newb question: --just want to clarify how to focus at DVinfo.net

Chris Miller · January 18th, 2007, 06:01 AM

-to focus, you 'zoom in' on the subject,
-focus (typically on a focus chart -as long as it's where the talent is)
-'zoom out' to the desired composition
...and the focus should remain unchanged.

is this correct?

thanks :)

Jay Gladwell · January 18th, 2007, 07:32 AM

Yes, that is correct, except you don't need a focus chart. In 35 years of production, I've never used a focus chart. These are used for testing of focus.

When focusing on a human or animal, focus on the eyes (generally speaking). With any other subject it's your choice as to what will or will not be in focus.

Jonathan Kirsch · January 18th, 2007, 09:34 AM

Jay's right...I've never used a focus chart either. I usually focus on an ear or farthest part of the shoulder...just in case they move around a bit...gives me some wiggle room. Works like a charm.

Jonathan

Rainer Hoffmann · January 19th, 2007, 12:53 AM

Hi,

just to add my 2 cents: the procedure is correct provided the backfocus of the lens is correctly adjusted. Otherwise the lens could well be out of focus once you zoom out.

Ryan Mueller · March 29th, 2007, 11:24 AM

This is my first post, so let me start off by saying that everybody on this forum is worthy of praise! I thank you very much for the plethora of info that you all have shared!

I do agree with Jonathan, I usually focus on an ear so if the talent moves forward or backward a touch, most of the detail in the target area will remain in focus.

Now, I recently purchased an XL2 and I absolutely love it. The only problem is that I think I have a bit of a backfocus problem. Yikes! Rainer mentioned something about adjusting the backfocus on the lense, can this be done with the stock Canon 20x lense?

I zoom in to get my focus, then zoom out to get the shot. The focus keeps until right before I'm all the way out. Any help would be appreciated.

Jonathan Kirsch · March 29th, 2007, 02:47 PM

Ryan,

I also have the stock 20x. There is no backfocus ring that we can manually adjust like there is on the 16x (wish I would have been able to tell my boss that before he bought the camera). I have had that happen a couple times in the last year. Didn't know how to replicate it or correct it.

Good to see another CO user!

Jonathan

Ryan Mueller · March 29th, 2007, 06:26 PM

Thanks Jonathan,

I guess I will be giving Canon a call. This problem is a consistant problem for me, and by consistant I mean every time that I backfocus.

I have read about other people with this problem too. Seems to be a strange problem to find on a $1,500 lense.

Oh well, as long as Canon will take care of it for me and it works fine after they do, I will be able to say that the XL2 is one very nice piece of machinery!

Ryan

"Great shots don't just happen!" - Dr. Don Dexter

Jonathan Kirsch · March 30th, 2007, 08:16 AM

Ryan:

If you hear anything from Canon, let us know. PM me if possible.

And say hi to Don for me next time you see him.

Jonathan

Georgi Ivanov · March 30th, 2007, 02:18 PM

We have the same problem. New camera - backfocus problem. Sent to Canon, they returned it back (checked, fixed?). The problem still exists.

Seth Kanne · April 2nd, 2007, 07:26 AM

I've got a Canon 3X wide lens and have found that the whole zoom in, focus, zoom out technique does not work with this lens. In this case, I'm pretty sure it's not a backfocus problem, just the nature of the beast.

John L. Miller · April 2nd, 2007, 09:58 AM

Quote:

Originally Posted by Chris Miller

-to focus, you 'zoom in' on the subject,
-focus (typically on a focus chart -as long as it's where the talent is)
-'zoom out' to the desired composition
...and the focus should remain unchanged.

is this correct?

thanks :)

I am a newbie with this camera also. Is this procedure done while set on Manual or auto focus? thanks.

Chris Hurd · April 2nd, 2007, 10:00 AM

It's done in Manual focus mode. It would be rather pointless in Auto focus mode. Hope this helps,

David Lach · April 2nd, 2007, 11:23 AM

Quote:

Originally Posted by Ryan Mueller

I do agree with Jonathan, I usually focus on an ear so if the talent moves forward or backward a touch, most of the detail in the target area will remain in focus.

Somebody correct me if I'm wrong, haven't had to check on that since filmmaking school, but the depth of field's properties do not change, no matter how deep or shallow it gets. The sharp areas are always 1/3rd in front of the focusing point and 2/3rd after. Meaning there is more head room in the back of the talent than in front (assuming the talent is facing the camera). Based on this, it seems the best way to allow for the actor's movement would in fact be to focus on the eyes (or nose), not the ears.

Of course, with a 1/3 CCD camera such as the XL2, the depth of field is so deep that it won't matter anyway unless you're zoomed in almost all the way. But just saying as far as the rule of thumb goes, it looks like it'd be best to focus on the eyes (or one of the closer parts of the talent/object you're focusing on).

Mark OConnell · April 2nd, 2007, 01:49 PM

"-to focus, you 'zoom in' on the subject,
-focus (typically on a focus chart -as long as it's where the talent is)
-'zoom out' to the desired composition
...and the focus should remain unchanged."

With the V1 if you start with the iris all the way open (not an unusual place to start given its light needs) and then zoom in to focus the aperture moves from 1.6 to 2.8 creating greater depth of field then you will actually have when you pull back out to frame your shot. Should that change theoretically have any effect on your final focus?

David Lach · April 2nd, 2007, 03:41 PM

Mark, your focusing point won't change, just the amount of acceptable sharpness back and in front of your subject. You still focus on the same thing no matter the aperture opening. Plus don't forget that zooming out will also increase greatly the depth of field you have, negating any depth you might be losing as a result of a bigger opening.

January 18th, 2007, 06:01 AM	#1
Chris Miller New Boot Join Date: Sep 2006 Location: New York, US Posts: 6	newb question: --just want to clarify how to focus -to focus, you 'zoom in' on the subject, -focus (typically on a focus chart -as long as it's where the talent is) -'zoom out' to the desired composition ...and the focus should remain unchanged. is this correct? thanks :)

January 19th, 2007, 12:53 AM	#4
Rainer Hoffmann Major Player Join Date: Aug 2004 Location: Syke, Germany Posts: 249	Hi, just to add my 2 cents: the procedure is correct provided the backfocus of the lens is correctly adjusted. Otherwise the lens could well be out of focus once you zoom out. __________________ Keep rolling Rainer

March 30th, 2007, 02:18 PM	#9
Georgi Ivanov Tourist Join Date: Dec 2006 Location: Walnut Creek, CA Posts: 3	Canon 20x backfocus problem We have the same problem. New camera - backfocus problem. Sent to Canon, they returned it back (checked, fixed?). The problem still exists.

April 2nd, 2007, 07:26 AM	#10
Seth Kanne New Boot Join Date: Mar 2007 Location: Minneapolis Posts: 7	focus with the 3X wide lens I've got a Canon 3X wide lens and have found that the whole zoom in, focus, zoom out technique does not work with this lens. In this case, I'm pretty sure it's not a backfocus problem, just the nature of the beast.

April 2nd, 2007, 10:00 AM	#12
Chris Hurd Obstreperous Rex Join Date: Jan 2001 Location: San Marcos, TX Posts: 27,366 Images: 513	It's done in Manual focus mode. It would be rather pointless in Auto focus mode. Hope this helps, __________________ CH Search DV Info Net \| 20 years of DVi \| ...Tuesday is Soylent Green Day!

January 18th, 2007, 07:32 AM	#2
Jay Gladwell Join Date: Jul 2002 Posts: 1,244	Yes, that is correct, except you don't need a focus chart. In 35 years of production, I've never used a focus chart. These are used for testing of focus. When focusing on a human or animal, focus on the eyes (generally speaking). With any other subject it's your choice as to what will or will not be in focus.

January 18th, 2007, 09:34 AM	#3
Jonathan Kirsch Major Player Join Date: Jul 2006 Location: Denver, Colorado Posts: 204	Jay's right...I've never used a focus chart either. I usually focus on an ear or farthest part of the shoulder...just in case they move around a bit...gives me some wiggle room. Works like a charm. Jonathan

March 29th, 2007, 11:24 AM	#5
Ryan Mueller Major Player Join Date: Mar 2007 Location: Highlands Ranch, CO Posts: 336	This is my first post, so let me start off by saying that everybody on this forum is worthy of praise! I thank you very much for the plethora of info that you all have shared! I do agree with Jonathan, I usually focus on an ear so if the talent moves forward or backward a touch, most of the detail in the target area will remain in focus. Now, I recently purchased an XL2 and I absolutely love it. The only problem is that I think I have a bit of a backfocus problem. Yikes! Rainer mentioned something about adjusting the backfocus on the lense, can this be done with the stock Canon 20x lense? I zoom in to get my focus, then zoom out to get the shot. The focus keeps until right before I'm all the way out. Any help would be appreciated.

March 29th, 2007, 02:47 PM	#6
Jonathan Kirsch Major Player Join Date: Jul 2006 Location: Denver, Colorado Posts: 204	Ryan, I also have the stock 20x. There is no backfocus ring that we can manually adjust like there is on the 16x (wish I would have been able to tell my boss that before he bought the camera). I have had that happen a couple times in the last year. Didn't know how to replicate it or correct it. Good to see another CO user! Jonathan

March 29th, 2007, 06:26 PM	#7
Ryan Mueller Major Player Join Date: Mar 2007 Location: Highlands Ranch, CO Posts: 336	Thanks Jonathan, I guess I will be giving Canon a call. This problem is a consistant problem for me, and by consistant I mean every time that I backfocus. I have read about other people with this problem too. Seems to be a strange problem to find on a $1,500 lense. Oh well, as long as Canon will take care of it for me and it works fine after they do, I will be able to say that the XL2 is one very nice piece of machinery! Ryan "Great shots don't just happen!" - Dr. Don Dexter

March 30th, 2007, 08:16 AM	#8
Jonathan Kirsch Major Player Join Date: Jul 2006 Location: Denver, Colorado Posts: 204	Ryan: If you hear anything from Canon, let us know. PM me if possible. And say hi to Don for me next time you see him. Jonathan

April 2nd, 2007, 01:49 PM	#14
Mark OConnell Major Player Join Date: Feb 2007 Location: Seattle WA Posts: 420	"-to focus, you 'zoom in' on the subject, -focus (typically on a focus chart -as long as it's where the talent is) -'zoom out' to the desired composition ...and the focus should remain unchanged." With the V1 if you start with the iris all the way open (not an unusual place to start given its light needs) and then zoom in to focus the aperture moves from 1.6 to 2.8 creating greater depth of field then you will actually have when you pull back out to frame your shot. Should that change theoretically have any effect on your final focus?

April 2nd, 2007, 03:41 PM	#15
David Lach Major Player Join Date: Oct 2002 Location: Montreal, QC, Canada Posts: 570	Mark, your focusing point won't change, just the amount of acceptable sharpness back and in front of your subject. You still focus on the same thing no matter the aperture opening. Plus don't forget that zooming out will also increase greatly the depth of field you have, negating any depth you might be losing as a result of a bigger opening.