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#1
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Is there a formula to convert digital lens focal length to 35mm focal length ?
Does it relative to CCD size?
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#2
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"narke" wrote in message ups.com... Does it relative to CCD size? Yes it is entirely dependent on CCD size. For DSLR's, most are close enough to 1.5x. The Olympus E1/E300 are the only lowish-priced SLR's that are significantly different, with a 2x equivalence factor. |
#3
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In article . com,
narke wrote: Does it relative to CCD size? Yes. To a first approximation, divide 43 by the diagonal of the sensor in millimetres. This will give you the multiplication factor for field of view/focal length (differing aspect rations will make this something of an inexact sicence, but it should be close). (43mm is the diagonal of a 35mm frame). |
#4
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narke wrote:
Does it relative to CCD size? The focal length does not change at all. The 'cropping' factor gives a final image similar to the effect of using a longer lens of FL * cropfactor. So, a camera with a 50mm lens and a 1.5 cropped sensor is said to be equivalent to a 75mm lens. (But the focal length does not change, the sensor is just smaller.) Cheers, Alan -- -- r.p.e.35mm user resource: http://www.aliasimages.com/rpe35mmur.htm -- r.p.d.slr-systems: http://www.aliasimages.com/rpdslrsysur.htm -- [SI] gallery & rulz: http://www.pbase.com/shootin -- e-meil: there's no such thing as a FreeLunch. |
#5
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Chris Brown wrote:
In article . com, narke wrote: Does it relative to CCD size? Yes. To a first approximation, divide 43 by the diagonal of the sensor in millimetres. This will give you the multiplication factor for field of view/focal length (differing aspect rations will make this something of an inexact sicence, but it should be close). (43mm is the diagonal of a 35mm frame). Just divide 36 by the width of the sensor. eg: the Canon 20D at 22.5 mm (x): 36 / 22.5 = 1.6 (Quicker than (36^2+24^2)^0.5 / (22.5^2+15^2)^0.5 and same result). Cheers, Alan. -- -- r.p.e.35mm user resource: http://www.aliasimages.com/rpe35mmur.htm -- r.p.d.slr-systems: http://www.aliasimages.com/rpdslrsysur.htm -- [SI] gallery & rulz: http://www.pbase.com/shootin -- e-meil: there's no such thing as a FreeLunch. |
#6
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understand. Thank You All
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