View Full Version : Metering modes most similar to what a videocamera uses


Jeff Harper
April 26th, 2011, 07:41 AM
When recording moves we have a variety of metering modes to choose from with the GH2. Is there a particular metering mode that would best emulate how a camera such as the FX1000 or EX1 would read and adjust exposure?

I might be on the wrong track, here's why I ask.

When using a conventional video camera, exposure is often nice and even, in the sense that the whole scene in properly exposed to account for the entire shot. Obviously, this is not always the case, but often it is, whether outdoors or in. I more often that not could rely on auto settings for all my cameras when shooting a wedding ceremony. Great focus, even exposure, etc, few overexposed spots. Again, not always. Many times I might have to go into manual exposure and adjust the iris, ISO, etc, but lots of time it wasn't necessary.

With the GH2 it seems often there is often times a huge contrast between subject and the outer areas of the scenes, and blown out highlights on the edges of the scene are often an issue. For example, on an altar shot that seemed to be perfectly exposed for most everything, the tiny candle flames on the edges of the scene were blown out. It was bizarre.

I obviously need to try out the various modes myself and try them out, but I just thought of this as another adjustment that might assist in run and gun work. Different situations will likely require different modes.

I also think the lens used, and the focal length can affect this as well. I noticed Sunday this problem is less with my 18-55mm f/2.8 than with say the 20mm F/1.7.

Any thoughts? Here are some shots using auto iso on three different lenses, exposure wide open, and what I find surprising is how much darker on the edges the image from the 20mm is. The 18-55 is actually better exposed overall. Maybe because it is widest, and has more scenery from which to calibrate the ISO settings.

From left to right 20mm, 30mm f/1.7, and bottom left is 18-55mm 2.8 lenses.

So much to learn about using these camera!

Nigel Barker
April 26th, 2011, 08:59 AM
Jeff, as you don't mention what aperture or ISO setting you used does that mean that you used automatic settings? If so then that accounts for the differences. You need to adjust exposure correctly by hand rather then rely on the camera getting it right (which clearly it didn't in this situation).

Jeff Harper
April 26th, 2011, 09:23 AM
I believe I was wide open on each lens, but it is possible I didn't adjust to ensure each lens was open as I should have, as I don't distinctly remember being careful to do that, but it was my intention. I was shooting a quick test and was rushed. The church is across the street. I'll go back Sunday and do it again, taking more time with a variety of settings.

Shutter was constant and ISO was on auto.

Bill Bruner
May 2nd, 2011, 11:23 PM
Jeff - if you used manual aperture and shutter settings, your problem may have been auto ISO. With this camera, I am turning into a big believer in manual settings for just about everything except focus (and when focus starts to "hunt", I go manual on that too!).

Bill

Jeff Harper
May 4th, 2011, 11:03 AM
Thanks for your input Bill.

Brian Luce
May 5th, 2011, 09:11 AM
Jeff - if you used manual aperture and shutter settings, your problem may have been auto ISO. With this camera, I am turning into a big believer in manual settings for just about everything except focus (and when focus starts to "hunt", I go manual on that too!).

Bill

that's how I shoot it. all manual, except for AF. and btw, you can set up AF so it won't hunt. It will be semi AF, AF will activate when shutter is half way depressed.

Jeff Harper
May 5th, 2011, 06:38 PM
Brian, you shoot ceremonies with set ISO? What do you do when your subject changes from say priest in well lit area, to a reader off to the side in very poorly lit conditions and you are already wide open? Slow down the shutter? I can't slow it down enough to compensate often times. Turn off the camera and reset it?

What about unmanned cameras? I run three. Though I do get to visit a couple of my unmanned cams here and there, I often cannot get to my balcony camera to change anything. One ceremony they lowered the lights after the ceremony started, the balcony cam was on set ISO, and the footage was seriously underexposed.

Brian Luce
May 5th, 2011, 09:47 PM
I'm not brave enough to shoot weddings. I do occasional concerts. What I do is expose for the darkest areas, set the camera up for that, then control the aperture and to a lesser extent, the shutter to get the best exposure.

Jeff Harper
May 6th, 2011, 12:38 AM
I thought about it, and I suppose for my primary, manned camera I could just use an ISO of say, 1000, and then close and open aperture as needed. Is that what you guys do? Otherwise I can't think of any way to have the latitude I would need for differing situations. It was my thought previously that auto ISO with a cap, of course, would provide smoother transitions in those situations when I cannot/do not want to stop and start to adjust ISO.

John Griswell
May 6th, 2011, 08:33 AM
What I have done at weddings with good success is to to use shutter priority mode (1/60 for 24p and 1/125 for 720p) and let the aperture and ISO float as needed to keep a good exposure. I then set the ISO limit to lowest I can get away with (normally 800 with the 20mm pancake).

Jeff Harper
May 6th, 2011, 08:57 AM
John, thanks, that was my thinking also. I haven't tried it yet, but seems to me to be the most logical for weddings. Why do you choose 1/125 for shutter, because it's double 60fps? I have read that double of frame rate is best, which is what you seem to be doing. But 1/125 would certainly be a bit on the "dark" side, wouldn't it? I have two f/2.8 lenses which need a bit slower shutter speed. Any harm in running 1/60 for shutter speed? Your thoughts?

To everyone else, full manual is how I shoot fun stuff, but weddings I need continual unbroken footage, and that is where the challenge comes in. I do use SP a lot even for fun stuff, as it allows for full manual control, except for the aperture, which is wherever I choose to leave it.

John Griswell
May 6th, 2011, 09:56 AM
>Why do you choose 1/125 for shutter, because it's double 60fps?

Yep. It has to do with the 180 shutter rule:

180 Degree Shutter - Learn It, Live It, Love It (http://blog.tylerginter.com/?p=385)

It is ok to go lower but not higher. So if you are really pushing a lens in low light with 720p mode you can get away with 1/60. Same for 24p mode and 1/25.

Jeff Harper
May 6th, 2011, 01:15 PM
Very useful link, John, thanks a million. I had a paid shoot today, followed the rule, looks great!

Nigel Barker
May 6th, 2011, 01:23 PM
What I have done at weddings with good success is to to use shutter priority mode (1/60 for 24p and 1/125 for 720p) and let the aperture and ISO float as needed to keep a good exposure. I then set the ISO limit to lowest I can get away with (normally 800 with the 20mm pancake).If you use auto-aperture you will get some weird looking footage where the DOF will change as the aperture opens & closes bringing objects in & out of focus.

Jeff Harper
May 6th, 2011, 05:36 PM
Great point Nigel, had not thought of that, but will not be a problem with Shutter Priority anyway, right?

John Griswell
May 6th, 2011, 08:58 PM
If you use auto-aperture you will get some weird looking footage where the DOF will change as the aperture opens & closes bringing objects in & out of focus.

While this is true I always run 2 cams at weddings (it's in my base package) so if I change composition which results in a change in aperture I can always cut to my B cam to avoid that effect (which you kinda have to do during a composition swap anyway).

Being in the right spot with the camera on the action is priority number one (at weddings) and using shutter priority mode allows me to focus on that.

Jeff Harper
May 6th, 2011, 10:30 PM
I've been mistaken in my assumption about SP. I was under the assumption the aperture stays the same as whatever Ieft it at in a previous mode, but it doesn't, does it? The aperture changes.

So all this time I've been wrong in my thinking, and this explains things that have been happening I didn't understand.

So for more control and flexibility, I would think it might be better to do as suggested: for my primary camera to be in full manual movie mode, but with the following additional:

I would want to start by setting my ISO to a fixed high value, say 800ISO or so. Then I would have the latitude to adjust my aperture as needed, leaving my shutter at 1/125.

Does this make sense?