Because you cannot get the incorrect notion out of your system that noise is a function of ISO setting and that the same ISO on differently-sized sensors results in a similar amount of noise. ISO 100 on m43 results in a vastly different amount of noise than ISO 100 on FF would. The question is really why you would not change ISO when changing sensor sizes? You change focal lengths when you change sensor sizes, why would you also not change the ISO setting? Changing the focal length (when changing sensor size) allows you to keep the AOV constant, changing the ISO setting allows you to keep the shot noise constant.
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ASPC vs 1 inch sensor and low light abilities (aperture)
- Thread starter Mmd66
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And AOV of a lens is also largely ephemeral without defining a sensor size. Sure, the lens projects an AOV limited by its image circle but as you say, without a sensor capturing it, that is rather ephemeral.
What is different is also that noise in images scales much better with total light on modern digital sensors than it ever did on film. An ISO 25 film on 135-mm was not quite equivalent to ISO 100 film on 6x7 MF (ISO 100 on 6x7 MF was better).
When using a bright prime on the larger sensor camera while being shutter time limited and DOF doesn't matter.
So an apples to oranges situation where any proper ILC will outwit any 1 inch camera.
I would never shoot the Rx100 mk 3 at F3.5 in order ro criple it compared to a a6000 with the 16-50mm garbage kit.
I would shoot both wide open and then the Rx100 would have a negligible advantage.
That said i shoot Fuji and therefore have access to a better faster kit lens. Which has a small advantage at the wide-end to a substantial advantage at the long end.
But those advantages do come at a substantial increase in both size and weight.
bobn2
Forum Pro
Would you object less if he had chosen some other word, like 'parity'? If so, just substitute the word of your choice each time you read 'equivalence'. Then you can stop belly-aching about it.
Really? A f/2.4 smartphone camera has more capability than a f/3.5 APS-C lens? Only if with capability you mean being able to fit the camera into your pocket.
bobn2
Forum Pro
He's confusing himself as always, partly because of not saying what he means clearly. He believes that some how cropping the FF sensor does not affect the 'total light' from which the image is made, because he sees 'total light' as a sensor property, not an image one.
Why? Because any given ISO values infers certain IQ properties to the photo taken? Of course, most of the discussion only applies in light (and thus shutter speed) limited situations (unless the smaller sensor has a correspondingly lower base ISO).
Why would two images, shot with two cameras with differently-sized sensors where the ISO was adjusted such that both images received the same total amount of light, not be equivalent if they had the same AOV, DOF and noise? Is the ISO setting a parameter that is visible in the final image beyond its effect on noise?
I suggest you look up the word 'equivalence' in a dictionary if you are not sure of its meaning. An example usage of the word from outside photography would be for example that an equivalent amount of currency would buy you the same goods or services in two different countries.Equivalence, what a wonderful word
It suggests to the innocents that one can get more for less ;-)
pkcpga
Well-known member
Check out this article, it shows why different setting were used for different size sensors to get similar photos. From personal experience I can tell you in studio I use different ISO, shutter speeds and apeture between my Nikon d810 and my mamiya leaf credo 50.
photographylife.com
They post a photo of a Nikon shot and iPhone shot one at f2.2 and one at f16 with different ISO and shutter speeds to get a similar photo than explain why.
Sensor Size, Perspective and Depth of Field
photographylife.com
They post a photo of a Nikon shot and iPhone shot one at f2.2 and one at f16 with different ISO and shutter speeds to get a similar photo than explain why.
bobn2
Forum Pro
and with his little quip 'it suggests to the innocents that one can get more for less ;-)' he has exactly reversed the situation. The people who think they are getting 'more for less' are the ones who think that by using a smaller sensor, they are getting a smaller, cheaper system with more depth of field that gives them no hit anywhere else. That's why they don't like equivalence, it quantifies rather precisely the hit they are actually taking. Many of those people also seem to believe that lack of equivalence stops with their preferred format - everything smaller indeed does take the hit.I suggest you look up the word 'equivalence' in a dictionary if you are not sure of its meaning. An example usage of the word from outside photography would be for example that an equivalent amount of currency would buy you the same goods or services in two different countries.Equivalence, what a wonderful word
It suggests to the innocents that one can get more for less ;-)
Well, it didn't mean a lot to me either. That's why I didn't struggle w/ the change. Anything for my friends. ;-)
dsjtecserv
Veteran Member
Agreed; I mentioned that above. Though at the time I don't think I was as cognizant of the reasons, it was pretty well accepted that there wasn't much you could do with ISO; there were only a few consumer films available with somewhat higher ISO ratings, and they inevitably involved a trade-off in grain and latitude. And pushing in development definitely did not produce equivalent images. I shot 4 x 5 and was acutely aware that if i wanted the DoF I could get with 35 mm, I had to choose subjects that worked with a longer shutter time.
Dave
bobn2
Forum Pro
A great example of the lengths some people will go to to avoid admitting they were wrong.
In this article, linked at the top of the one you put forward:
Sensor Crop Factors and Equivalence
photographylife.com
Nasim Masurov did his best to rubbish equivalence. A bit of a strange article, in fact, because he starts off reproducing every result of equivalence, then he chokes on his need to declare that 'smaller format lenses have exactly the same light gathering capabilities as larger format lenses at the same f-stop, for their native sensor sizes'. Of course it's nonsense, but having got that one wrong, he has to mangle everything else subsequently so as not to be wrong. So then they try to re-write 'Equivalence' (deftly substituting the word 'effective' for 'equivalent') reproducing all the results apart from noise equivalence, which must be discounted because Mr Masurov has declared that shot noise does not depend on 'total light'.
mostlyboringphotog
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I'm not belly-aching about what word I would use; it's the word that DPR uses that I'm belly-aching about.
bobn2
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I knew that. That's why I suggested that you mentally substitute whatever word you'd like to use instead and stop the belly-aching, which isn't getting anyone anywhere, and hasn't for a very long time.
mostlyboringphotog
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No, because one ends up thinking that a crop of a larger sensor image is less noisy than the same image from a crop sensor.
mostlyboringphotog
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What if a dollar beer cost 1000 pesos but 5 dollar whisky cost 10,000 pesos? ;-)I suggest you look up the word 'equivalence' in a dictionary if you are not sure of its meaning. An example usage of the word from outside photography would be for example that an equivalent amount of currency would buy you the same goods or services in two different countries.Equivalence, what a wonderful word
It suggests to the innocents that one can get more for less ;-)
If you put 50mm f/2 lens on a 4/3 camera and the AOV now looks like of 100mm and brightness now looked like f/4 of FF cam, I'll say yea, OK, 50mm f/2 is equivalent to 100mm f/4; but that's not the case, is it?
Personally, I would simply say the 4/3 image is equivalent to a cropped FF image. Rest will kinda fall in...
Why would one think that? Nothing said here would imply anything like this. Coupling a lens with a sensor that is smaller than the lenses image circle or taking a crop from a sensor (who is fully covered by the lens) results in the same reduced equivalent f-stop as using smaller-sensored camera with a matched lens.
Total light collected is the effectively used sensor area times the actual f-stop. And equivalent f-stop (like equivalent focal length) is the f-stop that produces the same image (using the same total light collected) as a lens+sensor combination of the reference sensor size (which has almost always 24 x 36 mm) would.
That problem doesn't exist with equivalent f-stops and focal length since the same factor applies for AOV (ie, the crop factor applied to focal length), DOF (ie, the crop factor applied to f-stop) and total light (ie, the crop factor applied to f-stop) and thus shot noise. And, in a calculated attempt to make your head explode, could also be extended to 'equivalent ISO' (though you'd need to square the crop factor for that).What if a dollar beer cost 1000 pesos but 5 dollar whisky cost 10,000 pesos? ;-)I suggest you look up the word 'equivalence' in a dictionary if you are not sure of its meaning. An example usage of the word from outside photography would be for example that an equivalent amount of currency would buy you the same goods or services in two different countries.Equivalence, what a wonderful word
It suggests to the innocents that one can get more for less ;-)
The brightness inside the camera is not the same but why do you care about the brightness inside the camera? You only care about noise in the recorded image, and that is the same in a m43 50 mm f/2 image as in a FF 100 mm f/4 image.
I'd suggest that you repeat after me:
"Noise is a function of the total light collected and not of the brightness of the projected image at the sensor, where total light is brightness times effectively used sensor area (and exposure time naturally)."
Because if you don't do so, I have to conclude that I am essentially talking to a brick wall.
If you crop a 50 mm f/2 FF image to 4/3 size, you get exactly the same thing as taking a 50 mm f/2 m43. Same as if you take a 10 x 15 cm piece of paper and compare it with the result of cutting down an A4-sized paper to 10 x 15 cm. The two piece of paper will end up weighing the same.
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