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02-07-2012, 08:09 AM   #76
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The K-5 and 645 D have the same over all sensor rating on DxO. The 645D has the higher low light and colour depth rating.. the K-5 has higher dynamic range.. you aren't getting your data from the same DxO I am.

QuoteQuote:
From what we know at this time, we cannot rule out that the sensor encased in the D800 is exactly that.
From what we know every camera manufacturer upgrades their sensors form time to time. I't ridiculous you would focus on the D800 as some kind of champion of this. There's some kind of Nikon love going on there. But more to the point, the 645D will at some time get it's sensor upgraded. Hopefully when the new Sony double layer sensors come out... which the D800 obviously will not have, since they aren't being released to the manufacturers for development until March. You can play this game endlessly. In one of the many other threads we have gone through the relationship of pixel density to image quality... and to date there is an edge to lower density FF cameras...until someone produces some test images that demonstrate that high density pixel counts can compete with low density pixel counts in image clarity... this is just theory. The simple fact is to date, larger size produces clearer, more accurate images. If sensor sensitivity can be increased then this could change and I'd be the first to argue this could happen. What I'm lacking is images that show it has happened.. whereas I can find image comparisons that show it hasn't. Just look through the 645 thread, the clarity of some of those images are pretty much mind boggling. That's not a valid test of anything, there are no comparable small sensor images to compare. But, all evidence suggests things haven't changed.

The way things currently stand, I hope they keep selling 645Ds until I've saved up my pennies to get one.


Last edited by normhead; 02-07-2012 at 08:14 AM.
02-07-2012, 09:21 AM   #77
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QuoteOriginally posted by normhead Quote
you aren't getting your data from the same DxO I am.

Yes I do. The problem with your interpretation is that the 645D's seemingly superior results are based on downsampled data, to wit: print performance measurement values ... derived from a RAW image after a normalization step that transforms all images, regardless of original resolution, to an 8Mpix image.

(Emphasis is mine.) That's why I wrote "color sensitivity per pixel." The per-pixel measurements are what we need to look at, if we want to find out how a K-5 sensor in Full Format (and hence, 36 megapixel resolution) would perform. To do this, you need to

(1) look at the individual measurement graphs, rather than merely skim the (misleading) overall scores, and

(2) be sure to check the "screen" tab rather than the "print" tab.

The "print" tab shows evaluations from downsampled data as explained above, while the "screen" tab shows the measurement values and graph derived directly from a RAW image when displayed on a computer screen at 100% magnification (i.e., one image pixel corresponding to one screen pixel).

And here we find out that on the pixel level, the K-5 bests the 645D in every single dimension:

38.7 dB vs 36.7 dB SNR
13.61 EV vs 11.37 EV dynamic range
8.62 bits vs 8.15 bits tonal range
22.2 bits vs 21.1 bits color sensitivity.

Therefore, my assertion still stands: If the D800 sensor performs, on a pixel level, as good as the K-5 sensor, then it will perform better than that of the 645D.

QuoteOriginally posted by normhead Quote
There's some kind of Nikon love going on there.

As far as I'm concerned, absolutely not. I'm totally promiscuous, so I couldn't care less whose label my camera bears.

Which of course means that I am totally lacking any brand loyalty. If that is a crime around here, so be it.

Last edited by Rainer Dynszis; 02-07-2012 at 09:37 AM. Reason: typo
02-07-2012, 09:45 AM   #78
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QuoteOriginally posted by Rainer Dynszis Quote
Of course Nikon's D800 has a much higher pixel density (i.e. pixel per square inch) than Pentax' 645D.

On the other hand, Pentax's own K-5 has also a much higher pixel density than the 645D. Does that affect the K-5's picture quality on a per-pixel basis? No, the 645D has only more megapixels, its pixel quality is, if anything, worse:

If you look at DXOmark.com, you will find that the K-5 produces actually less noise than the 645D at its lowest ISO setting, but more dynamic range, more tonal range, more color sensitivity per pixel.

Ergo, if one could retain the per-pixel quality of the K-5 and increase the sensor's pixel count by simply putting the same pixels on a full format area, then the resulting sensor would be better than that of the 645D.

From what we know at this time, we cannot rule out that the sensor encased in the D800 is exactly that.
And nice hypothosis, if all is equal, which it is not. Putting Tech Pan in a 35mm camera, does not make it a medium-format one. Sensor size matters. The Sony 24MP APS-C sensor in the Nex 7 gets slightly better marks than the Sony 24MP 35mm sensor in the A900. But then go to DPreview and compare the images. The Nex 7 is nice, but it is not a 35mm sensor. While numbers have meaning, they also need context. (And the 35mm Sony senor while having better numbers does not "beat" my Phase One P25+ back as far as the quality of the image.)

Here are other things to think about. While at a particular f-stop, the image plane will have a the same diffraction, the diffraction is minimized in the 645D because it is also a larger chip. And with lenses having the same angle of view, the 645D will have the larger entrance pupil at that given f-stop which will result in greater resolution of the object space (it will also have less DoF). I am also using the center of the image circle with the 645D, rather than the entire image circle with the Nikon lenses--which do you think will have sharper corners?

While we like to throw around numbers like they in-and-of-themselves mean something and somehow define the problem, cameras are complex systems where many factors influence the final result. Basically it is impossible to chose winners among different systems because we cannot make direct comparisons. Chose a system that gives you the qualities you want. This is an aesthetic choice and therefore subjective, numbers have nothing to do with it.
02-07-2012, 09:55 AM   #79
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Agree 100%.

02-07-2012, 10:27 AM   #80
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I am a photographer. From the bottom of my heart. I could not care less about these numbers. We are talking about nuances only tech nerds care about, nuances you don't even see in the final result but at 100% Photoshop view or on a wallpaper at the size of a football field. All I want to do is to take great photos and sell them, whether it is to publishers or married people, on stock sites or as prints. As long as it is a good picture, the last thing end-consumers are interested in is the camera the image was taken with and what dynamic range it has. They are not even interested in the damn pixels.

Last edited by phonoline; 02-07-2012 at 10:34 AM.
02-07-2012, 10:47 AM   #81
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QuoteOriginally posted by Yamanobori Quote
And nice hypothosis, if all is equal, which it is not. Putting Tech Pan in a 35mm camera, does not make it a medium-format one. Sensor size matters. The Sony 24MP APS-C sensor in the Nex 7 gets slightly better marks than the Sony 24MP 35mm sensor in the A900. But then go to DPreview and compare the images. The Nex 7 is nice, but it is not a 35mm sensor. While numbers have meaning, they also need context. (And the 35mm Sony senor while having better numbers does not "beat" my Phase One P25+ back as far as the quality of the image.)

Here are other things to think about. While at a particular f-stop, the image plane will have a the same diffraction, the diffraction is minimized in the 645D because it is also a larger chip. And with lenses having the same angle of view, the 645D will have the larger entrance pupil at that given f-stop which will result in greater resolution of the object space (it will also have less DoF). I am also using the center of the image circle with the 645D, rather than the entire image circle with the Nikon lenses--which do you think will have sharper corners?

While we like to throw around numbers like they in-and-of-themselves mean something and somehow define the problem, cameras are complex systems where many factors influence the final result. Basically it is impossible to chose winners among different systems because we cannot make direct comparisons. Chose a system that gives you the qualities you want. This is an aesthetic choice and therefore subjective, numbers have nothing to do with it.
agree

QuoteOriginally posted by phonoline Quote
I am a photographer. From the bottom of my heart. I could not care less about these numbers. We are talking about nuances only tech nerds care about, nuances you don't even see in the final result but at 100% Photoshop view or on a wallpaper at the size of a football field. All I want to do is to take great photos and sell them, whether it is to publishers or married people, on stock sites or as prints. As long as it is a good picture, the last thing end-consumers are interested in is the camera the image was taken with and what dynamic range it has. They are not even interested in the damn pixels.
Amen
02-07-2012, 10:53 AM   #82
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QuoteOriginally posted by phonoline Quote
...
As long as it is a good picture, the last thing end-consumers are interested in is the camera the image was taken with and what dynamic range it has. They are not even interested in the damn pixels.
+1

Nor are the customers interested in, and it does not show in the photograph, how easy, convenient or comfortable the camera is or even what the camera looks like which seems to make or break a camera around here.
02-07-2012, 10:58 AM   #83
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QuoteQuote:
And here we find out that on the pixel level, the K-5 bests the 645D in every single dimension:

38.7 dB vs 36.7 dB SNR
13.61 EV vs 11.37 EV dynamic range
8.62 bits vs 8.15 bits tonal range
22.2 bits vs 21.1 bits color sensitivity.
OK now that's just bizarre, you do know that from one stop to another you have an increase of 100% or a decrease of 50%. IN some of these cases you are talking a difference of less than 3%, in every case less than 10%. We're talking trivia and minutae here. They are both top 10 sensors. The 645 will give you a bigger image, and if you are printing big images will give you a sharper, cleaner looking image. If you printed at 40 inches by 60 inches your assertion that the K-5 is a superior image would make you the laughing stock of everyone present, except me, I'd just smirk, cause I'm polite.

02-07-2012, 11:46 AM   #84
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There's a phrase in British current affairs (been existence for years):

There's lies, damned lies and statistics. This thread is a very good example of that.
02-07-2012, 06:12 PM   #85
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Interesting guys, i can see all sides to these arguments, technical and end result (IQ) and for me its the print quality at large size and to that without getting technical, i have to agree that MF cameras , the ones i have seen prints from, out perform FF and of course APS-C by a country mile... At large size ie 30 x 30 Inch and up. If no need to do that then im sure it might not matter to the populace at large other than bragging rights, but it will cause some interesting debate and i guess like most, i will watch and wait with interest to see some images from this new Nikon and of course what will Canon do now.. edit ...of course can take 4-8 shots and stitch, but not always possible, but this would give the ability to also print large..
02-08-2012, 03:52 AM   #86
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QuoteOriginally posted by normhead Quote
you do know that from one stop to another you have an increase of 100% or a decrease of 50%.

Yes, I do know.

And I also know that EV, as in "13.61 EV vs 11.37 EV dynamic range," means Exposure Value, commonly referred to as a stop.

What exactly is your point?

QuoteOriginally posted by normhead Quote
IN some of these cases you are talking a difference of less than 3%, in every case less than 10%.

No, I'm not.

38.7 dB vs 36.7 dB SNR means a difference of 26%.
13.61 EV vs 11.37 EV dynamic range means a difference of 373%.
8.62 bits vs 8.15 bits tonal range means a difference of 38%.
22.2 bits vs 21.1 bits color sensitivity means a difference of 114%.

None of these differences, obviously, is less than 10%. You really need to familiarize yourself with the concept of logarithmic scales.

QuoteOriginally posted by normhead Quote
your assertion that the K-5 is a superior image

I have not made any such assertion. Please do try to engage in a discussion without resorting to dishonesty.

QuoteOriginally posted by normhead Quote
I'd just smirk, cause I'm polite.

I think you know perfectly well that you are anything but polite here.

Free advice: Arrogance and derision do not make you look superior.
02-08-2012, 04:49 AM   #87
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let it got, guys. And cool down with this:

02-08-2012, 05:58 AM   #88
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QuoteOriginally posted by phonoline Quote
I use Nikon, too, (D700) and will have a look at the D800E today. I highly doubt it can beat the image quality of the 645D but it could be a nice addition to my equipment, esp. for wedding photography (a field I don't use the 645D for). 4 pics/s is pretty grand at 36MP. And even if it'd just be 24MP
I gotta agree with itshimitis, though. It's not all about pixels. Heck, I just bought a Fuji GX680III.
Now there is a nice pocket able camera. My wife made some very nice 50 by 80 inch prints from a GX680 version 1.
02-08-2012, 06:32 AM   #89
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I am sooo looking forward to receiving the Fuji and starting shooting with it. I wonder if it can outdo the image quality of the 645D - but even if it can't, I am sure I will have lots of fun with the tilt & shift of this grand camera.
02-08-2012, 02:47 PM   #90
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I don't understand the "no support for a second body" part in the OP. You can always buy 2 bodies and switch lenses. The Pentax 645 offers the option to have one body be digital and the second be film. Film bodies are still dirt cheap and will be wider with shallower depth of field due to the lack of a crop sensor. No, it's not digital, and you wouldn't want to shoot a wedding on it if you could avoid it, but it's a backup, not a complete second camera system.

The 645D is hands-down the cheapest and most flexible option for a medium format digital system. To get anything equivalent would probably cost you double the 645D, and the 645D much more like a 35mm DSLR. I'd also imagine the 645D would be considerably more durable than a MFD back. That's the market Pentax is trying for, the same as the 645 and 67 series were targeted at. Will it work? Who knows, but just as a single datum I remember seeing a commercial for some "extreme photography" show on the Weather Channel a while back; the photog was using what looked like a 645D.

Last edited by Paul MaudDib; 02-08-2012 at 03:00 PM.
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