Here is a table of the luminance noise of each camera at selected ISO settings. The figures represent the signal to noise ration in dB and the higher the figure the lower the noise. This table shows overall luminance noise - which is an important point to remember. I'll be looking at colour noise later.

The most surprising result is the E-500. In the test pictures (http://dpnow.com/bb/cheaper-dslrs.pl?read=39) it showed some obvious noise artefacts above ISO 400. But its DXO s/n ratio result for luminance noise flatters the camera by comparison...

The Pentax *istDL doesn't show up very well in this test and, indeed, the Canon 350D isn't a stunner either; apparently flat last in the higher ISO levels - again this doesn't really tally with the test pictures.

But clearly you need to look a bit further than the raw figures - and there are more to come!

Incidentally, the table is reproduced as a gif image to preserve the formatting:

I'm assumimg the D50 is very similar chip wise to the D70 in which case these figures show a completely different picture to what comes off the camera, there is no way the noise at ISO200 is the same as ISO1600 off the D70.
Tony

Tony - very sorry about that. Unfortunately, the ISO figure is not included in the D50 EXIF data and I initially got the sequence the wrong way around, so the ISO 1600 and ISO 200 figures were repeated as teh ISO 1600 one. I have corrected the chart.

The Nikon D50 puts in the best overall result, which I'm sure you'll find agreeable

Interestingly, just as I found with the Konica Minolta D7, the D5's ISO 100 setting yields a slightly worse result than ISO 200, which might help explain why the Nikon D50 and Pentax *istDL, both using the same Sony sensor as the D5, don't offer ISO 100 settings.

Ian

Hi Ian,
I forgot to read this forum and it seems I have missed some interesting issues until now.

Well, about ISO 100 setting of the Sony sensor, thanks for that. Since Nikon traditionally put importance on picture quality, it's understandable.
yoshi

Thanks Ian, that's much more what I'd have expected. I've often wondered why the D70 started at ISO 200, looks like a reasonable explanation.
As has been said many times before it's not just the signal to noise ratio that affects peoples judgement of noise, it's the appearance of that noise. I'm fortunate in that both my cameras give crisp noise that looks like film grain, it's the over processed slushy noise thats objectionable to most ex-film types. I use the D70 at 1600 with a 50mm f1.8 Nikkor quite a lot for candids like the jazz shots and a 10x8 is less 'grainy' than using 400 colour neg film yet there are many who moan about such noise levels. They dont know how lucky they are.

Hi Yoshi,

I think it is a mistake to exclude ISO 100 because there will be occasions when the conditions are very bright and the camera will force a small aperture that will start to show diffraction effects and so soften the image.

Also, it does not help when you want to deliberately slow the shutter speed down for an effect.

In fact, I would sometimes find it useful to have ISO 50. The difference in noise between 200 and 100 on the Konica Minolta 5D is very small.

By the way, if you would like to receive a copy of all the posts from a forum board via email, you can subscribe (it's not charged!) to the board - see the link from the board index page.

Ian

> I think it is a mistake to exclude ISO 100 because there
> will be occasions when the conditions are very bright and
> the camera will force a small aperture that will start to
> show diffraction effects and so soften the image.

Hi Ian,
Yes, I should have been more deliberate when posting that. That message was too short and I want to add;

I personally prefer that manufactures give more choices to users. Whether you use ISO 100 or not in this specific case should be up to users. - clearly better for users to have more alternatives to choose.

Of course this assumes that having a wider ISO range for both ends in general does not result in lower quality in commonly used ISO ranges.

> In fact, I would sometimes find it useful to have ISO 50.

ISO 50 is one of the product features I'm waiting for. Maybe I'm too much influenced by film ideas but I prefer lower ISO to higher ISO. For films I mostly used ISO 50 (around 90% or more) and ISO 100-400 (the rest, mostly 100). This relates to some of my questions which I might post later at another board.

Incidentally, which do you think is more difficult technologically to achieve, higher ISO or lower ISO?

> By the way, if you would like to receive a copy of all the
> posts from a forum board via email, you can subscribe
> (it's not charged!) to the board - see the link from the
> board index page.

Well, I will look at it. I just haven't realized that service.
yoshi

> Ian

Hi Ian,
I looked at the e-mail service.
Do you mean hundreds of e-mails a day?
yoshi

The subscriber option is board-specific and some boards are busier than others. The average number of posts for the whole forum is around 50 posts a day, though it sometimes exceeds a hundred if there are some hot topics!

I would suggest that you set up a rule in your email client, if possible, and direct the forum subscription emails to a dedicated folder. That way you can scan through them easily and then delete them in one place once you have finished.

Ian

> Hi Ian,
> I looked at the e-mail service.
> Do you mean hundreds of e-mails a day?
> yoshi

> I think it is a mistake to exclude ISO 100 because there
> will be occasions when the conditions are very bright and
> the camera will force a small aperture that will start to
> show diffraction effects and so soften the image.

> Also, it does not help when you want to deliberately slow
> the shutter speed down for an effect.

> In fact, I would sometimes find it useful to have ISO 50.
> The difference in noise between 200 and 100 on the Konica
> Minolta 5D is very small.

Hi Ian

That's why I carry a couple of ND filters with the Nikon.
I'd rather do this than sacrifice some quality howerver small.
Tony

I'd argue that the hassle of having to fit the filter in the first place and the optical degradation of an extra piece if glass in front of the lens add up to inconvenience and a subtle reduction in optical quality that does not compare with a very slight increaase in noise, as demonstrated by the Konica Minolta D5.

Ian

The filters I use are optically flat high quality ones and only used once in a while so not a lot of hassel, most of the time I'm happy using ISO200 with the D70.
Also most people keep a skylight or UV filter on all the time and I'd bet some of those are low quality but you don't hear many complaints about them affecting image quality.

> The filters I use are optically flat high quality ones and
> only used once in a while so not a lot of hassel, most of
> the time I'm happy using ISO200 with the D70.
> Also most people keep a skylight or UV filter on all the
> time and I'd bet some of those are low quality but you
> don't hear many complaints about them affecting image
> quality.

Ah well, a filter still adds a couple of glass to air surfaces

When I was behind the counter selling cameras and stuff 20-odd years ago, I'd be depressed if I didn't manage to sell a skylight or UV filter for the lens, but you hardly every see them these days. I doubt you could buy one in Dixons anyway

How times have changed.

Ian

Hi Ian,
Your figures are really interesting and the ones for the KM5D track with my experience. What I have noticed is that at the higher ISOs there is some smoothing of detail, probably caused by the NR in the JPEG processing. This class of DSLR may be the test bed for processor ideas and upgrades for the higher end models. The balance between noise control and detail retension/sharpness vs. public opinion must be an interesting game.
Bob