View Full Version : Question from a newbie about Mysterium
Craig A. Macon
02-06-2009, 03:18 PM
So I tried to find an answer for this question using the search.
I didn't find what I was looking for (or maybe I did but didn't understand it)
The sensor is least sensitive to Blue light. Okay.
There are twice as many Green sensors on the Mysterium as Blue or Red. Okay.
If the Green sensors and Blue sensors were "flip flopped", giving twice as many blue sensors, would this increase the image quality?
Sorry, this really isn't my field. I'm just trying to get a grounding here. Blue sensitivity seems to be an issue on some level. I don't understand why there are more Green sensors than Blue if this is the case.
Graeme Nattress
02-06-2009, 05:06 PM
First, it's silicon based sensors in general that are insensitive to blue light. They all are, it's the native response of silicon.
There are two greens in a Bayer pattern colour filter array because the green is very close to "luma" and that's what the eye sees as resolution and contrast. The eye just doesn't see the same level of detail in blue or red.
The sensitivity of the sensor is not how many pixels of what colour it has, but how silicon itself works. The extra greens are not to make it more sensitive, but to give it more resolution.
Graeme
David Mullen ASC
02-06-2009, 05:18 PM
Don't you mean that it is less sensitive to RED light, not blue, and that it is more sensitive to blue light?
Brandon Fraley
02-06-2009, 05:26 PM
Don't you mean that it is less sensitive to RED light, not blue, and that it is more sensitive to blue light?
that threw me as well
Graeme Nattress
02-06-2009, 05:34 PM
Now you're confusing me! I've re-read what I said and it still says silicon based sensors are insensitive to blue light. "insensitive" - Lacking in sensitivity.
Graeme
Craig A. Macon
02-06-2009, 05:54 PM
Thank you for your quick reply.
I guess I am a little dense on this.
What you are saying is that adding more blue sensors would increase the range minimally because silicone is by nature insensitive to this part of the spectrum? And cutting out all those Green sensors which are the "meaty" part of the chroma would result in a hit to image quality.
So a trade off in Blue to Green sensors would mean giving up more than you would gain.
In laymans terms is this accurate?
Graeme Nattress
02-06-2009, 05:56 PM
Basically, the greens directly effect the resolution and detail you see. Less greens would mean less detail. Adding more blues would give you better resolution there, but you'd not really notice it. It would not add more sensitivity to blue.
Graeme
David M
02-06-2009, 08:19 PM
Don't you mean that it is less sensitive to RED light, not blue, and that it is more sensitive to blue light?
Silver halides (as used in film) are more sensitive to blue light than they are to red, and so were most TV cameras that used tubes (Image Orthicons, vidicons Saticons etc).
The response of silicon on the other hand is precisely the other way round: much more sensitive to red than it is to blue, and this trend continues all the way down to the infrared, which is why people have so many ND problems, because most current NDs don't block IR much or at all.
The first Sony 3-CCD SP Betacams actuallly used to have Peltier cooling chips fitted to the blue CCDs to keep the blue channel noise down.
Brandon Fraley
02-06-2009, 08:51 PM
lol Graeme's right. I think both David and I might have misunderstood the same concept. For some reason I took the fact that it's "daylight balanced" to mean sensitive to daylight. You "feed" it what it likes.
But yes, it makes more sense that it's INsensitive to blue light. It just for some reason sounds weird to me to say it's sensitive to red light, but I suppose it is... right? man, i'm confusing myself even now! All I know is that the pictures look better with blue light :)
Graeme Nattress
02-07-2009, 04:01 AM
Yes, silicon sensors don't like blue. Daylight is abundant in blue. That's why they work well together.
David Mullen ASC
02-07-2009, 10:39 AM
OK, now I get it.
I just had to remember that daylight-balanced film stocks have a slower (less sensitive) blue layer to compensate for the excess of blue in daylight.
Brian Chapman
02-07-2009, 10:53 AM
And this is why anyone shooting flourescents at night, will get a nice bright shot...due to the green tinted light?
Brandon Fraley
02-07-2009, 03:39 PM
And this is why anyone shooting flourescents at night, will get a nice bright shot...due to the green tinted light?
someone else can probably explain more intelligently, but I don't think it's a matter of a "brighter" shot, just a less noisy one.
David Mullen ASC
02-07-2009, 03:42 PM
When talking about the color of the light, remember we're talking about the affect on different channels -- using blue light at night may get you more exposure for the blue channel, but it doesn't necessarily mean more overall exposure.
Christian Tanner
02-07-2009, 03:49 PM
And this is why anyone shooting flourescents at night, will get a nice bright shot...due to the green tinted light?
another thing to keep in mind is that some fluorescent lights have quite the amount of blue in them as well.