DXOmark ranks DB image quality well below DSLR!

[ziocan]

May I ask what exactly "people" should use their eyes for? Honestly, do you have the slightest idea what the discussion is about?

is about:
Stop! otherwise you go blind!

[focusgroup]

is about:
Stop! otherwise you go blind!

Honestly do you have a clue?  This is they typical bs people discuss when they have little else to do and are dilettantes.  I mean who gives a care what DXO says?  Would you really buy a kit or make any sort of significant investment using their limited testing as a valuable resource?  

Yes, I have a bit of experience with this subject.

[BJL]

Aw c'mon - it's about GEAR! Sheesh....

No no, the game of "forum fantasy fotography" it is not just about numbers or just about gear: it is about proving the superiority of your gear with a single number, and arguing which single numerical measure should be used: MP, ISO, DR, DxOMark ...

[Ray]

No no, the game of "forum fantasy fotography" it is not just about numbers or just about gear: it is about proving the superiority of your gear with a single number, and arguing which single numerical measure should be used: MP, ISO, DR, DxOMark ...

No, no, no! It's about holding the manufacturers to acount. It's about getting precise and relevant information about the performance of equipment so that we end up buying what we thought we were buying.

MFDB owners who thought they were paying a huge premium for greater DR and lower noise than any 35mm format could offer, now have to reconsider in the light of the DXO results. However, DXO does not test resolution or the quality of specific lenses. There's no substitute for a really good lens, and a 39mp sensor will definitely produce higher resolution than a 21 or 24mp sensor, lens permitting.

[erick.boileau]

DXOmark results are a nonsense when you have in your computer thousands of photo with Canon 1Ds Mark III and P45 ...

[Guillermo Luijk]

I mean who gives a care what DXO says?

Among others, you. Otherwise you'll have to explain why you decided to invest your time in reading and posting on a thread entitled as 'DXOmark ranks DB image quality well below DSLR!'.

BR

[BernardLanguillier]

DXOmark results are a nonsense when you have in your computer thousands of photo with Canon 1Ds Mark III and P45 ...

Dxo Marks gives the P45+ 0.9 stop more DR than the 1ds3, don't you think that this is about right?

http://www.dxomark.com/index.php/eng/Image...d2)/Phase%20One

In what sense does that make no sense?

Regards,
Bernard

[selsoe]

Phase One P65+ just took the lead ahead of Nikon D3x:
http://www.dxomark.com/index.php/eng/DxOMark-Sensor

[Jonathan Wienke]

I think it's interesting that anywhere above 50 ISO the DSLRs beat the backs in terms of D.R. Often by one or two full stops, even though the backs have larger pixels. I am really wondering where the truth lies.

It's because if you use "fake" ISO settings, which most MFDB do for their higher settings, every stop above the highest "real" ISO comes directly out of DR. So if the back's highest real ISO is 50, and you shoot at ISO 400, then you're throwing away 3 stops of highlights. This will reduce the usable DR in the captured image by 3 stops. When compared to a DSLR that has a real ISO 400, the MFDB has a 3-stop DR handicap, and may very well do worse.

[gss]

ISO is probably an ancient term which should not be used with digital, but it is what we know and is what is familiar to us photographers.

I would agree with this if you had said ASA; ISO is just an upstart.  

[Eric Myrvaagnes]

I have just created the ultimate solution to this pressing question. I have just defined a new Universal Quality Index (or "UQI", pronounced "Yucky!") Keeping in mind the KISS Principle, I use a binary system. Any camera, lens, or other piece of photographic equipment, or photograph, photographer, photographer's assistant, painting, fine dining experience, fast food meal, comic strip, web site, etc., which I like gets a UQI value of 1. Anything i don't like gets a 0.

As an example, the Luminous Landscape website and forum both rate a 1. Some individual threads on the forum (this one, for example) do not.

[Panopeeper]

It's because if you use "fake" ISO settings, which most MFDB do for their higher settings, every stop above the highest "real" ISO comes directly out of DR

Not so. This is the way DSLRs adopt ISO steps without hardware support; this is an inexcusable dumb rubbish from the DSLR manufacturers.

MFDBs, at least those I have analyzed, work differently: they do not ruin the original pixel values by senseless multiplication (or division); they simply state, that the numerical range of the pixel values is now lower than with another ISO, but this occurs without causing clipping of the pixel values.

Thus the DR of the MFDBs does not change with the fake ISO increase, in contrast to DSLRs.

[ziocan]

geeeeeee!

[lisa_r]

Not so. This is the way DSLRs adopt ISO steps without hardware support; this is an inexcusable dumb rubbish from the DSLR manufacturers.

MFDBs, at least those I have analyzed, work differently: they do not ruin the original pixel values by senseless multiplication (or division); they simply state, that the numerical range of the pixel values is now lower than with another ISO, but this occurs without causing clipping of the pixel values.

Thus the DR of the MFDBs does not change with the fake ISO increase, in contrast to DSLRs.

What's the reason for the decrease in DR as the ISO increases as can be seen over at DXOmark? IT looks like as soon as you hit ISO 100 or above the DSLRs win in terms of D.R.. SLick on yhe dymanic range tab here:

http://dxomark.com/index.php/eng/Image-Qua.../(brand3)/Canon

[ejmartin]

What's the reason for the decrease in DR as the ISO increases as can be seen over at DXOmark? IT looks like as soon as you hit ISO 100 or above the DSLRs win in terms of D.R.. SLick on yhe dymanic range tab here:

http://dxomark.com/index.php/eng/Image-Qua.../(brand3)/Canon

The analog-to-digital converter (ADC) in the camera, which takes the analog signal from the sensor and digitizes it, has a maximum output value.  Every time the ISO is doubled, the amplification is doubled, and one more stop of exposure levels is pushed past the saturation point of the ADC.  Therefore the DR will decrease by one stop unless there is a compensating reduction in shadow noise.   In MFDB's there is typically no reduction in shadow noise with ISO increase, so DR decreases by about a stop for every stop increase in ISO (if ISO is implemented as a hardware amplification; if not there are some subtleties).

In Canon and most other CMOS sensor DSLR's, there is a reduction in shadow noise with the first few stops of ISO increase above base ISO (because the ISO amplifier and ADC are noisier than they ought to be, and increasing the ISO decreases their contribution to shadow noise), and so one sees the DR curve to be relatively flat for those first couple of stops.  Eventually the improvement in shadow noise ends, however, and the DR starts to drop.  Note, however, that if Canon were able to use cleaner electronic components for the ISO amplifier and ADC, their DR would be over two stops better than the MFDB for all ISO, not just high ISO; and would be about 14 stops at base ISO.

[Panopeeper]

What's the reason for the decrease in DR as the ISO increases as can be seen over at DXOmark? IT looks like as soon as you hit ISO 100 or above the DSLRs win in terms of D.R.

I don't know how they arrived at this result. However, the P45 Plus DOES have analogue ISO up to 800, at least I don't see any sign of digital manipulation. On the other hand, analogue supported ISO does not necessarily mean any noise reduction. For example the 5D2 has analogue gain up to 3200, but the loss of dynamic range from 1600 to 3200 is a full stop, because the analogue gain of 3200 is ineffective, compared to 1600.

I don't have P45 Plus raw files suitable for measurement, but guestimated from what I have, it would have been better not to adopt ISO 800 in the hardware. I don't know if ISO 400 is effective vs. ISO 200.

There is another side of this issue, for those using LR/ACR: Adobe did not notice, that the P45 Plus has hardware ISOs (I guess the P45 does not have) and the raw conversion automatically "makes up" for the "missing ISO" by applying +1 EV with ISO 400 and +2 EV with ISO 800 as "Exposure" adjustment (invisible on the slider). However, there is no missing ISO, thus ACR makes the images appear much brighter than they should be, it can even cause clipping, thereby reducing the apparent DR even more.

[douglasf13]

Not for low ISOs, but most owners beleive it can. See a very technical study of this topic (although I thought you had seen this on GetDPI).

Carsten, talk to Iliah Borg about this, as his studies show something very different...and he has multiple A900 cameras at his disposal to test.

[BJNY]

P65+ just received the highest score at dxomark.com database
beating previous leader Nikon D3x.

Probably pertains to P40+ as well since it's just a smaller wafer of same sensor?

[Ray]

P65+ just received the highest score at dxomark.com database
beating ptevious leader Nikon D3x.

Interesting! What I see from the graphs is that the D3X still trounces the P65+ with regard to dynamic range. In fact, the only advantages of the P65+ that are apparent in the DXOmark results are better noise, better tonal range and better color sensitivity, at base ISO only and on a small print (8"x12").

At 8x12" print size and above base ISO, the P65+ is no better than the D3X in any of the qualities measured. It's either approximately equal, or in respect of DR significantly worse.

If one compares performance at the pixel level, the D3X appears better or equal in all respects, except for an anomaly at ISO 800. It appears that the extrapolated results for the P65+ at ISO 800 take a big leap in performance with regard to all parameters tested. What's going on here? Anyone?

[Panopeeper]

This is all "kindergarten arithmetic". DxO, just like the vast majority of review sites, publish whatever garbage they want to, without any proof.