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focus shift vis focus breathing

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by Wildflower-nut on Thu Sep 07, 2023 11:58 am

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If you zoom in, focus on something and then zoom out, it will no longer be in precise focus. It will need to be touched up. Is this the same as focus breathing?

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by Anthony Medici on Thu Sep 07, 2023 12:27 pm

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What you are describing in a zoom lens is whether it is parfocal or varifocal lens. The description you give about a lens is that it was designed to be Varifocal as its focus changes as you change the focal length of the lens. Other lenses are designed to be Parfocal. Those lenses are designed to not change the focus distance as you go through the zoom range.

Focus Breathing is at the focal length changes slightly as you between minimum focus distance and infinity. If it's focus breathing, the composition changes as you change the focus. It's not focus breathing is it stays the same.

Tony

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by Wildflower-nut on Thu Sep 07, 2023 10:30 pm

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It is my understanding that change in focus with zoom is a common problem for still camera lenses. With movie and video, more effort is made to eliminate it?

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by E.J. Peiker on Tue Sep 12, 2023 6:29 am

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Wildflower-nut wrote: It is my understanding that change in focus with zoom is a common problem for still camera lenses. With movie and video, more effort is made to eliminate it?

That is correct although even for still photo oriented lenses, some are much better than other.

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