Though I have used SLRs for a long time, rangefinders are still somewhat new to me. The first one I bought was a Fujifilm GS645S Medium Format, which was a great camera, but I soon found that the way in which you use them is quite different.
When you look through an SLR prism, nothing is in focus until you adjust the lens so that the point you want is in focus. You can pick any point in the picture you want to be in focus when you manual focus. If you auto focus, you would select the focus point where you want to be in focus; OR point the middle focus point to the desired object, hold the trigger half way, recompose if necessary, then shoot. What you see is not completely what you get, unless you have the aperture wide open. An SLR always opens the lens up to maximum aperture for maximum viewfinder brightness, and then you use the Depth of Field button to check out what it looks like if you’re stopping down; or guess, if you don’t have that function. Interestingly though, when using DOF preview it makes the whole viewing experience darker and can be very dark (depending on the aperture), making it hard to see what the shot will look like.
|Cornwall Boats - Nikon D90 with Nikon 18-200mm|
With a rangefinder, when you look through the viewfinder, everything is in focus. You pick the point you want to be in focus, manually focus until the rangefinder patches align, recompose, then shoot. There is no way to check what sort of depth of field there is. You have to imagine it what it will be like. For narrow depth of field photography, this takes quite a bit to get your head around.
|Street Art - Leica IIc with Leica 50mm f2 Summitar|
With the new Electronic Viewfinder, Interchangeable Lens (EVIL) cameras, like the Sony NEX or Panasonic GH1, what you see is ALWAYS what you get. Stopping down the aperture automatically increases depth of field on the screen AND the screen / sensor automatically adjusts brightness to the proper level – very cool! When you change metering types (ie from matrix to spot) the camera shows you the results straight away; while with the other cameras you would have to rely on the meter read out to see the job is being done. When you focus too, changes on the screen are seen as you do it.
This is all very cool, but a couple of problems exist – 1) Big screen = big power draw, the batteries drain fast. 2) There’s nothing like seeing an actual ‘live’ scene than one being rendered by a screen, which feels ‘digitized’. The new NEX-7 view finder is meant to be amazing, and will fix both these issues.
|Fall Leaves - Sony NEX-3 with Leica 90mm f4 Elmar|