> -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Austin > Franklin > Sent: Wednesday, June 20, 2007 5:31 PM > To: [email protected] > Subject: RE: EOS A slightly silly query > > Hi Peter, > > > No Austin. If you and I take an image and I use a 10MP sensor on > > say a Rebel XTi and that is half frame camera. And you use one > > with 12.7 that is full frame, and let us say we take the same > > exact image of a group of people. I will have more pixels > > covering a small face in the crowd than you will. > > That's not right, and I would really like you to explain the math behind > that, because if you do, you'll find out it's wrong. > > > Austin >
Here's the math as I see it, using the specs of a 400D and a 5D as the 10 & 12mp cameras. Hopefully, we can all agree that if we use an identical 50mm lens on each camera (mounted side by side and facing the same subject), that we'll get two identical image circles, except that the lens with the smaller sensor will capture only a cropped part of the image. Now, our 12 mp sensor is 36x24mm with a resolution of 4368x2912, which works out to a nice even 121.333 sensors/mm in each direction. Using THAT density of pixels, if we were to "chop off" the sensor to make it the same size as our APS sensor (22.4x14.8mm), it would have a resolution of 2693x1795. At that size, both sensors would have the same image coverage, but the 12mp camera would have a 2693x1795 image versus a 3888x2592 image from the 400D. And it seems to me that 10,077,833,935 pixels in an image is more dense than one with 4.833.935 pixels. tomp * **** ******* *********************************************************** * For list instructions, including unsubscribe, see: * http://www.a1.nl/phomepag/markerink/eos_list.htm ***********************************************************
