Big sensor and landscape photography, DoF

Question

I've been an owner of point & shot cameras for some years. Now, I'm considering to move to bigger sensor cameras (4/3, asp-c) because I really hate the noise that small sensors produce on low light conditions/high iso settings.

My fear with bigger sensors is a narrower depth of field. I know this is fine for portrait, but I was thinking about landscape photography.

How does those sensor sizes behave for landscape photography? Can usually the automatic of the camera keep in focus all the scene?

Are low apertures usually needed? If so, is difraction usually a problem?

Thank you!

Answer 1

Landscape photography typically uses apertures at the sweet spot of the lens' sharpness which are usually narrow enough to allow for large Depth of Field(DoF), yet still wide enough to avoid problems with diffraction. Remember that the larger the pixel size of a sensor is, the narrower the Diffraction Limited Aperture will be. My 18MP APS-C camera has a DLA of f/6.9, my 21MP full frame camera has DLA of f/10.1. The best way to maximize DoF at middle apertures is to use the hyperfocal distance for focusing.

Answer 2

Perhaps one should mention that Ansel Adams shot his famous image "Moonrise, Hernandez" with an 8x10 camera (i.e., the film size was 8"x10", and the crop factor would be 0.14x). Now, granted, a view camera allows lens/film movement (tilt) so you can also use the Scheimpflug principal to increase the DoF, but generally speaking, no, shooting any currently common digital sensor format won't keep you from being able to adjust the aperture so you'll have sufficient DoF to cover a scene for landscape shooting. While a bigger sensor will decrease your DoF for the same framing and vantage point compared to your P&S camera, your P&S camera has a far smaller aperture range available. Most P&S cameras stop down to f/5.6 or f/8. Most dSLR/mirrorless lenses stop down to f/22. And Ansel Adams, well, there's a reason the group he participated in was called Group f/64. :)

Diffraction limit for micro four-thirds is theoretically f/5.6, but in practice, going up to f/11 doesn't pose any problem for me and I don't hesitate to use f/16 if I need to. I'm actually pretty happy shooting landscapes at f/8 or f/11 most of the time, without messing about with hyperfocal calculations.

See also: the "micro four-thirds images" thread on the fredmiranda "Alt. Gear" board.