Update from Canon
 

Another camera man I know took his camera down to the service center and showed them the problem. They are fixing it and sending it back today. I got a call today and they want me to send my camera in. They are doing a focus adjustment. Got to love that Canon service. Doesn't look like it is a problem with all the cameras. I read a post from a guy that works at a rental house. He said that of the 5 xf305s he has, 3 of them have the parfocal problem. So some people are having the problem and some are not.

That would be me. Looks to be a small, yet strong XF user group on DVinfo and vimeo.

If you're in the LA area and want to check out the XF I'm over at Film Independent (filmindependent.org)

Hey John

I'm glad you went there also. I saw your posts on Vimeo about having 5 305s and a couple with the parfocal issue. I was actually referring to Brian. We had been talking about the parfocal issue for a few weeks. I had know idea that you went to Canon already.

Re: Example of parfocal issue
 

If Canon could have placed an optically clear filter along side the internal ND's then there would be no issue.

Makes sense that adding a ND filter behind the lens (depending on thickness) will affect the lens parfocal performance.

Quick test, do you gain a tiny bit of wide coverage when you flick the ND on?

Re: Example of parfocal issue
 

Don't know if this is helpful, but Canon is offering a free camera inspection and cleaning at Creatasphere at Universal City.

Entertainment Technology Expo Universal City

(Scroll down to the bottom of the page.)

Re: Example of parfocal issue
 

Ah, I think you might be onto something James. Indeed, the camera is very noticeably wider when the NDs are engaged. Is this typical for cameras in this class, and does it mean the issue is cannot be resolved?

Re: Example of parfocal issue
 

I just did a test to see if there was any noticeable wide coverage. I see no difference at all. I was framed on a shelf that had vertical boards on each side. I then made sure I was framed to the edges, flipped on ND and no difference.

Re: Example of parfocal issue
 

I've just been testing my new 300 today for this focus issue - and I'm really glad to say that it was not apparent.
There was certainly no difference in the field of view with/without an ND filter either.
(Sighs of relief...)

Re: Example of parfocal issue
 

Robin,

Glad to hear all is OK, but to re-assure, my issue was corrected perfectly by lens re-calibration at Canon Service (Elstree).

I did not see the problem with the ND filters, but when zooming out from a correctly focused image.

I just hired in another 305 from a rental company and it was beautifully sharp all the way through.

Re: Example of parfocal issue
 

When I first got my XF300, it seemed as though if I zoomed in and focused, then zoomed out, that the subject of the focus was no longer in focus. Today, when searching around, I discovered that others have seen this. So, I have done a number of tests to attempt to replicate my previous issue but find I can't replicate the problem.

Here's my question: Is it possible I have gotten better at focusing which results in a better focus while shooting wide? I ask this because I am a novice. Or is it possible the issue is still there? I called Canon today and started the process to have it serviced. But I don't see a reason to send it in if there isn't a problem. Should the focus issue be 'in your face' obvious?

FYI: Until fairly recently, I had not used the Peaking or the magnification for focusing. I had, however, plugged into a 27" monitor to help with focusing, which helped, but the focus issue still seemed to be a problem.

What do you think? Send it in or keep on shooting?

Thanks.

Jerry

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.