Originally posted by clackers JS, you're obviously an okay guy because you also love Bill and Ted (I even have time for the sequel), but if you're getting your stuff from Clarkvision.com, he's unambiguous:
I've referred to him before, he seems to explain things very clearly.
Quote: His words are: "The ultimate in high signal-to-noise ratio, high dynamic range, and high ISO performance would be one large pixel ...
I've said this exact thing before, in the previous thread. Take the SOA pixel tech, apply it to one pixel, you get the best SNR possible. And you have a 1-pixel image to share!
Quote: When choosing between cameras with the same sized sensor but differing pixel counts, the one with larger pixels (and fewer total pixels) will have better high ISO and low light performance (assuming read noise and fixed pattern noise are similar, which may not be the case)"
Note the "
assuming read noise and fixed patter noise are similar, which may not be the case." He's not claiming a generic "larger pixels automatically mean lower noise", he's saying hat given the exact same pixel tech, you will probably see less image noise as you lower the pixel count.
There's a trade-off. I think Nikon found that taking their D800 pixel tech down to 12MP would gain them about 1/4 to 1/3 of a stop (thogan) - not enough to make it worthwhile from a marketing perspective.
The noise performance of the D800 already beats the D700 - I wouldn't buy a 12MP D800, losing all that resolution, just to get that extra 1/4 - 1/3 stop... would you? If I were *that* concerned about noise alone, to the point I'd be wiling to give up a ton of resolution I'd buy something like a D4s. And we see that going just from 36MP to 24MP gained *no* SNR in that comparison.
What happened between say 2004 and 2012 was people saw different things happening with sensor MP and pixel pitch and attributed gains directly to those changes, when really it was a combination of engineering things that those companies did that can't be attributed to pixel size alone - yet that's what people saw, so that's what they attributed it to. As in for example, "Canon 5D II has 21MP and worse ISO performance tha D700 which has 12MP, thus lower pixels are the causal link - less MP = always less noise!" when really the underlying pixel technology was better in that D700 as well.
Back to Dr Clark - he's a good source I think. He uses "True Exposure" in place of "Total Light", but he's describing the exact same thing
here.. I like Total Light better, because from past experience a term like "True Exposure" is going to make some people cranky, because it will suggest to them that they're using "fake exposure" and what they do is being discounted,. Kinda lie the "Full Frame" label makes some people cranky. So I like Total Light, but True Exposure works.
(quoted below in case the above is hard to read)
"
Exposure, Light Meters, and Digital Cameras
Discussions I have observed and participated in on the internet shows that many photographers do not actually understand exposure, including amateur, advanced amateur, and even pro photographers. Along with exposure confusion, there also seems to be confusion about light meters. With this article, I'll try and clarify exposure, and make a very important distinction between actual light collected during an exposure, versus camera exposure. Metered light, and camera exposure versus actual light (true exposure) recorded are usually quite different. It is different between camera formats (sensor size), pixel size, and even different focal length lenses of the same f/ratio.
Why is this important? In making choices between lenses and cameras understanding these concepts may allow one to make better choices, especially when pushing photographic limits, as in fast action+low light photography, including baby's first steps in a dimly lit room, to wildlife action near sunrise/sunset, to things like nightscape photography.
Definitions
Camera exposure: The relative exposure recorded by a camera. In a digital camera, this is how full a pixel is to a given reference level. Smaller pixels fill with fewer photoelectrons than do larger pixels. As ISO is raised, the reference level is reduced. For example, at ISO 200, the reference level is half the photoelectrons as at ISO 100. Thus, a "properly" exposed digital camera image records half the light at ISO 200 as at ISO 100.
True exposure: the actual amount of light recorded, e.g. expressed in photons (or photoelectrons) on the subject. Remember, the subject is what we are concerned about in our images, not pixels.
There is a significant distinction between the total light recorded (true exposure) from an object and the camera exposure on an object. Image quality is directly related to the amount of light collected by a camera and its lens. Exposure is about relative density of signal (density on film or relative signal level in a digital camera pixel). With film, the relative density is controlled by the film speed and the amount of development. On a digital camera, the exposure is a relative level determined by a post sensor gain level. Actual light recorded is dependent on aperture diameter and the angular size of SUBJECT on the sensor (film or digital).
There are digital cameras of many sizes, with different sized sensors and different sized pixels, and each can be set to a large range of ISO. Camera exposure may appear to be the same, but true exposure is different in these cameras with differing sensor and pixel sizes and even at the same ISO."