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  • #16
    The BMC is a 1.5:1 crop, as compared to S35. Well, at least, according to digital S35; if comparing to film S35 it's a 1.6:1 crop.

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    • #17
      Originally posted by Barry Green View Post
      The BMC is a 1.5:1 crop, as compared to S35. Well, at least, according to digital S35; if comparing to film S35 it's a 1.6:1 crop.
      Barry, how can I get to those numbers? I assume I need to consider the sensor size with fov? I'm not very good at math.

      Pietro Impagliazzo
      flickr.com/photos/impagliazzo

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      • #18
        Originally posted by Pietro Impagliazzo View Post
        Barry, how can I get to those numbers? I assume I need to consider the sensor size with fov? I'm not very good at math.
        Seeing as we're comparing the same aspect ratio, you can simply divide based on the widths of the sensors. S35 digital is 23.6mm, the BMC is 15.8mm wide, so 23.6 / 15.8 = 1.5. S35 film is 24.9mm wide, so 24.9 / 15.8 = 1.6.

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        • #19
          Does anyone know for sure if the 1080p mode for non-raw codecs are just cropped? I recall reading it somewhere but can't find my source anymore.

          Thought I'd throw it in there, as we're working out crop factors, and some people may be using in-camera codecs. I think it'd be closer to S16, I haven't done the math yet.

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          • #20
            Originally posted by joesiv View Post
            Does anyone know for sure if the 1080p mode for non-raw codecs are just cropped? I recall reading it somewhere but can't find my source anymore.

            Thought I'd throw it in there, as we're working out crop factors, and some people may be using in-camera codecs. I think it'd be closer to S16, I haven't done the math yet.
            I remember reading that 1080p modes would not be cropped but that they would be scaled.
            www.motionplaces.com
            andrewjulian

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            • #21
              I'm sure John said it's scaled. It would make no sense to crop it, because it'd be a crop of the raw sensor, which would then necessitate having to debayer that, meaning you'd end up with a mushy 720p's worth of data. I'm pretty sure that's not what they're doing, I'm pretty sure they're debayering and then scaling down the full sensor.

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              • #22
                That's good news!

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                • #23
                  For EF-S body users, multiply the focal length you want to test by 1.5 and do a test shoot. 24mm on the BMD is equivalent to 17mm on my 60D's crop factor.

                  I found that 17mm on my EF-S 17-55mm F/2.8 wasn't that wide, but was still within the field of view I would use when framing a shot. I plan on buying a super wide angle lens to cover those times when I need something moderately wide. I'm going to be shooting narrative / music video shots so the medium to long crop is exactly what I want.

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                  • #24
                    Originally posted by nickjbedford View Post
                    For EF-S body users, multiply the focal length you want to test by 1.5 and do a test shoot. 24mm on the BMD is equivalent to 17mm on my 60D's crop factor.

                    I found that 17mm on my EF-S 17-55mm F/2.8 wasn't that wide, but was still within the field of view I would use when framing a shot. I plan on buying a super wide angle lens to cover those times when I need something moderately wide. I'm going to be shooting narrative / music video shots so the medium to long crop is exactly what I want.
                    So is the Tokina 11-16 then really the widest, fastest option?

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                    • #25
                      Thanks everyone- really helpful information. Great spreadsheets as well!

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                      • #26
                        Sorry but I have doubt about that croping nightmare. Since a 50mm is still a 50mm and a 21mm is a 21mm and a 100mm is a 100mm, does the 21mm have the same specs or it gets a 50mm properties.

                        To be more clear does the 21mm have the wide lens look or instead flatten like a 50mm? If the answer is that it remain having the 21mm properties the crop factor just affect the distance where you put the camera to get the same frame as you will do in a full frame sensor, no?(I also read in Ken Rockwell that also affects in a slightly way the DoF).

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                        • #27
                          Originally posted by Fabián Matas View Post
                          Sorry but I have doubt about that croping nightmare. Since a 50mm is still a 50mm and a 21mm is a 21mm and a 100mm is a 100mm, does the 21mm have the same specs or it gets a 50mm properties.

                          To be more clear does the 21mm have the wide lens look or instead flatten like a 50mm? If the answer is that it remain having the 21mm properties the crop factor just affect the distance where you put the camera to get the same frame as you will do in a full frame sensor, no?(I also read in Ken Rockwell that also affects in a slightly way the DoF).
                          A 50mm 1.4 lens will have a same DOF on every camera. But because - to have the same picture - you will have to go further from the object, that's why it would be like that the depth of field will be larger.

                          A 21mm lens on a 5D has a wide angle look. You won't get that look, because with a smaller sensor you will crop inside that picture.
                          To get the same wide angle field of view, you would have to use a 9mm lens. (sigma has a 8-18mm lens)
                          C300 review | http://carousel.hu/c300/

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                          • #28
                            Thanks men!!!!!

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                            • #29
                              In my understanding the crop factor can be calculated by this math

                              full format =36mm width
                              Bmc format =15.6mm width
                              So 36/15.6= 2.3x is the crop factor when you using a full format lens on a Bmc camera.similarly an aps-c camera width=24mm.so, 24mm/15.6mm=1.5x Crop.
                              The focal length (ie) [The distance between the optical center of a lens & the sensor when its focused at infinity] wont change.But, the magnification of the lens will change based on what sensor we use that particular lens on.
                              So i made my calculations for the existing popular 5d lenses
                              Aps-c Lens:
                              1.Tokino 11-16 = 17mm-24mm on a Bmc Body
                              2.Canon 17-55 = 25mm-82mm on a Bmc Body
                              3.Sigma 30mm = 45mm on a Bmc Body

                              Full Format Lens:
                              1.Canon 16-35 = 37mm-80mm
                              2.Canon 24-70 = 55mm-161mm on a Bmc Body
                              3.Canon 50mm = 115mm on a Bmc Body
                              4.Canon 85mm = 195mm on a Bmc Body
                              5.Canon 100mm= 230mm on a Bmc Body
                              6.Canon 70-200= 161mm-460mm on a Bmc Body

                              I see lot of ppl calculate Tokino 11-16mm lens with 2.3x crop factor. It is made for Aps-c Body which is 24mm Width & 18mm Height so the crop factor must be 1.5x
                              If my calculations are wrong correct me
                              Thank you
                              Hope this will help you to find your right choice of lenses with BMC Body

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                              • #30
                                Originally posted by manigandan View Post
                                In my understanding the crop factor can be calculated by this math

                                full format =36mm width
                                Bmc format =15.6mm width
                                So 36/15.6= 2.3x is the crop factor when you using a full format lens on a Bmc camera.similarly an aps-c camera width=24mm.so, 24mm/15.6mm=1.5x Crop.
                                The focal length (ie) [The distance between the optical center of a lens & the sensor when its focused at infinity] wont change.But, the magnification of the lens will change based on what sensor we use that particular lens on.
                                So i made my calculations for the existing popular 5d lenses
                                Aps-c Lens:
                                1.Tokino 11-16 = 17mm-24mm on a Bmc Body
                                2.Canon 17-55 = 25mm-82mm on a Bmc Body
                                3.Sigma 30mm = 45mm on a Bmc Body

                                Full Format Lens:
                                1.Canon 16-35 = 37mm-80mm
                                2.Canon 24-70 = 55mm-161mm on a Bmc Body
                                3.Canon 50mm = 115mm on a Bmc Body
                                4.Canon 85mm = 195mm on a Bmc Body
                                5.Canon 100mm= 230mm on a Bmc Body
                                6.Canon 70-200= 161mm-460mm on a Bmc Body

                                I see lot of ppl calculate Tokino 11-16mm lens with 2.3x crop factor. It is made for Aps-c Body which is 24mm Width & 18mm Height so the crop factor must be 1.5x
                                If my calculations are wrong correct me
                                Thank you
                                Hope this will help you to find your right choice of lenses with BMC Body
                                First: Welcome
                                Second: Your BMC sensor width is off. It is 15.81mm not 15.6mm. It has changed since it was first announced.
                                http://www.blackmagicdesign.com/prod...era/techspecs/

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