Matching lighting from day to day.

[Ryan Wachter]

Quick question. Now during shooting, depending on the type of shot ie. short DOP shots you are going to want to open up the iris, but how does one go about making sure that lighting matches? I open up the stop a few and throw on a ND to counter it, but if both of these shots are outside in the same scene how do i keep them looking the same?
Thanks

[Rick Bravo]

Controlling your DOF is the easy part. Match lens, aperture setting and subject to "film plane" distance and you're good to go.

Your biggest problem in matching is going to have to do with time of day and weather conditions.

If you shoot one day in full sun and then re-shoot in overcast...well, you know the rest.

Also, your shadows can create a problem if you are shooting wide enough for them to be noticeable. A high noon sun will not be the same as a 9am or 4pm sun. This will also affect your color temperature.

Make sure that your key and rim lights are coming from the same direction in every shot and take serious notes on conditions.

RB

[Bryan Beasleigh]

If you do a manual white balance the lighting has to match.

[Rick Bravo]

Lighting and color temperature/balance are two completely different things. While your white balance may be correct, this will not affect your lighting.

Just because you matched your white balances, it doesn't mean that you are going to add or remove shadows caused by different lighting situations.

Here's a ferinstance...

Shoot a scene having properly white balanced your camera, let's say in full sun, then, switch filters and DO NOT white balance and shoot the scene again...same lighting, different color.

Now shoot a scene having properly white balanced, in full sun...wait for an overcast or give it a few hours so that your shadows are different...white balance...roll...same color values, different lighting.

RB

[Ryan Wachter]

Yes Im not worried about color and I dont have seperate lens, as most of you im sure dont...atleast the majority. I have a agdvx100 and for DOP I will have to adjust the iris and open it further than I normally would on a shoot, it doing so it gets brighter, so now I have to lower lights or in the case of outdoors use ND filters. So now that thats done how do I make sure its the same brightness from my none ND filtered stopped down iris to the ND filtered more opened iris shots?
Hope that explains it better.

[Rick Bravo]

Regardless of how you arrive at your exposure, whether it is by stopping down or opening up and adding NDs, you will achieve the same "brightness level" results. The change is going to be in your DOF.

Obviously, if you stop down, you are going to get more depth, and if you open up, you are going to end up with a shallower depth of field.

If you open up two stops and add an ND6, it is the same as stopping down two stops and pulling the ND when it comes to exposure. Again, the difference is going to be in the the DOF.

If you are exposing properly, I would be more concerened with keeping my "lighting" consistent from shot to shot within the same scene.

Hope this helps, RB

[Ryan Wachter]

thats what im asking how do I know Im getting the same exposure, it might look about right to my eye but when i get it in post it may turn out differently. Is there a ratio of the numbers on the ND filters to the amount of stops?
The agdvx100 give me a built in 8 and 64. If using the 8 how how many stops gets it exactly back to where it was?

[Rick Bravo]

An 8 & 64 what?

I seriously doubt that it is a 64ND. You might as well be shooting through a welder's glass!

Here is the breakdown on ND filters.

ND 3 =1 Stop
ND 6 =2 Stops
ND 9 =3 Stops
ND 12 =4 Stops

RB

[Ryan Wachter]

Thanks for the breakdown for me. As far as ND filters all I know is on the side of it it says 1/8 and 1/64 ND filters.

[Barry Green]

That refers to the amount of light transmission that gets through.

In setting #1, about 1/8 as much light will get through. In setting #2, 1/64 as much light gets through.

That corresponds to a 3-stop filter for each position. Consider the DVX as having two built-in ND9's, each which reduces the light by 3 stops. So when you go to ND1, you're cutting the light by 3 stops (1/2, 1/4, 1/8). When you go to ND2, you're cutting it by another 3 stops, for a total of six stops (1/16, 1/32, 1/64).

[Ryan Wachter]

excellent, thank you very much for your help guys. Now I should be able to keep the light almost identical and clean it in post if I have to.
Thanks