CMOS sensor

[Peter Lyons Collister, ASC]

I know that as a long time Red owner and as someone who has access to Graeme and Jim and Jarred,I should understand but people often single our Red sensors as sensitive to 5000 degree kelvin light.
Aren't all CMOS sensors ( Alexa, Canon, etc) balanced to 5000 degree kelvin light????

Sorry Graeme for my stupidity

Peter

[Tom.Wong]

most are balanced for daylight but don't have to be, but yes generally it's true which is one of the reasons the blue channel tends to suffer on cmos based cameras. the only exception i know of is the f65 which is actually balanced for 3200 tungsten. but red shouldn't be singled out at all. it's just that cameras from various companies have different ways with dealing with the blue channel better.

and 80d filter usually solves a lot of blue channel issues with any digital camera :)

[Mark Toia]

?... RAW is RAW... What what balance.?. You can shoot what ever kelvin you like and change it later.

I very worried about people when they think what you shoot is what you get. Thats a Arri PRO RES or Canon thinking... RED grading in RAW. You can change your mind what Kelvin you want 5 years later...

[Josh Beadle]

Yes Mark, but if you don't feed the sensor balanced light, you are just gaining up on single channels (thereby producing noise) when doing White Balance in post. RED likes light - lots of it and at 5600K when possible for the best image quality. That's why I gots some of them K5600 Bugs

[Andrew Gentle]

Isn't it less that the sensor is intentionally balanced for a particular colour temperature and more that the science behind silicon sensors mean that they are naturally less sensitive to blue light and therefore perform better when there is a greater blue component in your light source?

[Gavin Greenwalt]

?... RAW is RAW... What what balance.?. You can shoot what ever kelvin you like and change it later.

I very worried about people when they think what you shoot is what you get. Thats a Arri PRO RES or Canon thinking... RED grading in RAW. You can change your mind what Kelvin you want 5 years later...

Yes but if you have to gain up the blue and down the red you're losing dynamic range when white balancing.

[Josh Beadle]

@Andrew, that's my understanding. Chips, like our eyes, are less sensitive to Blue light - that's why folks can have a hard time pulling keys off a green/blue screen lit with 3200K sources - there's noise in the Blue channel caused by gaining it up through post WB.

[Scott Crawley]

I would love to hear something from Graeme on this. I have hypothesized on it some myself. I have read some articles and posts that went partially over my head about the number of blue samples in the matrix being fewer and that is why a sensor is lacking in blue, but is there any reality in this idea that the physical characteristics of silicon play a part?

Isn't it less that the sensor is intentionally balanced for a particular colour temperature and more that the science behind silicon sensors mean that they are naturally less sensitive to blue light and therefore perform better when there is a greater blue component in your light source?

[ericyoung]

I know that as a long time Red owner and as someone who has access to Graeme and Jim and Jarred,I should understand but people often single our Red sensors as sensitive to 5000 degree kelvin light.
Aren't all CMOS sensors ( Alexa, Canon, etc) balanced to 5000 degree kelvin light????

Sorry Graeme for my stupidity

Peter

Any photosensor based on silicon semiconductor technology is less sensitive to visible blue light than light towards the green and red end of the spectrum, so yes all silicon based CMOS sensors also "prefer" daylight balanced light.
But silicon CCD sensors are also better with daylight balance. It's the semiconductor substrate material and not the type of phototransistor that determines this.

[ericyoung]

I would love to hear something from Graeme on this. I have hypothesized on it some myself. I have read some articles and posts that went partially over my head about the number of blue samples in the matrix being fewer and that is why a sensor is lacking in blue, but is there any reality in this idea that the physical characteristics of silicon play a part?

This is confusing the wavelength sensitivity of silicon (which is poorer towards the blue end), with the choice to have a lower resolution of blue and red pixels compared to green ones in a Bayer pattern sensor, because the human eye is most sensitive to wavelengths in the green part of the visible spectrum, and perceived resolution/sharpness is biased towards the resolution of the green channel in an image. To be more exact, it's the resolution of the luminance (non-colour information) that mostly determines how resolved or sharp an image looks to the human eye, but the green luminance has the larger impact on the perception.