Pentax K-5 Hands-on preview

Pentax K-5 with vertical grip D-BG4 and lens DA* 55/1.4

Photokina 2010, the world's largest and most influencial photographic fair, has just closed its doors last Sunday. Monday, the day before Photokina officilally opened its doors in Cologne, members of the international press had a chance for a sneak preview and Pentax managed to show prototypes with firmware 0.30 of their new Pentax K-5 camera in the afternoon. I later consolidated my impressions at a further visit. However, any sample shots shown here are from Monday where all over Photokina, journalists were happily forcing their SD cards into whatever camera which appeared to be new. Pentax then better controlled it during the official show but, e.g., Nikon simply did not have enough staff to prevent people from putting their SD card into the new D7000. Me being no exception :)

So, I put the following disclaimer upfront: Any sample shot from the K-5 found on the internet today is not endorsed by Pentax and no conclusions must be drawn from it. It is from a prototype camera with preliminary firmware flewn into Cologne by Hoya the day of the announcement (2010 September, 20).

These are my preliminary impressions from my short test drive:

Pentax Germany presenting K-5 to international press  Falk Lumo 2010--1. The announcement

The Pentax announcement was a bit unlucky. Corporate Pentax was late for the event and announcements have been full of little mistakes, contradictions and appeared to be rushed out. This did not exactly help in creating any enthusiasm for the K-5 among the press. Pentax missed the opportunity to hold a press conference on Monday or Tuesday too. Maybe with an invited speaker from Tokyo and showing some pride in the product. What a pitty. So, the general reception of the K-5 is that of a K-7Super or a K-7mkII.

So, now it is important to have a closer look at the new Pentax flagship model which is going to hit the market soon. Maybe, the camera is able to create the excitement all by itself which is what happened with the popular K-x camera.

2. Market positioning

The Pentax K-5 is a semi-professional or enthusiast-level SLR camera and competes with its peers from Nikon and Canon, like the Nikon D7000, Nikon D300s and Canon 7D. Esp. the D7000 looks like an identical copy of the K-5, and if the K-5 is just a refreshed K-7, then it would be clear who copied who ;)

It is exciting that the K-5 is defending Pentax' market position in the market spot pretty much created by the K-7 (robust and compact and suitable for professional use). A spot which obviously attracted Canon and Nikon and now appears to be the most interesting market spot above $1000. According to a recent DPReview poll, D7000, Fuji X100 and K-5 are the most exciting Photokina news and then K-5 may be just a refreshed K-7.

3. Availability and price

The MSRP of the K-5 body is $1,399.- USD. Pentax is confused enough to not acknowledge this fact with their international corporation and to publish list prices as high as $1,599.- USD. I understand that Pentax was caught with their pants down when Nikon launched their D7000 body at $1,199.- USD just days before Pentax was going to announce their K-5 at a price, I am pretty sure about, closer to that of the D300s or 7D. But hey, if Pentax Germany can respond in a timely fashion, why not the corporation?

The German MSRP as announced at Photokina is 1,449.- € incl. 19% VAT and e.g., French online store digit-photo.fr already lists the K-5 body at 1,249.- € TTC and the D7000 body at 1,169.- € TTC, only 80 € less.

Both, K-5 and D7000 are announced to ship in October 2010 and you read it here first: when they hit the market, they will sell at equal price. And both cameras should sell very well, according from the first feed back I see.

4. Specs and first touch

That's easy: it looks and feels like a K-7. For many, this means they fall in love with the camera immediately. For some, it means the body is a bit small and the grip then may help or not. I tried the D7000. I am partial, I admit (for a subjective question like this). But the D7000 could not create the same kind of emotion when I tried it. At high ISO, one sees the lower noise floor in zoomed view, with the 18-55 kt lens, one feels the more aggressive AF, but other than that, it feels "K-7". With one notable exception: contrast AF. It almost feels like Pentax leapfrogged Canon and Nikon.

I hate redundancy on the web. So, rather than repeating what is easily found elsewhere, I refer to the sources for the specs and walk-thru:

Therefore, here I will focus on exclusive content maybe not found elsewhere. If you aren't familiar yet with the K-7 or Pentax cameras, you may want to start reading with any of the links above.

5. Image quality

Currently, everything I've seen let me hope that the image quality turns out to be impressive when studied in more detail. As far as I know, Pentax uses the Sony Exmor HD 16.2 MP APSC CMOS sensor with integrated column-parallel A/D-converters. Which may be the same as in the Nikon D7000. Pentax confirms using a sensor with embedded A/D-converter and that's all it needs ;)

5.1 High ISO noise

K-5 ISO 6400 noise chart  Falk Lumo 2010--Test chart at ISO 6400, Pentax K-5 prototype firmware 0.30. RAW developped in LR2 with all settings default (NOT flat!). 2900K white balance.

Pentax K-5 firmware 0.30 ISO 6400 raw image (Lightroom 2 default development)

[Download link to the -> 30MB DNG raw file]

 

Because the interest is huge and because high ISO JPEG samples are already floating the web, I decided to publish one ISO 6400 RAW sample. I took it Monday when all journalists played their card party but I respect Pentax interest to keep image files under closure. The RAW sample is less affected by changes to the firmware which is why it may be in the interest of Pentax to have at least one RAW if JPEGs are already in the wild. The high ISO JPG samples benchmark the in-camera v0.30 JPG engine first of all and should not be compared to D7000 JPGs. My RAW may provide an alternative.

The RAW published here has been already developed using various raw converters and NR settings, esp. in a very vivid thread at pentaxforums.com and by Gordon Goodman at dpreview.com. The general conclusion I draw from the discussion is:

  1. K-5 allows it to use AUTO-ISO ranges of up to ISO 6400 without hesitation (if it used to be 1600 like on my K-7). Some noise is visible, but is well treated by NR.
  2. At ISO 6400, the advantage wrt K-7 may be about 2 stops (almost). As I refuse to run quantitative lab tests yet, this is impossible to say exactly. This has to await until Pentax thinks it makes sense to run a lab test.
  3. Looking at Pentax K-x and Nikon D7000 and D5000, the performance looks similiar. The K-x has less pixels to be taken into account too. For me, it is currently difficult and too early to rank the three cameras.
  4. At lower ISO settings like ISO 1600, the advantage wrt K-7 is less. As to be expected if the progress comes from lower read-out noise rather than a higher quantum efficiency. ISO 400 shooters may be able to increase to ISO 800 only. Physics can't be beaten.

So, a first assessment is possible: The high ISO noise of the K-5 is within the best of its class.

Gordon B. Good went a step further and analyzed the raw histogram in the DNG (cf. link above). His conclusion (which can only be preliminary) is that pixel read-out noise (dark noise) is even less than with the Pentax K-x which excels in this regard. He found too that ISO 6400 is created from an ISO 1600 capture then boosting EV by +2 in camera.

Pentax K-5 ISO 100 photo  Falk Lumo 2010--out of camera5.2 Dynamic range, colors, pattern noise, AA filter, resolution

To the right is an unprocessed image out of the Pentax K-5 camera at ISO 100. So yes, the camera works at ISO 100 :)

If Gordon's preliminary analysis holds true (he looked at an ISO 1600 PEF too), then a pixel's full well capacity is on par with a K-x and the minimum recordable luminosity of a K-5 pixel should beat the value of 0.021% for the K-x (dynamic range as defined by an SNR of 0dB). E.g., a value of 0.017% (corresponding to Gordon's 2/3 black noise remark) at K-5's resolution would correspond to a dynamic range of 13.0 EV in DxO's terms. That would be a stunning value for an APS-C camera. 0.017% would use 12.5 bits (out of 14) too which makes the 14 bit format not a complete loss, compared to 12 bits which is an industry's first. If this analysis can be verified to hold true after production cameras ship.

Update: more recent remarks (made after analyzing the ISO 80 RAW black noise) claim dynamic range to be even better than 13EV. I'll soon edit this sentence to reflect a common preliminary assessment by Gordon and myself.

I did not evaluate color rendition, pattern noise, AA filter, and resolution.

5.3 Shutter blur

I'll take a detailed look at that as soon as I can. So, while I refuse to comment on the issue for the time being, I can still quote others who tried to find out, can't I? Ok, several other tried to see the shutter blur on the K-5 (in magnified playback) and told me to have a good feeling because they couldn't find it. Would they have seen it with a K-7? I don't know. But it is a positive sign and therefore, let's take it as such.

6. Autofocus performance

6.1 Phase AF

Pentax K-5 autofocus box  Falk Lumo 2010--New autofocus box at the bottom of the K-5 mirror box. It looks different from a K-7 AF box. You can see the large lens in the front of the box. Pentax K-5 cut model  Falk Lumo 2010--A cut model of the Pentax K-5 auto focus module as shown at Photokina 2010.

The K-5 uses a similiar AF module (SAFOX IX+) to the K-7 (SAFOX VIII+), but with larger AF lenses and/or more sensitive AF sensors. It has 11 AF sensors, 9 which of are cross type. All sensors are f/5.6, so it has no f/2.8 dual type center sensor (as far as Pentax Germany knows).

The AF performance in good office space lighting with the 18-55 mm screw drive kit lens is outstanding: It makes a noise which is so short that it sounds a bit like the AF hit the limiter. The algorithm has the SAFOX gene: if the focus has to travel (isn't close already), then the lens may be refocussed a second (or in rare cases) even a third time. But it is so fast one is not necessarily aware of it. I think it is a good thing that the Pentax AF still verifies focus "on arrival" and doesn't trust it blindly which may not be as accurate. But it can increase shutter delay. I didn't check if the new shutter priority modes in the K-5 AF settings bring a change in this respect.

I heard reports (caution: hearsay!) that the new DA 35/2.4 lens has a very remarkable high focus speed as well.

Wieland (aka blende8 from pentaxforums.com) and myself brought two DA* 16-50/2.8 SDM lenses and compared head to head, K-5 vs. K-7. It was difficult to tell if the K-5 was faster. The SDM speed is the same as for the K-7, limited by the lens motor. Wieland (who has it on video) and myself verified this. Lens travel was the dominating part in focus time. But for short lens travel (prefocus) I got the impression that the remaining focus time for the K-5 is significantly smaller. This must be benchmarked really. Moreover, Pentax Japan specifies autofocus operation to be possible at -1 EV. That may be false information, requiring the AF assist beam or be an impressive figure.

I didn't test continous autofocus. According to pentaxeros.com, the throughput in usable photos in AF.C may have doubled, relative to a K-7. Overall, my preliminary impression is that the progress made in autofocus performance from the K20D to the K-7, and from the K-7 to the K-5, may be comparable. This may or may not suffice to compete with a D7000 or 7D in this department.

I made a short test if the K-5 tries to track AF points, i.e., if the K-5 tries to predict the hop of a subject from its active AF point to the next. My preliminary impression is that the K-5 doesn't do that and it would be difficult with 11 AF points anyway.

Half pipe biker  Falk Lumo 2010--Half pipe biker at the Photokina 2010 Sony booth, captured by a Pentax K-7 in AF.C mode, DA*16-50/2.8 SDM lens at 50mm.

I tried the AF in the new Nikon D7000 and the new Sony SLT55 as well. I wasn't overwhelmed by the D7000 (the lens didn't have a fast focus though) and the SLT55 was cool. Sony had a half pipe with skate boarders and bikers and plenty of action. The SLT55 AF.C performed considerably faster than my K-7 (I loved to have a K-5 there but Pentax staff would have tortured me afterwards ;) ). But the K-7 didn't fail entirely and the SLT55 didn't perform flawlessly. In the end, the number of usable photos per half pipe turn may have been twice in Sony's advantage. Twice "only", maybe not out of reach for a K-5.

6.2 Contrast AF

A small video of the Pentax K-5 contrast AF at work
© 2010 by YouTube user SmalltimR

 

The contrast AF seems to be a complete rewrite. When you half press the shutter (or whatever activates AF) the live view image zooms into the appropriate focus rectangle and confirms with green border and beep, then zooms out. The entire process takes about 1 s. Compare that to phase detect AF which typically took about 0.4 s and then contrast AF is only slower by a factor 2-3.

It's even possible to switch contrast AF into AF.C. But the performance is poor: it only refocusses every 4 seconds or so when the change in contrast is obvious. But this is for a prototype firmware. Pentax may still work on this.

Another positive surprise is that contrast AF doesn't pump a lot (anymore).

Overall, my preliminary impression is that the K-5 (and K-r too) are the first Pentax SLR cameras where contrast AF is really usable. At least for subjects which don't move fast.

The new contrast AF should now be fast enough to allow AF during movie recording. But firmware 0.3 shows no signs of such a feature: pressing AF in video has no effect and there is no menu option for it. Pentax Germany says that they received no information regarding AF during video and it's not on the Japanese spec sheet either.

7. Live view

Except AF operation, LV looks the same as with the K-7. In manual focus mode, there still are additional 8x and 10x magnification steps. However, unlike with the K-7, the image quality doesn't seem to increase in the additional magnification steps: diagonal edges had a very visible staircase effect which was symmetric. The K-7 reduced the effect in one direction with the additional magnification steps at the expense of a slower frame rate. Overall, it's probably about the same to manual focus in live view. The resolution still seems to be limited to that of HD video. There is no auto-zoom in manual focus, e.g. by half pressing the shutter.

8. Video

One frame from a K-5 720p HD video (click for 100% size)

 

The K-5 sports 1080p HD video at 25fps (up to 25 min or 4GB). And smaller sizes at 25fps and 30fps. So, the sensor's read-out rate or processor performance are not sufficient for 1080p at 30fps and only Pentax knows why then they didn't incorporate a 24fps mode.

Video quality looks good but that's only a preliminary statement. I can see traces of pixel artefacts in the frame as are typical for all current video SLR cameras because the sensors must be subsampled. Note that the quality in production cameras can even be substantially better.

There are no manual controls (for shutter and ISO, that is) in movie recording, just manual aperture, exposure compensation and lock. The audio recording in the K-7 was fixed gain (manual only so to speak) and it may be the same for the K-5. I did not check it.

Pentax Germany had requested manual video controls in Japan. Obviously, it did not help much.

The K-5 has a programmable RAW button (Fx). The press material mentions that the video mode can be activated this way. Which is a great thing because turning the mode dial every time is awkward. Moreover, one could theoretically switch the mode dial to "M"and activate video, hoping that ISO and shutter controls are enabled (hope dies last). But I couldn't test because the video function for the Fx button was still missing in the firmware. I hope the press material is right about the possibility to map Fx to video. Because turning the locked mode dial every time is awkward.

9. HDR

In-camera HDR (high dynamic range) photography was pioneered by Pentax with the K-7. But they ommitted the feature to align images in-camera too which made the feature obsolete without a tripod. I demonstrated in a LumoLabs article right here that the K-7 hardware should be capable enough to do the alignment in-body as well. Pentax ignored me but they did not ignore Sony who then implemented the full feature in their NEX mirrorless cameras. So, the K-5 does now support in-camera image alignment too and additionally provides additional rendering parameters. Below is my free-hand HDR example using the various settings:

(click on the thumbnails for full size samples, appropriate to inspect alignment quality -- hover over a thumbnail to see the HDR setting)

Most of the time, the alignment works well and the HDR feature is a powerful extension of a photographers arsenal. The processing time is acceptable. However, the alignment isn't flawless (e.g., look at the "strong 2" sample in full size). Maybe, Pentax wants to license the LumoLabs algorithm? ;) Another disappointment is that the processor still doesn't write a linear DNG raw file without any tone mapping applied. And eventually, the alignment could have been available in multiexposure mode too but isn't. Sony calls the latter feature "steady night shot".

Nevertheless, Pentax and Sony are pioneering new creative possiblities with their cameras and this gives them an innovative edge wrt Nikon and Canon.

10. Many more things ...

The sections below are answers to questions I received via comments to my blog or forum posts.

10.1 RAW file bit depth and buffer size

The K-5 has an increased bit depth (from its A/D converter to RAW storage/processing) and increased number of pixels. An uncompressed RAW frame is 28.3 MB or 1.31x as much data as it was on a K-7. Which would reduce the buffer capacity to 10 raw frames (down from 14-15 on the K-7) somewhat in line with the Pentax specification of 8 raw frames. At 7 fps, this means that the buffer fills in 1.1 s (down from 2.7 s on the K-7). I confirmed by trying it out that the hi speed burst lasts for 8 raw frames. This means that the overall buffer size and write speed to SD card have remained the same.

The fps or bit depth cannot be configured and Pentax has no plans to release a mid speed burst mode where the buffer fills more slowly. Pentax thinks that action shot bursts are done in JPG and RAW bursts are mainly for bracketing and similiar applications.

It wasn't specified but the K-7 had an easter egg: With a high speed SD card, low quality JPG setting and all settings manual, the K-7 could burst at 5.2 fps until card full! The K-5 cannot do it anymore. Even at lowest quality settings and with a Sandisk Extreme III card, the burst breaks slow after about 29 JPGs or 4 seconds.

10.2 Prime II processor

The press material creates the impression that the Prime II image processor is changed. This isn't true. The DRAM memory (2GB AFAIK), the clock speed and processor itself (Prime II) are the same as with the K-7. Maybe, some of the algorithms are different (more pixels, 14 rather than 12 Bits) but that does not qualify the image processor to be considered "upgraded".

I compared the processing speed for lens corrections (CA+distortion). The image on the display of the K-7 appears just a second or so before that on the K-5. Which is exactly the expected difference with an extra of 11% more pixels to process on the K-5. For an image processor of equal speed that is.

10.3 Shake reduction

I could find no differences in the shake reduction feature. The specification didn't change either. However, there is a small change I noticed nevertheless: When you half press the shutter, the SR needs about a second to get ready. About the same for K-7 and K-5. But if you unpress the shutter, the SR stays ready until the VF INFO row is switched off a couple of seconds later. With the K-7, it didn't and another half press always had the delay for SR to get ready again. This may be a huge difference in certain situations. If it wasn't simply a display bug, then or now.

10.4 Top LCD light

The top LCD illumination is either on or off (depending on a menu setting) which is like the K-7 and unlike K20D. Most people like the K20D method better.

10.5 Bulb mode and DFS

DFS (Dark frame subtraction aka Long exposure noise reduction) can now be switched off even for bulb mode (exposures longer than 30s). I made a test with a 66s exposure at ISO 1600 and the image displayed immediately and the camera was ready again -- without a delay (firmware 0.30). ISO 1600 is the highest ISO setting for bulb mode. This is no limitation for raw shooting though because higher ISO are made in camera from ISO 1600 by exposure boost post processing; something easily done in the raw converter as well.

10.6 Tethering

The K-5 ships without a true tethering solution. An EyiFi card, remote trigger and HDMI connection are the only means available now. Pentax Japan confirmed to Pentax Germany that their request for a tethering solution has been acknowledged without saying if Pentax is going to release a tethering solution or not.

10.7 Flash sync time

The K-5 has a flash sync time of 1/180s. The rumor about a sync time of 1/250s, maybe in conjunction with faster Pentax flashes to be released soon, has been disclaimed by Pentax Germany.

10.8 SXHC support

The K-5 will receive SXHC support via a firmware update. This has been made public by the Pentax Imaging USA web site.

10.9 Intervall shooting

The K-5 allows to select the number of intervall shots to be between 1 and 999 (up from 99 on the K-7). The selection is by digit.

10.10 User modes

The K-5 now has 5 user modes. However, there is only one user mode position on the mode dial and you'll have to select which one of five modes to use.

10.11 Level meter

The K-5 has a level meter for two axes (roll and pitch). The K-7 has roll only. However, the K-5 only shows the roll level in the viewfinder and the top LCD. The rear LCD shows both.

10.12 Exposure bracketing with MLU

The K-5's Fx button can be configured to enable exposure bracketing to later produce HDR images -- with a single button press. However, on the K-5 and K-7, mirror lock-up (MLU) and exposure bracketing are mutually exclusive drive modes. Theoretically, the Fx button solution could solve this. However, an Fx button press selects the exposure bracketing drive mode and thereby deselects the MLU drive mode if it was selected before. No luck.

Nevertheless, exposure bracketing with mirror lockup is available on both the K-5 and K-7: use exposure bracketing from within live view (LV). Because of the improved LV focus performance this is a serious option with the K-5 actually. The Nikon D7000 calls it "quiet mode" and has it as a new feature.

10.13 Shutter noise

I compared a K-5 and K-7 side by side. They have identical shutter noise (at least without MLU and with no burst -- as I didn't check for those). Which means that K-5 continues to be state-of-the-art in this field.

Conclusion

Pentax K-5 cut model  Falk Lumo 2010--A cut model of the Pentax K-5 as shown at Photokina 2010.

Pentax K-5, the engineering masterpiece (photo © 2010 Falk Lumo)
Photokina 2010 exhibit, went back to Japan well before the show ended.

 

This concludes my hands-on preview report of the Pentax K-5 semi-professional APS-C SLR camera. It combines what may currently be the best APS-C sensor with a camera which has almost professional grade attributes but in a package which pleases the outdoor and street as well as the enthusiast photographer. It shares the genes of the applauded K-7 and improves on the three points which could have been considered its only weakness: ISO performance, autofocus speed, uncommon sources for blur (maybe).

The K-5 has only two rivals which however, can't beat it (except maybe for very fast action and long lenses): the very similiar Nikon D7000 and the bulkier and more expensive Canon 7D. If you now consider that only Pentax managed to pack a good sensor-shift stabilizer into the body which is the most elegant, sturdy, lightest and smallest of the three and is done by the smallest company of the three, then the K-5 is an engineering gem and a photographer's pleasure. No wonder it is the only SLR to receive this year's Photokina Star 2010.

Pictureword Girl  Falk Lumo 2010--A Photokina 2010 press tour model holding the globe with one hand.


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