Camera lens question

Jan 27, 2026 Last reply: 5 months ago 4 Replies
D

Good morning.



I watched a video of a man take apart an SLR lens today to clean it. He stated it was the first one he'd done and just as I predicted, he made a right old horlicks of it. Anyway, it made me think:



Does the rotatonal position of the individual lenses within a lens (objective?) matter to the image quality? I know the parallel-ness of the lenses to each other is, because that will impact the focal length or focussing of the light (please try to keep up with my technical language), but is the rotation of those lenses about the axis of the lense important? I would assume not, but I have also learnt not to assume anything when it comes to what I know or do not know.



Thanks in advance for any knowledge.


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J

I would expect for a "normal" camera lens the optical elements are symmetric and hence rotation would not alter the performance. For a cinematic anamorphic lens then the relative rotation of the anamorphic elements will need to be carefully controlled. Note that some do allow rotation (or counter rotation of pairs of elements) to facilitate variable anamorphic "zoom" - allowing the amount of horizontal image compression to be varied.

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T

Grey Lensman?

+i. even though not totally spherical or parabolic, lens elements are all 'rotationally symmetrical'.

Only polarisers are not.

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R

There is a category of anamorphic lenses, but presumably you'd know if you had one.

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T

Ive got lots of them. I have astigmatism :=-)

-- "Strange as it seems, no amount of learning can cure stupidity, and higher education positively fortifies it."

- Stephen Vizinczey

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