I have a 20mm f/1.4 lens on a full-frame 5D3 (5,760 x 3,840 pixels) and would like to crop a number of photos to 24mm to cut out star coma in the corners. E.g. make the photos look like they were originally shot on a 24mm lens.
Is this the correct math to determine the final resolution of the image cropped to 24mm?
20mm + 20% = 24mm
5,760 - 20% = 4,608
3,840 - 20% = 3,072
So, if I cropped the original resolution photo (5,760 x 3,840) down to (4,608 x 3,072), would this be the equivalent of a 24mm image? I need the final resolution to make an action in photoshop. Thanks!