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12-13-2009, 11:44 AM   #46
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QuoteOriginally posted by WerTicus Quote
K7 performing worse than the k20d is the trade off for 4 channel readout on the sensor.... aka video.

People on this forum were speculating the 4 channel readout might result in this long before the k7 came out and high iso noise performance was confirmed a while ago.

the k7 is a stop gap, fixes a few issues with the k20d (af light, frame rate) and ads video at the price we see here.

we will see a k7x before long.
And 5fps !

Well, if the K7 is a stop gap it is a mighty ******* good stop gap.

12-13-2009, 01:18 PM   #47
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QuoteOriginally posted by Nubi Quote
OK, let's go take some pictures.
Got to agree. We need to stop becoming so much like Canikon all the sudden. Sure the K-7 wasn't what few people wanted but jeeze it's just a bunch of complaining over and over of the same thing. Sure once is enough but this is ridiculous to the point of degradation, we need to start taking more pictures and less complaining.
12-14-2009, 12:22 AM   #48
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Yeah, I'll go take some nice pictures with my K-m. It's the worst in the graphs but it friggin rocks for me.
12-14-2009, 02:00 AM   #49
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QuoteOriginally posted by TLiivo Quote
Yeah, I'll go take some nice pictures with my K-m. It's the worst in the graphs but it friggin rocks for me.
That's the spirit! Anyone who's been paying attention knows it does a lot better than that chart implies anyways.

12-14-2009, 03:11 AM   #50
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QuoteOriginally posted by PentaxPoke Quote
I disagree with some here that say that the scores are BS.
The scores in the comparison graph provided by the OP suggest that the Nikon D90's sensor is practically twice as good as that of the K-7. Makes sense? Not to me...

There seems to be some circumstantial evidence that DxOMark scores aim to keep manufacturers happy. For instance, the Sony A900 score is (a little) better than the A850 despite the fact that the latter seems to be a slight refinement and, thus, features lower noise (according to a German magazine test). Same holds true for the E-510 and E-410 of which er1kksen thinks that they should be the same, yet they are separated by a margin that might be meant to justify a higher price for the E-510.

Falk, if you could pull off an improved "executive summary" of the DxOMark graphs, that'll be great. Could put Lumolabs into the spotlight.

Last edited by Class A; 12-14-2009 at 06:29 AM.
12-14-2009, 05:49 AM   #51
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The DXO Labs stuff is entirely credible. Not perfect but credible.

They are independent. They've tested hundreds of cameras from many many vendors over recent years. They have labs and have worked hard to develop their testing methods - in theory and practice. Let's recognise that.

Their results have not pleased everyone since the day they started testing cameras. That's just inevitable. Don't shoot the messenger...

I don't believe they care much about making camera makers happy. Their work on the whole DXOmark site is really just a by-product of work they do assessing camera sensor RAW performance as part of their continuing development of their software product - the DXO Optics RAW convertor and image editor. Which is an excellent tool, by all accounts, thanks in part no doubt to the detailed examination they do of various camera sensors and quirks.

It would be great if Adobe did the same as DXO and put up a website with information about their sensor evaluations - they must go through the same sort of testing procedures as DXO Labs in order to tune ACR for every new camera and sensor. But they dont, so at the moment DXOMark is the best resource we have for camera sensor evalutions.
12-14-2009, 06:39 AM   #52
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QuoteOriginally posted by rawr Quote
I don't believe they care much about making camera makers happy.
So how do you explain the circumstantial evidence I mentioned? I'm not saying they are wrong and I can prove it but I have not better explanation for the circumstantial evidence.

Your comment was probably addressed at others as well but note that I did not criticise DxOMark for their raw measurements and graphs.

As I see it, the biggest problem is the dumbing down of a number of complex graphs into a single number. To make that meaningful is very hard and even if you partially succeed it will be only useful for those who comply to all the assumptions made about weighting the multitude of criteria. A studio shooter cares about resolution not high-ISO, for some else colour accuracy is of utmost importance, and so on.

In essence, the single number (in particular if it is an aggregate of unstable "quality values") cannot possibly be very meaningful in general which implies that the differences between the cameras should not be large (with little meaning you can only have little discrimination). But they are huge. I see no credible way to justify this.
12-14-2009, 06:54 AM   #53
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Using a single number can be problematic, sure, but is not always useless. Look at how the inflation rate is calculated to produce a single number, or the weather forecast, or the GDP, or the ... etc. You get the point.

If the process that feeds into the number is credible - and DXO are very transparent about all their processes, equations, methods etc - the number is reasonably useful.

12-14-2009, 09:55 AM   #54
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QuoteOriginally posted by rawr Quote
I don't believe they care much about making camera makers happy.
I agree.

QuoteOriginally posted by rawr Quote
Using a single number can be problematic, sure, but is not always useless. Look at how the inflation rate is calculated to produce a single number
Inflation rate is a good example why it IS problematic. And in theory, inflation just measures the amount of liquid money ...

If I think about sensor metrics (w/o AA filter), I see the following six orthogonal properties:
  1. Resolution.
  2. Sensor surface \times Quantum efficiency.
  3. Full well capacity (limiting the max. possible dynamic range).
  4. Read-out noise between sensor and gain amplifier (incl. gain amplifier noise and dark current -- this is the amplified part of the noise).
  5. Read-out noise between gain amplifier and A/D converter (this is where the K-x excels).
  6. Bayer filter spectral sensitivity (3x3 matrix, e.g., how sensitive is a red cell for green etc.)

I'd rather see a score derived from the six figures (which can all be reverse-computed from DxO curve data, and a little brain energy ). As a spreadsheet and with adjustable weights so that one can derive a personal ranking.

One may rank high resolution [1] (now: zero weight in DxOMark), another low iso dynamic range [2, 3, 4+5], a third high iso noise [2, 4], a fourth good color metamerism [6].

But to be fair, this is all hard work and I haven't done it either ...

Last edited by falconeye; 12-14-2009 at 10:06 AM.
12-14-2009, 11:03 AM   #55
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QuoteOriginally posted by falconeye Quote
No.

When comparing sensors with different number of pixels, it is essential to click onto the PRINT button in the upper left corner of the chart. As otherwise, the comparison is meaningless!

When doing right, the K-7 is close enough to the rest of the pack.



No, look at the charts. K-7 and K20D are almost the same. Maybe 1dB advantage for the K-20D in 18% Gray noise and almost same Dynamic Range up to ISO 800. The K20D has an advantage in DR for ISO of 1600 and higher (by ~0.8EV). The DR advantage at ISO 100 is suspicious as it disappears at ISO 200.
Ok, thanks for the info.
I've been very impressed by the sensor in the K20/K7. From what I understand it the K7 handles better in some ways, and not quite the same as K20 in other ways.
From what I've seen, the Iso 1600 is looking good. And clean looking Iso 1600 is really all I need, along with the nice resolution.

I do understand those that had hoped for more, since the K20 was a small revolution when it came to high Iso, compared to K10. But Pentax turned attention on new areas.
Having the K10 now, I want the K20/K7 sensor in my new DSLR. K-x sensor is sweet, but too little resolution jump from what I have now, and I've really liked the output from the Samsung sensor.

Eos 7D has upped the stakes again, but it is just a matter of time before it is caught up once more.

Resolution and high Iso is already good in todays DSLRs. I hope the next area of competition is gonna be Dynamic Range.


QuoteOriginally posted by falconeye Quote
One obstacle is the retrieval of raw curve data from DxO's website. This data is currently fetched by a Flash applet and theoretically, one should be able to download the data by monitoring the TCP/IP connection. Anybody wanting to help?

BTW,
A good read is
Canon 500D/T1i vs. Nikon D5000
where DxO defends why the score can vary a lot when curves do not.

This link highlights the importance of Bayer matrix filter sensitivities as it affects the color sensitivities but NOT gray noise and dynamic range. Pentax is more like Nikon in this respect, leading to a better color sensitivity curve.
Thanks, will have a look at it

Last edited by Jonson PL; 12-14-2009 at 11:19 AM.
12-14-2009, 01:40 PM   #56
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Too bad!
I have the K7 for a couple of weeks now and I must admit that I am extremely happy with it.
Granted, there is somewhat "more" noise at High ISO's but that is easily taken care of using minimal noise reduction with a dedicated NR software, i.e.: NoisewarePro, Helican, Noise Ninja ... and the details STAY!
I rocks at 5.2fps, viewfinder is excellent, AF is faster than with my K20D, ... with my Carl-Zeiss T*Planar 85/1.4, the DA*300 F4 and the DA*16-50 F2.8, I have absolutely no complaint.
I haven't tried it yet on the Tamron Macro 90/2.8 nor with the FA 50 F1.4, but that will come soon enough and I predict good results there too!
JP
P.S.: stay posted for more K7 photos in my newly opened "Gallery" ... tests only in there for now.
12-14-2009, 01:48 PM   #57
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QuoteOriginally posted by JohnBee Quote
lol




RAW, I don't think our units have shot a single JPG frame since we've been shooting Pentax.
So a typical high ISO workflow(depending on the scene) would be, PEF > GBG TINGE REMOVER > ACR(0,0,0) > TIFF > NN(Noise Ninja) or CS4(Define 3) > OUTPUT.
Seems a little extensive but it's actually quite effortless when you get familiar with the types of noise and output objectives.

PS. we've really taken a liking to the latest version of Define's noise removal software. It leaves wavelet(noise ninja, neatimage etc) noise reductions technology in the dust(so to speak). and has put K20D ISO6400 in the map in a very big way.
Hi John,
Nice to see you reporting some noise issue for the K20D here, and how it can be taken care of.
I did ealier on ask you if this was feasible with the K7, since the GBG part was definitely "made" for the K20D?
I get to the last item: CS4 (define 3) ... what exactly is that?
I am not a pro at CS4, although I have it, and this is something I have no idea about.
Cheers.
JP
Forgot to ask: Define Noise removal software ... what you are saying is that it really "rocks", right?

Last edited by jpzk; 12-14-2009 at 01:50 PM. Reason: added a question
12-14-2009, 02:07 PM   #58
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QuoteOriginally posted by Jonson PL Quote

Resolution and high Iso is already good in todays DSLRs. I hope the next area of competition is gonna be Dynamic Range.

If the fantastic usable shadow DR from the K-x sensor is any indication, they're already on it.
12-14-2009, 04:22 PM   #59
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QuoteOriginally posted by kickboxingpenguin Quote
im embarassed... after months of researching the k-7 saying to myself "eh iso isnt that bad, look at all these features to distract you from that"... i might have to return my camera and go to canon =(
word of advice, go out and shoot some real pictures before you complain about DxO numbers. IMO, unless you shoot 80% of your shots at night or extreme low-light and not able to get decent pictures at ISO 3200, then getting a Nikon D700 is the way to go. otherwise, post-process your RAW pictures inorder to enhance your photo and eliminate NOISE or use Noiseware which could clean your image within seconds. also read about the "pull" exposure method. it's not that difficult.
12-14-2009, 05:40 PM   #60
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basing from the APS-C dslr DxO marks, probably we should buy ourselves a $300 dollar Canon 40D.

seriously speaking, even if the 40D is an APS-C dslr, I would choose it any day over the higher scoring full-frame Sonys'. the Sonys' are crap at HIGH ISOs. or if I were to get a cheapest full-frame, I'd rather get the 5D MKI, thereby opposing the Sonys' higher DxO marks. if I were to consider the DxO marks and consider the small price differences (somewhere close to each other and some are cheaper over the other) between full frame cameras Sony A850, A900, Canon 5D MK II, and Nikon D700, it is very obvious that the Canon and the Nikon are worth the value and DxO scores as seen in their real-world ISO performances. I don't know why those 2 Sonys are even up there in the first place. by that, the DxO tests are not entirely reliable or should automatically justify real-world use.

the fact that dslrs of the same sensor have varying DxO marks, shows inconsistency in the tests. this should be taken into consideration and should never be overlooked.

true, the DxO can be a useful reference, but it doesn't tell the whole tale of the tape. it is still susceptible to flaws.

Last edited by Pentaxor; 12-14-2009 at 08:06 PM.
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