Originally Posted by
GrumpyDiver
Adrian - There is no simple answer to your question or cookbook approach, as others have said. I shoot Aperture Priority for probably 85% of my work, and there I select the appropriate aperture to give me the depth of field I want. There are lots of iOS and Android DoF tools out there, so you might want to look at getting one or two and start figuring out depth of field. Ultimately, when I shoot Aperture Priority, that is what I do. A lot of my portraits are shot wide open to give me an extremely shallow depth of field and a lot of my landscape work is done at a small aperture to get a large depth of field.
The other 15% or so, I shoot shutter priority, and this is for situations where I am looking to either freeze motion or blur motion and am willing to let depth of field play a secondary role. I will also do this when I am shooting in situations where I don't want to drop below a certain shutter speed. Some street photography and wildlife photography are two instances where I will do this.
The only times I shoot manual is when I don't want the camera to change settings on my. Shooting panoramas is one such situation. The other involves flash photography; studio light work has to be done on manual and I will also use manual for more complex Speedlight shooting.
My suggestion is that you shoot a lot and see what look you are after.