A quick, no frills example of the parfocal issue that many of us (Robert, Steev, Reinhard, myself at least) have experienced with the XF. Please pay no attention to exposure/framing - I just wanted to get an idea for myself if Face Detect was a safer option than manual focus.

The issue is pronounced shooting wide, so these are all shot at f/2.8, ND1, 1/50 shutter, 25p.

Frame 1: Fully Zoomed in, 73.8mm, critical focus achieved

Frame 2: Zoom back to mid-position (15mm) with auto focus (Face detect mode) on

Frame 3: Zoom back to mid-position (15mm) with auto-focus off

Frame 4: Zoom back to mid-position (15mm) with auto-focus off and iris open (f/1.6)

The important comparison is between frames 2 and 3 - both begin at the same starting point, critical focus at maximum focal length, but as we pull wide focus appears to shift behind the subject in manual focus.

In frame 4, the problem is accentuated (ie: it's a complete waste of time zooming in to achieve critical focus, then pulling wide with the iris open - focus will be way off).

Some have noted a) their camera doesn't have the issue and/or b) if it did they would send the camera straight back to Canon.

Reinhard sent his back to Canon Germany who said they couldn't replicate the problem. In my case, when I explained the issue to my dealer yesterday he said it would likely take two weeks to get my camera back, and most likely the technicians will say the lens is performing "within spec".

Is less than perfect parfocal performance acceptable? For me, no, but can Canon claim it is?

I need the camera on a weekly, if not daily basis, so for now I will be sticking with Auto Focus, and only using manual focus when I don't have to make quick changes in focal length.

Well, I've looked, scruted and analysed those piccies (as best as these rather tired 'ol eye's will allow anyway) and there sure as heck is sommat going on with that lens, but I'm wondering if there really is a problem with some builds.

To me, everything at the wider lens setting is seriously less sharp than at the full zoomed in setting.

Analysing just what is in tack sharp focus in all four piccies, the only thing I can say 100% is the girls eyes in pic 1.

After that it sort of goes seriously down hill rapidly, no matter what mode you're in.

That the increased DOF at the wider setting doesn't keep things under control makes me wonder if there was a glitch with the production run somewhere and the lens really isn't running to spec.

I'd say "someone" who is experiencing this rather odd behaviour do some pretty precise target based trials to prove categorically that the lens is going off in wider settings (and when I say "off" I mean it's resolving power just seems to dissapear into quicksand).

Canon will only take this seriously when someone proves there is a problem, and I mean prove to the Nth degree.

Geez, glad I haven't bought one yet.


CS

Wow Josh! I have not had this problem. I did a test with my XF300 Zoomed in focused zoomed all the way out and everything stayed in focus. Josh when you have peaking turned on does it show that it is in focus through out the range?

I wonder if "the parfocal issue" depends on the focus mode (MF / Full MF) and the zoom mode (RING or ROCKER)?

Manual, page 77, Using the Zoom Ring, Notes:
When you set the ZOOM switch to RING, the zoom position will move to the current position of the zoom ring, which will change the picture angle. Also, the picture may become out of focus.

No word about the zoom direction - "Tele to Wide" or "Wide to Tele"...

In "Using the Zoom Rockers" no such the notes.

Thanks Ivan, that's very interesting!! I will check this out tomorrow. I have been using the Ring exclusively (as I much prefer it to rocker). I wonder if those reporting the issue are using he ring, with those saying their cameras are fine using the rocker.

This sounds plausable as the XF300 has a rocker/ring switch and won't let you use both without switching (which is a little annoying).

In my case the issue (using the rocker) is entirely repeatable (and obvious). Tomorrow I will test both in full MF setting and MF using the rocker.

Robert: the problem is generally too subtle to notice with peaking on, but it's pretty clear once I get back in the studio.

josh-

i know this thread is about the parfocal issue u r concerned about but...

...the 1st posted image of the young lady really shows the strength of the xf300/xf305 image quality.

wonderful color, good skin detail right down to her freckles.

i hope u resolve your issue soon so u can return to making lovely images.

be well

rob

Josh
There is a test Steev Dinkins did on Vimeo.

Link: XF305 Parfocal Accuracy Test on Vimeo

He says that Parfocal accuracy on the XF305 varies based on aperture and ND filters applied. Aperture fully open, with a subject in focus while zoomed in, there's a hint of softening when zoomed out. Furthermore, if ND filter 1,2 or 3 are applied and aperture is wide open, this phenomenon is noticeably worse. Its requiring a focus adjustment towards close focusing to truly get the image sharp. Closing down past f3.2 eliminates this phenomenon and focusing is very accurate through zoom range

[Thanks Robert: my testing concurs with Steev's findings]

Okay, I've just done thorough testing of my XF300 and my dealer's XF305 - results were identical with both cameras so I'm inclined this think this is an issue with all XF cameras, not just a few units.

Today I tested parfocal accuracy through the zoom range in four ways:
* Autofocus
* Manual focus using ring
* Manual focus using rocker
* Manual focus using full-time manual setting

Surprisingly, (given I've encountered the issue numerous time in the field) the camera held focus through the range in all instances.

Then I realised I'd encountered the problem predominantly outdoors. I switched on the ND filter and bingo!! The camera consistently lost critical focus when pulling wide, whether zoom, rocker or full time manual were used. This was with the aperture working at f2.8 or wider. (see attached pics of cleaning product).

To confirm it's not an issue particular to my camera, I went to my dealer and used his XF305. It took me two minutes to reproduce the problem (see attached grabs of Mamiya poster). With ND1 engaged, aperture @ f2.8, the camera clearly loses focus through the range.

To those who've said their XF's parfocal performance is perfect, please try the following: Set your camera to ND1@f2.8 and activate autofocus, zoom in fully on a subject and achieve critical focus, pull back to mid way through the range; now repeat with manual focus. Now compare focus in the mid-range shots.

I'm satisfied I can at least put this issue to rest: at wide apertures with ND engaged, the len's accuracy through the range is severely lacking. Outdoors I will either be closing down the aperture from now on or relying on AF :-P

Josh, does your dealer back you up? Maybe Canon will listen if one of their retailers lodges a complaint.

Unfortunately they're primarily a camera shop, and say because the issue is happening with both my unit and theirs my camera is not faulty, this will be a known "design limitation", performing within the spec of the lens etc, blah blah...

Basically it renders my standard outdoor proceedure (open aperture for tighter DOF, zoom in for critical focus, pull wide to frame) useless, and also means you can't do creeping zooms in MF unless you close down the aperture.

Josh,
Thank you for your very interesting and illustrative test, clarifying the situation with the problem.

I wonder what happens if you use an external ND filter?

Shooting at wide angle with the iris opened wide is not the optimal setting for any lens. I know with my HPX500, if I shoot wide, the image is soft. That's just the way it is with that camera. Perhaps the Xf300 has the same limitations.

Edit - actually, your images show the video isn't soft - the acute focus actually shifts to another point in the distance. Seems like a back focus issue, if it were an interchangeable lens. Didn't early EX1s have a similar problem? Is there a menu setting that helps correct this?

Shooting at wide angle with the iris opened wide is not the optimal setting for any lens. I know with my HPX500, if I shoot wide, the image is soft. That's just the way it is with that camera. Perhaps the Xf300 has the same limitations.

Edit - actually, your images show the video isn't soft - the acute focus actually shifts to another point in the distance. Seems like a back focus issue, if it were an interchangeable lens. Didn't early EX1s have a similar problem? Is there a menu setting that helps correct this?

Hi Glen, as noted in your edit, the image is sharp enough (autofocus works fine), but the focus shifts behind the subject as you pull wider with ND engaged. Unfortunately, there is no menu setting to correct this.

Also, the lens actually opens up to f1.6 (where the problem is even more pronunced). These images are wide, but not maximum aperture.

There are 3 situations for me where this is an issue (shooting outdoors, manual focus with ND engaged):
1 achieving critical focus zoomed in, then pulling wide to frame
2 capturing a creeping zoom, either in or out
3 quickly reframing during an interview (ie: I will have to refocus as well as reframe every time)

Work arounds:
1 Use AF face detect
2 Stop down to F/4 or greater
3 Use a screw on ND (as Ivan suggests)

Unfortunately, magnification and peaking are not much help at the wide end: it's only when you get back in the studio that you can tell if critical focus is achieved.

I wonder why this issue is just now appearing. These cams have been on the market for about 6 months now. I haven't heard of any issue with the focus until recently. When Alan Roberts performed all his critical tests (used by the BBC) he never mentioned the issue. Certainly, he would have reported it. I've seen beautiful images from the XF, at wide settings, and no problems. This makes me wonder if there's some kind of manufacturing problem that has recently come about.

Of course, Canon has looked at one our forum member's camera with this issue and reported it fit for duty. I would suggest all of you with this problem to write to Canon and make your position officially known. Maybe if they get many such complaints they will look into it. Just one camera being sent in for inspection won't convince Canon there's a bigger issue. I doubt they read this forum.

Glen, I bought my unit back in September I think... Steev bought his a little before me (and reported issue a long time ago)... The XF305 I tested today is hot off the shelf.

It's quite possible to get glorious shots wide with the XFs providing you do any ONE of the following:
A) don't use the NDs
B) use autofocus
C) use manual focus without zooming
D) stop down the aperture

In other words, I can understand why some people have not come across the issue. It's only snagged me from time to time - now I know what's going on I can live with it.

Would Alan Roberts have tested parfocal acuracy with NDs engaged? Is it a problem one would anticipate?

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.

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?

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.

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.

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

Josh

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

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.

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?

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.

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.

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.

...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.

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.

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

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.

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.

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

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.

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?

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 (http://createasphere.com/En/ete-universal.html)

(Scroll down to the bottom of the page.)

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?

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?

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.

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...)

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.

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

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.

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)?

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!

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!

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.