12 bit v's 14

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Erty

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I was playing with the settings on my D7200 and found that there is a lot more noise on the red and blue pixels in 14 bit than 12. Taking pictures with the lens cap on at various ISOs and then running the internal jpeg processing with +2EV and +1 brightness on the picture control showed this up, as did the histograms of the RAW red and blue channels. 14 bit had much worse noise than 12.

My D3400 (12 bit only version of the same sensor) was about the same as the D7200 in 12 but less noisy than it in 14.

Anyone else noticed this?

Erty
 
14 bit carries more precision (information). Rough analogy - think of 12 bit as rounded values.
Inevitably 12 bit output will contain more pixels rounded to the black (0,0,0) value. 14 bit will contain values like (0.01, 0, 0.02)
 
I think it is more than this. The histograms for red and blue extend further to the right (so have brighter noise) in 14 bits than 12. If the 2 extra bits are less than the smallest of 12 bits, I wouldn't really see it.

If 14 bits needs more amplification before it hits the A-D converter, this might push up the noise?
 
So, let me understand. You're taking a picture of complete darkness. So you're only picking up the noise. And a 14-bit image in this instance resolves more noise than a 12-bit image. If taking pictures with your lens cap on is your thing, might I suggest 2-bit images. They'll be right up your street.
 
I’ve not noticed this, even though a lot of my photos are taken with the lens cap on.
 
Erty said:
If 14 bits needs more amplification before it hits the A-D converter, this might push up the noise?
Click to expand...

Number of bits has nothing to do with amplification, it's to do with how its recorded/compressed.
 
adrianday said:
So, let me understand. You're taking a picture of complete darkness. So you're only picking up the noise. And a 14-bit image in this instance resolves more noise than a 12-bit image. If taking pictures with your lens cap on is your thing, might I suggest 2-bit images. They'll be right up your street.
Click to expand...
adrianday said:
You should have an exhibition of your favourites. I might even be tempted to buy a book.
Click to expand...

No need for that attitude, it's a fair enough question.
 
Erty said:
I was playing with the settings on my D7200 and found that there is a lot more noise on the red and blue pixels in 14 bit than 12. Taking pictures with the lens cap on at various ISOs and then running the internal jpeg processing with +2EV and +1 brightness on the picture control showed this up, as did the histograms of the RAW red and blue channels. 14 bit had much worse noise than 12.

My D3400 (12 bit only version of the same sensor) was about the same as the D7200 in 12 but less noisy than it in 14.

Anyone else noticed this?

Erty
Click to expand...

14 bits doesn't need more amplification than 12 bits. The difference is simply in the degree of precision with which the readings are recorded. 12 bits is simply 14 bits bits rounded back to 12. So of course there is more visible noise in 14 bits. Just as there is always more visible noise in a 24MP sensor compared to a 12MP sensor -- when you examine the pixels. When you print both at A4 or A3 the same amount of noise will be visible.
 
Tried to do it again to post sample pictures... And failed. I'm blaming the active d-lighting (now off) that was giving a big boost at low light levels. Live and learn.
 
Erty said:
Taking pictures with the lens cap on at various ISOs and then running the internal jpeg processing with +2EV and +1 brightness on the picture control showed this up, as did the histograms of the RAW red and blue channels. 14 bit had much worse noise than 12.
Erty
Click to expand...

I can ever imagine taking images in that way, personally i aim to get the exposure right and more importantly I take the lens cap off :)

Mike
 
I'm trying to decide if composition is easier or harder with the lens cap on.... ;)
... I'll get me coat. :(
 
GeeJay57 said:
I'm trying to decide if composition is easier or harder with the lens cap on.... ;)
... I'll get me coat. :(
Click to expand...
I understand that with modern cameras that have an evf, the presence of a lens-cap is immaterial, and they can see in the dark. If this is true, I'd better start saving up for one.

Any particular makes and models that I ought to consider?

And focal lengths?
 
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