Auto exposure issue (i think) at DVinfo.net

Nathan Quattrini · April 24th, 2007, 08:23 AM

Is there any way to lock the exposure while using the manual setting? My boss is bald so when we are out in the sunlight (don`t laugh...well at least not in his presence ha) but when his head catches the sun at different angles the A1 is adjusting itself and making the picture go lighter and darker to accommodate which is really screwing up the footage. The Exp Lock seems to only work on Auto mode, but then I can`t adjust anything else. How can I deal with this? If his head shines for a second thats SO much better than the picture darkening for a second then lightening again. We even tried makeup..but it doesn`t do much

David McGiffert · April 24th, 2007, 08:33 AM

Nathan:

Honestly, there should be a make-up
option for your bosses head...
I work in feature film production,
and although video blooming isn't an issue,
there is a film equivalent,
and good make-up really can help if properly done...
Good luck.

David

Nathan Quattrini · April 24th, 2007, 08:39 AM

well its not just his head at the core of the issue, lets say someone walks in frame with a bright colored shirt, the same will happen.

Curt Wrigley · April 24th, 2007, 08:40 AM

Quote:

Originally Posted by Nathan Quattrini

Is there any way to lock the exposure while using the manual setting? My boss is bald so when we are out in the sunlight (don`t laugh...well at least not in his presence ha) but when his head catches the sun at different angles the A1 is adjusting itself and making the picture go lighter and darker to accommodate which is really screwing up the footage. The Exp Lock seems to only work on Auto mode, but then I can`t adjust anything else. How can I deal with this? If his head shines for a second thats SO much better than the picture darkening for a second then lightening again. We even tried makeup..but it doesn`t do much

Use full manual mode. Then exposure is locked all the time. You may want to take auto gain off too.

Curt Wrigley

Nathan Quattrini · April 24th, 2007, 08:51 AM

Full manual is the M on the dial right? Thats what I am using :|

Oh crap....could a mod please move this over to the H1 forum...I am looking to buy an A1 so I posted here by accident, the camera I`m using at work is the H1...sorry

Curt Wrigley · April 24th, 2007, 09:17 AM

Quote:

Originally Posted by Nathan Quattrini

Full manual is the M on the dial right? Thats what I am using :|

Oh crap....could a mod please move this over to the H1 forum...I am looking to buy an A1 so I posted here by accident, the camera I`m using at work is the H1...sorry

If you are in manual mode, then you are setting the AP and Shutter to a specific value, ergo locking exposure. In A priority you are setting the A and letting the cam choose the Shutter speed. In Shutter Pri you set the shutter speed and let the cam select the A setting. In these "auto modes" the exposure lock lets you freeze the setting the cam chooses. If you are in manual mode, the exposre is forzen all the time to whatever you manually select.

Moving or panning the cam can make exposure settings want to change. Perhaps a little makeup on the bald head would help. Or some shade.

Curt

Nathan Quattrini · April 24th, 2007, 09:41 AM

heres an example of what is happening. This was in manual mode, doesn`t look very locked to me :(

http://www.kiukle.com/temp/exposure.wmv

Tom Hardwick · April 24th, 2007, 09:49 AM

Manual means manual. You've only got manual control if the camera can't influence the focus, the gain, the shutter speed, the iris, the audio levels or the white balance.

To stop your exposure from fluctuating you've got to lock down the shutter speed, the iris and the gain. There's very few situations in movie-making where you'd leave such decisions to the camera. The camera is a fast acting, accurate idiot, and you know better.

tom.

Curt Wrigley · April 24th, 2007, 09:50 AM

Quote:

Originally Posted by Nathan Quattrini

heres an example of what is happening. This was in manual mode, doesn`t look very locked to me :(

http://www.kiukle.com/temp/exposure.wmv

Thanks for the example. A picture is worth a thousand words. A video; several thousand.

If you are in full manual mode, then perhaps it is an auto white balance issue. Note the color changes when his sleeve or torso covers the center of the black frame. If you are in manual, the exposure should not be changing, so perhaps the white balance is what is auto adjusting.

But with no other info, I would guess this was shot in auto exposure mode. Im skeptical you were in manual mode.

Curt

Chris Hurd · April 24th, 2007, 09:56 AM

Moved from XH to XL H1 per request of OP.

Insure that Gain and White Balance are NOT set to Auto.

Trish Kerr · April 24th, 2007, 10:01 AM

It has to be the AGC. Even in manual it will adjust on the fly if set to 'on'.

Page 54 of the manual I think. Or at least on the online pdf vesion will show function availability in each setting.

If the auto white balance is set to 'on', I'm wondering if that also affects things.

I have everything turned off at this point.

Nathan Quattrini · April 24th, 2007, 10:33 AM

example 2. I just recorded this. Using M mode, factory custom preset 1. White balance preset 1. 60i, 1/120 shutter speed (did the same on 1/60). Thoughts? Shouldn't it not do that? How else could someone pass in front of the camera without throwing the picture off. Thanks for all your help in getting me to understand this

http://www.kiukle.com/temp/exposure2.wmv

*EDIT* I just saw Chris` post (thanks for moving this btw) and I just looked...the Gain is set to Auto. That was the ticket. Thanks so much

April 24th, 2007, 08:23 AM	#1
Nathan Quattrini Major Player Join Date: Jan 2007 Location: Warwick, Rhode Island Posts: 740	Auto exposure issue (i think) Is there any way to lock the exposure while using the manual setting? My boss is bald so when we are out in the sunlight (don`t laugh...well at least not in his presence ha) but when his head catches the sun at different angles the A1 is adjusting itself and making the picture go lighter and darker to accommodate which is really screwing up the footage. The Exp Lock seems to only work on Auto mode, but then I can`t adjust anything else. How can I deal with this? If his head shines for a second thats SO much better than the picture darkening for a second then lightening again. We even tried makeup..but it doesn`t do much __________________ Cinematography Site

April 24th, 2007, 08:39 AM	#3
Nathan Quattrini Major Player Join Date: Jan 2007 Location: Warwick, Rhode Island Posts: 740	well its not just his head at the core of the issue, lets say someone walks in frame with a bright colored shirt, the same will happen. __________________ Cinematography Site

April 24th, 2007, 08:51 AM	#5
Nathan Quattrini Major Player Join Date: Jan 2007 Location: Warwick, Rhode Island Posts: 740	Full manual is the M on the dial right? Thats what I am using :\| Oh crap....could a mod please move this over to the H1 forum...I am looking to buy an A1 so I posted here by accident, the camera I`m using at work is the H1...sorry __________________ Cinematography Site

April 24th, 2007, 09:41 AM	#7
Nathan Quattrini Major Player Join Date: Jan 2007 Location: Warwick, Rhode Island Posts: 740	heres an example of what is happening. This was in manual mode, doesn`t look very locked to me :( http://www.kiukle.com/temp/exposure.wmv __________________ Cinematography Site

April 24th, 2007, 09:56 AM	#10
Chris Hurd Obstreperous Rex Join Date: Jan 2001 Location: San Marcos, TX Posts: 27,366 Images: 513	Moved from XH to XL H1 per request of OP. Insure that Gain and White Balance are NOT set to Auto. __________________ CH Search DV Info Net \| 20 years of DVi \| ...Tuesday is Soylent Green Day!

April 24th, 2007, 08:33 AM	#2
David McGiffert Regular Crew Join Date: Feb 2007 Location: Topanga, CA Posts: 139	Nathan: Honestly, there should be a make-up option for your bosses head... I work in feature film production, and although video blooming isn't an issue, there is a film equivalent, and good make-up really can help if properly done... Good luck. David

April 24th, 2007, 09:49 AM	#8
Tom Hardwick Inner Circle Join Date: Mar 2003 Location: Billericay, England UK Posts: 4,711	Manual means manual. You've only got manual control if the camera can't influence the focus, the gain, the shutter speed, the iris, the audio levels or the white balance. To stop your exposure from fluctuating you've got to lock down the shutter speed, the iris and the gain. There's very few situations in movie-making where you'd leave such decisions to the camera. The camera is a fast acting, accurate idiot, and you know better. tom.

April 24th, 2007, 10:01 AM	#11
Trish Kerr Major Player Join Date: Mar 2007 Location: Canada Posts: 294	It has to be the AGC. Even in manual it will adjust on the fly if set to 'on'. Page 54 of the manual I think. Or at least on the online pdf vesion will show function availability in each setting. If the auto white balance is set to 'on', I'm wondering if that also affects things. I have everything turned off at this point.

April 24th, 2007, 10:33 AM	#12
Nathan Quattrini Major Player Join Date: Jan 2007 Location: Warwick, Rhode Island Posts: 740	example 2. I just recorded this. Using M mode, factory custom preset 1. White balance preset 1. 60i, 1/120 shutter speed (did the same on 1/60). Thoughts? Shouldn't it not do that? How else could someone pass in front of the camera without throwing the picture off. Thanks for all your help in getting me to understand this http://www.kiukle.com/temp/exposure2.wmv EDIT I just saw Chris` post (thanks for moving this btw) and I just looked...the Gain is set to Auto. That was the ticket. Thanks so much __________________ Cinematography Site