Mixing XL1s and Gl2 footage

[Rob Belics]

I'm making a shoot using an XL1s but I also have a GL2 available should the xl1s not be available. Would there be any noticeable differences in the footage when intercutting between the two. We'll be shooting in normal interior and low light scenes.

[K. Forman]

I can't say for sure, as I have the GL1. However, I had no problems using it with my XL1s... Unless dumbass me only put filters on one cam, or the operator of the day screwed up the focus or something. It should be fine... Just white balance to the same source.

[Glen Elliott]

I've intercut GL-1 footage with XL-1s footage on many occasions. For the most part the picture is pretty similar...if anything an edge in color to the GL-1 suprisingly. However this is noticable difference in low light. The GL-1's 1/4" CCDS can't hang with the low-light capacity of the XL-1s's 1/3" CCDs.

[Edwin Quan]

i went from a GL2 to an XL1s. gotta say the picture on the GL2 was much nicer, as far as color and even sharpness goes. the note about the XL1S whuppin' the GL2 in low-light is true though.

[Ken Tanaka]

Rob,
I have both cameras and routinely mix their footage. The ability to match well depends, to some degree, on the nature of the scene. But in general, the GL2 tends to look sharper and more neutral than the XL1S, which is softer and a bit more red-heavy. I generally turn up the sharpness of the XL1S a notch and turn down the color a notch. I've also noticed that my XL1S tends to take on a bit more of a green/blue tint under flourescent lighting (such as under a Lowell Caselight with daylight lams), even after manual white balance, than my GL2. On the two times this has occurred I've chosen to fix it in post. Be sure to shoot a few frames of a white card to help facilitate this, if needed.

But you should take time to experiment for yourself. It will pay off.

[Don Berube]

Well, as you know, even two of the same model cameras will not match perfectly without a little tweaking. That is why TV studio and broadcast engineers use external camera control units for each camera along with a chip chart and a waveform/ vectorscope to match cameras so they look the same before a multi-camera productions begins.

While miniDV cameras do not have provision for external camera control units, you can still follow certain procedures before every setup to help make your cameras match more evenly. I usually carry a Putora 7A9 "Magic Chart" in my bag for this purpose. http://zgc.com/html/7a9_test_chart.html. I also will carry a SMPTE color bar chart which can be made relatively easily by downloading the following color bar pattern at http://noisybrain.com/colorbars.gif and printing them out on a decent color printer on photo-quality paper. It's a good idea to have this printout laminated so that it will be less subject to wear and tear. The following procedure is most easily achieved using a quality video monitor that has two seperate video inputs (Each camera going to a seperate input of the monitor). This will allow you to quickly compare the output of each camera as you optimize their settings to best match each other. You probably won't be able to perfectly match both cameras 100%, but if done properly then you will be able to much more easily make the cameras match with a bit of color correction when editing...

Basically the first thing you should do (once you have setup all of the lighting and have established your camera positions and are ready to shoot...) is to point both cameras at the back side of the Putora chart which is white. Making sure that the white side of the chart is under the same lighting that your subject will be under during the shoot, fill the frame of each camera with the white card and white balance both cameras (using manual white balance setting). Next, turn the Putora chart around and fill the frame completely with the 7A9 chart as evenly as you can between both cameras. This will allow you to adjust the sharpness of each camera so that both cameras more or less have the same sharpness setting. Once this is done, record a good half minute or so of the chart on each camera. This will be helpful in post if you need to make further adjustments. Next, place the color bar chart that you printed out in front of the Putora chart and record those color bars for a good half minute or so. Now, you will be able to use this in post as a reference with the color correction controls of your NLE (such as FCP 3) - the idea is that these color bars that you recorded under the light that you are shooting in is a much more tangible reference than the internal electronic color bars that the cameras offer.

Again, you won't be able to match both cameras perfectly when shooting, but you will be a lot closer using this procedure. When shooting, learn how to constrain the exposure in the highlights (white areas) so as not to over-expose... that way, even if the color and detail settings on each camera vary slightly, at least you will have a balanced exposure. Nothing more difficult in trying to match up a second angle camera that is significantly over-exposed when compared to the main cam... Maintaining a balanced exposure on every camera is key and will make it MUCH easier to color correct second and third angle cameras in post. If you must use Auto Exposure for whatever reason, then at least try to stick with AV Mode (Aperture priority) and try setting the AE Shift to -1. If you cannot use Manual Mode for whatever your reason is, then do take the time to experiment with the AE Shift. In chaotic lighting situations where you have no control over harsh lighting, then perhaps try using a steeper shift, say -1.5. This can sometimes help to insure that you do not over expose your frame.

When you are editing, you can always refer to the color bars that you recorded as a reference to help match the cameras more using color correction. I find that this is a handy procedure to follow whenever your lighting setup changes. Of course, you should use the same Exposure Mode on both cameras when shooting and try to maintain the same type of balanced exposure while recording. Again, using a quality monitor with two seperate video inputs makes doing this a lot easier. I use a Sony PVM-8045Q field monitor. If you do not have access to such a monitor then at least use as high a quality video monitor as you can.

If you are unfamiliar with how to properly color correct when editing, I found that the "Color Correction for Final Cut Pro" DVD by DigitalFilm Tree is very helpful in explaining how to properly color correct in post.
http://www.digitalfilmtree.com/dvd_cc.html

Please do let us know if you have any other questions or comments,

- don