What is the Nikon D3200's diffraction limit?

Question

I'm new to the world of macro so do bear with me! I shoot pictures of fish through aquariums, so normally this means the lens is always perpendicular to the glass surface to avoid blurring.

However the cost of a perpendicularly positioned lens is that, if the fish is not presenting itself along its lateral aspect, I can't tilt. This leads to some unflattering head-only shots.

So I'm trying to find the highest aperture for my camera body, but want to avoid diffraction limiting the photo and adding more blur than I need.

Answer 1

It's a little more complex than the question seems to indicate. Intended display size also comes into play. This is because the Diffraction Limited Aperture (DLA) of a sensor is only the beginning of the effects of diffraction and the image must be viewed at full size (1 image pixel=1 monitor pixel) for the effect of that diffraction to be seen. Unless you are viewing your images at sizes approaching 60x40 inches with a 22MP camera you won't be able to see the effects of diffraction until well past the DLA.

For more about what the DLA is and what considerations should be weighed when deciding to use a particular aperture, please see Does sensor size impact the diffraction limit of a lens? and this answer to Do smaller apertures provide more depth of field past the diffraction limit, even if peak sharpness suffers?

Just for reference, the Nikon D3200 has a pixel pitch of 3.8µm. That gives a DLA of between f/6.0 and f/6.1. But keep in mind diffraction will only be evident at f/6 if you are displaying the images at 100% magnification on your monitor or printing at 60x40"!