General discussion

Fuji X-Trans sensor - what about the big green pixels?

Submitted by CEB21904 on

Forums: 

I'm learning my Fujifilm X-T30 II, which has an X-Trans sensor. The filter array in this has red, blue, and green photosites of the same size, and also green photosites of twice the size and four times the area. I gather that a pixel includes 2 red photosites, 2 blue ones, 1 green one of that same area, and 1 green one of four times that area, so green has 2.5 times the area overall. Why don't green pixels have much higher values in RawDigger as a result, for a gray photo? Is RawDigger rescaling them accordingly, or is the camera?

Canon 6D Mark II - maximum readout at different ISO settings

Submitted by Heinz Laab on

Forums: 

I just did a series of overexposed images from ISO 100 to ISO 12800.

The goal was to find out the maximum value stored in the RAW of my Canon 6D Mark II with RawDigger software.

I was surprised to see, that @ ISO 100, 125, 200 and 250 the maximum value for R, G, B and G2 is 15.871, but for ISO 160 it is an average of 13.118.

The next group of ISO is 400, 500, 800, 1.600, 2.000, 3.200 and 4.000 with a maximum of 14.335 wheras ISO 1.250 has a minimum of avg. 11.897,5.

How can that be?

Embedded Camera Profile

Submitted by Roger Breton on

Forums: 

Q1. Is RawDigger able to show the "Embedded in RAW" camera color profile?

I suspect Nikon does NOT use a "native" camera profile?
But RawDigger Preference is leading me to believe that Nikon *may* indeed use an "Embedded profile" somewhere in the RAW data?

Q2. I compared Preferences > Display Options > Camera color profile set to A) Embedded in RAW and B) Built-in and I confess I don't see a difference on screen?

Q3. I can see a huge difference between A) Built-in and B) No profile (raw color).

---

Recover Scene Luminance from exposure data

Submitted by Roger Breton on

Forums: 

I would like to get an estimate of original scene luminance from exposure data.

ISO = 250
Shutter speed = 1/640s
Aperture = f/10

Calculated EV = 15.97

I use this set of equations : https://1drv.ms/u/s!AkD78CVR1NBqlssbPh7nK5zxJRZv5A?e=wwIoKc
Where S = ISO, L = Luminance, K = Camera constant = 12.5
N(square) = Aperture and t = Shutter speed (exposure time)

Luminance = 3200 Cd/m2

Does that make any sense?

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.

Pages

Subscribe to RSS - General discussion