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-   -   Awful autofocus (https://www.dvinfo.net/forum/canon-xl-h-series-hdv-camcorders/82674-awful-autofocus.html)

Harry Bromley-Davenport December 28th, 2006 03:01 PM

Awful autofocus
 
Is the dreadful autofocus something that could be fixed by a future firmware update? Or do you think that we're stuck with it forever?

Best

Harry

Steve Rosen December 28th, 2006 05:10 PM

We're stuck with it. It's a very long focal length lens, which adds stress to its ability to auto focus quickly, plus it's just a bad design.. Canon apparently knows this because they introduced an exterior auto focus system on the A1/G1...

I used a Sony PD150 for 2 or 3 years as a "glove compartment" camera, something I used for grab shots and small places, like airplane cockpits.. I left it on auto focus all the time and it worked great, I never thought about it...

Sorry, but the Canon XL H1 just isn't (and should never have been thought of as) a "point and shoot" camera...

My recommendation - learn to live with manual focus - a Chrosziel DV Follow Focus helps a lot....

Harry Bromley-Davenport December 28th, 2006 05:37 PM

Ah well. Thanks for the reply

H.

Dan Keaton December 28th, 2006 06:21 PM

Dear Harry and Steven,

Under what condition are you having autofocus problems with the XL H1?

I tend to use the autofocus a lot since my eyes are not that great and I do not have one of the better 7" on-camera monitors.

I have had a few instances where the autofocus focuses on the background, which I immediately correct by manually adjusting the focus and then it seems to do what I want it to do.

I tend to use 1080i much more than 24p.

Overall I am very pleased with the autofocus.

I hope you understand that I am not trying to be argumentative, I just want to know under what conditions will the autofocus not work well.

Steve Rosen December 28th, 2006 06:51 PM

Dan: I shoot 1080i... my problem with the auto focus is that it is extremely sluggish, sometimes I feel like I could step outside and have a smoke while I'm waiting for it to decide... Then it doesn't always seem to hit the right spot, even when it is centered in the finder...

I have used it successfully ootdoors in contrasty light a few times (it can be nice to have the scene slowly come in to focus), but indoors in low, flat light (which is where I could really use it because of the mushiness of the viewfinder) it just doesn't seem to work at all..

Luckily for me, I've been shooting film cameras for many years and have no problem manual focusing (PEAKING on all the time), so I just don't use it..

If it works for you, that's great - just hasn't pleased me...

Harry Bromley-Davenport December 28th, 2006 07:10 PM

I completely agree with Steven. I'm shooting 1080p - sorry "f" at 24. In a bight daylit room if I pan the camera from a patterned wall 20 feet away to a piece of furniture filling the screen at 8 ft the camera can take 5 - 10 seconds to respond.

In fact, sometimes it doesn't repond at all.

best

Harry.

A. J. deLange December 29th, 2006 06:42 AM

As I'm sure you are all aware autofocus algorithms look for enhanced contrast as they adjust the focus hence a slower frame rate requires a longer time than a faster one and 24 fps is going to give the slowest performance you can get with this camera. In addition, autofocus requires certain conditions to work well and these are spelled out in the manual. Pooly lit scenes of inherently low contrast are not among those conditions.

The original question asked whether the autofocus could be fixed by a firmware change. The answer is that while all the shortcomings cannot be removed because of the limitations imposed by the hardware (servo motor characteristics, CCD pixel pitch, frame rate...) the parameters of the control algorithms (e.g. servo loop gain) or the algorithms themselves can probably be tweaked to the extent that improvement is possible.

Personally I would prefer to focus manually but especially with the 6x lens and the stock EVF (and the old eyes) I have difficulty and often rely on the AF button on the lens to do it for me. What is sorely needed is a better VF!

Bruce S. Yarock December 29th, 2006 07:50 AM

The stock vf(and af) really does suck in anything but good light and high contrast.
I tried my Fu 1000 monochrome vf on my H1 and it's fantastic.I used it on my XL2 for about a year, and it really helped me focus. The obvious problem is no color.I've thought about an on cam monitor along with the fu 1000, but I hate to spend more money and add more weight to my H1.
Would a smaller, less expensive lcd(coupled with the fu 1000) give me enough basic color info for wb, etc.? I know it wouldn't be like the $2000 Marshall, but would it be close enough for basic color reference? In addition to focus, I also learned how to trust the fu 1000 for exposure.
Bruce S. yarock
www.yarock.com

Jimmy McKenzie December 29th, 2006 08:00 AM

Autofocus is for vacation videos...
 
To me it's a bit odd that these auto-focus questions keep arising with regard to the servo lens on the xl series.

Suggestions of those who have never have shot film or a production video being the ones in charge of the development of this device leave me wondering ... where on what film or production video camera would one find the auto-focus?

This is a convenient feature for the truly novice beginner in keeping with the pro-sumer moniker. All 3 of my white lenses have a rugged peice of vinyl tape over the switch that keep it from accidentally being switched to the horrible auto-focus position.....

Marty Hudzik December 29th, 2006 10:21 AM

The autofocus on my 16x manual lens is even worse than what any of you are describing. It is horribly slow.

:)

Steve Rosen December 29th, 2006 11:02 AM

Yeah, mine too Marty... But the good thing is I can make it faster if I want...

Back to the original issue... I completely understand the way AF works and what it says in the manual and what to expect and what not to expect... The point, really, is that this should not have been an AF camera in the first place...

And, again, Sony certainly seems to have their s___ together.. I have a good friend who has a Sony HDV (the one with the XLRs, I don't do numbers well) and he uses autofocus all the time...

Just for the heck of it, I shot about ten minutes with his camera yesterday after commenting on this thread, for my own satisfaction.. With that camera the AF does a better job in almost every situation than I can do manually... Sony knows auto.. their AF is way better and, incidentally, so is the AGC (which is something I DO need to depend on from time to time) it doesn't breath like the Canon's....

Richard Alvarez December 29th, 2006 11:16 AM

Autofocus is certainly handy in run and gun documentary and ENG moments. There are times when the green square "IDIOT" mode can save your bacon. For instance, I was shooting behind the scenes documentary footage on a film shoot. So, panning from what was in FRONT of the camera - lit by hmi's - and over to the crew in deep blue shadow - and back and forth - auto exposure and autofocus and even auto white balance can be a life saver.

If you've got one hand on the stupid iris switch in manual, you don't have one hand on the lens for focussing, follow? So 'professionals' who might normally have an autofocus (Focus puller) standing NEXT to them, can benefit from auto-focus while racking aperture, or twiddiling gain controll in an ENG setting.

So yeah, I can think of situations where a 'pro' would need autofocus. I normally shoot with my 16x in a structured film like or interview setting. But was on the street with the 3x wide shooting the BTS footage. Yeah, the auto focus was slow. AND it doesn't track and zoom at the same time ... one servo split for two functions... bad design. BUT the autofocus button was handy in a pinch.

Still, I'd love to see it improved.. definately not the best situation.

Steve Rosen December 29th, 2006 06:58 PM

Interestingly, just received my 6x this morning.. the AF is useable on this lens. Fairly responsive...

So, assuming that the basic Canon AF design is the same, it IS probably the long focal length range of the 20x, as I thought and suggested earlier in this thread, that makes that lens sluggish...

In response to the pro vs whatever question above - I have been working as a professional cinematographer for nearly 40 years and I will gladly use auto anything - focus, exposure, gain, AGC, WB - if it works reliably all the time. I think the question in this thread is whether the Canon's 20x works reliably all the time...

Richard Alvarez December 29th, 2006 07:26 PM

Steve,

I suspect you are right, and the longer focal length is a function of the sluggishness of the 20x. (Though to be fair, the original 16x autofocus was even WORSE... especially the 'hunting'.)

I have my eye on the 6x... AND the XLh1. Definately on my list as a 'package' deal when I finally go HD(v). Tell me again the focal range on the 6x -

Harry Bromley-Davenport December 30th, 2006 02:31 PM

Steve,

Please let me know how the AF behaves on your new 6x when you have tried it out under low lighting conditions and at 24p ... oops, forgive my senseless blunder ... 24f, would you?

Thanks,

Harry


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