Take a picture of a grid of squares, evenly lit, straight on and at various focal lengths. Have a look at said images and I'm sure you'll see something there, probably just some slight blur or aberration on one side of the image.
Or maybe you lucked-out and its fine!
Take a picture of a grid of squares, evenly lit, straight on and at various focal lengths. Have a look at said images and I'm sure you'll see something there, probably just some slight blur or aberration on one side of the image.
Or maybe you lucked-out and its fine!