[Rainer]

[quote name='genotypewriter' timestamp='1295119308' post='5545']

14mm = 104.3 degrees (horizontal)

24mm = 73.7 degrees (horizontal)



Assuming 24MP = 6000x4000 pixels,

6000/(104.3/73.7) ~= 4240 pixels wide

Therefore, at a 3:2 aspect ratio the image would be ~= 4240x2827 = 11986480 pixels = 11.99MP ~= 12MP



But as I said... 12MP from 864mm[sup]2[/sup] (FF area) is likely to be better than 12MP from 431mm[sup]2[/sup] (the cropped area on the 24MP FF sensor).



[/quote]





[quote name='genotypewriter' timestamp='1295158616' post='5563']

Unless I've overlooked something in the arithmetic, I can't see what the problem is in my calculation.

[/quote]



You are treating the image as if the 104 degrees of the 14mm lens would be distributed

evenly over the 6000 pixels ... would that be the case, your calculation would be correct ...



But now ask yourself ... when taking an image with a superwide ... why do you place persons

in the center ... and what happens if you place them at the sides?



I believe you already gathered it ... the outer 10 degrees on each side consume much more pixels

than the 10 degrees in the center (that comes from the arctan-function in the rectilinear

projection) ... so in order to go from 104 to 73 degrees ... you lose more pixels, since

you have to get rid ouf the outer 15 degrees on both sides.



--> 6000 / (104 / 73) ~= 4240 pixels wide



This is the invalid assumption in your calculation. If you do relatively small changes, you can

approximate the change by a calculation like yours ... but from 14 to 24mm is to much a step

for this.