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Author Topic: 645D vs D3x  (Read 76124 times)
ErikKaffehr
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« Reply #40 on: February 08, 2011, 10:28:11 PM »
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Ray,

Thanks for your careful analysis.

I was much astonished by the color difference. I'm not that sure that calibrating color in ACR would help. Miles says that ACR/LR is said to handle Nikon colors badly. But the Nikon has been around a long time, so I'm pretty sure that Adobe has good data on it. The Pentax may be a different thing.

The sensivity curves of the human eye overlap very much for green and red, so I guess that much of the colors in the green/yellow range are reconstructed in the brain. Differences in spectral sensivity may explain some of the differences. I'll probably recheck the raws with a few special raw converters.

http://en.wikipedia.org/wiki/File:CIE_1931_XYZ_Color_Matching_Functions.svg


Best regards
Erik



What is most puzzling is the significant differences in color hue and saturation between these two images at the same Daylight WB setting in ACR.

One or both of these cameras need calibrating in ACR. I tend to get the impression the most natural result would be about half way betwee the two renditions.


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Ray
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« Reply #41 on: February 08, 2011, 10:57:37 PM »
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The sensivity curves of the human eye overlap very much for green and red, so I guess that much of the colors in the green/yellow range are reconstructed in the brain. Differences in spectral sensivity may explain some of the differences. I'll probably recheck the raws with a few special raw converters.


Erik,
Everything we know about is a construction in the brain. The idea that this is not true is also a construction in the brain.

Sorry! I sometimes can't resist slipping into philosophical mode  Grin .

That ACR does not handle Nikon colors well, is a bit of a worry. I have sometimes noticed that colors from my D700 do not seem to be as natural as those from my 5D, but I haven't yet taken the trouble to calibrate either camera. Too busy posting on LL  Grin .

Cheers!
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kers
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« Reply #42 on: February 09, 2011, 10:13:54 AM »
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Ray,
Thanks for your careful analysis.
I was much astonished by the color difference....
Erik

Erik, about the color difference...
maybe this is of importance

When i open the original d3x NEF in Nikon Capture i see the camera is set to  -vivid colors-  and the color balance is    -automatic-
so maybe that makes up for the color difference...?

Pieter Kers




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Pieter Kers
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Ray
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« Reply #43 on: February 09, 2011, 03:40:37 PM »
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Erik, about the color difference...
maybe this is of importance

When i open the original d3x NEF in Nikon Capture i see the camera is set to  -vivid colors-  and the color balance is    -automatic-
so maybe that makes up for the color difference...?

Pieter Kers


Pieter,
Both of the RAW files which I downloaded had a TIFF extension. The 645D RAW/tiff included pre-settings such as Daylight WB, sharpening at 90, 0.5 pixel radius, and lens correction profile enabled. The D3X RAW/tiff file contained no pre-settings as I recall, ie. WB As Shot, no sharpening and no lens correction enabled.

It's quite easy to make the D3X image more vivid using the vibrancy and saturation sliders in ACR, but more difficult to get the hue of the colors the same. The foliage in the D3X image tends to be closer to yellow whereas the foliage in the 645D image is closer to green. I'm sure a calibration of both cameras in ACR would fix the problem.
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eronald
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« Reply #44 on: February 09, 2011, 06:49:00 PM »
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ACR colors are kind of strange, and vary from version to version. I even have the impression that in CS5 the main color engine might have issues, I am seeing hue shifts as I adjust luminosity. ACR is not bad, it is just a world to itself.

Edmund

Ray,

Thanks for your careful analysis.

I was much astonished by the color difference. I'm not that sure that calibrating color in ACR would help. Miles says that ACR/LR is said to handle Nikon colors badly. But the Nikon has been around a long time, so I'm pretty sure that Adobe has good data on it. The Pentax may be a different thing.

The sensivity curves of the human eye overlap very much for green and red, so I guess that much of the colors in the green/yellow range are reconstructed in the brain. Differences in spectral sensivity may explain some of the differences. I'll probably recheck the raws with a few special raw converters.

http://en.wikipedia.org/wiki/File:CIE_1931_XYZ_Color_Matching_Functions.svg


Best regards
Erik


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Edmund Ronald, Ph.D. 
Noel Greene
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« Reply #45 on: February 10, 2011, 09:29:32 AM »
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With the announcement of the 25mm for the 645D today .. this puts a whole new perspective on the 645D capability .. the price seems to be 50% of what the 645D costs but maybe it will be worth it to have this level of wide angle on MF .. waiting to read what Llyod Chambers has to say about the new Lens before I take the plunge
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BernardLanguillier
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« Reply #46 on: February 10, 2011, 10:16:47 AM »
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What initially surprised me was the difference in exposure adjustments required to push the histograms to the same position, ie. +1.05 for the 645D, and +0.65 for the D3X. Whlist both images could be considered underexposed with regard to ETTR, the 645D is a good 1/3rd of a stop less exposed than the D3X image, according to ACR 6.3.

Having just checked again the DXOMark results for these two cameras, I see that the true sensitivity for the 645D at ISO 100 is actually 104, and that for the D3X, ISO 78.

The difference between ISO 78 and ISO 104 would account very closely for the exposure differences between these two images. This comparison once again confirms the accuracy and relevance of DXOMark testing, and I'm also impressed that ACR 6.3 is able to reflect such accuracy.

Except that the D3x should be 1/3 stop less exposed instead of being more exposed.

Cheers,
Bernard
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A few images online here!
Ray
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« Reply #47 on: February 10, 2011, 04:24:42 PM »
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Except that the D3x should be 1/3 stop less exposed instead of being more exposed.

Cheers,
Bernard


Bernard,
You are absolutely right  Grin . Thanks for pointing that out. It must have been that glass of wine that got me confused  Grin .

On the basis that the DXOMark ISO measurements are accurate, at least in a relative sense to each camera, I think it's safe to presume the the lenses used in these shots have a significantly different T/stop.

Cheers!
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Ray
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« Reply #48 on: February 10, 2011, 09:01:22 PM »
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With the announcement of the 25mm for the 645D today .. this puts a whole new perspective on the 645D capability .. the price seems to be 50% of what the 645D costs but maybe it will be worth it to have this level of wide angle on MF .. waiting to read what Llyod Chambers has to say about the new Lens before I take the plunge

That's one expensive lens. In 35mm terms, in relation to the 3:2 aspect ratio, it becomes a 20.5mm lens. Not particularly wide. In relation to the 4:3 aspect ratio of the 645D, cropping the 35mm format to the same aspect ratio, it becomes an 18mm lens. Better, but not as wide as the Nikkor 14-24/2.8 zoom which, incidentally is about the same weight but much lower cost. The difference between 14mm and 18mm is really quite significant. The flexibility advantage of a high quality zoom is even more significant. I look forward to comparisons.

I think I forgot to mention the wider F/stop advantage of the Nikkor, F2.8. One might be able to get almost the same shallow DoF with the Pentax 25mm/F4 at full aperture, not quite but let's not quibble, but a one stop advantage for a moving subject or a hand-held shot might well negate any resolution advantage of the 645D.

These are considerations that I take on board. For some they may not be significant.
« Last Edit: February 10, 2011, 09:21:52 PM by Ray » Logged
ErikKaffehr
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« Reply #49 on: February 10, 2011, 11:52:39 PM »
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Miles,

Thanks for very good images! I also downloaded the raw images and spent some time pixel peeping. Today I also tested Iridient Raw Developer.

What I see is:

1) The colors are very different. The same difference in color is seen in Raw developer.
2) Nikon greens contain much more yellow. It may be that Nikon has better Yellow Green separation. This is not obvious to me from DxO-mark data. I don't know if Pentax or Nikon is better but they are quite different.
3) Resolution on Pentax is significantly better, as expected
4) The Pentax lens seems to be very sharp across the field. Let's not forget that the 645D is a cropped format camera so the sweet spot of the lens may be used for the entire picture. Anyway the combo is very good.
5) I don't see a lot of difference between the two in shadow detail. In my view the DR of both cameras exceeds the DR of the subject.

The conclusion?

I'm impressed by the P645D. Regarding cost it needs to be kept in mind that it's camera and lenses. For someone having a bunch of excellent 645 lenses and demanding the uttermost image quality the P645D is a no brainer.

On the other hand the premium cost over a Canon 5DII or a Sony Alpha 850/900 is quite hefty.

Best regards
Erik


I've done some more testing outdoors with my 645D vs Nikon D3x

Daylight  landscape, ISO 100  RAW

D3x,   24-70 zoom lens     @ f8 live view manual focus
645D, 45-85mm zoom lens @ f11  autofocus

The focus point was the tree on the center of the image.

After capture daylight color balance in LR, no sharpening.
Sharpening in CS5 D3x shot USM 300,0.4,1   645D USM 300,0.4,1

Some adjustment in CS5 to match the color.
ACR does a poor job with D3x color as rumored.


This was shot near Angels Camp, CA in the Sierra foothills and it really  was very, very green.

Links.

D3x      http://wyofoto.com/Pentax_645D/Nikon_D3x_field_test.tif
645D    http://wyofoto.com/Pentax_645D/Pentax_645D_field_test.tif

Warning big files D3x is 44MB,  645D file is 77MB

Comments of course are welcome.   Wink

Enjoy....  


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Noel Greene
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« Reply #50 on: February 11, 2011, 07:22:51 AM »
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That's one expensive lens. In 35mm terms, in relation to the 3:2 aspect ratio, it becomes a 20.5mm lens. Not particularly wide. In relation to the 4:3 aspect ratio of the 645D, cropping the 35mm format to the same aspect ratio, it becomes an 18mm lens. Better, but not as wide as the Nikkor 14-24/2.8 zoom which, incidentally is about the same weight but much lower cost. The difference between 14mm and 18mm is really quite significant. The flexibility advantage of a high quality zoom is even more significant. I look forward to comparisons.

I think I forgot to mention the wider F/stop advantage of the Nikkor, F2.8. One might be able to get almost the same shallow DoF with the Pentax 25mm/F4 at full aperture, not quite but let's not quibble, but a one stop advantage for a moving subject or a hand-held shot might well negate any resolution advantage of the 645D.

These are considerations that I take on board. For some they may not be significant.

I agree Ray, it is very expensive and I also agree with your comment about the NiKon 14-24 .. but I think Pentax are beginning to move on a whole range of 645D Lenses .. I saw a PDF which outlines their production programme for MF Lens and it looks impressive. I will certainly wait and see what the reviews of the new Pentax 645D Lens tell me .. but thanks for your informed comments as above
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paratom
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« Reply #51 on: February 11, 2011, 08:43:05 AM »
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it is an expensive lens but it has to cover a larger image circle and for MF it is pretty wide.
I dont see much reason to compare the lens to the Nikon lens.
One lens fits the Nikon, the other the Pentax MF camera.

O have used both a D3x and a MF camera (Hy6) for some months and without doing technical comparisons I felt than I got some images with the MF rig which showed micro detail and tonality and clarity which I would not get with the D3x. Now I still have a D700 for the times when I need fast AF but my feeling is that MF backs deliever better IQ.
I also feel that I got some pretty good images handheld at 1/30 and 1/60 too - more difficult with MF but I would not say its impossible.

If you need the flexibility of a zoom, and if you want lenses wider than 18mm FOV then I guess the DSLR should be the better (only possible?) way to go.
I think it is allways a compromise one has to make between IQ/flexibility/price-no matter if one goes DSLR or MF (or something else)
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fredjeang
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« Reply #52 on: February 11, 2011, 08:55:48 AM »
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I still can't get the enormous success of those endless versus topics that show up regularly.
We all know what are the strenghs and wicknesses of each system (35mm and MF), we know that for ages, it has been discussed a zillion times and it has never changed since.

How can you compare 2 cameras with such a difference in sensor size and philosophy, aimed to different applications and needs (and in the case of the D3x, if needs can be similar the shooting style belongs to different tastes)?

What do you learn with such comparaison? If it was the lastest 80MP backs "Phase vs Leaf" I would understand, but here...

If you'd find silly to open a thread like "Canon G12 vs Canon 5D2", I don't get why don't you find as silly to compare a D3x to a Pentax 645D or any other big sensor's camera.
The days we'll see an Olympus EP1 vs Leica S2 are not far indeed.
Or maybe a Pentax K5 video vs an Arri could be a cool similar thread.

No, I have a good one: Canon S90 vs Arca Swiss RM3D noise comparaison.

« Last Edit: February 11, 2011, 09:19:39 AM by fredjeang » Logged
aaron
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« Reply #53 on: February 11, 2011, 09:32:41 AM »
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.........................
........................
.................
No, I have a good one: Canon S90 vs Arca Swiss RM3D noise comparaison.



I would take the Canon S90 any day, It has a sensor and a lens  Grin

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fredjeang
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« Reply #54 on: February 11, 2011, 10:17:48 AM »
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 Grin Grin
That's why I put the Arca, because it was absurd.
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ErikKaffehr
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« Reply #55 on: February 11, 2011, 10:39:43 AM »
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Hi,

The reason is that the original poster has recently acquired a P645D and had the opportunity to compare it with a cophotographers D3X on a landscape shoot. The original poster is normally using a Canon 5DII, among others. So the original poster wanted to share his experience with both cameras. In my view a very noble endeavor.

Also, the original poster made very good samples and even supplied raw files. It's really very seldom that we have that good material to investigate.

Best regards
Erik

I still can't get the enormous success of those endless versus topics that show up regularly.
We all know what are the strenghs and wicknesses of each system (35mm and MF), we know that for ages, it has been discussed a zillion times and it has never changed since.

How can you compare 2 cameras with such a difference in sensor size and philosophy, aimed to different applications and needs (and in the case of the D3x, if needs can be similar the shooting style belongs to different tastes)?

What do you learn with such comparaison? If it was the lastest 80MP backs "Phase vs Leaf" I would understand, but here...

If you'd find silly to open a thread like "Canon G12 vs Canon 5D2", I don't get why don't you find as silly to compare a D3x to a Pentax 645D or any other big sensor's camera.
The days we'll see an Olympus EP1 vs Leica S2 are not far indeed.
Or maybe a Pentax K5 video vs an Arri could be a cool similar thread.

No, I have a good one: Canon S90 vs Arca Swiss RM3D noise comparaison.


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Radu Arama
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« Reply #56 on: February 11, 2011, 10:53:31 AM »
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That's one expensive lens. In 35mm terms, in relation to the 3:2 aspect ratio, it becomes a 20.5mm lens. Not particularly wide. In relation to the 4:3 aspect ratio of the 645D, cropping the 35mm format to the same aspect ratio, it becomes an 18mm lens. Better, but not as wide as the Nikkor 14-24/2.8 zoom which, incidentally is about the same weight but much lower cost. The difference between 14mm and 18mm is really quite significant. The flexibility advantage of a high quality zoom is even more significant. I look forward to comparisons.

I think I forgot to mention the wider F/stop advantage of the Nikkor, F2.8. One might be able to get almost the same shallow DoF with the Pentax 25mm/F4 at full aperture, not quite but let's not quibble, but a one stop advantage for a moving subject or a hand-held shot might well negate any resolution advantage of the 645D.

These are considerations that I take on board. For some they may not be significant.

I won't get into zoom vs. prime, this millimeters  in MF vs. that millimeters in 135 format or the quality of a known lens vs. another one with exactly 3 out of camera jpegs as samples debates but I really don't understand why one would want to equal the pictures to an aspect ratio of 1.5 when virtually all large format print sizes are from 1.25 to 1.41 and if one prints from roll then it is up to one's taste.

My wish is for a sensor of 1.41 ratio that complies with the European A-sizes paper.

Radu
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kers
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« Reply #57 on: February 11, 2011, 12:25:03 PM »
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about the new 25mm pentax lens..

That's one expensive lens. In 35mm terms....

I have seen Diglloyd testing the 28mm lens from Hasselblad but he found it not up to the 40MP..+... backs.
Leica has not put out any wideangle yet for the S2- I am sure they are capable of making it but the price will be high.
It seems very difficult to make a good wide angle for MP at a reasonable price.. Obviously it will have to cost that 5000$ to produce something good.
As for the new 55mm Pentax it seems the "old" pentax 67 lenses are still better... (when used with an adapter)
The 4x5 inches lenses from Schneider only worked at d16-22 .. but were very good then... and they were more affordable...
« Last Edit: February 11, 2011, 01:05:14 PM by kers » Logged

Pieter Kers
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« Reply #58 on: February 11, 2011, 01:56:33 PM »
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about the new 25mm pentax lens..

I have seen Diglloyd testing the 28mm lens from Hasselblad but he found it not up to the 40MP..+... backs.
Leica has not put out any wideangle yet for the S2- I am sure they are capable of making it but the price will be high.
It seems very difficult to make a good wide angle for MP at a reasonable price.. Obviously it will have to cost that 5000$ to produce something good.
As for the new 55mm Pentax it seems the "old" pentax 67 lenses are still better... (when used with an adapter)
The 4x5 inches lenses from Schneider only worked at d16-22 .. but were very good then... and they were more affordable...


Just my humble expression: i have seen Diglloyd testing  lot of things.... i am sure he makes a lot of money with what he does. IMHO
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DeeJay
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« Reply #59 on: February 11, 2011, 02:30:00 PM »
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IMO the Nikon looks rough and nasty in comparison to the Pentax image. Color, detail and tonality all superior in the 645.

What are the price differences on these cameras?
« Last Edit: February 11, 2011, 02:32:52 PM by DeeJay » Logged
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