Example of parfocal issue

[Glen Vandermolen]

You are correct, Josh. I doubt Alan would have been aware of the issue with his tests. I'm certain he did the tests without using ND filters. He's very active on another forum. Perhaps I should join it and post a message to him, but he doesn't have an XF, it was lent to him by Canon.

I hope you guys contact Canon about this. You can do so through their website. I already did, and gave links to this forum. as you guys have presented clear evidence of something amiss. I wonder what their response will be (if any).
I am a potential purchaser of this camera. I really like what I've seen from it - until now. I suppose I could work around any shortcomings, but I prefer the issue be looked at by Canon.

[Nick Wilcox-Brown]

Hi Josh, everyone,

Interesting to see this. I used a client camera (XF305) for a shoot last week and was surprised how soft it was at the wide end. The camera was one of the very first retail cameras in the UK, so May / June last year. To be clear, this was shot with no ND filters.

We have been in touch with Canon service and the camera has an issue with back focus calibration (remember that EX users?) and apparently an easy fix in the service department.

I have shot with many XF 300 and 305s and this is the first camera I have seen with an issue. If back focus correction is possible for this, I wonder if your own camera can be tuned for ND filters in place? Perhaps a comprise between optimal ND and non-ND focus?

[Robert John]

Hi All
I just did a test with and without ND filters. I get the exact same problem that Josh has. I contacted Canon here in the US earlier today. Of course they said no one has reported this problem. The service rep told me he would email a shipping slip and a form ( I have yet to receive the email from him) I don't think we should have to come up with work arounds. These cameras are new and should work properly.

[Robert John]

So Canon sent me a UPS shipping label & Paper work told me to send it to them. The rep had me write out detailed description of the parfocal issue. He wanted me to include links to this forum. I will post the results when they get back to me.

[Josh Dahlberg]

Thanks for the update Robert, can't wait to hear what the verdict is, and if it can be fixed!

[Robert John]

Josh

Let's hope they don't give the standard "We can't find anything wrong".

[Robert John]

Hi Guys

Canon has still got my camera. I had given them the link to this forum and they read what was going on. They had me upload some sample footage with my parfocal problem. Still waiting to here back.

[Nick Wilcox-Brown]

Hi Robert, Josh and Glen,

I have been watching this with interest. The XF305 I used a couple of weeks back suffered a very similar issue to what you describe and demonstrate, albeit without the ND filters in play. It has now been re-calibrated and fixed.

The interesting point about this is that when initially tested on the Canon diagnostic machinery, the camera passed all tests and, without my intervention, would have been returned to the owner untouched.

Hearing that it was supposedly OK, I sent in clips that clearly showed the camera was so soft as to be unusable when zoomed back. Further tech testing by Canon matched my own findings, the camera focus system was re-calibrated and the owner is now happy.

There are lessons to be learnt from this by both sides: Technicians have been trained to respect their test equipment and much of the time it is very accurate. However, when there is a problem that clearly is not showing, tests should always be queried. Ideally evidence of any problem should be provided with notes describing and clips showing the issues (preferably original MXF files on CF card).

One point that has come up is that, as we all know, the XF 305 / 300 cameras do not have a constant aperture throughout the zoom range. Focusing at the 'long end' of the zoom is done at f2.8. If the lens is 'wide open', it will open out to f1.6 when the lens is zoomed back. The depth of field changes substantially between these apertures with 1/3" sensors and many of the problems seem to show at the point where the aperture changes.

Although what I describe is without ND filters, I suspect many of the effects will be similar when the inline ND filters are used.

Hope this may help a little?

Separately from these tech discussion with Canon, I was talking to a very experienced technician from one of the big rental companies last week, and the subject of parfocal lenses came up. His point was very simple: 'you pays your money, you takes your choice' - he said that he always expects focus to slip a little on this type of camera, whatever the brand. He did not think it reasonable to expect perfection at the price point of these cameras.

Food for thought perhaps?

[Robert John]

Well so far I'm hearing the same thing that they can't find anything wrong. They seem to be working with me asking for clips.

[Josh Dahlberg]

Hi Nick,

Thanks for contributing to this discussion. It's good to hear you got a positive result.

If it is simply a matter of these cameras needing recalibrating (let's hope so), then there's a pretty big gap in QC as they leave the factory, with so many XFs exhibiting the same issue.

Originally Posted by Nick Wilcox-Brown

One point that has come up is that, as we all know, the XF 305 / 300 cameras do not have a constant aperture throughout the zoom range. Focusing at the 'long end' of the zoom is done at f2.8.

With this in mind, my testing was conducted at a constant f2.8. It's indeed more pronounced if you go wider, but to rule out aperture ramping as the primary cause, I can confirm my camera has parfocal issues even when there is no aperture change.

Originally Posted by Nick Wilcox-Brown

...he said that he always expects focus to slip a little on this type of camera, whatever the brand. He did not think it reasonable to expect perfection at the price point of these cameras.

Hmmm... but this shift is so clear that many common shooting practices become untenable.

I've owned numerous 1/3" Sony, Panasonic and Canon cameras (the XHA1 and XLH1 among them) that didn't suffer from anything remotely close this. It's a very long way from perfection.

Thanks for the update Robert - I'm very keen to hear what happens, and hoping for a positive outcome.

[Robert John]

Canon is sending back my camera today. They could not duplicate the problem. They are also keeping this open. I needed my camera back as I have a 3 day shoot. They said when I have time that they would like me to come down and work with their technician. They also told me they have sent this problem to Japan. I think they are very concerned about this. They saw my clips of the problem just can't duplicate it. So maybe next week I will go down there and work with them. All I can say is my experience with them has been great. I have never had customer service at this level. I will also be doing another test at 2.8 all the way through to see if I still have the problem. Before I was at 2.8 zoomed and 1.6 wide.

[Reinhard Kungel]

Same to me: Canon was not able, to duplicate the problem. But the problem still exist!

When working with this nice camera in manual focus mode, you never know, if it is sharp or not.

Best regards,

Reinhard

[Lou Bruno]

Hummmm.......I picked up my new XF-300 yetserday and immediately began testing the camera for the problem being discussed. I followed all of the instructions listed on the threads and can't duplicate any of the focus problems.

[Glen Vandermolen]

I also tried to duplicate the problem on my 305. Shot outdoors, manual focus, on ND 3. I looked at it on a 55" TV and the video was all in focus.
Thank goodness!

p.s. - the video from this camera is amazing! It blows away the images from my HPX500, 2/3" chips or not.

[Robin Davies-Rollinson]

Glad you like it Glen - mine should be arriving end of week...
Will certainly give it all the focus tests.