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Another question - How to convert medium format lens to equivalency of a 50mm normal lens (35mm camera) in APS-C digital cameras
What needs explaining here is what at 'standard lens is - and
that is simple. It is the lens which has a focal length equivalent to the longest measurement of the format in use, i.e. the diagonal. It this follows that a 'standard' lens for 35mm will, by Pythagorus, be about 42mm, and for 645 will be 75mm. AP-C cell sizes vary, but assuming 23x15mm this would make a 'standard' lens about 27mm. The ratio of 35mm to AP-C is thus about 42/27 or 1.5 which is what is generally accepted as 'about' the magnification factor. Due to fanufacturing processes and the way the brain 'sees' a picture, 50mm (with a magnification factor or 50/42 or 1.2) is usually accepted as 'standard' for 35mm. By the same token a 645 'standard' lens on an AP-C camera will be 75/27 or about 2.8, which in 35mm lens terms would be the equivalent of about 140mm. HTH -- Woody harrogate three at ntlworld dot com |
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Another question - How to convert medium format lens toequivalency of a 50mm normal lens (35mm camera) in APS-C digital cameras
On Sun, 31 May 2009 10:13:23 +0100
"Woody" wrote: What needs explaining here is what at 'standard lens is - and that is simple. It is the lens which has a focal length equivalent to the longest measurement of the format in use, i.e. the diagonal. It this follows that a 'standard' lens for 35mm will, by Pythagorus, be about 42mm, and for 645 will be 75mm. 44.4mm 70.6mm Just in case anyone thought Pythagoras was playing up. :-) |
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Another question - How to convert medium format lens to equivalency of a 50mm normal lens (35mm camera) in APS-C digital cameras
"Rob Morley" wrote in message
news:20090531180949.58a0297b@bluemoon... On Sun, 31 May 2009 10:13:23 +0100 "Woody" wrote: What needs explaining here is what at 'standard lens is - and that is simple. It is the lens which has a focal length equivalent to the longest measurement of the format in use, i.e. the diagonal. It this follows that a 'standard' lens for 35mm will, by Pythagorus, be about 42mm, and for 645 will be 75mm. 44.4mm 70.6mm Just in case anyone thought Pythagoras was playing up. :-) Sorry - fogot the spel-chequer! -- Woody harrogate three at ntlworld dot com |
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Another question - How to convert medium format lens to equivalency of a 50mm normal lens (35mm camera) in APS-C digital cameras
"Woody" wrote in message
... "Rob Morley" wrote in message news:20090531180949.58a0297b@bluemoon... On Sun, 31 May 2009 10:13:23 +0100 "Woody" wrote: What needs explaining here is what at 'standard lens is - and that is simple. It is the lens which has a focal length equivalent to the longest measurement of the format in use, i.e. the diagonal. It this follows that a 'standard' lens for 35mm will, by Pythagorus, be about 42mm, and for 645 will be 75mm. 44.4mm 70.6mm Just in case anyone thought Pythagoras was playing up. :-) Let's split the difference shall we? (36^2+24^2)^0.5 = 43.2. (60^2+45^2)^0.5=75 as I said. (This using Windows Calculator.) Try your Pythagoras again maybe? -- Woody harrogate three at ntlworld dot com |
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Another question - How to convert medium format lens toequivalency of a 50mm normal lens (35mm camera) in APS-C digital cameras
On Sun, 31 May 2009 19:04:40 +0100
"Woody" wrote: Let's split the difference shall we? (36^2+24^2)^0.5 = 43.2. It seems I succumbed to one of the fundamental laws of Usenet. (60^2+45^2)^0.5=75 as I said. (This using Windows Calculator.) The neg size of 645 is more like 56×41.5mm, because 120 film is based on 2 1/4", not 60mm. Try your Pythagoras again maybe? Next time I'll double check before posting. Or just try to abstain from nitpicking. :-) |
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