Video Terms: Parfocal lens

-adjective
1. A zoom lens that remains in focus as you zoom from one focal length to another.

-Why you should care
2. If you manually focus by zooming in on a subject and then zooming out to take a picture.
3. If you want to zoom while shooting a video segment.

-Idioms
4. Some feel the 70-200mm L IS lens is not parfocal at distances less than 20 feet from the camera [9]
5. I want to get a parfocal zoom lens with the longest zoom range possible.

-Origin
6. par + focal (par = a level of equality)

-Discussion
7. DPReview.com: Not all zoom lenses are parfocal
8. DVInfo.com: Is a parfocal lens necessary?

-References
9. Doug Chinnery Photography: Canon Parfocal Lenses
10. Wikipedia: Parfocal lens

-Other
Canon does not officially list lenses as being parfocal, but these L lenses are considered by most to be parfocal. You can find a list of other lenses at [9].


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