What mode is best for sit-down interviews? at DVinfo.net

Charles Penn · May 10th, 2006, 02:51 PM

I shot an interview last night with my XL2 using the manual mode. And while I was sure to focus on my interviewee's eyes, I noticed a lack of depth of field (I believe this is an accurate way to describe this). When I zoomed in. I actually lost focus.

Is there a better mode, or best mode to shoot in when doing interviews? I experimented with Auto before but was taken aback by the iris fluctuations with people with light colored clothing. So I opted for manual but did not make any adjustments except for the iris. Was it the shutter speed or what was it that caused me to lose focus?

I should mention I used a Rifa 44 soft light (250 watts) as my sole lighting source. There were overhead ceiling lights that I left on. I white balanced prior to rolling tape.

Right now, I'm leaning toward going back to Auto "A," particularly since with very little camera movement, it's one less thing to worry about.

Am I on the right track or am I completely off base with my analysis. Please advise.

Chuck

Peter Costello · May 10th, 2006, 03:42 PM

always use manual. zoom into the interviewees eyes and focus. You should not have to focus again during the interview. Depth of field is a whole different issue.

Peter Costello · May 10th, 2006, 03:43 PM

sounds like your back focus is out.

Charles Penn · May 10th, 2006, 05:17 PM

How do I adjust the back focus?

Also, the manual says if you focus, then leave the camera run for a while, you may lose focus due to the rise in temperature in the camcorder interior and lens.

Peter Costello · May 10th, 2006, 05:46 PM

during the questions you could quickly zoom in a re-focus on the eyes. back focus, pick an object far away, usually with some pattern on it, focus, then pull out wide. check to see if the object is in focus, if not, use back focus to tweek focus.

Charles Penn · May 11th, 2006, 08:43 AM

Thanks, Peter, but where, physically, is the back focus control located on the XL2?

Hunter Sandison · May 11th, 2006, 01:21 PM

Hey Charles
On the 16x manual lens the back focus is the ring on the lens closest to the lens mount on the body. You loosen by turning a little knurled stick near the underside of the lens. After you loosen it the the back focus ring can be set and then locked down via the stick again(its kind of like a hose clamp on a car engine). I don't know about the 20x lens but every video zoom I've ever used pretty much has this set up so I'd wager it(the 20x) is similar. The best way to set back focus in my experience is to set a focus chart about 6 to 10 feet from the camera. In a pinch you can use anything with high contrast like the front page of a newspaper but a Siemens Star chart is really helpful. You can download and the print out a pretty good focus pattern at www.rondexter.com (there is a ton of other useful info at that site too). Open your iris all the way to ensure minimum DOF use NDs if you need to. Zoom in all the way to the chart and focus by eye. Zoom out all the way and focus the chart using the back focus. Repeat the last two steps until the chart is perfectly in focus at both ends of the zoom. Lock the back focus. As you mentioned the heat of the camera can affect the back focus. Also any time you remove the lens or jostle the camera very much you'll want to reset the back focus. Now when you use the "zoom in to the eyes" method, your critical focus will remain where you set it regardless of focal length, T stop or distance to subject. I tried to give a very complete answer so please forgive me if I just told you a bunch of stuff you already knew.
Regards,
Hunter

May 10th, 2006, 02:51 PM	#1
Charles Penn Regular Crew Join Date: Mar 2006 Location: Port St. Lucie, Florida Posts: 103	What mode is best for sit-down interviews? I shot an interview last night with my XL2 using the manual mode. And while I was sure to focus on my interviewee's eyes, I noticed a lack of depth of field (I believe this is an accurate way to describe this). When I zoomed in. I actually lost focus. Is there a better mode, or best mode to shoot in when doing interviews? I experimented with Auto before but was taken aback by the iris fluctuations with people with light colored clothing. So I opted for manual but did not make any adjustments except for the iris. Was it the shutter speed or what was it that caused me to lose focus? I should mention I used a Rifa 44 soft light (250 watts) as my sole lighting source. There were overhead ceiling lights that I left on. I white balanced prior to rolling tape. Right now, I'm leaning toward going back to Auto "A," particularly since with very little camera movement, it's one less thing to worry about. Am I on the right track or am I completely off base with my analysis. Please advise. Chuck

May 10th, 2006, 03:42 PM	#2
Peter Costello Regular Crew Join Date: Dec 2005 Location: Phoenix, AZ Posts: 29	focus always use manual. zoom into the interviewees eyes and focus. You should not have to focus again during the interview. Depth of field is a whole different issue.

May 10th, 2006, 03:43 PM	#3
Peter Costello Regular Crew Join Date: Dec 2005 Location: Phoenix, AZ Posts: 29	back focus sounds like your back focus is out.

May 10th, 2006, 05:46 PM	#5
Peter Costello Regular Crew Join Date: Dec 2005 Location: Phoenix, AZ Posts: 29	back focus during the questions you could quickly zoom in a re-focus on the eyes. back focus, pick an object far away, usually with some pattern on it, focus, then pull out wide. check to see if the object is in focus, if not, use back focus to tweek focus.

May 10th, 2006, 05:17 PM	#4
Charles Penn Regular Crew Join Date: Mar 2006 Location: Port St. Lucie, Florida Posts: 103	How do I adjust the back focus? Also, the manual says if you focus, then leave the camera run for a while, you may lose focus due to the rise in temperature in the camcorder interior and lens.

May 11th, 2006, 08:43 AM	#6
Charles Penn Regular Crew Join Date: Mar 2006 Location: Port St. Lucie, Florida Posts: 103	Thanks, Peter, but where, physically, is the back focus control located on the XL2?

May 11th, 2006, 01:21 PM	#7
Hunter Sandison New Boot Join Date: Jan 2006 Location: Los Angeles, CA Posts: 21	Hey Charles On the 16x manual lens the back focus is the ring on the lens closest to the lens mount on the body. You loosen by turning a little knurled stick near the underside of the lens. After you loosen it the the back focus ring can be set and then locked down via the stick again(its kind of like a hose clamp on a car engine). I don't know about the 20x lens but every video zoom I've ever used pretty much has this set up so I'd wager it(the 20x) is similar. The best way to set back focus in my experience is to set a focus chart about 6 to 10 feet from the camera. In a pinch you can use anything with high contrast like the front page of a newspaper but a Siemens Star chart is really helpful. You can download and the print out a pretty good focus pattern at www.rondexter.com (there is a ton of other useful info at that site too). Open your iris all the way to ensure minimum DOF use NDs if you need to. Zoom in all the way to the chart and focus by eye. Zoom out all the way and focus the chart using the back focus. Repeat the last two steps until the chart is perfectly in focus at both ends of the zoom. Lock the back focus. As you mentioned the heat of the camera can affect the back focus. Also any time you remove the lens or jostle the camera very much you'll want to reset the back focus. Now when you use the "zoom in to the eyes" method, your critical focus will remain where you set it regardless of focal length, T stop or distance to subject. I tried to give a very complete answer so please forgive me if I just told you a bunch of stuff you already knew. Regards, Hunter