Camera Dynamic Range

Submitted by Roger Breton on

Forums: 

I asked Nikon Tech Support to tell me what the Dynamic Range for my D810 is but they declined to "disclose" this information.

In DPreview, they say "13EV at ISO 64" according to this link :
https://www.dpreview.com/reviews/nikon-d810/15

My question, is there any way to relate the bit range of a camera to its 'Dynamic Range", mathematically?
Like, my NIkon D810 has a 14bit range.

Dear Roger,

Submitted by LibRaw on

Dear Roger,

Dynamic range is the ratio of max signal to noise. It has little to do with bit range. In my measurements Nikon D810 dynamic range caps at slightly less than 12 stops.

Camera Dynamic Range

Submitted by Roger Breton on

OK 12 stops -- thanks so much for responding.

For my benefit and those of other readers, what 12 stops corresponds to, in your experience, in terms of Luminance range?

I ran some quick numbers through the EV = LOG2(LS/K) formula, in Excel, and got :

- using ISO = 400 and K = 12.5
- 40,000 Cd/m2 = 20.29 EV
- 10 Cd/m2 = 8.32 EV

For a difference of 11.97 EV

Dos that make any sense?

www.graxx.ca

Dear Roger:

Submitted by LibRaw on

Dear Roger:

log2(40,000/10) = 11.97, simple as that.

Camera Dynamic Range

Submitted by Roger Breton on

Thank you!!
Can I ask, then, where would "Middle Gray" fall in that 12 stops/EV range?
It's not just a simple as 40,000 divided by 2? Since "Middle Gray", in terms of Brightness is not "linear"?
Sorry for making things seemingly more complicated than they actually are...

www.graxx.ca

Dear Roger,

Submitted by LibRaw on

Dear Roger,

Middle gray is nothing more than a convenience. As I mentioned, you can set it to your liking, that's what on-camera EC is for. Customary values are 2.5 EV down from clipping and 3 EV down from clipping; meaning max/2^2.5 or max/2^3.

Camera Dynamic Range

Submitted by Roger Breton on

I guess I will let the whole idea of Middle Gray "percolate" since I am not sure what exactly I have in mind in relation to Dynamic Range...
But, one thing is clear, now, to me; if I was to apply some kind Ansel Adams "Zone System" analysis to a scene, I could expect my Nikon to allow me to capture a maximum of 12 distinct brightness levels from that scene. It would be up to me to meter the scene and decide where, on this 12 EV scale, to "place" each "tones"? So, if you say customary values are 2.5 to 3 EV down from the maximum, if the brightest tone in a scene is 40,000 Candelas/m2 then I could expect "Middle Gray" to land at EV9 to EV9.5. Only 2.5 to 3 stops down from the max? Typically?
-
Have to think about this....
A BIG THANK YOU!!

www.graxx.ca

Dear Roger:

Submitted by LibRaw on

Dear Roger:

> It would be up to me to meter the scene and decide where, on this 12 EV scale, to "place" each "tones"?

Absolutely.

Zone V is what, 5 stops down from extreme highlights?

Here is the problem: placing the midtone lower than possible results in adding noisiness to the image, especially to shadows.

So that "idea of Zone V"

Submitted by Roger Breton on

So that "idea of Zone V" inherited from "silver-halide days" could not be readily "transported" 1:1 into the digital world, without the added noise?
That was my intuitive impression, in the sense that, given a 12 stop range and a calculated EV9 "Middle Gray" placement/expectation, we would have 9 EV stops of image range to cram into Middle Gay down to Black? It seems like an "inefficient" or "unwise" use of camera bits...
-
In my humble view, a better use of that range would be to place Zone V at EV8 or EV7, to allow more of the highlight details.
-
I guess I am getting in a non-technical and subjective discussion here... Sorry about that.

www.graxx.ca

Dear Roger,

Submitted by LibRaw on

Dear Roger,

In fact the way I read AA - he suggests to "place zones", and what I do - I meter the exposure for the highlights I need to keep and, knowing that my spot-meter will reprofuce it as 12.5 .. 12.7%, add 3 EV. I tried to explain this placement method (as well as metering for shadows) in https://www.fastrawviewer.com/blog/spot-meter-exposure

Camera Dynamic Range

Submitted by Roger Breton on

Here is quick and interesting experiment...
It's winter outside my house today, so I thought I'd stay home and start with something "humble", like the wall in our living room, illuminated by the light bouncing off the snow, mid day (big snow storm outside, not a whole logt of light.

So here is the RAW file : https://1drv.ms/u/s!AkD78CVR1NBqlsJl9xNeAPnhSe69rw?e=SNDq7i
Here is the Exported 16 bit Uncompressed TIFF: https://1drv.ms/u/s!AkD78CVR1NBqlsJmQ8M8v6BFhpkKLQ?e=kiSxRp
(I guess you don't need the TIFF? I won't send it next time)
And here is the PDF of my analysis: https://1drv.ms/b/s!AkD78CVR1NBqlsJk1oH9rGn2SCZLTw?e=io38mB

I made several Luminance measurements of the scene using my Minolta CS-200 which you can find in the PDF.
Then I compared the Maximum scene Luminance to ther Minimum and estimated about 6.2 EV difference.
This is far below my Nikon D810 Max 12 EV dynamic range.

What is interesting is that the EV scale on the Histogram agrees with this estimate!!

www.graxx.ca

Dear Roger,

Submitted by LibRaw on

Dear Roger,

Going by your page 3: for the sample #106, G=6145; for #0.8 G=72

log2(6145/72) = 6.4 EV

Depending on the sample size you've used in RawDigger, I would say you got an excellent match.

 

Camera Dynamic Range

Submitted by Roger Breton on

Next step is to "master" the concept of "White Balance" on my camera BEFORE taking the picture?
I always have my camera set to "Auto1 (NORMAL"; is that "optimal"?
Given the huge difference between each RGBG Max Channel values?
Is this covered in anyone of your fine articles?

Thank you very much for your kind and continued help by the way :-)

www.graxx.ca

In most cases, white balance

Submitted by lexa on

In most cases, white balance settings do not affect the raw data.

There are a few known exceptions:

  • Nikon D1
  • Canon and Nikon 'small raw' modes.

 

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