Effective megapixels after cropping from 1.3 to 1.6

philthejuggler

philthejuggler

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Hi all, I bet this question has been answered before but I don't know what to search on!

I'm about to get a 1DmkIII. If I crop a photo to give the same framing my 50D would have given with the same lens, subject distance etc, how many megapixels would the resulting image be?

Thanks!

Phil
 
Its not as simple as you might think due to pixel size being different on the two cameras.

But

15.1/1.3 = 11.6 megapixels
 
philthejuggler said:
Hi all, I bet this question has been answered before but I don't know what to search on!

I'm about to get a 1DmkIII. If I crop a photo to give the same framing my 50D would have given with the same lens, subject distance etc, how many megapixels would the resulting image be?

Thanks!

Phil
Click to expand...

1.6x format is 64% the area of 1.3x (22.3x14.9 vs 27.9x18.6mm) so 64% of 10.1mp is 6.46mp.
 
HoppyUK said:
1.6x format is 64% the area of 1.3x (22.3x14.9 vs 27.9x18.6mm) so 64% of 10.1mp is 6.46mp.
Click to expand...

Whoops read the question wrong :bonk:

But how does sensor size determine the amount of megapixels as you haven't factored in the size of the pixels..?

I would have thought it would be 10.1/1.3 = 7.7 Megapixels
 
Liam said:
Whoops read the question wrong :bonk:

But how does sensor size determine the amount of megapixels as you haven't factored in the size of the pixels..?

I would have thought it would be 10.1/1.3 = 7.7 Megapixels
Click to expand...

Pixel density is already factored into the area and pixel count.

And 1.3x is the crop factor relative to full frame. And that is a linear measurement, but it's the area that matters :thinking:
 
Hmm, I still think you can't do it like that not with the sensor size. You could do it with the pixel dimensions..

15.1x10^6 / 10.1x10^6 x 100 = 66.94%

10.1 / 100 x 66.94 = 6.76 Megapixels
 
Liam, perhaps you are misunderstanding the question. Phil is trying to compare a 1D3 to a crop format camera (15.1mp is irrelevant). Basically, if the 1D3's sensor was cut down to the smaller size, in order to simulate relative effective reach between the two formats, how many pixels would be left.

So the key figure is that a 1.6x crop sensor is 64% the area of a 1.3x. Therefore the answer is 64% of 10.1mp, ie about 6.4mp.
 
A 1D3 has 138 pixels/mm in each axis = 19044 pixels/mm2
50D sensor is 22.3 x 14.9 = 332.27 mm2

19044 x 332.27 = 6.328 Mp (as per Richards answer above)

Bob
 
Canon Bob said:
A 1D3 has 138 pixels/mm in each axis = 19044 pixels/mm2
50D sensor is 22.3 x 14.9 = 332.27 mm2

19044 x 332.27 = 6.328 Mp (as per Richards answer above)

Bob
Click to expand...

Typo Bob :D
 
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