exposure issues with manual

[Stephen Goldberg]

I am having problems locking exposure in manual mode. I shot a scene in a studio and set everything on manual mode. I noticed that as I moved the camera slightly or zoomed in and out the exposure would adjust itself. I thought perhaps this was just showing up on this way of the LCD but when I veiw the file the exposure is shifting in the video, getting lighter and then darker etc. Should not manual mode be fully manual? Can anyone provide some insight into this? I should not have to lock exposure in manual mode.
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SteveG

 

[MikeK5117]

Many modern zoom lenses are variable aperture, at least in their maximum aperture. So, if you are using maximum aperture on manual and you zoom out, then the aperture changes and the exposure will get darker.

Not sure if this is what you are seeing but it is an option.

 

[Ednaz]

I believe some m4/3 won't do manual for video. My G2 manual is hard as daylights to understand on many issues, but says that when in motion picture mode (why not video mode?) the ISO is set to AUTO, which pretty much defeats manual exposure settings. Throughout the "how to use aperture priority" and "shutter priority" etc, there's a note that says: "Note: It will be a normal motion picture recording when recording a motion picture." That note appears like a disclaimer all over the place every time the manual talks about exposure settings.

 

[photoSmart42]

The LCD/EVF brightness adjusting has nothing to do with the actual photo EV, so don't confuse the two. In manual mode, your EV is fixed by the value of your aperture/shutter/ISO. If all those variables are set on manual, your EV can't adjust automatically. The screen brightness, however, adjusts to give you the best view of the scene.

 

[Stephen Goldberg]

Yes this is what I am seeing. So is there a way around this?
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SteveG

 

[Stephen Goldberg]

The camera is the Panasonic GH1 which has full manual control supposedly but now I am confused about what's going on with it.
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SteveG

 

[Stephen Goldberg]

Here is a clip which shows the exposure shifting in the scene. The camera was on manual. http://www.youtube.com/watch?v=PWsX8SnLuGc
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SteveG

 

[photoSmart42]

And you're in full manual mode for sure? Manual aperture, manual shutter, manual ISO, custom WB? Some people have reported issues with exposure changes with the kit lens when you zoom the lens in or out while in video mode, but from your video you're staying at fixed zoom, so that's not it.

 

[photoSmart42]

Are you using AE lock to lock in your exposure just in case?

 

[MadsR]

1. Using a more expensive lens with the same opening throughout the zoom area.
2. Not touching the lens and reverting to good old fashioned manual zoom (Move camera)
3. Using A mode and let camera adjust. Use EV compensation to take care of flash system.
4. Follow the actual aperture of the new focal length and calculate new closing speed.

 

[Stephen Goldberg]

Yes everything was in manual mode. I did a custom white balance as well. That is why I am perplexed
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SteveG

 

[Stephen Goldberg]

I did try AE lock but not on that shot. I later changed the custom setting on the AE loc button to lock only exposure. But when shooting in manual mode you should not have to lock exposure using the AE lock button. This is supposed to only be when you are using on of the priority modes. Manual is supposed to be manual. You set what you want and it should nt alter unless you change it. I am wondeing if I should post this problem to the Panasonic talk forum.
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SteveG

 

[rrr_hhh]

I did try AE lock but not on that shot. I later changed the custom setting on the AE loc button to lock only exposure. But when shooting in manual mode you should not have to lock exposure using the AE lock button. This is supposed to only be when you are using on of the priority modes. Manual is supposed to be manual. You set what you want and it should nt alter unless you change it. I am wondeing if I should post this problem to the Panasonic talk forum.

If everything is fixed, manually on your camera, then what about your lighting ?

I have looked at your video and I can see only one change of light a few time after the beginning : the peson turn her back in another direction and the picture become somewhat overexposed. Where was your light source ? may be that when the person turned her back she suddenly caught more light and since your exposure was fixed, the blacks were then somewhat washed out ? I'd say that the change is very subtile and since it is accompanying a movement, I won't bother too much about it.
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rrr_hhh

 

[Stephen Goldberg]

That is quite an astute observation. The lighting was 4 point. 2 lights bounced into umbrellas were used to light th backdrop on either side. Another light bounced into a silver lined umbrella was used at about a 45 deree angle to the subject on camera left. Another light at camera right was used as a fill. Perhaps when the model turned the light from the background bounced mre onto the subject.

However I have another scene that was shot outdoors where you also see the exposure lightening and then darkening. I will see if I can upload a clip of that.

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SteveG