BobDiaz
The Professor
Ignoring chip size for the moment, 2 things impact DOF (Depth Of Field): (1) The iris or F-Stop of the lens. (2) The size or mm of the lens.
(1) The smaller the number or F-Stop, the less the DOF. F 16 has more DOF than F 2.8
(2) For any given F-Stop as the mm of the lens increases, the DOF decreases. At maximum telephoto on the HMC40, I can get a shallow DOF, but at maximum wide angle, almost everything is in focus.
Take a lens like a 35mm lens. On a full frame 35mm camera, this is a wide angle lens, BUT put hte same lens on my Nikon D5100 and it acts like a 1.5 x 35mm = 52.5mm lens. The reason is simple, the APS-C sensor is smaller than the full frame 35mm sensor. Thus the image is cropped and acts like a normal lens as far as field of view. The magnification factor for my Nikon is 1.5x.
Move to a micro 4/3s sensor and the magnification factor is 2x. So the 35mm full frame lens acts like a 70mm lens on the micro 4/3s camera.
Now we take a 40mm lens on a full frame camera. At F 2.8 the DOF is shallow and the lens is slightly wide angle or we could say it's at the low end for normal.
Put the same lens on a APS-C and it acts like a 60mm lens which is slightly telephoto. (1.5x)
Put the same lens on a micro 4/3s and it acts like an 80mm telephoto. (2x)
Put the same lens on a Nikon 1 CX image sensor and it acts like 109mm lens. (2.7x)
Put the same lens on a 1/4" chip and it acts like a 450mm lens. (11.25x)
It's all the same depth of field, but the effect of the viewing angle is changed depending on the size of the image sensor.
Now it's not impossible to get shallow DOF on the HMC40, you just have to shoot at maximum telephoto to get it as this clip shows:
https://vimeo.com/22826646
Bob Diaz
(1) The smaller the number or F-Stop, the less the DOF. F 16 has more DOF than F 2.8
(2) For any given F-Stop as the mm of the lens increases, the DOF decreases. At maximum telephoto on the HMC40, I can get a shallow DOF, but at maximum wide angle, almost everything is in focus.
Take a lens like a 35mm lens. On a full frame 35mm camera, this is a wide angle lens, BUT put hte same lens on my Nikon D5100 and it acts like a 1.5 x 35mm = 52.5mm lens. The reason is simple, the APS-C sensor is smaller than the full frame 35mm sensor. Thus the image is cropped and acts like a normal lens as far as field of view. The magnification factor for my Nikon is 1.5x.
Move to a micro 4/3s sensor and the magnification factor is 2x. So the 35mm full frame lens acts like a 70mm lens on the micro 4/3s camera.
Now we take a 40mm lens on a full frame camera. At F 2.8 the DOF is shallow and the lens is slightly wide angle or we could say it's at the low end for normal.
Put the same lens on a APS-C and it acts like a 60mm lens which is slightly telephoto. (1.5x)
Put the same lens on a micro 4/3s and it acts like an 80mm telephoto. (2x)
Put the same lens on a Nikon 1 CX image sensor and it acts like 109mm lens. (2.7x)
Put the same lens on a 1/4" chip and it acts like a 450mm lens. (11.25x)
It's all the same depth of field, but the effect of the viewing angle is changed depending on the size of the image sensor.
Now it's not impossible to get shallow DOF on the HMC40, you just have to shoot at maximum telephoto to get it as this clip shows:
https://vimeo.com/22826646
Bob Diaz