nyer82
Senior Member
Just curious, is there any historical reason for this? Nikon's multiplier is only 1.5x while Canon's is 1.6x but both sensors are marked as APS-C.
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Why is APS-C different sizes for Nikon vs. Canon?
- Thread starter nyer82
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007peter
Forum Pro
agree, I don't get it either.
djones
Well-known member
APS-C is 25.1 x 16.7mm, which just happens to be close in size to the sensors. None of the manufacturers use a sensor which is exactly sized to APS-C.
Canon - 22.3 x 14.9mm
Nikon - 23.6 x 15.8mm
Sony - 23.6 x 15.8mm
Pentax - 23.6 x 15.8mm
Minolta - 23.5 x 15.7mm
Olympus - 18.00 x 13.50mm (4/3)
It would be interesting to see whose was manufactured first, and by whom, and whether it is coincidental or was an intentional step by the other manufacturer(s) to size their sensors differently.
My guess is that in the early days of digital, each manufacturer wanted to set and define the standard, perhaps even with the idea of branding and licensing it.
It is a curious question that I'd like to know the history of as well.
Canon - 22.3 x 14.9mm
Nikon - 23.6 x 15.8mm
Sony - 23.6 x 15.8mm
Pentax - 23.6 x 15.8mm
Minolta - 23.5 x 15.7mm
Olympus - 18.00 x 13.50mm (4/3)
It would be interesting to see whose was manufactured first, and by whom, and whether it is coincidental or was an intentional step by the other manufacturer(s) to size their sensors differently.
My guess is that in the early days of digital, each manufacturer wanted to set and define the standard, perhaps even with the idea of branding and licensing it.
It is a curious question that I'd like to know the history of as well.
Greg Kovacs
Senior Member
Canon designs and manufactures it's own sensors, while Nikon buys them from Sony. This is the reason behind every engineering difference between them. The APS-C moniquer mainly denotes their similarity, it never meant an exact size.
http://en.wikipedia.org/wiki/APS-C
Greg
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It is dangerous to be sincere unless you are also stupid
-- George Bernard Shaw
http://en.wikipedia.org/wiki/APS-C
Greg
-----
It is dangerous to be sincere unless you are also stupid
-- George Bernard Shaw
djones
Well-known member
tom sugnet
Senior Member
It think Nikon crop is better,
my 135 f/2 behaves like 216 f/3.2 on a 1.6 crop
If I had 135 f/2 on a Nikon, it would behave like a 200 f/2.9 Dofwise.
SO, the 1.6 crop is a bit too much, for example
my Sigma fisheye has only 160 degrees on my Rebel, and not 180 degrees as the one used in the Nikon mount.
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Feel free to visit my photo sites:
http://tom.st , http://www.foto.tom.st
my 135 f/2 behaves like 216 f/3.2 on a 1.6 crop
If I had 135 f/2 on a Nikon, it would behave like a 200 f/2.9 Dofwise.
SO, the 1.6 crop is a bit too much, for example
my Sigma fisheye has only 160 degrees on my Rebel, and not 180 degrees as the one used in the Nikon mount.
--
Feel free to visit my photo sites:
http://tom.st , http://www.foto.tom.st
nyer82
Senior Member
that 8mm wide angle Sigma lens for example is 12mm equiv on a Nikon crop, and 12.8mm on a Canon crop. The .8mm should make a difference especially on the wide end, Nikon gets a wider lens! No fair! Oh well.
I noticed how all the sensor sizes even Nikon crop are smaller than true APS-C. What would that multiplier have been if someone ever made that size?
I noticed how all the sensor sizes even Nikon crop are smaller than true APS-C. What would that multiplier have been if someone ever made that size?
djones
Well-known member
The "crop factor" is merely the diagonal of referencing format (35mm) divided by the diagonal of the imaging area you're comparing to (the sensor in the case of digital). The formula can then be expressed as:
sqrt(36^2 + 24^2) / sqrt(25.1^2 + 16.7^2)
So real APS-C format would be a 1.435 crop.
Even better, WolframAlpha can do the math for you. Go crazy, alter the latter two numbers to any width and height, real or imaginary.
http://www.wolframalpha.com/input/?i=sqrt%2836%5E2+%2B+24%5E2%29+%2F+sqrt%2825.1%5E2+%2B+16.7%5E2%29
sqrt(36^2 + 24^2) / sqrt(25.1^2 + 16.7^2)
So real APS-C format would be a 1.435 crop.
Even better, WolframAlpha can do the math for you. Go crazy, alter the latter two numbers to any width and height, real or imaginary.
http://www.wolframalpha.com/input/?i=sqrt%2836%5E2+%2B+24%5E2%29+%2F+sqrt%2825.1%5E2+%2B+16.7%5E2%29
nyer82
Senior Member
Ohhh it's based on the diagonal, I kept thinking it was based on the area, which is why I kept getting nonsense answers when I tried to calculate it myself. Thanks for this.
nyer82
Senior Member
So I tried to figure out the multiplier for a dslr medium-format. One of the Hasselblads has a 49x36.7mm sensor.
sqrt(36^2 + 24^2) / sqrt(49^2 + 36.7^2) =
I got 0.71 as the multiplier for that. Kinda interesting.
sqrt(36^2 + 24^2) / sqrt(49^2 + 36.7^2) =
I got 0.71 as the multiplier for that. Kinda interesting.
djones
Well-known member
I think it depends if you're calculating with a 35mm lens or not, since a medium format lens on a medium format camera is a different reference point than a 35mm lens on a 35mm camera. A medium format camera and lens is going to have something more along a 1.5 crop in comparison to a 35mm body and lens with the same focal length . I think.
nyer82
Senior Member
I think you got it backwards, the 35mm "full-frame" would be the 'crop' in comparison to medium format, which should be the reciprocal of the multiplier I came up with to compare vice-verse.
So the field of view from a 100mm lens on a medium format would equal the field of view of a 71mm lens on "full-frame", which would be 44.4mm on Canon APS-C.
That is if I did everything right.
So the field of view from a 100mm lens on a medium format would equal the field of view of a 71mm lens on "full-frame", which would be 44.4mm on Canon APS-C.
That is if I did everything right.
djones
Well-known member
"crop" is just a term given because the term is used commonly to compare smaller sensors to 35mm. In reality, it's just a ratio, so the "crop" is the value of the thing being compared, regardless of what you're comparing to.
Also see: http://uk.fotopunto.com/articulo-crop-factor-and-focal-length-equivalence-calculator_128
Also see: http://uk.fotopunto.com/articulo-crop-factor-and-focal-length-equivalence-calculator_128
The main point still is that it doesn't really matter. They use a different sensor manufacturer, and stuck with the historical sizes that were around when they started the lines so people wouldn't get confused. Not a huge deal...
hesbehindyou
Senior Member
Why else would people pay so much for 800mm lenses? 
birdbrain
Senior Member
The f number remains the same! It is a function of the focal length divided by the diameter of the from element. The fact you put the lens on what is described as a crop body in no way changes the focal length of the lens which always remains the same. As the focal length is a physical function of the actual lens regardless of what sized sensor you may bolt it to.
It is just that the sensor is looking at a smaller portion of the lenses projected image.
Phil
It is just that the sensor is looking at a smaller portion of the lenses projected image.
Phil
hesbehindyou
Senior Member
He knows this; he was saying what f/number the lens would be on a full frame camera to give the same depth of field so that idiots like me could understand him!
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