Focus issue solved, faulty camera now replaced
 

Admin note, update from Dec. 18th: Alex took our advice and sent his camcorder to Canon service, where it was found to be faulty and has been replaced. See the post from Alex at the end of this thread. The issue is now considered as resolved. Thanks to all who participated -- CH


Please, please, please I need your help. I've sent my XH-A1 back to the dealers because of problems with the focus (which can be seen at www.19media.com/xha1).

However, they had a quick play and say the performance is normal. But I'm convinced it's not right. If any XHA1 owners could try the following tests (preferably in 24F or 25F) and report back, it would really help me to convince them to send it back to Canon for repair...

1. With IAF on, zoom to the long end of the lens and fill most of the screen with a nearfield object so the object is in focus, and the background is out of focus. On the slowest zoom setting zoom out for a few seconds and then back in again. Do you see any sort of pulsing in the out-of-focus part of the image?

2. With AF off, zoom in and point the camera at something that should be easy to focus on. Manually defocus and then press the IAF button. Try this a few times.
2a. How long (in seconds) does it take your camera to focus?
2b. Does your camera ever rack focus in the wrong direction?
2c. Do you get consistent results each time you press the IAF button?

3. With IAF on zoom into an object like a poster on a wall. Let the camera focus. On maximum speed, zoom out and zoom back in again straight away. Has the camera lost focus?

Thank you, thank you, thank you. I would be so greatful for your reports. And I'll buy any of you a beer if you ever find yourself in Northampton, UK (though frankly you're probably lost or on the way somewhere else if you do find yourself here!)

I don't have the A1, but I do have the HV10, which also has the Instant AF and sometimes exhibits similar behavior when aiming at something in the foreground that is just left or right of the middle; because the IAF is so fast, it looks like the spastic pulsing you described. Have you tried turning off the instant AF and using normal AF?

Yes, the behaviour is the same both with IAF and AF. And I've tried it on a shot where three quarters of the shot was in focus foreground, and just the very left edge was out of focus, and it exhibited the same behaviour there too.

Also the pulsing only happens while zooming.

I'm hoping that someone else with an A1 can let me know how their cameras respond to the tests I've suggested so that I can say to my dealer "these aren't normal - other people's cameras aren't behaving like this..."

A much better clip to show the problem. Apologies for doubting you.

The XL-H1 couldn't focus while zooming so I am wondering if the XH-A1 is limited in the same way and what you are seeing is the camera switching between focus and zoom very quickly causing the shimmering effect. The shimmering has a regular looking "beat" to it.

Can you manually focus and zoom at the same time on these XH-A1s?

Focus being lost on zooming doesn't sound good to me. If you've zoomed in made critical focus, zoomed out to record the zoom in you would expect focus to be there. This sounds like a fault.

There haven't been any other reports like yours and a good many people seem to be very happy with their A1s. Sounds like a trip back to the dealer.

All the best

TT

I see it too with the A1 but I mostly use manual focus so it doesn't bother me that much, you can't rely on auto focus with any brand, I do have Sony Z1 and it does not hunt like A1 but I don't really use auto on it either.

I agree wiyth Khoi. AF is a crutch we depend on, but it's less than perfect. I had a heck of a time getting AF to work in low ligh on my A1.

btw you couldn't zoom and focus at the same time on the GL1 and 2 , don't know about the XL and XH series.
Apparently you can do this with the sony PD 150.170 etc.
Andy

You know, I think I saw something similar to this with my A1 while shooting some taller buildings at night. Most of the frame was pretty dark and seemed OK, but the lights on the building were sort of "pulsing" just slightly in and out of focus. I'll have to review that footage over the weekend to confirm.

The XL and GL series cameras can't zoom and focus at the same time because they share a single servo motor. Like Tony mentioned, if you zoom in and get critical focus, it should hold focus all the way back out and in so you shouldn't need focus while you do the zoom. If it doesn't hold focus, it's a back focus issue which I believe has an auto correction available via the menus. Also known as flange back adjustment.

-gb-

I feel the most effective way to use autofocus on any of these compact cameras is in a semi automatic mode. By that I mean making use of the one push AF control. Zoom, make focus with the one push AF, zoom out and re-frame. I have found it a much quicker approach than to fight the, generally, spongy controls on compact cameras. With a should mount camera I could usually focus and zoom at the same time as bother hands were operating the lens. Not so easy to do with a compact camera when one hand is supporting its weight.

I cannot stress how important it is even with the most intelligent super duper autofocus system in the world to zoom, focus and reframe subjects. Sooner or later the autofocus will guess wrong and you'll lose an important shot. Very easy to do with such small VFs and LCDs that these cameras have and you won't notice until you get back to the edit room and play out to an HD monitor.

Sermon over....

Alex,

I am demoing the XH-A1 and Sony V1e tomorrow and will have a look at the autofocus system on the A1 to see if I can replicate your issues. I'll be in the HD club by the end of Saturday afternoon! :)

TT

Thanks guys for comments and help so far...

Tony - I'm totally with you on semi-auto. I've NEVER shot with AF left on... (well maybe once or twice)... but what I do feel I have a right to is a camera that works properly.

I cannot even use the "push-to-grab-focus" workflow, because the IAF button either shunts the focus the wrong way, or is painfully slow taking up to 8 seconds to get focus.

I've NEVER had a camera that displayed either of those phenomena before.

What I want to assertain (and thanks for offering to help) is whether the phenomena I've seen are just unfortunate quirks of this camera and I'm being oversensitive (as usual).

Greg - I might have thought it was a back focus issue, but focus holds in manual focus. However, I've just noticed in the manual that it states "Autofocus may not work on faster zoom settings". I'm starting to think that the pulsing and the focus on zoom issues could well be to do with the single motor focus/zoom assembly of the lens. A bit crummy really.

If that's the case (and I'd love other people to try it on theirs to see if it is) then I'm still left with very slow focus response.

Thanks guys

Alex

Is there anything obscuring the IAF sensor?

Do you know whether the camera has two servos one for zoom and other for focus? If its just one then that might account for the pulsing of focus in that latest clip. Does anyone else know??

On these slow creeps does it happen all the time? If you speed up the zoom does the pulsing happen at a similar rate?

Don't worry about being overly sensitive as you rightly point out you deserve to have a fully functional camera for the best part of £3k. I'd be the same in your position. The beauty of video is that many people shoot many different things and that can highlight problems that others have not noticed or will ever notice.

Anyway check back on Sunday and I'll let you know what I've found.

Cheers
TT

Thanks Tony, there's definately nothing blocking the IAF sensor (I tried with the lens hood on and off, and I even gently cleaned the sensor with my lens cloth).

The pulsing on slow creeps only happens when the autofocus is on. And it does seem to pulse at a rate that is related to the speed of the zoom.

I look forward to your findings.

I have not experiencd that pulsing seen in your clip on my A1. Although I have noticed it having difficulty when trying to find focus on things like clouds. But I do not leave the IAF on EVER. Manual focus or use your focus preset.

You might want your camera to be looked at.

Alex. You're going about this in the wrong way completely.

Stop posting on message boards and get your camera in to Canon UK service immediately. You should not have to go through your dealer. I understand that your dealer is saying this is normal, however your dealer is not Canon service! Only when you send your camera to Canon service will you get a definitive answer as to what is going on and whether or not something is wrong with your camera.

An internet message board is going to do nothing conclusive for you. If you're serious about this camera, then you *must* get it into the Canon factory service center over there just as soon as you possibly can. That's the only way you can know for sure. Again, if your dealer says there's nothing wrong, well that's fine but it's not a definitive answer. You should be able to contact and interact directly with Canon factory service without having to go through your dealer or anybody else.

Please do so immediately, and be sure to report here how this goes for you. Thanks in advance,

Chris, I completely disagree that Alex should stop posting his problems here. Doing so is helpful for all who are about to buy this cam - like myself.
Best regards, Michael Mann