December 11th, 2009
New Kit – f/1.4 and the View Finder
I decided to actually sort out what about my camera made focusing my f/1.4 manual lens so hard and I found this article about fast manual lenses and modern DSLR cameras. The root of the problem is how the camera splits light between the view finder and the auto focus sensors. The long and short of it is, that no matter how big your aperture, what you see in the view finder will likely be f/4 or smaller equivalent (at least with a entry or mid level DSLR).
This matches my experience. The depth of field in the view finder is huge even when the aperture is wide open (and you can verify that it is open by looking in the front of the lens). Even more frustrating is the fact that live view very obviously shows the correct depth of field.
This makes finding sharp focus through the view finder impossible, or at least very improbable and unrepeatable if you are using a very fast manual focus lens. The solution: use main sensor based live view and on screen zoom (when possible) to achieve razor focus.
Leave a Reply
You must be logged in to post a comment.