Monday, January 30, 2012

My K-5 Impressions after the First 1,000+ Shots (Somewhat Detailed)

Here is a quick pure textual first review of mine. So, please don't ask me for any picture, sample nor any supporting test data, as there is none! Bear in mind everything could be subjective and not scientific, but then I am trying to be as objective as I could be when writing these! ;->

1. Focus Accuracy and Speed

The AF speed is fast and responsiveness is good when the lighting level is good (and of course the object is at least somehow contrasty). But when lighting level is dropped and especially when there is yellow light, it is noticeable that the camera needs to think for more time before the AF motor starts to move. I am sure that the K-r does not have such a delay and the difference is quite significant. However, the AF focusing accuracy of the K-5 under yellow light is obviously better and it is just more reliable. Nonetheless, if I had a K-r and set a -10 focus adjust, the AF is clearly more snappy than the K-5 and the K-r wins here! :-o

Btw, here are two Youtube videos which show the AF speed and performance of K-5 in good daylight, the first is with the DA18-135 DC and the second demo is with the DA*55 SDM, presented by the same Japanese K-5 user:-

K-5+DA18-135 DC AF Speed Demo:-
http://www.youtube.com/watch?v=XYhjhnM4FRs

K-5+DA*55 SDM AF Speed Demo:-
http://www.youtube.com/watch?v=nWj97A5TdDk

2. Metering and Exposure Accuracy

The 77-segment metering of the K-5 is pure junk, I am afraid, as what I've commented before for times each time I used it (I meant for both the K-7 and K-5). It is as worse as (or even worse than!) the old 16-segment metering system of my 2003 *ist D, which I hated much about its erratic metering. Once again, the K-5 "77"'s behaviour is totally unpredictable and it tends to under or overexpose the picture in large amount with great errors without any good enough reason! And the underexposure tendency is actually higher and the error is even large. Really Damn It! In fact, the 16-segment metering of the K-r is far mature although it still by no means can be called intelligent, when it is compared against other truly intelligent metering systems of the Nikon and Canon.

Now, I've switched back to Centre-weighted Average (CWA) metering with my K-5, which yet to be quite good and reliable and this one is indeed more accurate and consistent than the CWA meter of my K-r. When it is used with the AEL, automatically (I set AE to be locked by default when AF is locked and use the central AF point only for most of the time) or manually (to override the former by first pressing the AEL button), my K-5's utter stupid crappy 77-segment metering problem is completely resolved! :-o But then still the sad thing is that I lose completely a modern metering system and I have come back to the old days decades ago when I first learned to shoot! :-(

3. Image Quality

(i) Colour Response

The K-5's colour is more "pure" than the K-r, which depending on whether one would like it or not, one could call the colours "fake" if liked and it could be more Disney looked, no matter how I fiddled with the Custom Image profiles and settings for my own "preferred" colour response.

(ii) Dynamic Range

DR of the K-5 is actually not really superior as highlights are easily clipped. There is not enough DR tolerance and highlight headroom above the mid-tone, which I believe it is just worse than the K-r which is doing a better job for this aspect. It is therefore it is not a good news for those who don't want much post processing and does not want to shoot RAW nor those who want to "expose it to the right". As I told here from my various researches before, most of the DR of the K-5 is at the shallow side, which means that the K-5 is a camera which is very suitable to be underexposed when taking pictures. And now I finally know that why the 77-segment meter likes to underexpose the pictures for many occasions whenever it likes! ;-p "Yes!" "The pictures can be saved!" :-o

(iii) Noise Performance and Noise Reduction/Processing

The K-5 is the true low-light camera ever for its superb high ISO performance. Set everything at Auto including the high ISO NR. With the default Auto ISO selected up to ISO 3200, the low noise level, colour and details retained are all amazing and it is indeed very impressive. Consider that the sensor has 16MP in just APS-C size (which is only 44% area of the 135 full frame), I must praise Pentax has done a really great job here. The K-5 clearly outperform the K-r from ISO 800 to 3200 in this regard of which is yet better than that of my NEX-3 (16MP Vs 12MP Vs 14MP Sony CMOS sensor with the same gene, I believe).

4. P-TTL Accuracy

With only the built-in flash I have used, the reported P-TTL overexpose issue at higher ISO is found to be real. I programmed the latest firmware 1.12 in my K-5 shortly after I'd purchased it. The strange thing is that this problem is more obvious with older Pentax FA lenses than the DA ones. Up to ISO 1600, I can see at least a +0.5 exposure difference (overexposure) than when it is at ISO 100 with my FA lenses (primes or zooms), such that manual negative (-ve) exposure compensation is a must. (Maybe at ISO 800 a -ve 0.3EV flash exposure compensation is always required.) The problem is made worse here as K-5 is rather weak at the highlight side where it is easy to clip. But the tricky thing is that for and with DA lenses (primes or not), the problem seems to be not as noticeable and severe.

5. Mirror/Shutter Jumping and Disorder (a battery related issue, I bet)

I experience three times of double shutter actuation amongst the first 1k-shot use of my K-5. All these happened when I used a third party replacement-type battery and when the outdoor weather is a bit cold (10 deg. C something) and when the battery voltage is at extreme level (two times for just fully charged and one time when the yellow battery warning indicator was seen). Lucky that I haven't experienced the same problem with my original Pentax battery. So, I think other manufacturers like Sony and Canon have been doing the right thing to prohibit the use of 3rd party batteries with their newer firmwares.

In fact, this problem actually is not an uncommon one with my K-x, when new Li batteries (with higher voltage) or NiMH batteries (with much lower voltage of the type) were used and when it was used in the same colder weather in Winters.

I think my K-r is the most stable Pentax body for escaping from this problem so far. This double shutter actuation issue only happened once for my 8k+ shot use of it, IIRC (or maybe two at most).

Nonetheless, the K-5 mirror disorder is a widely report issue. In the course of watching the AF speed demos by the above user, I so happened to notice that he had his K-5 mirror jumped crazily for what he also uploaded for videos to show what happened, here they are:-

http://www.youtube.com/watch?v=6bOHhtyRzPs

http://www.youtube.com/watch?v=buOrrYsKBfw

Maybe the above user just used his K-5 to do the AF for too many times but without firing the shutter so that the camera finally decided one day that it should fire back all the shutter counts that it should have fired (but had not been fired by the user!)! ;-D =_="

With that infamous problem of the K-5 (which were widely and mostly reported in the last Summer), I actually dared not to buy a grey market K-5 as I really need one-year warranty of it and am required to wait for the next Summer to come, before I could know if my K-5 will go nuts or not in the field, despite that the grey market goods are more than US$100 cheaper! :-(

Okay, I would opt to stop here this time and maybe if I have more to say later, I shall post back and write the next part.

Well, some might be interested on what are my judgement on the build and user friendliness of the K-5, which I think is trivial. I always give almost full marks there. When it comes to all these and customisation of a camera, the Pentax deigns are always well thought and carefully designed, and with the best ergonomics.

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