Steven Wyatt Posted September 3, 2007 Share Posted September 3, 2007 Hello, I've gota problem which has been bugging me for some time now so I thought this would be the best place to post it. I was working on a short film a few days back and the DP hired out a set of 35mm Carl Ziess Planar lenses in the focal length of 50, 85 and 135mm. From what I know of 35mm optics on 16mm, doesn't the image become magnified? However the problem that arised in this case was that the images we were getting on 35mm primes didn't seem quite as telephoto. We tested a Canon 11-165mm T2.5 zoom at its telephoto end against a 135mm T2.1 Ziess Planar prime and the field of view it was giving us was pretty much the same. The primes themselves were clearly marked as 'arriflex 35mm' above there pl mount along the barrell. Having only worked on proffessional shoots on occasion, I was boggled by this, so I would appreciate if any one could find the time to answer this. Thanks, Steven Link to comment Share on other sites More sharing options...
Premium Member Stephen Williams Posted September 3, 2007 Premium Member Share Posted September 3, 2007 Hi, A 35mm lens is always a 35mm lens regardless of the camera you fix it to. A lens is an optical device, it can't change. For some absurd reason some prosumer cameras talk about 35mm equivalents, that confuses the matter further as the reference is a 8 perf Nikon still film camera not a 35mm movie camera. The zoom will show a marginally tighter shot due to the fact it's longer than the equivalent prime, move the camera a few inches back to compensate, then they will match exactly. Stephen Hello, I've gota problem which has been bugging me for some time now so I thought this would be the best place to post it. I was working on a short film a few days back and the DP hired out a set of 35mm Carl Ziess Planar lenses in the focal length of 50, 85 and 135mm. From what I know of 35mm optics on 16mm, doesn't the image become magnified? However the problem that arised in this case was that the images we were getting on 35mm primes didn't seem quite as telephoto. We tested a Canon 11-165mm T2.5 zoom at its telephoto end against a 135mm T2.1 Ziess Planar prime and the field of view it was giving us was pretty much the same. The primes themselves were clearly marked as 'arriflex 35mm' above there pl mount along the barrell. Having only worked on proffessional shoots on occasion, I was boggled by this, so I would appreciate if any one could find the time to answer this. Thanks, Steven Link to comment Share on other sites More sharing options...
Steven Wyatt Posted September 3, 2007 Author Share Posted September 3, 2007 Thanks, so in answer to my question do you mean that there is no magnification of the 35mm lenses despite it being utilised on a smaller format? I'm just curious as to why this occurance happens on a technical level. Regards, Steven Link to comment Share on other sites More sharing options...
Premium Member Stephen Williams Posted September 3, 2007 Premium Member Share Posted September 3, 2007 Thanks, so in answer to my question do you mean that there is no magnification of the 35mm lenses despite it being utilised on a smaller format? I'm just curious as to why this occurance happens on a technical level. Regards, Steven Hi Steven, Correct no magnification, you are just cutting out a 16mm frame from a larger image. Stephen Link to comment Share on other sites More sharing options...
Steven Wyatt Posted September 4, 2007 Author Share Posted September 4, 2007 In that sense wouldn't a 135mm 35mm lens be longer than a 165mm 16mm lens if the 35mm lens was used on 16mm? Link to comment Share on other sites More sharing options...
Premium Member Charles MacDonald Posted September 4, 2007 Premium Member Share Posted September 4, 2007 Correct no magnification, you are just cutting out a 16mm frame from a larger image. Stephen two lenses both say 50mm one for a 16mm camera and one for a 35mm camera should give teh same size image on a 16mm Camera... BUT if you go from a 16mm camera to a 35mm Camera to shoot the same shot, (same subject same camera position) you would need to use a longer lens on the 35 than you use on the 16. Stick a 50mm Pentax SLR lens on a K-3 and it makes the same size image as a 50mm C mount lens on a filmo, if both cameras are the same distance from the same subject. Link to comment Share on other sites More sharing options...
Premium Member brentfinley Posted September 18, 2007 Premium Member Share Posted September 18, 2007 We tested a Canon 11-165mm T2.5 zoom at its telephoto end against a 135mm T2.1 Ziess Planar prime and the field of view it was giving us was pretty much the same. "Pretty much the same" Well the difference between 135 and 165 is not that much... depending what you're looking at ... it might look pretty much the same. The 165mm zoom will be a bit tighter.... but unless you quantify it... you might not really notice... using this equation.. FOV (rectilinear) = 2 * arctan (frame size/(focal length * 2)) a 135mm lens gives you a horizontal FOV of 5.25 degrees across a 12.35mm super 16 neg a 165mm lens gives you a horizontal FOV of 4.3 degrees So the 135mm lens give you 5.25/4.3 (1.22) or 22% more image horizontally That's not "pretty much the same"... but if you're filming a person down the street who fills 15% of the image height... it might LOOK pretty much the same... The zoom lens might really NOT be zooming through the entire range... but when it says 135... they should match. Link to comment Share on other sites More sharing options...
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