Wednesday, April 11, 2018

Amazing Landscape Photography - Maximizing Depth of Field and Sharpness

Maximizing depth of field and sharpness when you're shooting landscapes is not the black art that many people seem to think. There is a lot of confusion, misleading information and incorrect assumptions being made on the Internet when it comes to f-stops and focusing distance.


Common Mistakes


One common and misleading assumption is that to get maximum depth of field you simply choose an aperture of f16 or above and focus about one third of the way into the scene. This method may work to a degree, but you are not getting the maximum depth of field or maximum sharpness from your lens, particularly if you are using an ultra wide lens in the 10 to 24mm range.


Maximizing Depth of Field


If you look at any depth of field table, which incidentally are freely available on the Internet, you will notice that the depth of field increases as focal length shortens, which means that a lens with a focal length of 50mm will have less depth of field than a lens with a focal length of 17mm at the same f-stop. I highly recommend you to check your own focal length against these tables to get the approximate hyperfocal distance for your lens.


For wide and ultra wide lenses you will want to set your focus point to roughly four feet into the scene, as this is approximately where the hyperfocal distance will be for these type of lenses. This will mean that everything from about two feet in front of the subject to everything behind the subject will be in sharp focus. Remember, as you increase the focus distance you actually decrease the amount of sharpness in front of the subject.


Maximizing Sharpness


If you want to maximize sharpness, especially if you are planning on doing large prints then you need to ensure that you are using appropriate apertures. A common misconception is that setting the aperture to f22 will make everything sharp. Not true! All lenses, even the most expensive pro models suffer from diffraction. It has nothing to do with build quality but rather the law of physics! Diffracted light is light that is reflected off the edge of the aperture blades. At large apertures it is not a problem but at small apertures the amount of diffracted light increases to the point of affecting image sharpness quite noticeably. Therefore I would not recommend using anything beyond f16.


If you are doing very large prints at A2 and above then I would not recommend using even f16 but instead using f11. Obviously if you do use f11 you will not get the same range of depth of field  as you would with f16 but what you can do in this instance is take two exposures. Take one exposure at the hyperfocal distance then take another at infinity. This will ensure you have maximum sharpness across the two. You can then blend them both together in Photoshop for a super sharp image.

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