XL1 / XL1S focus hunting backfocus problems

James Emory · August 18th, 2002, 08:03 PM

Dave,
Howdy. No, you're not alone. I use four XL-1's all bought at the same time and, you guessed it, every damn one of them will not hold a focus from a tight to a wide after a tight manual focus. Occasionally with AF you can get an uninterrupted focus with a slow zoom in or out. From what I have read and heard from other users, it's caused by these servo lenses and really the only way to go for reliable critical focus is the manual lenses. The only very simple work around that I have found that works is to either push to focus and release or use AF until you have settled and then lock it by switching to manual. As far as focus drifting described by another poster, it happened to me a while back once in an interview situation.......once! I was using AF and not paying attention and the subject was soft enough to notice the whole time and the background and its activity was just so nice and clear, you can just imagine the feeling when reviewing the footage. Luckily, documentary shooting has some tolerances. This was an interview with the subject screen left or right. Apparently, the lens focuses on the center of the screen at all times. So the beam shoots right past the subject if framing is set left or right of center. A recommended fix is to set your framing with the subject CENTERED, manually or AF until you know that it's sharp, leave it on manual and then pan left or right to compose the offset interview. If you don't leave it on manual, then any activity or static, dominant source in the background will cause the focus to search and give the camera away, at least the fact that you're using one with AF, not a good feeling, especially when you're telling the producers that you were using Betacam. Ha! From what I've read, heard and occasionally experienced about AF is that it searches for dominant fields to adjust to and goes into overdrive with a solid, neutral background. Just wait and see how fun it is to shoot through thick limbs and leaves with that good ole AF. Hope this helps.

September 27th, 2002, 01:46 PM

Can someone tell me if this is a common flaw of the cameras? Have they been fixed in the newer models?

Im very close to getting one, but the biggest complaint I have heard have been focusing problems.

Chris Hurd · September 27th, 2002, 01:56 PM

See http://www.dvinfo.net/xl1faq.htm

John Klein · September 27th, 2002, 06:37 PM

Don't think I've used AF for much of anything. I'm a fan of the "push AF" button. Since I still use manual focus 35mm cameras, I found it helpful. I suppose if I were used to auto everything, I wouldn't have bought the xl1S.

Nathan Gifford · September 27th, 2002, 07:52 PM

Read the link Chris has provided. This has been over the years an item of considerable debate. I have never had the problem with my XL-1.

Dean Sensui · September 27th, 2002, 10:00 PM

The biggest complaints are regarding auto focus.

I keep mine turned off and that avoids the problem entirely.

Mike Butler · October 9th, 2002, 07:36 PM

Exactamundo, Sensui, leave the AF off and it won't hunt around, which is the biggest source of complaints about focus--it's all about the lens not being able to decide which point to focus on when objects are at different distances. Like 1 Jophoto, I like the "push AF" button.

Phil French · October 9th, 2002, 08:42 PM

I use the push AF quite a bit - probably too much. I would prefer to manually focus more, but due to the shortcomings of the stock EVF (poor resolution), I find I'm not always confident that the focus is right on. I am getting more used to the EVF, but I would like to try the optional B&W one or an external LCD like the one described in Chris' article on the five best accessories. Beautiful "in focus" shots are the norm for the XL1s, but being confident that my shots are OK is not. I usually am a bit anxious until I get home and view my days work on a monitor. I also recommend experimenting with the camera hooked up to a monitor once in a while. I should mention that almost all of my work is outdoors-run and gun stuff.

John Dimasi · January 13th, 2003, 07:57 PM

I don't know if this is a back focus problem like I see others getting succesfully fixed by Canon or not. My lens problem is when the lens is at the widest setting the focus seems to just drift whenever it feels like it. I have to keep pushing the autofocus button every 5 seconds to get it back in focus. This all occurs when I'm in the "A" setting and the lens is set to manual focus. I've tried zooming in on a distant object focusing sharp then backing up and zooming in again the object is still in focus. It just seems like the autofocus is never turned off even though I'm 100% sure that it is. Is this a Canon fix or do I have to keep spending money for Canon's add ons ie 16x manual lens to fix problems they engineered into their products?

Ken Tanaka · January 13th, 2003, 08:25 PM

Your desciption does not sound like a back-focus problem. (That's where the lens does not hold focus on an object as you zoom in and out.) Rather, it sounds like your autofocus is a bit flakey and, as you speculate, may not be disengaging when you switch to Manual Focus.

No big ideas here, just a wild shot. If you've not already tried this, you might try removeing the lens and re-mounting it. The lens and body communicate through a series of contacts that are seated when the lens is squarely mounted. Maybe something's flakey there.

Otherwise that will definitely be a Canon repair.

James Graham · February 4th, 2003, 03:55 PM

I've noticed a similair to the effect you are experiencing when my XL1s is in the (M)anual mode. Although I don't get the wide angle drift the XL1s seemed incapable of holding focus when zooming in and out. At first I though that I had a back focus problem.

Strangely, setting the gain control to +0dB (or whatever) rather than (A)uto completely eliminates this problem. I've tested this several times. The last time being 5 minutes before making this post.

I know that this isn't quite your problem but try it out - you never know.

Sorry if that was of no help at all!

John Dimasi · February 4th, 2003, 06:24 PM

James,
Thanks I'll give it a try. I've never tried this method.

Johnathan

Don Palomaki · February 4th, 2003, 09:16 PM

Hmmmm. Zoming when in auto gain mode may canse hot spots to move through the metering zones and cause changes in expsoure. And similarly, an area that is poor for autofocus (no contrast) may move through the AF sensor sampling zone. Also, auto focus needs some light, about 50 lux, to work well.

John Dimasi · February 12th, 2003, 09:06 PM

What?

Don Palomaki · February 13th, 2003, 05:48 AM

The point being that during zooming (or during action in the iscene) the image presented to the various automatic-mode sensors is changing, and these changes could induce unwanted changes in aperture, shutter speed, gain, and focus.

Also changing aperture may change apparent focus of items inthe scene as thedepth of field changes.

(Also, I cleaned up some typos in the earlier post)

August 18th, 2002, 08:03 PM	#106
James Emory Regular Crew Join Date: Aug 2002 Location: Atlanta, Georgia Posts: 1,892	XL-1 focusing issues - which one? Dave, Howdy. No, you're not alone. I use four XL-1's all bought at the same time and, you guessed it, every damn one of them will not hold a focus from a tight to a wide after a tight manual focus. Occasionally with AF you can get an uninterrupted focus with a slow zoom in or out. From what I have read and heard from other users, it's caused by these servo lenses and really the only way to go for reliable critical focus is the manual lenses. The only very simple work around that I have found that works is to either push to focus and release or use AF until you have settled and then lock it by switching to manual. As far as focus drifting described by another poster, it happened to me a while back once in an interview situation.......once! I was using AF and not paying attention and the subject was soft enough to notice the whole time and the background and its activity was just so nice and clear, you can just imagine the feeling when reviewing the footage. Luckily, documentary shooting has some tolerances. This was an interview with the subject screen left or right. Apparently, the lens focuses on the center of the screen at all times. So the beam shoots right past the subject if framing is set left or right of center. A recommended fix is to set your framing with the subject CENTERED, manually or AF until you know that it's sharp, leave it on manual and then pan left or right to compose the offset interview. If you don't leave it on manual, then any activity or static, dominant source in the background will cause the focus to search and give the camera away, at least the fact that you're using one with AF, not a good feeling, especially when you're telling the producers that you were using Betacam. Ha! From what I've read, heard and occasionally experienced about AF is that it searches for dominant fields to adjust to and goes into overdrive with a solid, neutral background. Just wait and see how fun it is to shoot through thick limbs and leaves with that good ole AF. Hope this helps.

September 27th, 2002, 01:46 PM	#107
dvmonkey2 Posts: n/a	Heard a lot of negative reviews on focus problems with XL1s Can someone tell me if this is a common flaw of the cameras? Have they been fixed in the newer models? Im very close to getting one, but the biggest complaint I have heard have been focusing problems.

September 27th, 2002, 01:56 PM	#108
Chris Hurd Obstreperous Rex Join Date: Jan 2001 Location: San Marcos, TX Posts: 27,368 Images: 513	See http://www.dvinfo.net/xl1faq.htm __________________ CH Search DV Info Net \| 20 years of DVi \| ...Tuesday is Soylent Green Day!

September 27th, 2002, 06:37 PM	#109
John Klein Regular Crew Join Date: Dec 2001 Location: Wisconsin, USA Posts: 182	Don't think I've used AF for much of anything. I'm a fan of the "push AF" button. Since I still use manual focus 35mm cameras, I found it helpful. I suppose if I were used to auto everything, I wouldn't have bought the xl1S. __________________ < >< . . . . . < >< . . . . . < ><

September 27th, 2002, 07:52 PM	#110
Nathan Gifford Wrangler Join Date: Sep 2001 Location: Tickfaw, LA Posts: 1,217	Read the link Chris has provided. This has been over the years an item of considerable debate. I have never had the problem with my XL-1. __________________ Nathan Gifford Southern Cyclist Magazine & Productions For quick answers try our Search! To see me and Rob Lohman click here

September 27th, 2002, 10:00 PM	#111
Dean Sensui Inner Circle Join Date: Oct 2001 Location: Honolulu, HI Posts: 2,054	The biggest complaints are regarding auto focus. I keep mine turned off and that avoids the problem entirely. __________________ Dean Sensui Exec Producer, Hawaii Goes Fishing

October 9th, 2002, 07:36 PM	#112
Mike Butler Machinist Mate Join Date: Oct 2001 Location: Southern Connecticut Posts: 644	Exactamundo, Sensui, leave the AF off and it won't hunt around, which is the biggest source of complaints about focus--it's all about the lens not being able to decide which point to focus on when objects are at different distances. Like 1 Jophoto, I like the "push AF" button. __________________ I ain't straight outta Compton, I'm straight out the trailer. Cuss like a sailor, drink like a Mc. My only words of wisdom are just, "Radio Edit."

October 9th, 2002, 08:42 PM	#113
Phil French Regular Crew Join Date: Feb 2002 Location: Lousana, Alberta, Canada Posts: 146	I use the push AF quite a bit - probably too much. I would prefer to manually focus more, but due to the shortcomings of the stock EVF (poor resolution), I find I'm not always confident that the focus is right on. I am getting more used to the EVF, but I would like to try the optional B&W one or an external LCD like the one described in Chris' article on the five best accessories. Beautiful "in focus" shots are the norm for the XL1s, but being confident that my shots are OK is not. I usually am a bit anxious until I get home and view my days work on a monitor. I also recommend experimenting with the camera hooked up to a monitor once in a while. I should mention that almost all of my work is outdoors-run and gun stuff. __________________ Nature Boy

January 13th, 2003, 07:57 PM	#114
John Dimasi Regular Crew Join Date: Mar 2002 Location: Pittsburgh, PA Posts: 51	XL-1 focus problem I don't know if this is a back focus problem like I see others getting succesfully fixed by Canon or not. My lens problem is when the lens is at the widest setting the focus seems to just drift whenever it feels like it. I have to keep pushing the autofocus button every 5 seconds to get it back in focus. This all occurs when I'm in the "A" setting and the lens is set to manual focus. I've tried zooming in on a distant object focusing sharp then backing up and zooming in again the object is still in focus. It just seems like the autofocus is never turned off even though I'm 100% sure that it is. Is this a Canon fix or do I have to keep spending money for Canon's add ons ie 16x manual lens to fix problems they engineered into their products?

January 13th, 2003, 08:25 PM	#115
Ken Tanaka Retired DV Info Net Almunus Join Date: Dec 2001 Location: Chicago, IL Posts: 6,943	Your desciption does not sound like a back-focus problem. (That's where the lens does not hold focus on an object as you zoom in and out.) Rather, it sounds like your autofocus is a bit flakey and, as you speculate, may not be disengaging when you switch to Manual Focus. No big ideas here, just a wild shot. If you've not already tried this, you might try removeing the lens and re-mounting it. The lens and body communicate through a series of contacts that are seated when the lens is squarely mounted. Maybe something's flakey there. Otherwise that will definitely be a Canon repair. __________________ Lady X Films: A lady with a boring wardrobe...and a global mission. Hey, you don't have enough stuff! Buy with confidence from our sponsors. Hand-picked as the best in the business...Really! See some of my work one frame at a time: www.KenTanaka.com

February 4th, 2003, 03:55 PM	#116
James Graham New Boot Join Date: Feb 2003 Location: Liverpool, UK Posts: 24	I've noticed a similair to the effect you are experiencing when my XL1s is in the (M)anual mode. Although I don't get the wide angle drift the XL1s seemed incapable of holding focus when zooming in and out. At first I though that I had a back focus problem. Strangely, setting the gain control to +0dB (or whatever) rather than (A)uto completely eliminates this problem. I've tested this several times. The last time being 5 minutes before making this post. I know that this isn't quite your problem but try it out - you never know. Sorry if that was of no help at all!

February 4th, 2003, 06:24 PM	#117
John Dimasi Regular Crew Join Date: Mar 2002 Location: Pittsburgh, PA Posts: 51	James, Thanks I'll give it a try. I've never tried this method. Johnathan

February 4th, 2003, 09:16 PM	#118
Don Palomaki Wrangler Join Date: Sep 2001 Location: Northern VA Posts: 4,489	Hmmmm. Zoming when in auto gain mode may canse hot spots to move through the metering zones and cause changes in expsoure. And similarly, an area that is poor for autofocus (no contrast) may move through the AF sensor sampling zone. Also, auto focus needs some light, about 50 lux, to work well.

February 12th, 2003, 09:06 PM	#119
John Dimasi Regular Crew Join Date: Mar 2002 Location: Pittsburgh, PA Posts: 51	What?

February 13th, 2003, 05:48 AM	#120
Don Palomaki Wrangler Join Date: Sep 2001 Location: Northern VA Posts: 4,489	The point being that during zooming (or during action in the iscene) the image presented to the various automatic-mode sensors is changing, and these changes could induce unwanted changes in aperture, shutter speed, gain, and focus. Also changing aperture may change apparent focus of items inthe scene as thedepth of field changes. (Also, I cleaned up some typos in the earlier post)