#CAMERA LENS DISTORTION BIG FACE MOVIE#
How this works in a 3D movie would be interesting, as you could get a lot closer in 3D without the distortion, but then the 2D version would suffer the distortion. Now cover one eye, and see the distortion effect appear. Try looking at a persons face from 10 inches, with both eyes. We don't see these effects with our eyes to the same degree because we see in 3D, and therefore our brains have more than just size on the image to judge distance and size of a subject. Move the cam to 8 feet from subject and that nose is now only 1/32 of the cam distance closer than the ears are, making the difference negligible, so looks more natural. So if the camera is 12 inches from the nose, the nose is a 1/3 of the camera distance closer to the sensor, and will image that much larger than the ears, and look horrible. A nose sticks out 3/4 inch from the face and is say 4 inches in front of the ears. The reason this all works is simple, although the above example is easily the best real world demo I have seen of it.Ī head is 8 inches from nose to back of head.
If you're shooting super 35, then to get the same distortion characteristics as the examples show, on any given lens, the camera would have to be moved back to allow for the crop factor of super 35mm. Novemat 6:37AM, Edited September 4, 7:54AMĪpologies if went off topic, but there seemed to be confusion that a crop factor made no difference, which of course it does, as stated accurately in the video.Īs for filming, the crop factor is very relevant.
It's hard to explain, but it makes sense if you draw a lens side on, and see the rectangle ratio and mark where the light passes through the lens.
#CAMERA LENS DISTORTION BIG FACE FULL#
So if you use the centre of a 100mm lens on a 1.6 crop, the ratio between the focal length and the centre portion of the image circle your sensor is using, is now the same ratio as a 160mm lens where your using the full circle, so the optical characteristics are the same, the light travels at the same angle through to the sensor and the image is identical, as long as the crop sensor is moved proportionally further back to ensure the same subject is filling the frame on both cameras. One is a long tube and one is a wide angle block.ģ5mm is just an accepted standard of reference but a 100mm lens with an imaging circle to suit four thirds is a completely different ratio to one for 35mm ff and very different from one with a circle to image MF or LF.Įven on a crop where you still use a 100mm with a 35 image circle, the crop is still only using a smaller circle, and that extra glass might as well not exist, as the lens now acts like a longer lens, with a different focal/circle ratio. Light passes through these two lenses at vastly different angles, yet by the logic displayed here, they are both 100mm and therefore both the same. A 100mm lens for four thirds is very long and thin. The focal length of a lens is irrelevant if it's imaging circle isn't known.Ī 100mm lens with a 100 diameter image circle is almost square side on. Four thirds imaging circle is smaller than EF of course. Oh but it does, as it's imaging circle (diameter) is made for the sensor size.
Yeah, ‘A lens is a lens is a lens, and it doesn’t know what size sensor or film gate is placed behind it’ Novemat 12:45AM, Edited September 4, 7:54AM I didn't read this wikipedia article, but the begining seems to be right. That's why this math works as a good reference almost all the times when comparing sensor sizes and lenses distances. Roughly and in very lame terms a longer lens has the effect of "cropping" the field of view when compared to a wider lens. A 50 mm in a 1.6 crop factor will give you a frame size similar to a 80mm in a full frame. That extra distance would end up flattening the perspective a little bit or a lot depending on the crop ratio.įor instance a 50 mm that is considered to render a normal perspective on a full frame camera (normal perspective meaning similar to the way our eyes work) is considered a tele-photo when used in a cropped frame.
To get a proper frame on a cropped camera you would need to back the camera from the subject to create more room to frame decently the subject's face. No because the image would be cropped compared to a full frame, and you would end up losing features from the subjects face like the ears, chin, forehead.
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