So, I have a bunch of lenses that overlap when it comes to focal length. What I can not figure out is why the field of view is so different at the same focal length. For instance, my old 35-80 vs 77 the 77 at a couple of meters is giving me much less FOV than the 35-80 @ 80. Anyone with a good explanation?

The specs says 30 degrees vs 31.5 so it should be the other way arround...

[othar]

So, I have a bunch of lenses that overlap when it comes to focal length. What I can not figure out is why the field of view is so different at the same focal length. For instance, my old 35-80 vs 77 the 77 at a couple of meters is giving me much less FOV than the 35-80 @ 80. Anyone with a good explanation? The specs says 30 degrees vs 31.5 so it should be the other way arround...

if you are focusing on close objects you might experience focus breathing, the FOV is determined for the infinity position on the lens.

[Lowell Goudge]

with many zooms especially those with fixed rear elements and / or internal focusing, part of the close focusing function is achieved by changing focal length. focal length is only accurate at infinity.

this topic comes up from time to time in the forums

---------- Post added 08-30-2016 at 02:47 PM ----------

if you are focusing on close objects you might experience focus breathing, the FOV is determined for the infinity position on the lens.

focus breathing is air going in and out of the lens due to changing physical length, it is not related to change in focal length as a function of focus distance

[othar]

focus breathing is air going in and out of the lens due to changing physical length, it is not related to change in focal length as a function of focus distance

I think I have heard this expression for this behavior too, but in any case I ment the same thing as you said

Thanks for the info, infinity is the key.


Focus breathing was explained to me as that the FOV changed when focusing from one subject to another at a different distance.

[DougieD]

focus breathing is air going in and out of the lens due to changing physical length, it is not related to change in focal length as a function of focus distance

I think the term "focus breathing" or "lens breathing" usually refers to a changing FoV as the focus distance changes. If that isn't the official definition, that's how the term is commonly used, anyway.

[Unregistered User 8]

Focus breathing was explained to me as that the FOV changed when focusing from one subject to another at a different distance.

I hope this little video helps.

You Tube

You Tube