I can't get 0 0 0 for RGB readings is there something wrong with my camera please?

[Bettyboo]

Hi,

Sorry newbie question. I have a D3100, my first SLR and have only had it a month or so.

I am doing a course to try and learn from scratch and for this module you have to produce your own grey scale.

I have gone through the exercise over ten times with different settings (i.e. D lighting on or off, different WB), in different locations, open shade outside, inside etc but even when I run out of shutter speed I still can't get below 1 0 1.

I wondered if my lens/camera was letting in light or something?

Many thanks in advance.

Lynne

[arith]

Try taking a photo with the cap on and very high speed and small aperture. If you can't get black I'm sure somebody here knows why.

If you use levels in photoshop, a little dropper on the left of three can be used to set black.

[Jan de Vries]

Hey Lynne, in my opinion there is nothing wrong with the camera. There is always some noise from different sources on the sensor. You have to cool down the sensor very much to avoid some of that noise. Then the processing in the camera adds also some extra glitches. What you read is the total result of all this. Getting one bit in a channel as the final result is not bad at all.
The difference between 1.0.1 and 0.0.0. will be on paper or on the screen hard to notice.

Maybe it is also a part of the noise reduction system of Nikon. I read something about that at dpreview.com. They thought to see that even when NR is off there is still some noise reduction. By setting the lower limit in the red and blue channel on 1 then there is some flattering of the noise.
Jan

[Bettyboo]

Thanks arith. I tried as you suggested but it would't let me do that with the lens cap on, it said it was too dark. But I tried the fastest speed and smallest aperture on both the grey card and in a darkened room and still can't get past 1 0 1.

I don't have photoshop and I think the exercise is about discovering the grey scale range of your camera, i.e. the Zone System like Zone 0 to Zone X? So I probably shouldn't be tinkering with the images anyway?

I didn't know if the Nikon programme is changing them somehow? I taking the photos in RAW but that is changed to NEF in the ViewNX2 programme, perhaps that is why? Boy does my head hurt

I am sure I am missing something important, but I just don't know where to start. The little manual which came with the camera isn't very helpful really, as I would like to try out about the WB things. When I change to another setting it come up with a grid with different shades on it, with A-B and G-M on it, and perhaps I need to change one of these?

Anyway, thanks for your suggestions, I will keep trying. It is a shame as I love exploring the camera and the wonderful world of photography but when you get so stuck on something it takes the 'fun' out of learning!

Best wishes, Lynne.

[Bettyboo]

Hi Jan, sorry I must have been typing when you added your post, many thanks.

I will try to find out more about noise reduction for my camera as you suggest, thank you.

Ik wens u een prettige dag

Lynne

[Jan de Vries]

Hey Lynne, NEF stands for Nikon Electronic Format and is only the file extension name for a RAW file from a Nikon camera.
In ViewNX2 you see normally the enclosed jpg picture of the RAW picture. This jpg picture is compressed. As a result of this compressing the lowest bits of a channel can be fixed.
In View NX2 is just left above the picture the button [RAW]. Then you see the RAW picture with the processing done that you see on the right side. Then I can find the 0.0.0. values in a dark picture.
Success. By the way you can say ‘je’ to me.
Have many nice day too.
Cheers, Jan

[Bettyboo]

Hi Jan, thanks again. Having gone back through the last couple of tests I can see that I must have been playing around with the picutre quality settings and managed to put it back to JPEG, thinking it was still on RAW!! I have just redone the last part of the test and got 0 0 0!!!

Thank you so much for your help, I probably would not have thought to check that if you hadn't of mentioned it. Another thing learnt today

Bonne apres midi!

Lynne