(Wasn't sure where to put this, as we don't have a 'Lens' Section, but since 35mm is the general public's standard, I figured I'd put it here.)
Now that I'm shooting MF as well as 35mm (and APS-C), this question has really been bugging me.
I understand that the focal length of a lens is determined by the distance of the focal point to the film plane, whether it be label in mm, cm, or inches. But when you change formats, what an Xmm lens captures changes from format to format. In other words, a 50mm lens on a 35mm format camera will capture ~46° of the scene. But a 50mm lens on a 6x7 will capture ~81° of the scene. Same focal point to film plane distance, but a completely different image results.
Now it can be said that the general public knows what a 'XXmm' lens will give them as a final image, but that's only because it became the standard way back when. I know for a fact that people new to photography have a difficult time grasping the difference between what they will get as a final between a 24mm, 50mm, and 135mm. Many just don't have any idea what that means, and I'm sure back in the day it wasn't any difference. There is no (IMO) logical relationship between 50mm and 46°, that can be (relatively) immediately understood by a novice.
But if I say to someone who has a basic understanding of geometry that your eyes see ~200° of a scene, and that lens A gives you an image that represents 81° of that scene, I think they might have a better comprehension of what the end result will be. They can take their hands, hold them up to their face, and make blinders that give a 81° view of the scene, and get an idea of what they'll get in their image.
I personally try and convert a 'mm' lens into AOV lens, so I can 'see' what I'll get without having to try different lenses. In other words, I'll look at a scene, and say to myself I want approximately 55° of what I am seeing to be captured, and then grab the lens closest to that.
Labeling a lens as a 52° AOV would standardize the entire lens lineups across formats. No matter what format you're using, a lens with an AOV of 52° will give you 52° of the entire scene. So, in my case, my 24mm (35mm format) lens would be labeled as 81° AOV, as well as my 50mm MF lens (Mamiya RB67). But the way it is now, I have two lenses that are named the same, but give 'wildly' different results.
Discuss....
Now that I'm shooting MF as well as 35mm (and APS-C), this question has really been bugging me.
I understand that the focal length of a lens is determined by the distance of the focal point to the film plane, whether it be label in mm, cm, or inches. But when you change formats, what an Xmm lens captures changes from format to format. In other words, a 50mm lens on a 35mm format camera will capture ~46° of the scene. But a 50mm lens on a 6x7 will capture ~81° of the scene. Same focal point to film plane distance, but a completely different image results.
Now it can be said that the general public knows what a 'XXmm' lens will give them as a final image, but that's only because it became the standard way back when. I know for a fact that people new to photography have a difficult time grasping the difference between what they will get as a final between a 24mm, 50mm, and 135mm. Many just don't have any idea what that means, and I'm sure back in the day it wasn't any difference. There is no (IMO) logical relationship between 50mm and 46°, that can be (relatively) immediately understood by a novice.
But if I say to someone who has a basic understanding of geometry that your eyes see ~200° of a scene, and that lens A gives you an image that represents 81° of that scene, I think they might have a better comprehension of what the end result will be. They can take their hands, hold them up to their face, and make blinders that give a 81° view of the scene, and get an idea of what they'll get in their image.
I personally try and convert a 'mm' lens into AOV lens, so I can 'see' what I'll get without having to try different lenses. In other words, I'll look at a scene, and say to myself I want approximately 55° of what I am seeing to be captured, and then grab the lens closest to that.
Labeling a lens as a 52° AOV would standardize the entire lens lineups across formats. No matter what format you're using, a lens with an AOV of 52° will give you 52° of the entire scene. So, in my case, my 24mm (35mm format) lens would be labeled as 81° AOV, as well as my 50mm MF lens (Mamiya RB67). But the way it is now, I have two lenses that are named the same, but give 'wildly' different results.
Discuss....
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