i think its best to try out both and get a feel for stuff. because for video, you will generally want to work with a different combination of shutter speed and frame rate that is video specific which all effect exposure in conjunction with iso and aperture. but i also think that by taking lots of pics, its a much better, more instant way of seeing how all of the variables have an effect on the picture and quality (as in correct exposure, WB, so on and so forth)
so really best to do lots of both and learn inside and out before you get going on something big and mess it up to where you can't fix it in post.
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