D2X Blue Channel
Discussion
Take a look at the noise levels in each channel below. The photo was shot as ISO 200, with a flash. It was a bit cold looking so the blue channel has been boosted slightly, but even still, it's a bit of a shocker. The order of the pictures is RGB, R, G, B
>>> Edited by dcw@pr on Monday 11th April 11:44
>>> Edited by dcw@pr on Monday 11th April 11:44
Not exactly mind blowing quality is it? I find the D100 can produce hefty amounts of noise seemingly at random, independant of ISO rating. Generally speaking anything shot in low light levels (especially red) will have some noise, occasionally the noise is really bad - bad enough to ruin a shot for anything more than thumbnail use. Annoying to say the least, and a shame as its one of the few things that disappoints in an otherwise excellent camera.
...and not forgetting that noise is associated with any low light situation. It's a bit of an urban myth that noise is an ISO related issue.
I think this proves that technology still has further to go in this respect.
Also shows that whatever kit you use, intimate understanding of its good and not so good points can help you tremendously in getting the best out of it.
I think this proves that technology still has further to go in this respect.
Also shows that whatever kit you use, intimate understanding of its good and not so good points can help you tremendously in getting the best out of it.
I should point out that this isnt the whole picture, it's a 100% crop taken from this...
I can't agree that ISO has nothing to do with noise at all. If you go out on a bright day and take a photo at ISO 100 and one at ISO 1600, the higher sensitivity WILL (on this camera at least) have more noise. Or am I missing something?
>> Edited by dcw@pr on Monday 11th April 13:03
I can't agree that ISO has nothing to do with noise at all. If you go out on a bright day and take a photo at ISO 100 and one at ISO 1600, the higher sensitivity WILL (on this camera at least) have more noise. Or am I missing something?
>> Edited by dcw@pr on Monday 11th April 13:03
beano500 said:
...and not forgetting that noise is associated with any low light situation. It's a bit of an urban myth that noise is an ISO related issue.
I think this proves that technology still has further to go in this respect.
Also shows that whatever kit you use, intimate understanding of its good and not so good points can help you tremendously in getting the best out of it.
Indeed; increasing the sensitivity via the ISO rating will of course amplify any existing noise regardless of the light conditions - the fact that higher ISO's tend to be used in lower light probably give's credence to the myth that noise is *caused* by higher ISO rather than amplified.
I agree technology does have further to go, although some of the latest offerings are superb in this respect film remains king for ultimate quality.
I know what you mean about understanding the limitations / abilites helping to extract the best shot from your camera - it took me loosing several noisy shots before I started to understand how to get round it, although it still pops up from time to time. Annoying, but not the end of the world.
trackdemon said:
Indeed; increasing the sensitivity via the ISO rating will of course amplify any existing noise regardless of the light conditions - the fact that higher ISO's tend to be used in lower light probably give's credence to the myth that noise is *caused* by higher ISO rather than amplified.
OK, but that's really semantics. Of course any photo (digital or film) will have some degree of noise, and when you amplify it during developing/printing, or in photoshop, it will get worse. But taking the same photo in the same conditions with different ISOs will show that the higher ISO has more noise than the lower. Therefore I think it would be pedantic to say that ISO and noise aren't related?
Apart from any semantics, I have been busy looking up various techniques and workflow solutions and by coincidence came upon this:
Maximizing S/N Ratio in Digital Photography
Now I don't like the style in which it's written, but it does offer some food for thought on how to get the best out of what you've got......
Hope it helps.
Maximizing S/N Ratio in Digital Photography
Now I don't like the style in which it's written, but it does offer some food for thought on how to get the best out of what you've got......
Hope it helps.
beano500 said:
Maximizing S/N Ratio in Digital Photography
'Exposing to the right' seems to me analagous to recording sound at the correct level. The less you subsequently need to amplify it, the less noise you get also. However, there is little margin for error - too much to the right and you clip the whites.
Having spent much of the day going through wedding photos, I'm happy to be conservative and use Levels to correct. A little noise in the dark areas is better to me than a big chunk of blasted white.
trackdemon said:
Have to agree with you there John, I occasionally take to conservatively exposing a stop under in the hope of preserving highlights - I shoot RAW so there is always more than enough latency to add a couple of stops during processing if its a little dark.
A slight underexposure in order to avoid blowing the highlights does seem to be a Nikon trait. I find that leaving the D100 on either -1/3 EV or no adjustment quite often gives images that would classically be called underexposed but a bit of work with curves sorts this out no problem.
Chris
Ah, the ever increasing pixel count starts to do it's dirty work. Blue photosites have to work a bit harder to convert those pesky photons so I'm not that surprised. It always used to be the red channel that was bad due to the proximity of the colour to infrared but I'm guessing the reduced size has just moved the problem.
It is odd though. Is the D2X sensor still the classic Bayer pattern? How does the faster shooting business work? If it's by cropping is the noise consistant across the image?
We must be near the point where the sensors are actively cooled to reduce the noise (something even the amature telescope guys have done for years).
It is odd though. Is the D2X sensor still the classic Bayer pattern? How does the faster shooting business work? If it's by cropping is the noise consistant across the image?
We must be near the point where the sensors are actively cooled to reduce the noise (something even the amature telescope guys have done for years).
dcw@pr said:
Blue photosites have to work a bit harder to convert those pesky photons so I'm not that surprised
ahhh really? why is that?
Well, when I did some work a few years back on a <cannot be named on pain of death> project we found some interesting effects with some silicon sensor types. You seem to get a lower pad charge the higher the wavelength. What exactly this was due to I was never privy to. I do remember that the sensor construction was pivotal though. Maybe CMOS is much better in this respect?
Then again, maybe your D2X is a lemon. Finding one to compare it with is rather tricky at the moment I'd imagine though.
ThatPhilBrettGuy said:
Well, when I did some work a few years back on a <cannot be named on pain of death> project we found some interesting effects with some silicon sensor types. You seem to get a lower pad charge the higher the wavelength. What exactly this was due to I was never privy to. I do remember that the sensor construction was pivotal though. Maybe CMOS is much better in this respect?
Then again, maybe your D2X is a lemon. Finding one to compare it with is rather tricky at the moment I'd imagine though.
interesting. the D2X has a CMOS too. I don't think mine is a lemon - I only checked beacuse I read about it in the camera review in amateur photographer a few weeks ago. maybe one of the other d2xers here could comment?
beano500 said:
...and not forgetting that noise is associated with any low light situation. It's a bit of an urban myth that noise is an ISO related issue.
I think this proves that technology still has further to go in this respect.
Also shows that whatever kit you use, intimate understanding of its good and not so good points can help you tremendously in getting the best out of it.
Take several shots in the same lighting conditions at differing ISO's, they'll be more noise at the higher ISO's. Not an urban myth as you suggest.
ThatPhilBrettGuy said:
Blue photosites have to work a bit harder to convert those pesky photons so I'm not that surprised
ahhh really? why is that?
Well, when I did some work a few years back on a <cannot be named on pain of death> project we found some interesting effects with some silicon sensor types. You seem to get a lower pad charge the higher the wavelength. What exactly this was due to I was never privy to. I do remember that the sensor construction was pivotal though. Maybe CMOS is much better in this respect?
In a curious parallel, early film wasn't sensitive to blue light - which is why skies were plain white. Seems like we need the digital equivalent of panchromatic film
It would be interesting to know if the same degree of effect is evident when working in various types of natural light (you mentioned flash I think?).
Might it be something to do with internal adjustments related to the colour of the light? Long shot but just a thought passing through my head ...
Might it be something to do with internal adjustments related to the colour of the light? Long shot but just a thought passing through my head ...
LongQ said:
It would be interesting to know if the same degree of effect is evident when working in various types of natural light (you mentioned flash I think?).
Might it be something to do with internal adjustments related to the colour of the light? Long shot but just a thought passing through my head ...
indeed it is. the white balance setting will affect this problem as with an incandescent setting guess which channel is boosted to compensate?? Yes that's right....
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