Definitive A900/D3X noise/ISO samples

[mdcromer]

Pako,

The sony files are underexposed, it is not surprising that the noise is "painful".

Also, a touch of color NR will do wonders. I prefer to leave the luminance noise in place though.

[pakodominguez]

Pako,

The sony files are underexposed, it is not surprising that the noise is "painful".

Also, a touch of color NR will do wonders. I prefer to leave the luminance noise in place though.

Got the A900 last weekend (I borrowed from the Adorama Rentals) and used it for a couple of small gigs and I went to the Brooklyn Botanical Garden (the greenhouse is my favorite place during winter time...)
JPGs @ 400 ASA are really bad, reminds me to the A100 JPGs -since I only needed 6MP for those gigs, noise wasn't that notorious.

Painful, yes...

[mdcromer]

Pako,

1) Why are you shooting jpegs?

2) If you are going to shoot jpegs, have you tried David's modification to the jpeg parameters that drastically reduce the noise?

[KevinBarrett]

Pako, you had an a900 for the weekend and shot 6 MP JPGs?

[pakodominguez]

Pako,

1) Why are you shooting jpegs??

What's wrong about shooting JPGs?
1. I was spoilewd by 7D's JPGS
2. there were small gigs, internet only -no prints and, if printed, in small sizes. No need for more (and they don't pay for more)
3. I'm not getting on an useless debate RAW vs JPG. Period.

2) If you are going to shoot jpegs, have you tried David's modification to the jpeg parameters that drastically reduce the noise?

David didn't "discover" those parameters, but a guy from Rusia (or ex-soviets) that post it on DPR forum. Then: noise is there. You know that. I know that. Sony people knows that and they know they have to improve the JPG engine and other software issues, firmware and IDC.

I know we will get to a better noise files (not to a low-available-light camera) but changing the Zone Matching + sharpness it's just a tric, not a solution.

Regards

[pakodominguez]

Erhmmm...it ain't DK's modification and the settings do not drastically reduce noise...what actually happens is the effective ISO is reduced and on some frames the shadows are being crushed using the aborgasta ZM settings. The smart thing to do at high ISO is expose to the right.

-Sonolta

Don, all this discution happened while your camera was on service. Did you ever tried those settings? You right about exposing to the right, but I'm just curious...

[mdcromer]

Don,

You are correct that the Alpha 900 overrates ISO (although less than the Canon 5D2). We don't know yet whether or not the Nikon overrates ISO.

What I am trying to present is some reasons why the Alpha might need more light than the Nikon.

I think it is important that David figure out which of these is the case if he wants to present the true "Definitive" noise comparison.

For example, if it is simply a difference in the transmissivity of the lenses, inaccuracies in shutter speeds, or inaccuracies in aperture, that's very important.

[David Kilpatrick]

Thanks for the info David.

Looking at the ISO 6400 shots, I am still seeing a significant increase of exposure with the Nikon over the Sony. At least 2/3 stop. This includes highlight areas, where the Sony is much less blown out than the Nikon.

I have noticed this in real life (not test) general shooting and remarked on it already. The Nikon is around 1/3 to 2/3 stops more sensitive at the high ISO end, do not judge on the low ISO exposures because the metering response is not linear. When doing flash tests at a fixed aperture, it is obvious that the Nikon is nearly one full stop more sensitive (=bright) than the Canon 5D MkII at the same nomal ISO rating. Yet technical tests (DxO, dPreview etc) often don't flag up these extreme differences. It is also clear that the Sony ISO is non-linear.

I could do a similar test using a dozen different methods - variable exposure bracketing in 1/3rds then picking the result to exact match density by eye/histo, constant fixed exposure (manual), constant metered exposure with correction initially to match manual (the method used). I used this method because it reflects the actual performance of the camera, when used with its own built in metering system. The one thing I have learned from doing test shoots like this is that no matter what method is used, people will complain that the field is not level etc etc etc.

The Nikon definitely outperforms the Sony, which is what we expected to see. Pako commented on CA on the Micro Nikkor VR 105mm; this image is such a small section from the frame (only 5 megapixels of the 24, and centered) that the outer field is excluded. I believe the Minolta 100mm f2.8 is a better lens, based on working with the test files and shooting several other sets in the process of working out how best to do these. This is subjective.

David

[David Kilpatrick]

Pako,

The sony files are underexposed, it is not surprising that the noise is "painful".

Also, a touch of color NR will do wonders. I prefer to leave the luminance noise in place though.

The Sony files are correctly exposed. The Nikon tends to overexpose, or is more sensitive at the higher marked ISOs. The image is intended to have some dark or murky areas, it was set up to show colours fully lit, a specular reflected highlight which is difficult to render, fully lit colours with a range of light contrast (beans not colour patches on a checker) and a dark area (shadow of the jar on the tile).

See the complete image and its histogram, click it to open (Mac 24 inch screen shot) - the histogram also has figures, it's just about ideal in containing the tonal range:

However, I do have a complete set of Nikon files adjusted in exposure bias to resemble the Sony more closely as shot; these are visible to the left of the thumbnail strip, the Sony (cooler) to the right. I can substitute those tonight, they will be a better match although the EXIF data will no doubt get Nikon folk claiming the test is invalid. I'll do that before creating a main website post showing the results.

David

[pakodominguez]

Pako, you had an a900 for the weekend and shot 6 MP JPGs?

Enough quality for this: http://newyork.joonbug.com/photos/oFrMa6zowqM" onclick="window.open(this.href);return false;

[InTheSky]

So many different things are going on under-the-hood with these cameras that it's almost impossible to do a perfect test of this type. The best thing to do if you are a raw shooter is take non-underexposed files from each camera and use several processors to see what you come up with as an optimum result. Not a default result but an optimum result. Make sure you captures scenes in varying amounts and types of light, as well as with varying amounts of shadow and background detail from each camera or you will be short changing yourself on the final result. If you are testing high ISO capabilities then you may want to expose-to-the-right when shooting the tests.

If you are a JPG shooter then do the same thing after tweaking all of the settings in-camera for the specific scene and then fire away to see what you get straight-out-of-the-box.

The bottom line is the longer you work with a camera, the more you get to know how it meters, where your settings need to be, and how your camera makes top images in general. All of the testing in the world does not mean much unless you have at least figured out the cameras' and the converters' fine nuances to make sure you have given the cameras the best chance to give you top results.

In-other-words...firing away at the same aperture and shutter speed at the same target these days sometimes does not mean a lot.

-Sonolta

Hum ... this is not a bad idea ... why not start a kind of game ... , where David you are putting Raw file at ISO 200, 1600 and 6400 like ... After that ... we have to take a Pro Nikon PP user, and a Pro Sony PP user. The rules, cannot add element from another files ... but for the rest, make you best to bring us the best picture. But ... this is dangerous, because for me I'm a lover of Vignetting, this means that if I'm working on the picture i will add some .

Probably some person has there tricks to make the picture looks better. But I'm agree with the fact that in this word ... the JPEG compare is the only solution from camera , asking which camera can bring the best inside PP.

On my side, i have accepted after first few days that my A900 is plenty of noise over ISO 1600, but... I'm dealing with it. And in low light concert ... I'm reducing my size to 1500x1500 maximum and it look good for myspace website . But this is my own utility.

But ... a Raw challenge will be interesting to see , and will save DK time too.

Regards,

Frank

[David Kilpatrick]

But ... a Raw challenge will be interesting to see , and will save DK time too.
Regards,
Frank

Not with this challenge yet, because there are too few converters out which can handle the files. ACR or Lightroom won't tackle D3X yet, nor C1Pro, not Lightzone, not Aperture, not DxO - and so on. Some don't even do the A900 yet and it has been out since September.

When all the converters out there can handle the files from both cameras, a mass 'find the best solution' using a 6400 raw file could be possible. It is easy to set up a single shot with different parts overexposed and underexposed (the shot I set up is already in that category) so a range of exposure is not really needed, just a range of light levels across a group of subjects. Rather more taxing is the size of the files, the Nikon raw files at 49.9MB for example are not all that friendly for hosting and download - though I've got solutions for that.

David

[pakodominguez]

Pako, you had an a900 for the weekend and shot 6 MP JPGs?

Enough quality for this: http://newyork.joonbug.com/photos/oFrMa6zowqM" onclick="window.open(this.href);return false;

Good post, Pako. Just what I figured... Looks like you had a lot of fun with the a900!

-Sonolta

Just a job to do...

[mdcromer]

David,

Nice work, very well done comparison versus what I have seen done elsewhere to date.

I think there are two final steps to do before posting your final comparison.

1) Test using other lenses and see if the Nikons are always about 2/3 stop more sensitive at the same EV, or if it might be an issue with the transmissivity of the glass you tested here or perhaps out of spec aperture values.

2) Do the test at a long shutter speed so you can easily tell if the shutter speeds might be out of spec.

If 1 and 2 come out the same and yet the Nikon is still 2/3 stop more sensitive, then that's that. But we can't make a final judgment on sensitivity until we are certain there is no variation on EV caused by the lens configurations or by inaccuracies in shutter speed.

[David Kilpatrick]

I have now updated the samples to use the Nikon images which are matched in density to the A900, rather than those which were matched in EV setting (aperture/exposure time at ISO 200). I have also three histograms which are of some interest technically, because they show how the A900 can cope with a large dynamic range while the D3X can not (or at least, appears not to based on whatever raw extraction is carried out on both filetypes by RAWDeveloper).

Here is the A900 histogram at ISO 200 (0.8sec, f16, tungsten balance set manually on the camera):

The red and blue channels are clipped at the shadow end, but the green (main luminance channel information) is at level 5. The highlight is held just below 255 on all channels, indicating a perfect raw file for normal post-processing with no highlight clipping. The exposure was set for these tests to avoid highlight clipping.

Here is the D3X histogram at ISO 200 for exactly the same highlight clipping avoidance - 0.6sec was required instead of 0.8. The shadow ends of the channels are all clipped (0,0,0):


You can see clearly how the Sony tungsten balance is almost exact for studio flash modelling lights at full power; the Nikon balance is warm (the separation between the red, green and blue in the main peaks).

Here is a Nikon image taken at the same actual exposure as the Sony, 0.8s at f16:


It shows clipping at both ends, though in the actual image the midtones are definitely the best defined. The tungsten balance is still warm. This was the original example file posted at ISO 200, now replaced by the version which matches the Sony highlight positioning. If the Sony exposure was increased to the point of highlight clipping, it is likely that the shadows would be falling short (all levels above 0). This type of tone curve tends to emphasise noise, while Nikon's tone curve (sacrificing the shadows, pulling the midtones up, and accepting some clipping at the top end) tends to reduce it.

One of the common criticisms of Sony images is that they are 'soft', which certainly doesn't mean lacking sharpness; it seems to be a judgment of their midtone contrast function or slope, combined with retention of shadow detail when it's perhaps not really needed, and retention of highlight detail. A more contrasty range is being squeezed into the 256 steps per channel, like printing a contrasty negative on Grade 1 paper instead of using Grade 2 and getting some nice dense shadows and paper-white highlights. Technically, the Sony approach is 'better' but doesn't always look as good. It results in best of class results for dynamic range but can give some pictures, especially those in darker or dull conditions, a bit of a flat muddy appearance. The D3X strategy is closer to consumer camera tone curve. This is all marginal; where the Sony positions the average tone (value 128) around level 113 for this scene, the Nikon positions it around 135 (for the same nominal exposure). But when the Nikon's highlights are reined in to avoid clipping, its average is darker than the Sony at 110.

If you were to measure ISO by the old film standard of 'first measurable density above fog level' where fog level is 1,1,1 (insignificant bit level) Sony would actually have higher ISOs for the given setting than the Nikon. But if you measure using EI (Exposure Index) based on a digital midtone (128,128,128) Sony is 1/3rd stop lower. If you were to measure the sensitivity at 255,255,255 Nikon would be at least 2/3rds of a stop 'higher'. These histograms and others (RAWDeveloper is a useful program for this purpose) confirm practical experience so far with the cameras.

The solution, as ever, is Sonolta's favourite - 'expose to the right' with the Alpha 900.

David