photography help.

[garra671]

so these are 2 pictures of a blasto i have in my tank. i was wondering. is there a way to change the entire background to black? or to darken the entire background so it looks like empty space? like in those pictures of deep water fish in magazines and such? (im using a canon t4i)

 

[saltyfilmfolks]

in Lightroom you can add a vignette around the picture. also you can add with a brush dark areas.
to capture it in camera you need to use little "flags" to cut the light from the unwanted areas.
lightroom has a trial and also a monthly subscription now