6:10 Discussing the 50mm lens and crop sensor combination. I might be mistaken, but isn't it true that the depth of field is primarily determined by the lens rather than the sensor size? From my understanding, using a cropped sensor (APS) with a 35mm lens results in a narrower field of view, yet the depth of field and perspective essentially remain consistent with those of a 35mm lens. So, in the end, you achieve a full pixel cropped view. For instance, consider the M8 - attaching a 35mm lens imparts all the characteristics of a 35mm lens, but with an approximately 50mm angle of view. I acknowledge that I might have misunderstood the points made in the video, in which case I apologise for any confusion. I would greatly appreciate it if someone could kindly correct any inaccuracies in my understanding. Thank you!
That's correct. The lens retains the characteristics. Maybe it wasn't clear enough from my side, so I will try to make up for that. First, the smaller crop sensor captures only a part of what a full sensor would capture when using the same focal length. Therefore a picture shot with the crop sensor looks like it is magnified compared to what the full frame shows. It looks like the picture is shot with the focal length of the lens and then multiplied by the crop factor. Secondly, the focal length on a lens is always the real physical focal length, and it has (as you mentioned) nothing to do with the sensor size. Further explained, this means the focal length of lenses made especially for crop sensors is not corrected for the crop sensor. A 50mm lens for a crop sensor has the same focal length as a 50mm for a full-frame sensor. When we talk about depth of field (DOF) there are some factors to realize. The depth of field is influenced by the sensor size indirectly and this is when we are changing parameters to end up with the same picture. The focal length and the distance to the subject are changed to achieve the same framing, and this is part of the reason why the depth of field is different between a full-frame sensor and a crop sensor. The longer the focal length of the lens is, the shorter the DOF. But other factors affect DOF, especially focus distance. That`s maybe how it becomes a bit confusing and maybe a bit difficult to explain.
