20mm f1.7 = what in FF equiv?

Matthew P

Matthew P

Well-known member
If you put the Panny 20mm 1.7 on a M4/3 camera, you get 40mm equiv in full frame terms.

What lens would you need on a full frame camera to mimic the dof and fov that the 20mm has on M4/3? I understand that it would be a 40mm, but I'm wondering about the aperture value.
 
dof on a 4/3 as it is with fullframe, but your just looking at the middle section (assuming the light being put into the camera is the same and the sensors are equally good at collecting light to)
 
erm when they call a lens 20mm 1.7 they are refering to it as if it were on a 35mm camera? right...

its just in this case it wouldnt work on a 35mm cam cuz its for a cropped camera, if you wanted to find a lens that would look identical on two different sensors then i believe the focal lenth should change but the f number should be constant... as you will be collectling the same amount of light from the same area


(ASSUMING THE SENSORS/FILM IS EQUAL AT GATHERING LIGHT)
 
Jordan Cadby said:
erm when they call a lens 20mm 1.7 they are refering to it as if it were on a 35mm camera? right...
Click to expand...
Never. They're referring to the actual focal length, which is 20mm.

its just in this case it wouldnt work on a 35mm cam cuz its for a cropped camera, if you wanted to find a lens that would look identical on two different sensors then i believe the focal lenth should change but the f number should be constant... as you will be collectling the same amount of light from the same area
Click to expand...
If you wanted to make an equivalent-looking picture on a "full frame" camera, you would need a 40mm focal length, yes. For equivalent exposure you'd want to use the same f-stop, yes. BUT, for equivalent depth of field, you'd have to stop down the lens on the "FF" camera to f/3.4 to equate the two. Which would mean having to use an ND filter on the m43 camera.
 
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