 relatively quickly after the K-S1 came out. However, despite the similarities in name, it’s not a replacement for the K-S1 – instead, it sits slightly above it in Pentax’s range. Internally, it shares a lot of the K-S1’s specifications, but much of the camera’s physical design and usability has been reworked.

You won’t find the KS-1’s flashing lights adorning the front of the camera, but that’s not the only thing that will please enthusiast photographers. The fact is that behind all the gimmicks and flashy lights, the K-S1 was actually a decent camera, so it’s great to the K-S2 using much of the same technology in a much more serious camera.

Never mind the weather

Pentax claims that the K-S2 is the world’s smallest and lightest weatherproof camera, which should make it capable of resisting the odd rain shower or two – particularly useful for landscape and street photographers.

Ricoh/Pentax has thrown in a few other firsts here as well – at least for the brand, if not for the DSLR market as a whole. For example, this camera features a fully articulating screen (though it’s not touch sensitive). This screen uses airless gap technology which fills in the space between the LCD and its protective cover in order to improve visibility in bright light.

Another first for Pentax is inbuilt Wi-Fi and NFC, which can be used in conjunction with a free Image Sync app available for iOS and Android to both control the camera and download shots taken with it for quick uploading to social networking sites and the like.

There’s more. Pentax has introduced a new kit lens for the K-S2. It’s an 18-50mm f/4-5.6 optic, which retracts in on itself to reduce the overall size of the system when it’s in storage or when you’re carrying it around.

Unlike Canon and Nikon, which use lens-based image stabilizers, Pentax uses a sensor based SR (Shake Reduction) system inside its DSLRs, including the K-S2, to help reduce blur when hand-holding the camera.

Other useful features include 5.5 frames per second continuous shooting and a maximum shutter speed of 1/6000 sec – that’s a touch faster than most of its direct rivals, which offer a maximum of 1/4000 sec. The benefit of fast shutter speeds like this is not simply for freezing fast-moving subjects – you can also shoot in bright light with wide apertures to increase background blur without overexposing.

Sensor and AF system

The sensor is the same one you’ll find in the K-S1: a 20-million pixel APS-C sized sensor which features a maximum sensitivity of ISO 51200. There’s no anti-aliasing filter here, which is starting to become increasingly common and helps to maximise the detail output of the camera. In order to avoid the problems associated with this design – namely the risk of moiré patterns appearing when photographing something with fine repeating patterns – Pentax has come up with a novel and interesting solution. If see any moiré effect, you can use the camera’s anti-aliasing ‘simulation mode to retake the shot. This applies a tiny vibration to the sensor during the exposure, minutely shifting the photosites and therefore replicating the effect of a low pass filter.

The autofocus system has 11 AF points that can be used with the K-S2, of which 9 are the more sensitive cross-type. This is not the most sophisticated on the market, and you may find the system quite coarse and noisy when using some of Pentax’s cheaper lenses which don’t have their own AF motors. The new kit lens does, however, have its own built-in DC motor.

The KS-2’s viewfinder not only offers a 100% view, but it’s also a proper glass pentaprism – cheaper DSLRs tend to use a pentamirror which offers only 95%, 96% or 97% coverage.

There’s full HD video recording, as you’d expect in an up to date DSLR, while a range of digital filters and the ability to process raw files in-camera round off the specifications list of the K-S2.

Build Quality and Handling

It’s the smallest weatherproof DSLR on the market, and the K-S2 has a diminutive size which makes it feel almost more akin to some of the larger compact system cameras on the market. Furthermore, the kit lens and some other lenses which you can buy for the system are also pretty small, making it a good choice if you’re concerned about weight and size.

You need to hold down a small button on the side of the retracting kit lens to extend it before you can take your first shot. This can add a couple of seconds to shooting time, so if you’re planning on taking a few shots, it’s best to leave it extended. To zoom in and out, you rotate a small ring on the front of the lens – it takes a bit of time to get used to the positioning of this ring, especially as the focusing ring directly behind it is roughly the same size. At times, I found it quite frustrating, when compared to the much larger, easier to find zoom rings of other kit lenses.

Control layout

The K-S2 has quite a small grip when compared with other cameras of its kind. However, it still feels pretty comfortable in the hand, with a small indent allowing your middle finger to rest nicely. The two scrolling dials – one on the front of the grip, and the other on the rear – make changing the settings feel easy and natural.

Both of the dials control a different function, depending on which exposure mode you’re currently using. In manual exposure mode, the front dial alters shutter speed and the rear dial alters aperture. If you’re working in shutter priority mode, only the front dial will work – and the opposite if you’re working in aperture priority. The good news is that if you prefer to work in a different way, you can customise how each of the scrolling dials work in different exposure modes via the main menu.

The vast majority of the KS-2’s buttons are on the right hand side of the camera, which means it’s pretty quick to make changes with just one hand. There are however, some buttons on the left side, notably the Live View button. There are a couple more on the side of the camera, including the AF/MF switch. A customisable button marked ‘Raw/FX’ allows you to choose from one of six different functions (when shooting).

One of the most useful controls on the camera is the green button on the top-plate, just behind the shutter release button. This restores certain settings (such as exposure compensation) back their defaults.

Wi-Fi and NFC

There’s also a button on top of the camera which you can hold down to activate the camera’s Wi-Fi system. Using the app and connecting to the camera from your smartphone or tablet is very easy. If you have an NFC enabled phone, you simply hold the two devices together and – if it’s the first time you’ve done that – you’ll be prompted to download the free Image Sync app. Alternatively, if you have a Wi-Fi only phone (such as an iPhone), you can download the Image Sync app from the App Store and connect to the camera’s Wi-Fi in your phones setting.

Pressing the ‘info’ button on the back of the camera gives you access to a quick menu which helps you to change certain key settings more quickly, such as Custom image, JPEG quality and metering settings. It would have been nice if you could customise this menu depending on how you like to work best, though.

Once you’re connected, the app is excellent to use. It gives you complete control over pretty much all of the camera’s settings, which is refreshing to see and genuinely useful. The only things you can’t change are mechanical, such as whether the flash is raised, or the focal length of your lens. It’s also fairly easy to transfer images across to your phone for sharing on social networks, once you get the hang of how to select and download a photo.

Although it’s nice to have a 100% viewfinder, as it is optical rather than electronic, it means that you won’t be able to see any changes made to settings until you look at the shot on the LCD afterwards.

Performance

As the K-S2 uses the same sensor and processor combination as the K-S1, I had little doubt that performance in terms of image quality would be almost identical.

Image quality is one of the best things about the K-S2’s sibling, and it continues to impress well here. I found that the JPEG images are nicely saturated with vibrant colours which pop well even when using the ‘Natural’ setting.

Click here for a full size version.

Click here for a full size version.

If you’re shooting in raw format this gives you good scope for post-production adjustment and more muted results. Our labs results also show that the K-S2 puts in a good performance for dynamic range across the sensitivity range, being reasonably close to the Nikon D5500 – this is borne out in real world shooting, too and again it gives good scope for post-capture adjustment.

You can change the way colours look direct from the camera in a couple of different ways. First of all, you can choose a different ‘Custom Image’ – all the normal options are here including Portrait, Landscape and so on, but there are also a couple of ‘out there’ choices, like Bleach Bypass and Reversal Film, which are fun to experiment with. Alternatively, you can use one of the Digital Filters, which are generally a little wackier, but also worth a look.

Click here for a full size version.

Click here for a full size version.

Sharpness and noise

As we saw before with the K-S1, the K-S2’s sensor can resolve a good amount of detail, thanks in part to the removal of anti-aliasing filter. At 100% magnification on-screen JPEG images taken at low sensitivities appear very sharp and there’s very little image smoothing. Even when looking at images shot at higher sensitivities, such as ISO 3200, detail is still resolved well, and at normal printing and web viewing sizes the overall impression of detail is fantastic.

The camera’s Shake Reduction system also works well to combat blur in images, meaning you can use it one handed, or shoot quickly without worrying too much if the camera is 100% steady.

It’s clear that the camera applies a fair amount of noise reduction when shooting at high sensitivities, as it’s possible to see speckling and chroma noise in the raw files. This gives you good scope for applying your own noise reduction to raw files.

It’s possible to shoot at a maximum sensitivity of ISO 51200, but it isn’t something I’d recommend doing routinely as you will be left with very noisy and grainy images. The maximum setting that I’d generally recommend is ISO 12800, or below 3200 for the best quality. Our labs results indicate that the K-S2 performs very well for signal to noise ratio, both for JPEG and raw files – you can read more in depth analysis on the pages which follow this.

Click here for a full size version.

At the time of writing, it’s not possible to open and edit the KS-2’s PEF raw files using Adobe Camera Raw, but the camera can also shoot in DNG format, which is a universal raw format you should be able to open in any software with DNG support.

On the whole, the K-S2’s automatic white balance system copes well with a variety of different light sources. However, at times it can be a little confused some scenarios, such as overcast, dim light. When shooting under artificial lighting, the camera is fairly capable, but it can err towards the warm side. For best accuracy, you can switch to a more appropriate white balance setting, such as Cloudy or Tungsten. Or, if you shoot in raw format, you can change this setting after the event if it hasn’t quite got it right.

Click here for a full size version.

In most average situations, the camera’s all-purpose metering system produces good exposures, but a little extra exposure compensation is required every now and then to get a bright, accurately exposed shot when light levels are a little on the dark side, or there’s high contrast.

I’ve seen it before with some Pentax lenses, and it’s a little unfortunate to see it here too, but purple fringing can sometimes be seen around edges in very high contrast situations when using the kit lens. It’s not something that happens with every shot, but it’s a shame to see it occurring at all.

On the plus side, autofocusing is quicker using this camera’s kit lens than the one that accompanied the K-S1. Most of the time it will get the subject in focus quickly and easily, perhaps hunting a little more as light levels drop.

Click here for a full size version.

Click here for a full size version.

Lab tests: Resolution

We’ve carried out lab tests on the Pentax K-S2 across its full ISO range for resolution, noise (including signal to noise ratio) and dynamic range. We test the JPEGs shot by the camera, but we also check the performance with raw files. Most enthusiasts and pros prefer to shoot raw, and the results can often be quite different.

We’ve also picked out three of its chief rivals so that you can compare their performance directly.

• Canon 700D: Until the new EOS 750D and 760D become available, this is still Canon’s top beginners camera.

• Nikon D5500: Nikon’s most advanced beginners camera impressed us with its resolution.

• Olympus OM-D E-M5 II: It looks and handles just like a DSLR but it’s actually a compact system camera.

Resolution test chart

We test camera resolution using an industry-standard ISO test chart that allows precise visual comparisons. For a full explanation of what our resolution charts mean, and how to read them, check out our camera resolution test process.

Pentax K-S2 resolution

JPEG analysis: The Nikon D5500 has a clear advantage over its rivals right up to ISO 3200, but the Pentax K-S2 and Olympus E-M5 II put in a good performance not far behind. The EOS 700D and its older sensor trail behind except at ISO 3200 and above.

Raw analysis: The K-S2’s raw files show better detail than its JPEGs and it runs the Nikon D5500 a very close second. The E-M5 II is a little behind but it’s still ahead of the EOS 700D.

Lab tests: Dynamic range

Dynamic range is the range of tones the sensor can capture. Cameras with low dynamic range will often show ‘blown’ highlights or blocked-in shadows. This test is carried out in controlled conditions using DxO hardware and analysis tools.

Dynamic range is measured in exposure values (EV). The higher the number the wider the range of brightness levels the camera can capture. This falls off with increasing ISO settings because the camera is having to amplify a weaker signal. Raw files capture a higher dynamic range because the image data is unprocessed.

Pentax K-S2 dynamic range

JPEG analysis: Interestingly, the Olympus scores highest here, particularly at higher ISOs. The Pentax K-S2, Canon 700D and Nikon D5500 deliver almost identical results.

Raw analysis: The pattern changes with raw files, where the E-M5 II still leads but with a smaller margin. The EOS 700D is now second best, while the Nikon D5500 and Pentax K-S2 trade places at different ISOs.

Lab tests: Signal to noise ratio

This is a test of the camera’s noise levels. The higher the signal to noise ratio, the greater the difference in strength between the real image data and random background noise, so the ‘cleaner’ the image will look. The higher the signal to noise ratio, the better.

Pentax K-S2 signal to noise ratio

JPEG analysis: The K-S2 delivers similar results to the E-M5 II and EOS 700D right up to ISO 1600 and opens up a slight gap at higher ISOs. It’s clearly better than the Nikon D5500, even though the K-S2 also dispenses with the anti-aliasing effect.

Raw analysis: Here, the Pentax fares slightly less well compared to its rivals. The innate noise levels in its raw files appear to be slightly higher, though it still beats the Nikon D5500.

Verdict

There’s a lot to like about the K-S2. Pentax is offering a good range of functions here for the money, and if you’re not in the Nikon or Canon (or maybe even Sony) camp, then this makes a good alternative. It’s especially good if you’re keen on something small and light, particularly when you consider the lenses for the camera are also on the small side too.

The weatherproofing is fantastic to have, while a 100% viewfinder is unusual in a camera at this level.

It’s taken Pentax a while to include a fully articulating screen, and while it’s not particularly novel any more, it remains useful nevertheless for composing shots from awkward angles, or when you’re shooting movies.

Although it may not be something many people give consideration to, the app which accompanies the K-S2 is also genuinely useful and a delight to use. So many of the wireless remote apps which I use offer little to no control, other than to trip the shutter release, so it’s nice to have one here which gives you full exposure control when you’re controlling remotely.

In use the camera also feels natural, and it doesn’t take too long to get to know its idiosyncrasies, with a good range of external dials and buttons to make settings changes quickly and easily.

Obviously the most important aspect of any camera is its picture quality, and the K-S2 also performs very well here too. Images are nice and bright, and there’s good scope for getting shots exactly how you want them with different Custom Image and Digital Filters etc which give you lots of room for creativity. Being able to shoot in the universal DNG format is also useful for post-production too. Detail is also resolved well thanks to the lack of an anti-aliasing filter.

It’s a shame that image quality is brought down a touch by evidence of purple fringing when using the kit lens in some situations, but it’s not something that should plague most everyday shots – it’s just something to keep an eye out for. It’s great that the kit lens itself retracts down to a small size when you’re storing or transporting the camera, but it does mean that the ring for zooming is a little more fiddly – it’s something you get used to with time, though.

We liked

The overall handling of this camera is great, and it feels very natural to hold. The free Image Sync Wi-Fi app has to be one of the best currently on the market as it gives you pretty much free rein over the camera’s settings, making it genuinely useful for enthusiasts who need to be able to shoot remotely for whatever reason, rather than just being a gimmick for group shots and selfies.

We disliked

In fact, there’s not too much to dislike about this camera, but the evidence of purple fringing when using the kit lens is somewhat disappointing.

Verdict

For those who can’t find a Canon or Nikon camera to suit them, or perhaps those who have vintage Pentax lenses, the K-S2 makes for a fantastic first time DSLR.

With a great feature set, good quality images and a natural way of using it, it’s easy to recommend the K-S2 to a wide range of people.