Re: Example of parfocal issue
 

My Camera definitely has the issue, it's very noticeable with a broadcast monitor. However, I'm working around it (simply using other means to focus rather than zooming in) because I would have to send my camera away for a couple of weeks and Canon are very equivocal about whether they will do anything about it - I can't afford to send it away only to have it returned uncorrected (as has happened to others on this forum).

I'm sure Nick (earlier in this thread) won't mind me saying, he eventually gave up on the XF because of this issue and switched to Sony EX.

In my case it only happens with the NDs engaged. As most of my work is shot indoors I can live with it, reluctantly.

Re: Example of parfocal issue
 

The last post on this problem is from September 2011. I've recently had a lot of equipment liberated from me and am actively considering acquiring a XF 300. Does anyone know anything more current on this subject? I have used backfocus with zooms for so many years with so many lenses it is reflex. Do the XF 300 and 305's as now leaving the factory perform with parfocal precision? Was it truly a calibration question and not a result of drift? Was there too much fully open aperture in usage? As an aside: Do these cameras as outfitted with what I understand is outstanding glass have a sweetspot (i.e. ƒ4-ƒ5)?

Re: Example of parfocal issue
 

Just wondering, Have you tried shooting the mid ones (15mm) with the iris closed a few steps down? I know that 1/3" sensors have low/no DOF but sometimes if I am doing wide shots, with good lighting, I rather close the iris to 5.6 or 7 instead of using ND filters and if I need a ND filter I use a glass one and it keeps the image a little bit sharper than if I shoot at f/1.8 - f/2.8.

I dunno if this can help, but if so, let us know!! Good Luck!

Re: Example of parfocal issue
 

Rodolfo, Doug Jenson recommends avoiding smaller apertures for the XF300/305 in the Vortex Media ‘Mastering the Canon XF300/305’ guide, because of diffraction. I can say as I have made extensive tests, because I generally try to take that advice on board and use whatever ND selection gets me at about f5.6 or wider. Small sensors are more prone to diffraction as well as lacking the inability to create narrow DoFs. I know the sweet spot on my old Canon G10 P&S was f3.5 for instance.