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

No it is not at all helpful for those who are about to buy this cam, because there is nothing conclusive about Alex's situation until he can get a definitive answer from Canon service. His camera is either operating properly or it is not. The only conclusive way that this can be determined is to obtain a verdict from Canon service. Efforts by other owners to duplicate his issue will have too much variation despite their best intentions. The whole point of this forum is to be helpful to those who are about to buy or already own the camera. Nothing helpful can be derived from this until Alex submits his camera to the Canon service department and reports their conclusions here. That's the only way that we'll know for sure if there's actually a problem. Thanks in advance,

Chris is correct -- not because he owns DVinfo -- but because we are obviously well past the point of realizing that what Alex really needs to know is if his camera is, or is not, functioning within Canon's spec. Only Canon is going to be able to establish that. We'll be eager for that answer, but until then it is all just idle chatter. If it is faulty, well, bad luck and they'll get it fixed or replaced. If it is in-spec, then that's information that might guide Alex and others in their choice of cameras. But until Canon looks at the camera, it is all just off-the-cuff opining, or worse.

EDIT: Ah, Chris beat me to the punch. Although he said it better, we're saying the same thing...must be something to it!

And it doesn't become helpful until Alex tells us what Canon has to say about his camera.

Chris, I see your point, but I still disagree:
Of course I hope we get a verdict by Canon to see whether this behaviour is normal or not. But I find the fact alone that (maybe only) Alex's A1 shows the described behaviour a RELEVANT information. (My MH10 does the same, maybe that's why.)
No offense, Michael Mann

This is absolutely an issue that should be on the boards because
I want to know about it,

I want to ask about it if I go to buy one.
He should be able to ask others if they have the same issues.

My Hv-10 which i assume may have the same parts in the IAF
does keep focus sometimes when zooming, it would be hard to believe that the more expensive model couldnt do this.

Thats not to say that the Hv-10 doesnt lose focus or hunt, cause it does.
It loves to hunt and if you zoom too close it doesnt focus at all on a close object.

I am going to a dealer today to test and ask about this.
Thanks for the post.

Alex said himself that this might be a case of unrealistic expectations about how the IAF operates... so again, it's not a even a "real" issue until he knows one way or the other if his camera is faulty. Like I said... we won't know that to be a fact until he sends it to factory service and gets an answer.

Until then, it's not a fact. I'm not operating this board in order to start rumors. This site is intended for factual information only. We don't have any facts yet. The only fact available to us is that Alex is not sure what is happening with his camera.

Doesn't sound like anyone is trying to start any rumors to me, just the original poster noting odd focus behavior -and Dave Lammey noting his HV10 displays the same when the IAF quickly hunts. And that fact brought up of the Canons overlap of AF zoom function is also worth knowing.

It's your forum Chris, but I've found the more a tech forums posts get restricted or censured, the less useful it becomes. Let people speak freely.

You might be in the wrong place then, Vlad, because this site is without a doubt one of the most heavily restricted tech forums on the web. It's also one of the most popular tech forums for digital video precisely *because* of those restrictions. And I'm not stopping anyone from speaking freely... the internet is huge and I encourage everyone to exercise their right to freedom of speech and start their own web site / message board / blog / whatever, and run it exactly the way they want to. Meanwhile, I'll continue to run mine as I see fit, and that particular way has always been to filter out as much noise as necessary in order to keep the signal level as high as possible. That's how we define usefulness around here. Thanks in advance for understanding,

I think that so called facts almost always start as an hypothesis.

The hypothesis is to figure out if this persons IAF is faulty.

The fact can also be understood, if compared to others cameras
Though subjective it is still a fast and valid method to procure information.

The example would be that I went out and tested 2 A1's at different stores.

Neither of them displayed what we're speaking of, I then bought one and will test that unit.

Obviously my testing is a simple visual procedure but valid still.

So it is very useful if he determines that it helped him gather the information to move to the next step which would be to send it in.

The first step is NOT to immediately send in the camera, why let go of your new camera, until your sure.

I think that Vlad is posting in the RIGHT place, anywhere that he posts is the right place if its where it is helpful to others, is that not what this board is for.

So, I found it very helpful, thanks, love your post.

and I will post new info on my new cam and see if it does this.

I agree with Chris. He has restricted my speech, and refined it to a more pleasing demeanor in the past, and I respect it. My negativity may have been warranted by bad experiences, but it didn't help anything, it was meaningless whining banter.

I appreciate the usefulness and relevance that this forum offers.

I haven't found anything so succinct and pertinent to my questions, and I find it very mature and objective. If I have a question, I usually find it very quickly.

That is not to say that subjectivity is not desired here, it is very much a core function. But once things debated to personal bias and conflict arises, Chris quickly becomes a mediator and stomps out the posibble fires.

I hear your pain Alex. I have had significant problems in the past with Canon's customer service and faulty lens elements not properly focusing. If you feel that something is wrong, send it in with a tape highlighting the problem and be firm in your decision to have them thoroughly fix it. It is too bad that you possibly got a bad unit after spending a good chunk of change. I can only hope that Canon treats you well and makes things right with you.

The only way that can be accomplished with any degree of certainty is for Alex to send his camera in to the factory service center. And that's what I've been urging him to do (and to please report back to us as well), so that we will all know for sure whether there is or is not something wrong with his camera.
You don't seem to understand. The only way that he *can* know for sure is to send it in to the authorized factory service center. That's the entire goal, to figure out if there's something wrong with the camera! The *only* resource available that can provide him with a definitive answer is the Canon factory service center.

And with that, I'm closing this thread for now until Alex is ready to report back.

Closure
 

Thanks to all those who offered their suggestions and tested their cameras for me.

On Friday Canon confirmed the camera was faulty and shipped out a new one, which I will get tomorrow. Hooray! Just in time for Christmas. :-D

I am glad you are getting a new camera. Might I suggest updating your webpage for people who are only checking there for info? :)

Many thanks for the update, Alex -- I've changed the title of this thread to suit.

Much appreciated,

Alex, meanwhile I have noticed, that my A1 shows the very same zoom focusing problems like the ones you described in this thread. (I can upload a short file for documentation if anyone is interested.)

Please let me/us know whether you new camera gets rid of this problem. Thanks in advance.

Hi Michael. Until about half an hour ago I thought that my new camera had fixed *all* the issues that the previous camera had.

However, after reading your message I tested the "focus-pulsing-during-zoom-with-auto-focus-on" problem on this camera... and I can confirm that it does display it too.

I certainly don't have any of the other AF and IAF issues that I had before (AF and IAF are now quick, stable and pretty reliable). But it does have the focus pulsing. It's much less pronounced - I would say almost unnoticable through the viewfinder or LCD, especially on faster zooms. But it's there.

I suspect this may be a weak point in the design of the camera...

Hi Alex, thanks for the update. Quick question, are you seeing the pulsing in 24F, 30F or 60i? If you haven't tested that out yet, try to compare 24F and 60i on the same subject/environment...

Interesting...

I tried the test again (I'm in Europe, so it was at 25F and 50i).

At 25F the pulsing is slight but noticable on out-of-focus portions of the image during slow zooms at the long end of the lens. It pulses at around 4x per second at ZS 1 and gets faster on quicker zoom speeds. By ZS 8-10 you can't really see it because the image is moving too quickly.

At 50i the pulsing turns into a much slower oozing! You probably wouldn't notice it if you weren't looking for it, but it slowly pulses once every 2 to 3 seconds at ZS1. Again at faster zoom speeds it oscilates faster, but it becomes more or less imperceptible by ZS 4-6.

And its gone with manual focussing and zooming. Zoom in -focus - zoom out -start shot - zoom in. Like you do with all the professional lenses.

After I noticed this phenomena a couple of weeks ago I did some testing. I found that situations that are challenging for auto focus cause a pulsing focus when zooming in or out in 24F mode. The exact same shots and zooms in 60i were fine (I was watching live output on a 42" display to watch any focusing issues). As Raymond just mentioned, setting the lens to Manual Focus elimates the pulsing altogether.

If I had to guess, I'd say this pulsing is related to auto focusing issues that most (all?) 24P camcorders have. The XH A1 actually finds focus fairly quickly in 24F mode, probably much faster than many other 24P camcorders. Perhaps the downside to this faster focusing at slower framerates is the focus pulsating back and forth as it tries to compensate for zooming? It would be interesting to compare the XH auto focus to some of the other 24P camcorders in a controlled test.

In any event, I think Raymond is pretty much right on. Especially in 24F, I'm just going to shoot manual focus only. The focus ring is pretty decent, the lens holds focus well and the distance readout plus peaking makes it pretty much bullet proof.

Alex, thanks for your fast reply.
You can download two short native demonstration clips here (25F, fast auto focus mode):

http://www.filefactory.com/f/f5656740836b15ad/


The problem only occurs in either of the two auto focus modes. If I switch to manual focus, the problem is gone.

Since I use manual focus in most cases I really can live with this "problem". But sometimes - when doing snapshots for example - I just have no time to focus manually, and then the "pulsing" results are very annoying (see clips above).

By the way, my HV10 shows a similiar focus pulsing when zooming.

Chris, I suggest to change the title of this thread again, since this focus pulsing issue does not seem to be solved at all.

Personally I think I *could* see the effect in 50i too - but it was extremely subtle because it changed from a pulsing to a much softer undulation.

If it is trying to compensate for zooming then it's a fault with the design of the camera. The back-focus on the lens should be setup in such a way that as you zoom in an out the focus stays the same (and in fact it does if you turn AF off).

I personally think it's more likely to have something to do with the mechanical aspect of using a single motor for zoom and focus - especially as the rate of pulsing seems to increase as the speed of the zoom increases.

Either way, you and Ramond are correct. The best way to work is with AF off. I wouldn't normally have it on - but regardless, this effect demonstrates some sort of a design flaw if it's being seen across multiple units.

Thanks for sharing these clips Michael. You can clearly see the pulsing effect. It's fairly pronounced and makes AF effectively useless to be left on. I guess we've found (one) of the camera's Achilles heel's!

Not sure "design flaw" is the right description for 1 motor instead of 2. Probably a financial decision there. The A1 boys seem to have done a pretty decent job of "two things at the same time" for one motor, - just not perfect. I bet that for more bucks ...

I think you're right Brad, that Canon have generally done a pretty good job with the A1. But personally if something doesn't work properly by design, I'd call it a design flaw - even if the underlying root of that flaw is one of providing a cheaper product.

One expects certain things from a product for it to be considered of "merchantable quality" - and one of those things (in my opinion) is that the advertised features work, and can actually be used.

I think we can see from Michaels clips (and my own experience with two A1s) that the auto-focus cannot be used on slow speed zooms towards the long end of the lens.

To me that's a design flaw. Just because it's a feature that isn't left "on" by most professional videographers, or just because we can be "understanding" of the problem because we're getting something at a certain price point, doesn't mean that the manufacturer can then go on to advertise it as a revolutionary new instant AF system... and not mention that you can't use it whilst zooming.

Having said all that, I am happy with my A1, even with its flaws.