low iso noise A900

[David Kilpatrick]

The Nikon D3 is unassailable at 6400-25,600 (until we know more about the Canon alternative) but to suggest that the A900 is no better than the D5D or A700 within its ISO range is nonsense. It may be no better pixel for pixel, at 100 per cent view, but there is a stack more detail present overall.

The real question is whether anyone really needs 24.5 megapixels at high ISO settings. They are normally used for sports/theatre/concert/events, typically with long lenses where the full frame is a disadvantage; and such pictures are rarely used in a way which demands more than 12 megapixels, or indeed 6. The majority end up on the web, on TV or in newspapers where 2 megapixels would be fine most of the time. If they had issued the A900 with an ISO range of 50-400 like an 'old' (2006!) Kodak full framer, I think I would be perfectly happy with that.

Because of what you shoot, I don't think you will be queuing up for an Alpha 900. Should you ever lay hands on one, you'll probably stop being so negative. But then, you've not shot with a D3 either - so in the end you have no direct, personal experience of any of this.

D3 at ISO 400 from a press/PR shot which came in today - 100 per cent clip of normal size file:

A900 clip from my ISO 1600 D3-size reduction as last shown:

Ok, just two random samples and not a strict comparison in any way - but really, the D3 is not some entirely noise-free wonder. Like the A900, it does actually display visible noise at anything over ISO 200 - and like the A900, the more detail and texture you throw at it, the less that noise becomes apparent. That's why in order to even see this type of noise, you have to clip a bit of unfocused neutral tone.

David

[David Kilpatrick]

Don, I don't think anyone has praised the D3 more than I have. I was one of the first to use one, and one of the first to see how exceptional its results were at ISO 200 let alone high ISO. Mind you, the comparison was with the Olympus E-3 which I was using alongside it.

One of the things about the best D3 files at low ISO is the rounded, three-dimensional quality they have (it's entirely different from Canon 5D). The lenses may have a lot to do with it. I am not getting the same sort of 'luscious' tonal contours from the Alpha 900 - there is something more 'dry' about the way it images.

But - I have not used a CZ lens on it. If you think I am totally happy with the A900, think again. I actually found the extra depth of field from the A700 useful, while everyone clamours to have less depth of field. No! I really need more not less, and I like the 4/3rds and smaller formats for that reason. And I'm missing the tele reach of the 70-300mm SSM on the A700 - 450mm equivalent. Not only have I lost that, I've gained a load of vignetting and distortion which was not visible on the A700. Of course, I can crop the frame - but the A700 has finer resolution at APS-C size, and overall a better image quality with v4 (pixel for pixel).

Where the A900 scores for me is focus accuracy (so far, perfect); use of my 50mm and 100mm macro lenses at their 'normal' view angles, which with the 50mm, means my copystand can be used for some commissioned work instead of a rig up of tripod and wall etc; and the feeling in ultrawide (17mm) views, which is somehow better than using 11mm on APS-C, maybe it's just the visual effect of the large finder. But it is also proving very good at ISO 800-1600 compared to the A700, once the file is sized for a typical magazine use (say 13cm wide). And I'm very pleased with the potential to return to some types of fine art and landscape work which digital has not been convincing on so far.

Fortunately I have never used flash much, so the lack of the flash and wireless flash is no big thing. But for certain jobs I do, I will have to use the A700 or by a 58 flash. More expense, not happy.

David

[markowp7]

hi david,

The in-camera JPEG - which I won't post - is worse, an Sony must address this because even an A100 ISO 1600 JPEG can look better for chroma noise than the A900 - there is clearly something not right with the firmware for JPEG production, unless it is absolutely necessary to use strong NR, which I have been avoiding. This shot was on Normal NR, and that could mean some raw NR processing is present. NR Off images seem to me to have sharper noise grain.

ok, that explains the visible traces of NR. i did my tests with NR off and, yes, the noise had more color grain. still, the images looked processed, can't tell how, but strange. as if the noise layer was put 'on top' of the image layer.


But it is also processed to leave every trace of noise visible, and uses a Medium Contrast curve without any adjustment of the black level in ACR. Take the same raw file, give it ACR NR 24 luminance, 50 chroma, and drop the black level from 5 to 2 (increases shadow noise but greatly improves midtone densities); size it down to an exact match for Nikon D3/D700 in Photoshop; do not apply any web sharpening; and you get this -

http://www.pbase.com/davidkilpatrick/image/103948712

still blotches in her phase. these are dreaded by people who write NR software. very hard to avoid them though, canon has a lot of it, nikon much much less.
I don't how familiar you are with Nikon D3 shots under similar conditions - I'm very familiar with them! - but it really is very similar to a D3 ISO 1600 processed to similar parameters


well here we disagree somewhat, but i admit, downscaling improved the image significantly.


Quite apart from that, the A900 has some qualities which the D3 lacks. One of these is exceptionally good tolerance to a wide range of lenses. I spent 20 minute on the phone today to a freelancing amateur I know and respect, who uses several systems (Leica M8, Olympus E-3, Nikon D3 and more) who is considering selling the entire Nikon kit to go with the A900 because his main interest in landscape, and he has found the 24-70mm Nikon disappointing for ultimate fine detail on the D3. I found it very good, but then got a poor sample on the D700, so the lens is not the perfection I first thought.

well, my 24-70 nikon is quite good, the 14-24 is better though. and the 24 PC lens is fantastic. i have never used minolta lenses, just realized that the CZ 24-70 produces a lot of (removable) CA. other than that it is very good.

This shot is taken on the 28-75mm KM, and no chromatic abb correction has been applied (f/5 aperture). There is no hint of bokeh-chromatic effects, despite the adverse light on some contrast boundaries, and overall it's a very smooth and even reception of the image from this lens. I know from daily dealings with pro Canon and Nikon users that this simply can not be expected even with an EOS 5D or a D3, let alone a 1Ds MkII or MkIII; lenses are their biggest problem. You can't imagine how happy I have been to discover that the A900 works so well with so many older Minolta/KM lenses, obviously some better than others.

as far as canon goes we agree totally.

Don't assassinate the A900 before it has seen six months' service in the hands of a wide range of users. I showed a set of A2 size full bleed Epson 3800 A900 prints to assembled professionals on Tuesday, and while they were baffled by why anyone would use a Sony, they looked long and hard at the results and the one thing most commented on was the price of the camera - they couldn't believe it was so low, and this was coming from Canon users fully aware of the 5D MkII. Of course the 5D MkII is a full £500 ($1000) more expensive on list price than the current best retail on the A900 here in the UK, and is not on sale yet.

all agreed too. pixel peeping is one thing printing another. and the price point of the sony is wonderful, a real steal. still, i feel (and hope) that the sensor of the alpha 900 will not make it into a future D3x (D4).
peter

The one thing which put them off most was the flash shoe. They all use Pocket Wizard and similar triggers, not sync cables any more, and expect their radio triggers to fit directly.

David

[markowp7]

sorry, the formatting of my last post was bad, i hope you can figure it out nevertheless. peter

[Jonathan K]

David,

you stated repeatedly (and showed a lot of convincing samples) that the A900 works astonishingly well with a range of lenses that intuitively would be considered too "weak" to do so, such as the KM17-35, the KM28-75, beercan etc etc.

Do you have a theory why that would be? Is it a hidden quality in the lenses? Maybe some strengths that could not be shown off on APS-C in the same way for some reason? Or is the A900 more tolerant (i.e. AA-filter)?
Anyway it makes the A900 become an option for the future (when price has gone down to 1500€ )

Thanks

Jonathan

[David Kilpatrick]

First of all, the A900 has exceptional sensor shading mapping. I noticed how good this was (partly because of the dramatic noise increase in the corners with 17mm) straight off. Anders Uschold presents some facts on it in today British Journal, and makes no detailed comments except to say "the camera applies a quite complex corner shading compensation function...hats off to that". Secondly, Sony claim their sensor is physically flatter than rivals - that they have kept it plane over the full area, where Nikon or Canon may not necessarily be as perfectly flat. Thirdly, I think that the focus is far more accurate on the A900 than any Sony or Minolta I have ever used before. There is zero BF/FF error on the two lenses I am now using (17-35mm and 28-75mm). Most of the poor sharpness on my D7D, A100, A700 must be put down to focus error though it did not seem that way.

Finally, maybe these lenses are better than I thought. I have always treated them as cheap brought-in designs to substitute for the expensive G series 17-35 and 28-70mm - a sort of poor man's G. Perhaps Minolta tested them from Tamron and decided they were entirely suitable as a G-series replacement. Whatever the case, so far I'm getting excellent results all the time. I also find that they don't have the same direct reflected flare patches which the CZ designs tend to produce when a light source is included in the pic.

The AA filter is more tolerant. It does have a lower value, and it is placed further from the sensor surface. This will definitely improve the corner sharpness with wide-angles, no doubt.

Other people may find differently but I've been putting up shots with zero CA correction applied in conditions where it would be expected.

David