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Relative Focal Length, Angle of View, and CCF Chart

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    #61
    I think we need to stop using the term crop factor. I found a cool tool from AbelCine. Check it out. http://www.abelcine.com/fov/
    Barry I just got your af100 book and it is Phenomenal! Thank you!
    Last edited by tmjstudios; 02-07-2011, 12:09 PM. Reason: added one more line

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      #62
      Glad you like it, tmj!

      Yeah, part of the reason I came up with this chart was to push the idea of a Cinema Crop Factor. The "crop factor" is relevant only for stills cameras, and really has no bearing on cinema. The Cinema Crop Factor attempts to relate a given camera system to the prevailing standard of 35mm cinema film.
      ..
      The AU-EVA1 Book - The DVX200 Book - The UX180 & UX90 Book - Lighting For Film & TV - Sound For Film & TV

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        #63
        Hi Barry,

        I hate to drag this out further, and I know it must be completely doing your head in to relentlessly answer these questions, but I have a question regarding the (eek! I hate to say it) "crop factor" of GH1 in 16:9 movie mode, compared to AF100.

        Some people on another forum swear that the GH1's real crop factor (as related to full frame compensated to 16:9) is closer to 1.85x rather than the 2.0x which is often touted, due to i) the crop required in the 5Dii sensor to achieve 16:9 and ii) the fact that GH sensor is larger than 4/3 to allow it to make 16:9 image larger than it would otherwise be. The point being made is that a given lens on the GH1 camera exhibits a wider angle of view than on the AF100.

        Can you confirm of squash this notion for me please?
        Digital film-maker, Bristol, UK.

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          #64
          The GH1's sensor (and the GH2, for that matter) are slightly oversized and, yes, the crop factor is less when in 16:9 mode on a GH1 (or GH2) as compared to the 5D Mark II. Panasonic hasn't, as far as I know, released the exact true width of the GH1/GH2 sensor, but from pixel calculations we think it's using an area of 18.9 x 10.6 or thereabouts. That is bigger in width than the 17.3x13 size that is commonly used for Four Thirds sensors, and that's the reason the "crop factor" of movie mode is less than the "crop factor" of stills mode.

          The AF100 doesn't use the same sensor or the same sized sensor as the GH1/GH2. Its 16:9 image is made from a slightly smaller patch, it uses 17.8 x 10mm. As such, the "crop factor" is closer to 2.0 as compared to a 5D, and the GH1/GH2 do exhibit a slightly wider field of view than the AF100 does. It's a difference of about 5%.
          ..
          The AU-EVA1 Book - The DVX200 Book - The UX180 & UX90 Book - Lighting For Film & TV - Sound For Film & TV

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            #65
            Great. Thankyou. I still wonder where it would squeeze in on that lovely chart you made up.

            Calculations by others, based on the Panasonic diagrams, are for a 1.85x crop from 5D2's 16:9 movie mode, making 27mm the "standard" lens.
            Digital film-maker, Bristol, UK.

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              #66
              any way great work by barry green once again. i am not questioning your work at all, you calculated by taking measures from panasonic's given manual. but with my curiousity i am asking this. if AF 100's sensor size is 17.3*13 mm then it can record the 16*9 image size in 17.3mm*9.731mm only. how it can record in 17.8*10mm. if i am compleately wrong about math and cameras technology, please excuse for my ignoranse. if possible clarify this to me Mr Barry Green.
              thanks for your valuable chart work.

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                #67
                So, essentially this is saying if you want a normal viewpoint (the normal category obviously), then you would need a 25mm lens, correct? I'm having trouble figuring out what size still camera lens I would purchase to use on the Af100..

                I'm new to the whole lens thing, but I am going to buy the af100 in probably six months (unless I opt for something else, or hear of a better option).

                Any help would be really appreciated. Thanks!

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                  #68
                  25mm is roughly equivalent to the field of view you get on a 50mm lens on a 35mm stills camera, yes.
                  Digital film-maker, Bristol, UK.

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                    #69
                    Originally posted by nageswara rao s View Post
                    how it can record in 17.8*10mm.
                    The specifications in the Panasonic manual put the sensor size at 17.8 x 10mm. It is not a 17.3mm sensor, it's 17.8mm.
                    ..
                    The AU-EVA1 Book - The DVX200 Book - The UX180 & UX90 Book - Lighting For Film & TV - Sound For Film & TV

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                      #70
                      ok, thanks Mr Barry Green.

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                        #71
                        Originally posted by Barry_Green View Post
                        The Cinema Crop Factor was designed around the standard 35mm cinema frame, and in that scenario the AF100 is 1.19...
                        Do you all agree that academy aperture is handy starting point for comparison?
                        Hardly no movies are shot in that format in this millenium and there's no digital cameras using that format.
                        Maybe some real world physical object that is in use would be easier to understand?

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                          #72
                          Actually our factory just posted this lens calculator which I think is a bit more helpful than others I have seen:

                          http://www.geocities.jp/dvcpro24/lens_calculator.html

                          Best,

                          jan
                          Jan Crittenden Livingston
                          Panasonic System Communications Corporation
                          Partner Sales Manager, NY and NJ

                          Comment


                            #73
                            This chart rocks, Barry.

                            After reading your book I feel like I'm talking to a celebrity whenever you post here, man.

                            Thanks for helping us out so much. Really appreciate it.

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                              #74
                              This is a very useful chart.

                              But the 1/4 stop DOF difference between M43 and Academy is a little misleading as Academy hasn't really been the standard for about a decade now. Super 35 is, and the other digital cinema cameras are based on the Super 35 frame size. So it would have been more useful to compare M43 with that. Also, even though M43 is extremely close in size to even Super 35, when you look at tests like the ones bellow you can't help but see that in practical applications the DOF seems much shallower in Super 35 than in M43.



                              Last edited by Adamsenoj; 08-25-2012, 05:35 AM.
                              Cameras: Panasonic AF100, GH2 (x2) and Sony EX3.
                              Lenses: Zeiss CP.2 primes

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                                #75
                                Wasn't Batman Begins shot Academy 35? And Black Swan S16? People get far to hung up on all these standards.

                                It should be noted that the speedbooster is giving the AF100 the S35mm field of view and DOF from still lenses, so I imagine on the various multi mount PLs out there you could possibly achieve a field of view that's greater than S35 when using said lens via the Speedbooster

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