What Is Resolution?
Ok, so most people equate resolution to the number of Megapixels, especially when comparing digital camera qualities, but this is not entirely accurate. Image resolution is basically the amount of detail an image can show. It is the quantification of the degree to which two lines next to each other can be visibly resolved, or discerned from each other. If a camera, film or lens can produce an image where you can see clearly defined edges of the smallest details, the resolution is said to be high.
A DIGITAL CAMERA WOULD HAVE TO BE 156 MEGAPIXELS TO GIVE YOU THE SAME KIND OF DETAIL AS 35MM FILM.
So, Megapixels then become a kind of unit of measuring resolution in digital images. Resolution is determined by the size of pixels present in the image, and the more the pixels, the smaller they are. However, naturally, this has to take the size of the area in question as well. Plus, there are other considerations as well, such as the image processing algorithms and interpolation of pixels, which we will discuss further shortly.
Film resolution is measured in lines per millimeter, and these lines comprise pairs of a dark and a light line, also known as line pairs per millimeter. Since film records details naturally, there are no algorithms and computer interpretations to mess things up and the details you see are extra-ordinary, especially with medium and large format sheet film.