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Author Topic: Lloyd Chambers compares D3x - 5DKII shadow performance  (Read 21493 times)
digitaldog
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« Reply #60 on: January 27, 2009, 10:37:01 AM »
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Quote from: NikosR
Nonsense. Everything is a compromise. I don't see how offering an option (you don't HAVE to use Auto ISO) is anything but a good thing.

I agree, that would be an awesome feature. I really love the Auto ISO on the 5DMII which I didn't have in my previous 5D. An option as you describe would be useful in some situations.
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Andrew Rodney
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ErikKaffehr
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« Reply #61 on: January 27, 2009, 10:51:40 AM »
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Bernard,

Doesn't the D3x has two readout modes? A fast 12-bit and a slower 14-bit?

Best regards
Erik

Quote from: BernardLanguillier
This isn't you Gabor, is it? Tell me that somebody hacked your login/password and is trying to damage your reputation with this non sense?

How is the availability of lower image quality options in a camera relevant when discussing the best output it can produce? Why did you stop there and didn't you comment on the stupidity of Nikon providing the option to shoot in medium resolution jpgs? Using the same logic you are using above, you could have written "If Nikon provides medium resolution jpgs, it must mean that the quality of a medium resolution jpg file is as good as that of a 14 bits raw".

You know full well that 12 bits/lossy options with the D3x can be useful sometimes because of the smaller file sizes and higher frame rate they boast. The availability of these options says nothing about the quality gap between them and the best available 14 bits mode.



How on earth are you able to make assumptions on the behaviour of a 14bits file from a 12 bits file? How rigorous and scientific is this approach?



I stopped believing in conspiracies a few years back. I have no reason to doubt the credibility of these information sources, and you have so far not brought any evidence to the table indicating that they could be wrong. You are measuring something different.

All I am saying is, please do an apple to apple comparison by measuring the same thing they are measuring.

If you are not interested in doing this, please avoid commenting on the quality of their results.

Cheers,
Bernard
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Ray
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« Reply #62 on: January 27, 2009, 03:20:48 PM »
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Quote from: digitaldog
I agree, that would be an awesome feature. I really love the Auto ISO on the 5DMII which I didn't have in my previous 5D. An option as you describe would be useful in some situations.

How does that work, Andrew? According to dpreview's preview of the 5D2 it has, to quote, " Auto ISO (100 - 3200) in all modes except manual". I presume that means in aperture priority mode the camera can select a reasonably fast shutter speed and ISO to suit. Does it vary the balance according to the lens focal length?
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digitaldog
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« Reply #63 on: January 27, 2009, 05:14:06 PM »
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Quote from: Ray
According to dpreview's preview of the 5D2 it has, to quote, " Auto ISO (100 - 3200) in all modes except manual". I presume that means in aperture priority mode the camera can select a reasonably fast shutter speed and ISO to suit. Does it vary the balance according to the lens focal length?

It appears to balance according to the lens. Not totally sure what's happening under the hood but for fast action, or casual shooting, the mode is really sweet.
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Andrew Rodney
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BernardLanguillier
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« Reply #64 on: January 27, 2009, 06:08:37 PM »
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Quote from: ErikKaffehr
Doesn't the D3x has two readout modes? A fast 12-bit and a slower 14-bit?

Hello Erik,

I am sure how they do it. I do not have any priviledged relationship with Nikon and don't have any information besides what is publicly available.

The level reached by this generation of bodies (whether they are from Sony, Canon or Nikon) is such anyway that I feel I can stop to worry too much about the internal magic and just use the camera.

In a way, the DR provided by the D3x reminds me of B&W shooting, just get the exposure approximately right and deal with it in post. Of course, you can get much better results if you nail the exposure and the quality of those perfect files viewed at 100% on screen is such that you are naturally drawn to perfection, but the fact is that in most cases the camera ends up being very forgiving.



I assume that the same can be said about the 5DII and A900.

Cheers,
Bernard
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A few images online here!
ErikKaffehr
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« Reply #65 on: January 27, 2009, 06:37:08 PM »
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Hi!

According to Thom Hogan ( http://www.bythom.com/nikond3xreview.htm ) the D3X shoots 5 FPS at 12 bits but only 1.8 FPS at 14 bits. A suggestion was on this forum that 14 bit readout is achieved by combining two 12 bit readouts with different preamplifiaction before the column DA converters.

This may explain some of the differences between DxO findings and Panopeepers findings. Panopeeper downloaded 12 bit data from Imaging Resource, and that could very well be shot in 12 bit mode and therefore having DR similar to A900. DxO may have used 14 bit mode in their lab shooting and therefore have extended DR.

My concern is not DR on it's own, but the discrepancy between Panopeeper's and DxO's results.

Best regards
Erik

Quote from: BernardLanguillier
Hello Erik,

I am sure how they do it. I do not have any priviledged relationship with Nikon and don't have any information besides what is publicly available.

The level reached by this generation of bodies (whether they are from Sony, Canon or Nikon) is such anyway that I feel I can stop to worry too much about the internal magic and just use the camera.

In a way, the DR provided by the D3x reminds me of B&W shooting, just get the exposure approximately right and deal with it in post. Of course, you can get much better results if you nail the exposure and the quality of those perfect files viewed at 100% on screen is such that you are naturally drawn to perfection, but the fact is that in most cases the camera ends up being very forgiving.



I assume that the same can be said about the 5DII and A900.

Cheers,
Bernard
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BernardLanguillier
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« Reply #66 on: January 27, 2009, 06:55:12 PM »
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Quote from: ErikKaffehr
This may explain some of the differences between DxO findings and Panopeepers findings. Panopeeper downloaded 12 bit data from Imaging Resource, and that could very well be shot in 12 bit mode and therefore having DR similar to A900. DxO may have used 14 bit mode in their lab shooting and therefore have extended DR.

That's exactly what I have been commenting about in this thread. DxO and all the other testers who have had a D3x in their hands have been testing the 14 bits mode while Gabor has so far only worked on 12 bits samples.

Not knowing how the camera works, it is impossbile to draw any conclusion about 14 bits files from 12 bits files. This is by no means a criticism of Gabor's testing methodology.

Cheers,
Bernard
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ErikKaffehr
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« Reply #67 on: January 27, 2009, 07:01:39 PM »
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Bernard,

I really appreciate that comment. I felt we had a little to much agitation on this thread recently.

Best regards
Erik

Quote from: BernardLanguillier
That's exactly what I have been commenting about in this thread. DxO and all the other testers who have had a D3x in their hands have been testing the 14 bits mode while Gabor has so far only worked on 12 bits samples.

Not knowing how the camera works, it is impossbile to draw any conclusion about 14 bits files from 12 bits files. This is by no means a criticism of Gabor's testing methodology.

Cheers,
Bernard
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ejmartin
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« Reply #68 on: January 27, 2009, 08:10:24 PM »
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Quote from: ErikKaffehr
Hi!

According to Thom Hogan ( http://www.bythom.com/nikond3xreview.htm ) the D3X shoots 5 FPS at 12 bits but only 1.8 FPS at 14 bits. A suggestion was on this forum that 14 bit readout is achieved by combining two 12 bit readouts with different preamplifiaction before the column DA converters.

This may explain some of the differences between DxO findings and Panopeepers findings. Panopeeper downloaded 12 bit data from Imaging Resource, and that could very well be shot in 12 bit mode and therefore having DR similar to A900. DxO may have used 14 bit mode in their lab shooting and therefore have extended DR.

My concern is not DR on it's own, but the discrepancy between Panopeeper's and DxO's results.

Best regards
Erik

Using two different 12-bit amplifications would yield telltale signs in the RAW data -- highlights would only populate the top 12 bits of the 14.  I haven't analyzed D3x RAWs though, so I can't say whether this is what's going on.

As far as Gabor's results, I suspect he isn't measuring what he claims to be; I gave a detailed analysis in a parallel thread over at DPR:

http://forums.dpreview.com/forums/read.asp...essage=30809618
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emil
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« Reply #69 on: January 28, 2009, 12:41:35 AM »
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Quote from: NikosR
PS2. I've just gone over Lloyd's latest comparison in DAP in which he extracts details out of the shadows in a very high contrast image by pushing in the raw converters by 2 stops. I don't care if somewhat different results might have been achieved by different selection of raw converters. The difference between the 2 cameras can only be descibed by 'Wow!'. Since for a digital capture to be a photograph it has to go through the demosaicing phase, what does it matter if the difference in noise in the raw files can be measured as 0.5EV or 1.7EV? Just looking at Lloyd's comparison does not leave anyone with a doubt about the GREAT difference in low level detail that can be extracted in the two cameras and the quality differences resulting from the 2 stop push.The difference is well beyond pixel-peeping territory. It's about the difference I see between my D70 and my D700. It jumps up and smacks you in the face. I hope I'm not infringing any copyright here since the same can be seen in his free overview.

Good lord, as a primarily night photographer (and constantly dealing with those low values) I'm scared to subscribe now as I may end up feeling like I should have waited longer instead of buying the 5D2!  

In any case, while way over my head, this discussion is interesting and I appreciate all the info those who have contributed are posting!
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NikosR
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« Reply #70 on: January 28, 2009, 01:07:21 AM »
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Quote from: brianchapman
Good lord, as a primarily night photographer (and constantly dealing with those low values) I'm scared to subscribe now as I may end up feeling like I should have waited longer instead of buying the 5D2!  

In any case, while way over my head, this discussion is interesting and I appreciate all the info those who have contributed are posting!

Be aware that we're talking base ISO here.
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Nikos
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« Reply #71 on: January 28, 2009, 01:15:18 AM »
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Quote from: NikosR
Be aware that we're talking base ISO here.

Yeah, I've been making heavy use of the higher ISO capabilities of the 5D2 so there's really no way I could justifiably get rid of it...but that the potential for such clean deep shadows exists is exciting.
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erick.boileau
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« Reply #72 on: January 28, 2009, 01:27:12 AM »
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IQ  and dynamic range at 100 ISO seems really the best
« Last Edit: January 28, 2009, 01:31:30 AM by erick.boileau » Logged
BJL
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« Reply #73 on: January 28, 2009, 01:21:17 PM »
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Quote from: ErikKaffehr
According to Thom Hogan ( http://www.bythom.com/nikond3xreview.htm ) the D3X shoots 5 FPS at 12 bits but only 1.8 FPS at 14 bits. A suggestion was on this forum that 14 bit readout is achieved by combining two 12 bit readouts with different preamplifiaction before the column DA converters.
Another proposal (also made for the 14-bit mode of the D700) is that the same photosite charge is run through the sensor's ADC four times, each with the 12-bit ADCs of the Sony sensor, and the digital levels are summed. With the 12-bit ASC levels being integers from 0 to 4095, the sum is an integer from 0 to 16380, nicely fitting the 14-bit range from 0 to 16383.

That would average over time-random variation in ADC output for the same input. Four reads would only be expected to improve S/N by a factor of sqrt(4)=2, or a "one bit improvement", but if that is enough to go beyond the S/N ratio that 12-bits can record, the normal jump in bit depth is to 14 rather than 12, especially as that allows simply adding the four twelve-bit levels.


Some might raise the objection that A/D conversion destroys the charge in the sense capacitor at the bottom of the column. But that charge gets there from the photosite using charge gain amplification, not actual transfer of electrons, so the photosite-to-sense-capacitor transfer could be repeated. Doing that would have the advantage that the averaging also applies to the noise in the charge amplification process, which I have reason to believe is a significant source of noise in CMOS sensors.
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jani
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« Reply #74 on: January 28, 2009, 04:50:54 PM »
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Quote from: BJL
That would average over time-random variation in ADC output for the same input. Four reads would only be expected to improve S/N by a factor of sqrt(4)=2, or a "one bit improvement", but if that is enough to go beyond the S/N ratio that 12-bits can record, the normal jump in bit depth is to 14 rather than 12, especially as that allows simply adding the four twelve-bit levels.
Hmm. If I recall correctly, one frequent poster to these forums has already clearly stated that of the 14 bits, 13 are clearly used, but the 14th isn't necessary to encode the signal range. If so, that makes sense considering what you write above, and vice versa.
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Jan
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