I want to know whether a zoom lens keeps focus as you change focal length (parfocal) or needs refocusing (varifocal), and whether there is any reliable list online. Specifically, I’m asking about these lenses: - Canon EF 70-200mm f/2.8L IS II - Canon EF 24-70mm f/2.8L II - Canon EF 24-105mm f/4L - Sigma 12-24mm f/4.5-5.6 Is there a quick way to tell without extensive testing, and are any of these lenses parfocal?

How can I tell whether a zoom lens is parfocal, and are these Canon and Sigma zooms parfocal?

Asked 4/19/2013

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I want to know whether a zoom lens keeps focus as you change focal length (parfocal) or needs refocusing (varifocal), and whether there is any reliable list online. Specifically, I’m asking about these lenses:

Canon EF 70-200mm f/2.8L IS II
Canon EF 24-70mm f/2.8L II
Canon EF 24-105mm f/4L
Sigma 12-24mm f/4.5-5.6

Is there a quick way to tell without extensive testing, and are any of these lenses parfocal?

video varifocal lenses parfocal zoom-lenses

Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0

Photography Stack Exchange contributor

13y ago

2 Answers

Here is a link with parfocal lenses: http://www.lensrentals.com/blog/2011/02/photo-lenses-for-video/4 This list is from February 2011, so if your lens was published after this time it could still be parfocal.

For your lenses:

Canon 70-200mm f/2.8 L ii --> No.
Canon 24-70mm f/2.8 L ii --> No.
Canon 24-105mm f/4 L --> No.
Sigma 12-24mm f/4.5-5.6 --> No.

Originally by user7718. Source · Licensed CC BY-SA 4.0

user7718

13y ago

AI Answer

Generated from our catalog & community — verify before relying on it.

A quick practical check is to focus on a subject, switch to manual focus so the camera won’t refocus, then zoom the lens. If the subject stays in focus throughout the zoom range, the lens is parfocal; if focus shifts, it’s varifocal.

Based on the community answers, none of the listed lenses are parfocal:

Canon EF 70-200mm f/2.8L IS II — not parfocal
Canon EF 24-70mm f/2.8L II — not parfocal
Canon EF 24-105mm f/4L — not parfocal
Sigma 12-24mm f/4.5-5.6 — not parfocal

There are online lists of lenses reported to be parfocal, but they may be incomplete or dated, so they’re best used as a starting point rather than a guarantee. In practice, a simple focus-then-zoom test is the most reliable way to check a specific copy and setup.

How can I tell whether a zoom lens is parfocal, and are these Canon and Sigma zooms parfocal?

2 Answers

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