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Author Topic: Mother of God - D800 scores 95 DxOMark  (Read 77946 times)

Astro

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Re: Mother of God - D800 scores 95 DxOMark
« Reply #75 on: March 24, 2012, 05:34:30 PM »
The main problem with DXO metrics is that they interpret the results based on a 8 megapixels downsampling of the measurements they made.  I find this inapropriate.
 

it´s a normalization.

Quote
As discussed above, the DxOMark Sensor score is "normalized" to compensate for differences in sensor resolution. To summarize: the DxOMark Sensor benchmark doesn't "punish" high-resolution sensors for having lots of small pixels that are each individually noisier. And similarly, the benchmark doesn't favor using large pixels despite their lower per-pixel noise. This is not some kind of ideology: it is just estimating the resulting noise level when viewing the entire image

for a fixed print size that makes sense. as downsampling is applied anyway.
once you exceed the acceptable noise for the printsize we can discuss if it is usefull.

« Last Edit: March 24, 2012, 05:42:26 PM by Astro »

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Re: Mother of God - D800 scores 95 DxOMark
« Reply #75 on: March 24, 2012, 05:34:30 PM »

Gothmoth

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Re: Mother of God - D800 scores 95 DxOMark
« Reply #76 on: March 24, 2012, 05:50:00 PM »
BTW, every time someone points out how wrong DxO's test results are, someone else jumps in and claims "well, you have to understand the test. Read this link." No. Sorry. It doesn't work that way. DxO can't present a score which explicitly says A is better than B, then backtrack and say we don't understand the score if we think it means A is better than B. Same for individual tests with results stated using industry standard terms (i.e. DR in stops). If their scoring is confusing that's their fault, not the reader's. And if their test results fail to correspond to real world use, again that is their fault, not the reader's.

but you measure the combo: sensor + software demosaicing + your individual develop settings.

how will you get a objectiv (comparable) result about the sensor that way?
apply a different  gamma curve and you will have more DR, but what about the noise level if you do so? it will raise into regions that are not acceptable. luminance can be pushed around easily. you need some fixation and that is the acceptable noise level.

DXO measures the RAW info and noise levels.

« Last Edit: March 24, 2012, 06:03:37 PM by Gothmoth »

elflord

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Re: Mother of God - D800 scores 95 DxOMark
« Reply #77 on: March 24, 2012, 09:36:39 PM »

DxO does not know how to properly measure dynamic range. If you want accurate DR values, please view test results at DPReview.


What specifically is wrong with the way DxOMark test dynamic range ?

The DxOMark tests basically show Canon's sensors flattening out in dynamic range by ISO 400 (that is, dynamic range doesn't improve for low ISO) whereas the Sony sensors (also used in Nikon sensors) continue to improve at ISO 200-100.  At higher ISOs it goes more or less as you'd expect -- the bigger sensor wins by about a stop.

Are you saying that this is due to some flaw in DxOMarks method ? If so, what is the flaw ?

Quote
What Sony APS-C camera would that be? It looks to me like they are no better than Canon's 18 MP bodies when DR optimization is on or when RAW is used under best possible settings. That would leave Sony's APS-C sensors a solid 1 stop behind the Canon 5D2. I doubt the 5D3 has less DR.

DxOMark has the NEX 5N and Sony Alpha 77 beating the 5D Mark II for dynamic range at low ISOs.

wickidwombat

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Re: Mother of God - D800 scores 95 DxOMark
« Reply #78 on: March 25, 2012, 04:43:15 AM »
i would have read all of this thread but i've been out all weekend shooting with my 5Dmk3 ;)
since i don't really follow the lab tests or particularly care about them for that matter, 95 is good is it?
APS-H Fanboy

briansquibb

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Re: Mother of God - D800 scores 95 DxOMark
« Reply #79 on: March 25, 2012, 04:47:14 AM »
i would have read all of this thread but i've been out all weekend shooting with my 5Dmk3 ;)
since i don't really follow the lab tests or particularly care about them for that matter, 95 is good is it?

Most good bodies score in the 80's

Personally I feel the score is so much higher that this cynical old man wonders about the accuracy

ssrdd

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Re: Mother of God - D800 scores 95 DxOMark
« Reply #80 on: March 25, 2012, 05:38:57 AM »
finally 5dmark 3 has proved to be S____ for the price point.
ha ha haaa...

briansquibb

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Re: Mother of God - D800 scores 95 DxOMark
« Reply #81 on: March 25, 2012, 05:44:52 AM »
finally 5dmark 3 has proved to be S___ for the price point.
ha ha haaa...

I can tell you have done your research - you spotted the 'knock the 5DIII and praise the D800' bandwagon and jumped on.

DXOMark comparing the 5DIII and the D800

http://www.dxomark.com/index.php/Cameras/Compare-Camera-Sensors/Compare-cameras-side-by-side/%28appareil1%29/795|0/%28brand%29/Canon/%28appareil2%29/792|0/%28brand2%29/Nikon

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Re: Mother of God - D800 scores 95 DxOMark
« Reply #81 on: March 25, 2012, 05:44:52 AM »

psolberg

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Re: Mother of God - D800 scores 95 DxOMark
« Reply #82 on: March 25, 2012, 07:44:05 AM »
The main problem with DXO metrics is that they interpret the results based on a 8 megapixels downsampling of the measurements they made.  I find this inapropriate.

Most of us are cropping our pictures.

I'd certainly prefered having an indicator about pixel quality.  I know how many megapixel I need and how many megapixel there is on the body I am considering.

I'd argue most of us crop the same regardless of mp count since we crop for composition an not resolution. Thus the advantages of low resolution sensors are nullified. Dxo's arguments is that pixel quality 100% crops are not representative of actual quality for most uses and thus they normalize the field by the downscale. If you're selling tiny 100% crops blown to 8x10, you should disregard their findings. But if you sell prints of 90% if your original , their method is more accurate than the side by side comparison of crops you see on the web.

thure1982

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Re: Mother of God - D800 scores 95 DxOMark
« Reply #83 on: March 25, 2012, 09:13:42 AM »
Have you guys matched it with the 5D2?
 Sure it got 95 "points" at he scoreboard but the aqual difference is not the obvois when you look at the diagrams.

elflord

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Re: Mother of God - D800 scores 95 DxOMark
« Reply #84 on: March 25, 2012, 09:32:47 AM »
i would have read all of this thread but i've been out all weekend shooting with my 5Dmk3 ;)
since i don't really follow the lab tests or particularly care about them for that matter, 95 is good is it?

Most good bodies score in the 80's

Personally I feel the score is so much higher that this cynical old man wonders about the accuracy

That would make it about 1.5 stops better than current APS-C bodies, which seems plausible. Full frame bodies aren't released very frequently, so there aren't that many comparable bodies that have been tested. However, Nikon do have a couple of other FF models that score close to 90.

D.Sim

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Re: Mother of God - D800 scores 95 DxOMark
« Reply #85 on: March 27, 2012, 08:27:30 AM »
finally 5dmark 3 has proved to be S___ for the price point.
ha ha haaa...

I can tell you have done your research - you spotted the 'knock the 5DIII and praise the D800' bandwagon and jumped on.

DXOMark comparing the 5DIII and the D800

http://www.dxomark.com/index.php/Cameras/Compare-Camera-Sensors/Compare-cameras-side-by-side/%28appareil1%29/795|0/%28brand%29/Canon/%28appareil2%29/792|0/%28brand2%29/Nikon

So do u fan boy.


So sayeth the Nikon fanboy...


Gee I miss the karma system... some of the comments are just getting out of hand -_-

briansquibb

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Re: Mother of God - D800 scores 95 DxOMark
« Reply #86 on: March 27, 2012, 12:42:54 PM »
finally 5dmark 3 has proved to be S___ for the price point.
ha ha haaa...

I can tell you have done your research - you spotted the 'knock the 5DIII and praise the D800' bandwagon and jumped on.

DXOMark comparing the 5DIII and the D800

http://www.dxomark.com/index.php/Cameras/Compare-Camera-Sensors/Compare-cameras-side-by-side/%28appareil1%29/795|0/%28brand%29/Canon/%28appareil2%29/792|0/%28brand2%29/Nikon

So do u fan boy.

What bandwagon is that?


awinphoto

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Re: Mother of God - D800 scores 95 DxOMark
« Reply #87 on: March 27, 2012, 01:44:37 PM »
finally 5dmark 3 has proved to be S___ for the price point.
ha ha haaa...

I can tell you have done your research - you spotted the 'knock the 5DIII and praise the D800' bandwagon and jumped on.

DXOMark comparing the 5DIII and the D800

http://www.dxomark.com/index.php/Cameras/Compare-Camera-Sensors/Compare-cameras-side-by-side/%28appareil1%29/795|0/%28brand%29/Canon/%28appareil2%29/792|0/%28brand2%29/Nikon

So do u fan boy.

What bandwagon is that?

As far as DxO's preliminary comparison, look at the specs... Canon 5d mark III = professional.  Nikon D800 = Semi-Pro DSLR.  Now let me duck out before the bullets/knives/forks come flying out from the left.   
Canon 5d III, Canon 24-105L, Canon 17-40L, Canon 70-200 F4L IS, Canon 100L 2.8, Canon 85 1.8, 2 430EX 2's and a partridge in a pear tree.

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Re: Mother of God - D800 scores 95 DxOMark
« Reply #87 on: March 27, 2012, 01:44:37 PM »

briansquibb

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Re: Mother of God - D800 scores 95 DxOMark
« Reply #88 on: March 27, 2012, 05:09:48 PM »
finally 5dmark 3 has proved to be S___ for the price point.
ha ha haaa...

I can tell you have done your research - you spotted the 'knock the 5DIII and praise the D800' bandwagon and jumped on.

DXOMark comparing the 5DIII and the D800

http://www.dxomark.com/index.php/Cameras/Compare-Camera-Sensors/Compare-cameras-side-by-side/%28appareil1%29/795|0/%28brand%29/Canon/%28appareil2%29/792|0/%28brand2%29/Nikon

So do u fan boy.

What bandwagon is that?

As far as DxO's preliminary comparison, look at the specs... Canon 5d mark III = professional.  Nikon D800 = Semi-Pro DSLR.  Now let me duck out before the bullets/knives/forks come flying out from the left.

DxO haven't done a review of the 5DIII therefore any comment against it must have been made by a Nikon fanboy. Personally I dont care less - I am not getting a 5DIII as I already have a camera that fills that requirement.

sarangiman

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Re: Mother of God - D800 scores 95 DxOMark
« Reply #89 on: March 27, 2012, 05:37:02 PM »
Quote
If Nikon/Sony were to make a 22MP sensor that used the same technology as the 36MP sensor in the D800 and that 22MP sensor were made to be a full-frame 35mm sensor, then I expect that you would have a sensor that blows the socks off of the one in the D800.

Um. Isn't that the D4 (well, 16MP instead of 22MP, so even more advantage)? And yet DXO rates the D4 as having less DR than the D800? Normalized or not, that makes me think:  :o

Quote
sony/nikon seem to backup those who say SNR is independent from pixelsize.

On a per-pixel level, SNR is absolutely related to pixel size. Upon normalization, in this case downsampling (or pixel binning), the difference might become negligible between a higher resolution sensor & a lower resolution one. But, in my understanding, the DR or SNR can never be better for a downsized image from a higher resolution sensor vs. the image from the lower resolution sensor w/ bigger pixels.

Why?

Because the higher resolution sensor will have more read noise because it had to read many more pixels. Yes, the read noise will be averaged upon downsizing, but averaging the read noise of, say, 4 pixels, down to one can't possibly give you lower noise than reading just 1 pixel to begin with off a sensor of 1/4 the resolution.

Hardware-binning, on the other hand, was invented to combat this problem. Phase One's Sensor+ tech bins pixels at the sensor level so that you don't have as many read events when you shoot at a lower resolution (on the same sensor), thereby increasing your overall SNR.

Until the greater inter-pixel spacing of higher resolution cameras no longer affect QE, & read noise goes to 0 (not likely), high resolution sensors cannot have the same SNR performance of lower resolution sensors of the same generation, barring other factors that might make the higher resolution sensor better.

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The DxOMark tests basically show Canon's sensors flattening out in dynamic range by ISO 400 (that is, dynamic range doesn't improve for low ISO)

This is likely because of dirty downstream signal processing, which Nikon/Sony has less of. Therefore, the signal at which SNR = 1 for Nikon/Sony images is lower than for Canon; hence the higher DR at lower ISO. ISO 400 is unity gain for 5DII; below that ISO, >1 electron is used per 1 digital unit (DU) in the resulting image file. For example, at ISO 100, 4e- = 1DU (I believe), which means that lower signals are now more prone to noise injection from dirty electronics.

That's my understanding, anyway. Feel free to discuss.

Also, though't I'd point out that according to sensorgen.info, which basically pulls data from DXOMark, the D7000's read noise remains the same even at low ISO, something pretty much atypical of all other cameras:
http://sensorgen.info/NikonD7000.html

This also has the effect of making the DR on the D7000 literally plummet as soon as you raise the ISO. By ISO 200, it's down to D4 levels of DR at ISO 100; The D4 DR drops rather slowly from ISO 100 to ISO 800 (http://sensorgen.info/NikonD4.html).

But the D7000 having a lower read noise at ISO 100 than the D4 and higher DR than the D4 by 1.4 stops?

Really??  :o

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Re: Mother of God - D800 scores 95 DxOMark
« Reply #89 on: March 27, 2012, 05:37:02 PM »