43 replies to this topic

[Drew]

I can't believe you're posting Rockwell tests now Alex. I feel the need to send you to your room for that.

[photovan]

Can't help thinking, FINALLY after years of this stuff, Canon has something to be compared to.....

[Drew]

Especially since Rockwell uses a probably OOF uprezzed shot to compare. Woo hoo. I don't know why he would put up such flawed comparisons. I also noticed no one compares the 1Ds3 to the D3x. Similar pro body, AF performance, dual cards, weather sealing (well that's debateable since the lens is the other part of the equation) AND the $ value is similar too.

[loftus]

When I used to read his stuff; I read somewhere that he does not think tripods are too important.

[Drew]

That's cos he IS a tripod in his own mind!
Thinking about it, I guess it is unfair to compare the D3x to the 1Ds3 since the 1Ds3 has been out for over a year (that's like 40 years in human terms). Opps are we back to Nikon playing catch up again?
I do find it interesting that the last 4 years, Canon users are accustomed to higher megapixel cameras like the 1Ds2, which until the 1Ds3, was the queen of megapixels. Nikon users have been stuck at 12mp for so long then comes a monster 24mp D3x. It must be like shellshock... I know I was a little giddy going from the Nikon D2H to Canon 1D2. 4-8 mp...woohoo.

[loftus]

Thinking about it, I guess it is unfair to compare the D3x to the 1Ds3 since the 1Ds3 has been out for over a year (that's like 40 years in human terms).

Fair or not, that's the camera it should be compared to because of the market niche at which the D3x is clearly aimed. A year ago, the DSMkIII was king of that hill, today it's the D3x. Whenever, Canon brings out a MkIV they will likely be king of the hill again.
For Canon 5DMKII should be compared in my opinion to the D700; for those who want or need MP and video, the 5DMkII is clearly the best choice. For those who don't feel these two issues are important the D700 is a winner with regard to other features like high ISO, DR (maybe), focus, built in flash and frame rate. I think Canon has created a new market niche with the 5DMkII and chosen to forsake larger pixels for more of them.
Nikon at this point seems to be staying with the two camera strategy - one large, one small pixel approach. If they bring out a D700x then that will confirm my theory, if not and then my theory goes down the crapper.

[Alex_Mustard]

Some more pixel peeping from Thom Hogan - a much more agreeable chap than Rocky.
http://www.bythom.co...ond3xreview.htm

Those diffraction tests are really dramatic. Never seen such a dramatic effect - and surely a DX camera of 12MP should be worse?

Alex

[Drew]

Alex, go out and test the 105VR from f4-22 with your D2x... you'll be amazed what you see from f8 onwards.

[craig]

I did something similar back in August. Diffraction effects are predictable. Thom's review provides a good demonstration.

[loftus]

Reading Thom Hogans review, one really starts to get a sense that using the 20+ MP cameras might actually be counterproductive, except under the most controlled conditions.

[Drew]

I dunno Jeff. I just read it and the tone of his review is more like I wish I didn't buy this camera with my own money. His suggestion of picture stitching with just the D700 can be further taken down to a D70 or even a D1x. To make suggestions like that shows his personal views more than objective testing. A little disappointing from him really. Almost as bad as the happy happy joy joy reviews one gets.

[PRC]

How typical is that amp noise that Thom points out ?

Is that a killer for the astro-photography fraternity or are they all using other devices for image capture ?

Paul C

[loftus]

I dunno Jeff. I just read it and the tone of his review is more like I wish I didn't buy this camera with my own money. His suggestion of picture stitching with just the D700 can be further taken down to a D70 or even a D1x. To make suggestions like that shows his personal views more than objective testing. A little disappointing from him really. Almost as bad as the happy happy joy joy reviews one gets.

I think that he clearly thinks the image quality is superb, just seems to imply that unless the setup is ideal he might defer to his D3. Back to the old argument that there is a price to be paid for more MP everything else being equal.
Let's put it another way, if one is fortunate enough say to own a D3 and a D3x, there are times when one might choose to use the D3, rather than the D3x. I don't think this is much different to the Canon guys who own a 1D and 1DS.

Edited by loftus, 13 January 2009 - 04:17 AM.

[jeremypayne]

How typical is that amp noise that Thom points out ?

Is that a killer for the astro-photography fraternity or are they all using other devices for image capture ?

Paul C

I've read and heard that it makes digital Nikons completely useless for astro work and that currently the ideal astro-cameras are all Canons - with the 40D held up as ideal.

The hot pixel issue can be solved by the long exposure NR, but that "eats stars" (making some stars just vanish) - and does so at the RAW level ... it works for long exposure landscape stuff, but not atro stuff.

[craig]

I've read and heard that it makes digital Nikons completely useless for astro work and that currently the ideal astro-cameras are all Canons - with the 40D held up as ideal.

The hot pixel issue can be solved by the long exposure NR, but that "eats stars" (making some stars just vanish) - and does so at the RAW level ... it works for long exposure landscape stuff, but not atro stuff.

The problems with Nikon in that application are (1) that Nikon was very late to the low noise party, and (2) that they don't use a DC offset between the sensor and the ADC. The DC offset which Canon implements makes noise reduction easier in the darkest shadows. For astro photography, Canon apparently has advantages but it isn't amp noise that's the issue. People often confuse the DC offset issue and claim instead that Nikon does noise reduction before the RAW output. All they do is clip the negative swing of noise at the zero point and it would take action on their part not to.

The amp noise of the D3x is characteristic of the integrated ADCs on the sensor and is shared with the Sony cameras and the D300. It is not shared with the D3. The amps on the Sony sensors are especially good at low ISO but are bad at high ISO. For underwater photography this shouldn't be an issue unless a lot of your critical shooting is done at 1600+.

[jeremypayne]

The problems with Nikon in that application are (1) that Nikon was very late to the low noise party, and (2) that they don't use a DC offset between the sensor and the ADC. The DC offset which Canon implements makes noise reduction easier in the darkest shadows. For astro photography, Canon apparently has advantages but it isn't amp noise that's the issue. People often confuse the DC offset issue and claim instead that Nikon does noise reduction before the RAW output. All they do is clip the negative swing of noise at the zero point and it would take action on their part not to.

The amp noise of the D3x is characteristic of the integrated ADCs on the sensor and is shared with the Sony cameras and the D300. It is not shared with the D3. The amps on the Sony sensors are especially good at low ISO but are bad at high ISO. For underwater photography this shouldn't be an issue unless a lot of your critical shooting is done at 1600+.

Conclusion
The readout noise of the Nikon and Canon CMOS detectors is very similar. The high ISO sensitivity displayed by Nikon is for the marketing: Nikon D3 CMOS (and also the CMOS D300 CMOS - Sony origin) is a very high quality sensor, but in the end, Nikon just rises now the level of Canon technology.The behaviour of Nikon DSLR are radically different from the Canon ones for long exposure:- For Nikon, the hot pixels are eliminated by a sophisticated digital processing external to the sensor. During this digital processing, the signal of the neighboring pixels is also affected. The damage of such processing is well-known in astronomy: the weak stars are also eliminated and the image loose photometric qualities on stellar like objects.- For Canon, the thermal signal is reduced for each pixel by a differential reading method. The thermal signal level measured at the output of the sensor is very low. The residual can efficiently be removed during the image processing (a simple substraction of a reference dark signal map).[b]It is tragic to see that Nikon solved the problem of thermal signal by a digital processing of the RAW files (i.e. NEF files do not contain true raw data). This processing can surely meet the daytime users and the high performance for main application is evident. But by repeating the same mistake made on the D70 and the D200 (equipped with a CCD) on the news Digital SLR Nikon probably divorces once more with the astronomical community.Today the Canon and Pentax cameras seem to be the only ones useable digital SLR for efficient and advanced astronomy.

link: http://www.astrosurf...n_test/test.htm

[Formatting edit by mod to increase legibility]
[Thanks! - jsp]

Edited by jeremypayne, 13 January 2009 - 07:54 AM.

[craig]

A notable takeaway from your quote applicable to more maintream photography:

"This processing can surely meet the daytime users and the high performance for main application is evident."

Yes, Nikon's implementation has a weakness for astro photography. It's hardly relevant here.

I consider this aticle's conclusion weak, BTW, and it's written with a decided Canon bias. The chief difference between Canon's and Nikon's implementations is the DC offset. I would suspect Nikon doesn't do it because adding the offset may introduce another noise source. For conventional photography, all testing thus far suggests that the D3x is competitive with Canon's high res FF sensor in noise performance and nothing Canon makes is better than the D3 for high ISO.

The same companies that modify cameras for astro photography, the ones that used to be Canon-exclusive, now support Nikon bodies. Why do you think that is? Demand perhaps?

[jeremypayne]

Yes, Nikon's implementation has a weakness for astro photography. It's hardly relevant here.

Totally agree - except it directly answers Paul's question ...

The same companies that modify cameras for astro photography, the ones that used to be Canon-exclusive, now support Nikon bodies. Why do you think that is? Demand perhaps?

Likely - but I wonder how would they modify a Nikon to address this issue ... It would seem a tricky problem to address. The problem would also not affect "non-stellar" astrophotography, ie lunar, etc.

[craig]

Totally agree - except it directly answers Paul's question ...

It isn't, though, because it's not a matter of amp noise. Nikon's D3 doesn't have the same amp noise characteristics because it uses an off-sensor amp that offers better high gain noise performance. The answer to Paul's questions are (a) it is not typical of Nikon cameras but rather typical of recent Sony sensors, and (b) the D3x is probably not the right choice for astro photography irrespective of amp noise.

Likely - but I wonder how would they modify a Nikon to address this issue ... It would seem a tricky problem to address. The problem would also not affect "non-stellar" astrophotography, ie lunar, etc.

They don't. Astro modifications include removal of the hot mirror and AA filter. Those people will still tell you that Canon is a better choice, but the choice of Canon is largely historical. Now that Nikon cameras are more competitive they have more demand. My D300 is modified in that way but a year ago none of them would consider modding my D3.

[jeremypayne]

Thanks for continuing to drop mad science on my head!