08-21-2017, 06:51 AM
(This post was last modified: 08-21-2017, 07:02 AM by Brightcolours.)
Lens equivalence is not about "establishing whether one is better or not" (quoting Wim).
Nor is it about "pixel densities (as well as pixel arrays: X-Trans and Foveon sensor also are APS-C, not just the normal Bayer patterns), lens tolerances, noise behaviour (and strategies to minimize noise)" (quoting JoJu).
These two notions are, how to put it... ok, I'll quote Wim again: " it is about time that people start realizing it is utter nonsense."
Lens equivalence is just about understanding how lenses on different systems relate to eachother in the two fundamental properties of lenses: FOV and the aperture properties of DOF and how much light they let through.
So no, lens equivalence is not about pixel densities. If one takes issue with different pixel densities, one can't compare a Nikon D3s with a Nikon D5, or D750, or even a Sony A99 II.
Again, it is just about understanding that.... for instance this 7.5mm f2 Loawa on MFT is equivalent to a 15mm f4 lens on FF (like an IRIX 15mm f2.4 set to f4). That those will give similar FOV, similar DOF and that the apertures are the SAME size, letting through the same amount of light and the sensors capture a similar cone (or rather a king of pyramid?) of light. You only have two options with lenses to shape your image... Selecting the FOV and selecting the f-stop. That is it.
Of course, among similar lenses (or equivalent lenses on different platforms), one can choose which lens one likes best (using criteria like for instance coma performance, sharpness, CA performance, contrast, OOF rendering, size, price, weight, build quality or even AF performance). But that is not what lens equivalence is about It is about the understanding the two fundamentals (FOV and DOF), when the numbers are different (focal length and f-stop).
So it is about understanding how to get to fit a building in the frame with MFT, when one is used to FF, for instance (or the other way around). Or to understand how to get the right amount of subject isolation with APS-C when one is used to using MF.
Lens equivalence is about selecting the gear that is appropriate (right lens (focal length) and settings (f-stop)), for whatever reasons (FOV, DOF), and sometimes realizing that one can't do something with a certain camera and that then a different setup would be required.
One does have to wonder why some have such a big problem with wrapping their mind around the simple notion of lens equivalence. Do those who keep on fighting these fundamentals have problems understanding what it means to use a teleconverter between lens and camera? Or a focal reducer?
Nor is it about "pixel densities (as well as pixel arrays: X-Trans and Foveon sensor also are APS-C, not just the normal Bayer patterns), lens tolerances, noise behaviour (and strategies to minimize noise)" (quoting JoJu).
These two notions are, how to put it... ok, I'll quote Wim again: " it is about time that people start realizing it is utter nonsense."
Lens equivalence is just about understanding how lenses on different systems relate to eachother in the two fundamental properties of lenses: FOV and the aperture properties of DOF and how much light they let through.
So no, lens equivalence is not about pixel densities. If one takes issue with different pixel densities, one can't compare a Nikon D3s with a Nikon D5, or D750, or even a Sony A99 II.
Again, it is just about understanding that.... for instance this 7.5mm f2 Loawa on MFT is equivalent to a 15mm f4 lens on FF (like an IRIX 15mm f2.4 set to f4). That those will give similar FOV, similar DOF and that the apertures are the SAME size, letting through the same amount of light and the sensors capture a similar cone (or rather a king of pyramid?) of light. You only have two options with lenses to shape your image... Selecting the FOV and selecting the f-stop. That is it.
Of course, among similar lenses (or equivalent lenses on different platforms), one can choose which lens one likes best (using criteria like for instance coma performance, sharpness, CA performance, contrast, OOF rendering, size, price, weight, build quality or even AF performance). But that is not what lens equivalence is about It is about the understanding the two fundamentals (FOV and DOF), when the numbers are different (focal length and f-stop).
So it is about understanding how to get to fit a building in the frame with MFT, when one is used to FF, for instance (or the other way around). Or to understand how to get the right amount of subject isolation with APS-C when one is used to using MF.
Lens equivalence is about selecting the gear that is appropriate (right lens (focal length) and settings (f-stop)), for whatever reasons (FOV, DOF), and sometimes realizing that one can't do something with a certain camera and that then a different setup would be required.
One does have to wonder why some have such a big problem with wrapping their mind around the simple notion of lens equivalence. Do those who keep on fighting these fundamentals have problems understanding what it means to use a teleconverter between lens and camera? Or a focal reducer?