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Author Topic: DXOmark ranks DB image quality well below DSLR!  (Read 33227 times)
Ray
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« Reply #20 on: April 25, 2009, 08:21:44 PM »
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Quote from: GLuijk
DxOMark put the different resolution into the equation with the 'Print' option in the DR and SNR18% tests:

Yes it does. When I first saw this option "print", I actually thought it was asking me if I wanted to print out the results. (Duh!)

At this relatively small print size one can see a fairly dramatic shift in most of the results. The P45 actually has better SNR than the D3X, at base ISO of 50. But only slightly better   .
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Guillermo Luijk
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« Reply #21 on: April 25, 2009, 09:23:56 PM »
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Quote from: photolinia
Oh - very interesting - thanks!

So, does that mean that in Nikons all the"Hi" and "Low" settings are the fake software ISO's and the ones designated with actual numbers are real internal amp setting ISO's?

I wouldn't say that, it has to be analysed because manufacturers lie more than they speak.
I don't know about Nikon's ISOs, but I can tell you in the Canon 5D MKII, ISO6400 is fake but if you read the camera user manual ISO6400 is groupped together with 100, 200, 400, 800, 1600 letting you believe it's a real ISO. They never say it is an electronic ISO, but they let the user believe it.

Funnily yesterday I found someone in the DPreview forums claiming that ISO6400 on the 5D2 is fantastic, noise-free and far better than ISO3200.

BR


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dfarkas
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« Reply #22 on: April 25, 2009, 09:30:10 PM »
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Quote from: BernardLanguillier
Now, these 39MP back are old technology, and it would be interesting to see what companies like Kodak and Dalsa could do with 39MP if they tried today, but it seems that they have been stucked in the MP race like everybody else and will not develop any new sensor with that kind of resolution.

Cheers,
Bernard

The Leica S2 uses a newly designed Kodak 37.5 MP CCD sensor based on the latest 6um pixel architecture.

David
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David Farkas
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Panopeeper
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« Reply #23 on: April 25, 2009, 09:46:46 PM »
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Quote from: photolinia
So, does that mean that in Nikons all the"Hi" and "Low" settings are the fake software ISO's and the ones designated with actual numbers are real internal amp setting ISO's?
The designation is meaningful only in one direction: the ISO steps with special designation like "Hi" or "boosted" are usually fake; however, those not designated as such may be real or fake.

Examples

Nikon D300 and D90: ISO 6400 is designated as "boosted", but already 3200 is fake

Nikon D3: this is "correct", i.e. ISO 6400 is analogue supported.

The same is happening in the Canon line.

However, this is is much less interesting than the factual usefulness. Most of the top analogue ISO steps are purely eye-wash; there is nothing to gain over 1600, no matter if Canon or Nikon. The only exception is perhaps the Canon 1DMkIII, 3200 seems to contribute a tiny bit compared to 1600.
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Gabor
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« Reply #24 on: April 26, 2009, 12:16:20 AM »
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Besides the noise and resolution, I'll bet there are color accuracy differences between MFDB and DSLR cameras.   Does DXO measure this too?    


Quote from: Panopeeper
The designation is meaningful only in one direction: the ISO steps with special designation like "Hi" or "boosted" are usually fake; however, those not designated as such may be real or fake.

Examples

Nikon D300 and D90: ISO 6400 is designated as "boosted", but already 3200 is fake

Nikon D3: this is "correct", i.e. ISO 6400 is analogue supported.

The same is happening in the Canon line.

However, this is is much less interesting than the factual usefulness. Most of the top analogue ISO steps are purely eye-wash; there is nothing to gain over 1600, no matter if Canon or Nikon. The only exception is perhaps the Canon 1DMkIII, 3200 seems to contribute a tiny bit compared to 1600.
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lisa_r
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« Reply #25 on: April 26, 2009, 08:51:05 AM »
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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 easy to find threads here and elsewhere where one guy claims that in terms of D.R. his back "blows away" his Canons, and then right after that someone else says that their back is no better than their Canon. Maybe it's because they are shooting at different ISOs...

Click the Dynamic Range tab here to see what I am talking about:

http://www.dxomark.com/index.php/eng/Image...d3)/Phase%20One

Maybe it's the fashion guys who are often shooting at higher ISOs because they are mixing daylight with strobes and such - and are therefore not seeing the DR advantage of the backs (because there is apparently no advantage at 400ISO) and the landscape/architecture guys who are seeing the backs as having better D.R. only because they are shooting at ISO 50?

I do not currently have a back in my possession or I would attempt to confirm this on my own...
« Last Edit: April 26, 2009, 08:52:08 AM by lisa_r » Logged
ErikKaffehr
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« Reply #26 on: April 26, 2009, 09:15:45 AM »
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Hi,

I got the impression that "dynamic range" is not that easy to test.

My guess is simply that DSLRs lead regarding noise related factors, because of better sensor technology (including preamplification) while MFDBs lead with regard to resolution/MTF related factors.

Best regards
Erik

Quote from: lisa_r
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 easy to find threads here and elsewhere where one guy claims that in terms of D.R. his back "blows away" his Canons, and then right after that someone else says that their back is no better than their Canon. Maybe it's because they are shooting at different ISOs...

Click the Dynamic Range tab here to see what I am talking about:

http://www.dxomark.com/index.php/eng/Image...d3)/Phase%20One

Maybe it's the fashion guys who are often shooting at higher ISOs because they are mixing daylight with strobes and such - and are therefore not seeing the DR advantage of the backs (because there is apparently no advantage at 400ISO) and the landscape/architecture guys who are seeing the backs as having better D.R. only because they are shooting at ISO 50?

I do not currently have a back in my possession or I would attempt to confirm this on my own...
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Guillermo Luijk
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« Reply #27 on: April 26, 2009, 09:49:12 AM »
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Quote from: lisa_r
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.
If you read carefully this thread you will find the answer: backs have only one or two real ISOs, the rest are fake ISOs obtained by overexposing in software a lower real ISO. With every extra fake ISO stop, you are losing 1 stop in the ability to capture DR.

Are backs wrongly designed? no way, they were designed for applications where usually the base native ISO is used everytime.

BR

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photolinia
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« Reply #28 on: April 26, 2009, 11:13:01 AM »
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Quote from: GLuijk
If you read carefully this thread you will find the answer: backs have only one or two real ISOs, the rest are fake ISOs obtained by overexposing in software a lower real ISO. With every extra fake ISO stop, you are losing 1 stop in the ability to capture DR.

Are backs wrongly designed? no way, they were designed for applications where usually the base native ISO is used everytime.

BR


Regarding this REAL ISO question...  Do MFDB people admit to this?  I'm attending a Hasselblad event on Tuesday and will ask them about it.  
If the higher ISO's are fake software options, then no one should really ever use them, but I've heard from many people (including on this
forum) who use higher ISO's regularly...

-ilya
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« Reply #29 on: April 26, 2009, 11:50:43 AM »
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Quote from: GLuijk
With every extra fake ISO stop, you are losing 1 stop in the ability to capture DR.

If you increase ISO by roughly shifting the pixels in the histogram one stop to the right, then yes, 1 stop of DR is lost.

But is there a way to fake ISO by smartly pushing up only shadows and slightly lighting up the midtones, without blowing out the highlights?

16-bit depth would allow this no problem, I guess.
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Guillermo Luijk
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« Reply #30 on: April 26, 2009, 01:50:33 PM »
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Quote from: photolinia
Regarding this REAL ISO question...  Do MFDB people admit to this?  I'm attending a Hasselblad event on Tuesday and will ask them about it.
Sadly they will probably not understand a word about what you're talking about.

Quote from: R_Medvid
is there a way to fake ISO by smartly pushing up only shadows and slightly lighting up the midtones, without blowing out the highlights?
Sure! you are talking about... postprocessing   that's easily done in Photoshop, or even in the RAW developer with the Brightness control, which unlike the Exposure control allows to lift the shadows without blowing the highlights.

BR
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douglasf13
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« Reply #31 on: April 26, 2009, 02:01:11 PM »
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The A900 is somewhat similar in that it actually performs better by never going over ~ISO 400, and boosting in the converter....assuming you're not using ACR, but rather a converter with high quality output like RPP, Raw Therapee, etc.
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paulmoorestudio
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« Reply #32 on: April 26, 2009, 02:12:38 PM »
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[quote name='GLuijk' date='Apr 26 2009, 07:50 PM' post='279096']
Sadly they will probably not understand a word about what you're talking about.


give me a break!
when I bought my hasselblad back a few years back the back rep clearly stated to me that the base iso is what the back performs best at and that any higher than that, it is just software manipulation..
so I think they would understand..maybe they aren't as clever as you but I think they understand how their backs work.
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« Reply #33 on: April 26, 2009, 02:18:20 PM »
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Quote from: GLuijk
Sure! you are talking about... postprocessing   that's easily done in Photoshop, or even in the RAW developer with the Brightness control, which unlike the Exposure control allows to lift the shadows without blowing the highlights.

BR

But, this is understood. My question was obviously about the on-chip shadow-pushing-up before making up of the RAW file. I'm talking about a smarter ISO faking. Is it possible?
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Roman Medvid
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« Reply #34 on: April 26, 2009, 02:30:59 PM »
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Quote from: paulmoorestudio
so I think they would understand..maybe they aren't as clever as you but I think they understand how their backs work.
It's not a question of being clever, but just interested in those matters. I am glad to see the people you bought the back from were not only informed but also honest. I hope photolinia will tell us how was his event.


Quote from: R_Medvid
My question was obviously about the on-chip shadow-pushing-up before making up of the RAW file.
That's RAW cooking, and nobody should be interested in that. First because is useless (it can be done better in postprocessing), and second because it would ruin the virgin and linear condition of the RAW file.

BR
« Last Edit: April 26, 2009, 02:35:14 PM by GLuijk » Logged

Mort54
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« Reply #35 on: April 26, 2009, 02:45:08 PM »
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OK, I'll throw some gasoline on the fire :-)

I shoot primarily landscapes and use a P45+ on a Mamiya 645 II, as well as a D3 (one of these days I'll upgrade to a D3X). The only thing the P45+ gives me is more pixels, and no AA filter getting in the way of those pixels. There, I said it out loud. Believe me, I take no pleasure in saying that, given how much I spent on the P45+ kit. But that's what I'm seeing.

More pixels is no small thing, and the lack of an AA filter further helps out,  and in fact these are the two primary reasons I got the P45+ kit. The detail available in a MFDB file is breathtaking. But as for all the other so-called advantages attributed to MFDBs, I'm not seeing them. If anything, I agree with DxO's assessment here. Maybe these other advantages were real a few years ago, but with the latest crop of DSLRs, the gap has narrowed considerably. I have no trouble pulling clean sharp detail out of the shadows with my D3. If anything, I rank the D3 slightly superior to the P45+ in this regard (based on using the D3 at ISO 200 and the P45+ at ISO 50, their respective base ISOs). And the D3 has more mid-tone to highlight DR than the P45+, again at base ISOs. The P45+ saturates at around 2 and 2/3 to 3 stops over mid-tone. The D3 highlights don't hit the limit for another two thirds to a full stop beyond that. And the D3X is reportedly even better in this regard.

On top of all this is the convenience factor in Nikon's (and Canon's) favor. I have excellent quality super wides to super telephotos, and everything in between. I have an excellent selection of tilt/shift lenses. I have blazingly fast AF. My batteries last days, not hours. And I have superb in-camera live view that allows me to achieve critical focus to a much more repeatable and precise degree than I've ever been able to achieve with my MF kit.

One of these days I'll get a D3X, and I doubt I'll pull the P45+ kit out much after that, based on what I've seen to date.

Regards,
Mort.
« Last Edit: April 26, 2009, 03:03:42 PM by Mort54 » Logged

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« Reply #36 on: April 26, 2009, 02:48:14 PM »
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Hi,

Real ISO is achieved with preamplification. Fake ISO is achieved by essentially multiplying the signal after analogue to digital conversion. Preamplification may be boosted so far that signal to noise ratio is not improved, in this case the increase in ISO will be essentially be fake.

Check this article: http://www.clarkvision.com/imagedetail/dig...ary/#unity_gain

Best regards
Erik




Quote from: photolinia
Hmmm...  Could somebody explain this real ISO vs fake ISO issue?
I thought that all cameras had one base ISO  (50 for most MFDB, 100 for D3X, 200 for D3), but then
used amps to simulate the effect of higher ISOs - is that not the case?

what is the difference between the way D3X and H3D-39 derive higher ISO's?

-ilya
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Panopeeper
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« Reply #37 on: April 26, 2009, 02:57:02 PM »
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Quote from: lisa_r
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
The cases have to be separated.

For example the Phase One P45 Plus has analogue ISO steps up to 800 (I don't know about 1600; perhaps there is no such step at all). This means, that the dynamic range gets reduced by every ISO step increase; the magnitude of the loss needs to be measured. I don't have suitable raw files, so I can't make any statement, but I find it hardly believable, that the P45 Plus does not profit anything from the analogue gain, according to the DxO chart.

On the other hand, the fake ISO steps of the MFDBs do not reduce the DR by any amount, in contrast to DSLRs.
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« Reply #38 on: April 26, 2009, 03:03:58 PM »
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Quote from: Mort54
OK, I'll throw some gasoline on the fire :-)

That you definitely did

I've been always skeptical about the hand-waving of MFDB aficionados, and the dismissive claims of "micro-tonality" (whatever that is) and "3D-look" (I don't see it). I shoot MF and 35mm film (well, shot, although I'm seriously thinking re-starting limited MF shooting), the only difference in Velvia and Provia out of those two cameras is that there's lots more detail.

Sure, if I had 50k to throw away I'd buy a 65+ or S2 in a heartbeat. But I'll be happy with 12 megapixels - I was happy with 8 previously...
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ErikKaffehr
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« Reply #39 on: April 26, 2009, 03:18:22 PM »
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Hi!

So you see benefits from MFDB regarding detail but not on dynamic range? That makes sense to me...

In a sense this is academic. If the MFDB images are better than that's it. It doesn't really matter if they are better because of high MTF, better microcontrast or higher DR. On the other hand, being an engineer I prefer explanations which are consistent with theory and measurements.

Best regards
Erik

Quote from: Mort54
OK, I'll throw some gasoline on the fire :-)

I shoot primarily landscapes and use a P45+ on a Mamiya 645 II, as well as a D3 (one of these days I'll upgrade to a D3X). The only thing the P45+ gives me is more pixels, and no AA filter getting in the way of those pixels. There, I said it out loud. Believe me, I take no pleasure in saying that, given how much I spent on the P45+ kit. But that's what I'm seeing.

More pixels is no small thing, and the lack of an AA filter further helps out,  and in fact these are the two primary reasons I got the P45+ kit. The detail available in a MFDB file is breathtaking. But as for all the other so-called advantages attributed to MFDBs, I'm not seeing them. If anything, I agree with DxO's assessment here. Maybe these other advantages were real a few years ago, but with the latest crop of DSLRs, the gap has narrowed considerably. I have no trouble pulling clean sharp detail out of the shadows with my D3. If anything, I rank the D3 slightly superior to the P45+ in this regard (based on using the D3 at ISO 200 and the P45+ at ISO 50, their respective base ISOs). And the D3 has more mid-tone to highlight DR than the P45+, again at base ISOs. The P45+ saturates at around 2 and 2/3 to 3 stops over mid-tone. The D3 highlights don't hit the limit for another two thirds to a full stop beyond that. And the D3X is reportedly even better in this regard.

On top of all this is the convenience factor in Nikon's (and Canon's) favor. I have excellent quality super wides to super telephotos, and everything in between. I have an excellent selection of tilt/shift lenses. I have blazingly fast AF. My batteries last days, not hours. And I have superb in-camera live view that allows me to achieve critical focus to a much more repeatable and precise degree than I've ever been able to achieve with my MF kit.

One of these days I'll get a D3X, and I doubt I'll pull the P45+ kit out much after that, based on what I've seen to date.

Regards,
Mort.
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