gdanmitchell
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 p.5 #12 · Fuji's marketing concept? | |
zhangyue wrote:
There are theory beneath it.
Let's say we have two systems all take "exact image" using "proper focal length". 40X30, 20X15.
Case A: If they all share the same resolution with sensor area difference: means larger sensor has "larger" pixel that can collect more light (in this case 4X) "for the same scene" before photon saturation, you could exposure "more" to improve Signal level to improve signal to noise ratio. (noise is square root of 4, and signal is 4, SNR improvement will be 2X)
Case B: If they all share the same pixel pitch, larger sensor has more resolution. Obviously, a advantage for print but this is separate topic. let's focus on SNR signal to noise ratio here. Per pixel SNR will be same as your post wrote as well as a few others. However, we need bring target display resolution or target print size to this discussion. As ultimately, for artwork to show, it has to be displayed in its target form, either screen or print. Say: 20X15, a 10M resolution camera, 40X30 will be 40M. Once down size to the same target resolution, there is a concept call over sampling. Basically signal is sampled 4 times, but noise is random so it will be again squre root of 4. so the SNR is again 2X.
Talk about per pixel SNR is OK but it is not very helpful in term of sensor size/area technical discussion here. To think this in extreme term, considering you have a single pixel camera, you can't say you have the same performance compare to 100M medium format sensor just because per pixel performance is the same. ...Show more →
That’s why I wrote this in that post:
gdanmitchell wrote:
The analogy here, as far as I can tell, is that a larger sensor can:
1. Allow more photo sites and those record more detail, OR…
2. Allow images to be made in somewhat lower light.
(Or some balance of the two.)
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ruthenium wrote:
Dan, by the way, thinking along the lines "Let’s say my garden occupies a half acre and my next door neighbor’s garden occupies a full acre. It is true that twice as much rain falls on my neighbors garden" - this is not how things work in photography. The nearest analogy is not rain, but watering a garden through a hose (the hose being the lens in front of a sensor). The amount of water that falls on the ground is decided by the diameter of the hose and the time between opening and closing of the water tap. The size of the garden is irrelevant. ...Show more →
Let’s try a thought experiment: Think of two cameras whose sensors have the same pixel pitch. I believe that this is the case with the Sony sensor used in Sony’s 60MP FF cameras and in Fujifilm’s 100MP miniMF cameras.
There’s no question that a greater quantity of light falls on the larger area of the miniMF sensor than on a FF sensor. But the intensity of the light is the same. In either case, a photosite getting light from the same point in the subject image will record the same number of photons, and each will fill (be saturated) at the same point. So the “more light” business doesn’t accomplish anything other than greater resolution and smaller noise grain.
Now if you compare (theoretical*) sensors in the two formats that have the same number of megapixels, the larger sensor’s individual photosites will be exposed to more photons due to their larger area. In low light situations (such as the darkest tones in a very wide DR subject) this can extend the dynamic range of the sensor with the larger area.
* I don’t think there are currently any otherwise identical sensors in the two formats that both use the same pixel dimensions and MP.
Another thought experiment: If you take a wide dynamic range photograph from the 100MP miniMF sensor and crop it to 60MP FF dimensions, do you lose dynamic range? How so?
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ruthenium wrote:
Dan, with due respect, this is inappropriate to quote a sentence taken out of the context. What you qouted had been preceeded with a clear conditional clause: "to compare the largest amounts of light they can collect (at base ISO, assuming no bias in how the different system define ISO)"
Naturally, I don't expect you meant to misrepresented me intentionally and assume your reading of my post as a generalized claim was a mere misunderstanding.
OK. Here’s the entire post I was responding to:
ruthenium wrote:
Another way of looking at the differences between the three sensors is to compare the largest amounts of light they can collect (at base ISO, assuming no bias in how the different system define ISO).
The GFX100 sensor collects 1 stop of light more than a FF sensor, while a FF sensor collects 1.5 stops more light than the APS-C.
I fail to see how I am taking anything out of context. I was just addressing your point about “largest amounts of light they can detect” and “collec[ing]… “more light.”
Edited on Nov 28, 2025 at 04:32 PM · View previous versions
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