Parfocal Zooms List

[Henry Gentles]

Been buying a lot of Lenses in the past 2 years for stills and video but never occurred to me to look for Parfocal as they are particularly useful in maintaining focus if you need to zoom in to lock in a focal point then back to wide. I found this list for Canon Zooms. Might be useful if someone had a list of all the Parfocal Zooms? 

http://www.funkytwig.com/blog/canon-dslr-lense-parfocal-constant-aperture

[Brian Caldwell]

Been buying a lot of Lenses in the past 2 years for stills and video but never occurred to me to look for Parfocal as they are particularly useful in maintaining focus if you need to zoom in to lock in a focal point then back to wide. I found this list for Canon Zooms. Might be useful if someone had a list of all the Parfocal Zooms? 

http://www.funkytwig.com/blog/canon-dslr-lense-parfocal-constant-aperture

A caution here:  parfocality in a zoom lens is strongly dependent on sample variation.  So, even if a zoom is designed to be parfocal, then a typical as-built lens won't necessarily maintain precise focus through zoom.  High-end cine zooms rely on post-assembly re-machining of at least one of the cams controlling the various zoom group motions.  Needless to say, this is a very expensive process.