Guys i have a querry regarding digital photography... u know soon iam going on vacation so i thought i will brush up my knowledge on photography and graduate from a amatuer to professional... Fashion photographers watch out for me... ok getting serious... i want to know that how do we measure the size of the image sensor when the standard size is given(as given on the left hand size,below),i tried all kind of mathematics but failed to reach any conclusion. The table below is obtained from one of the websites but how will i calculate the size of sensor whose size is say 1/2.5 in. or 1/2 in. Image Sensor Size (approx.) full frame 24 x 36 mm half frame 24 x 15 mm 2/3 in. 8.8 x 6.6 mm 1/1.8 in. 7.2 x 5.3 mm 1/2.7 in. 5.3 x 4.0 mm also is there any method by which i can find out the size of the image sensor using the following information available to me, focal length aperture exposure time iso setting actually all the above can be obtained by clicking the properties of any image which is taken by a digital camera.