f/1.8 on m4/3, ASP-C, FF; are they the same?

Started Nov 1, 2010 | Discussions thread
MadsR Senior Member • Posts: 2,235
Correct But ... Please read OP post

OP was asking if exposure would change... He was confused by all the people here with knowledge of exposure who uses the f numbering haphazardly for DoF (When even that is incorrect and a HUGE approximation)

The question was if his µ4/3 camera with set ISO100 and the Panasonic 20mm f1.7 lens needed to stay open longer than a FF camera with a 40mm f1.7 lens... The answer to that question is a resounding NO even with a 500mm f1.7 lens the shutter time would stay the same (But your arms may have trouble carrying the lens :D)

Now, people who want to have that shallow DoF effect are also quite confused on how to calculate it, and rightly so... Because it is not easily calculable... I know that some funny/unknowledgeable/troll people on this forum is trying to setup easy rules for DoF...

You can get Shallow DoF with a µ4/3 camera... Yes, it does take a somewhat different approach... Putting the same lens on your µ4/3 camera as on a FF camera will get you roughly the same DoF (depending on the resolution of the sensor) then you just need to rearrange your scene to match the narrower FoV, and bingo, you have shallow DoF... A different way of getting the same shallow DoF is to (calculating for the resolution difference) having a roughly half f number lens with the half focal length... So for a 50mm f1.9 on a 48mp FF camera, the 25mm f0.95 lens should give a comparable DoF.

 MadsR's gear list:MadsR's gear list
Olympus PEN E-P1 Panasonic Lumix G 20mm F1.7 ASPH +2 more
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