View Full Version : Dealing with dark and uneven lighting
August 6th, 2010, 11:45 PM
So I'm a Newbie in the video world... My main job is a sound engineer and I'm just getting into video work as a suplement to my income. Much of the sound work I do is with live shows where the lighting is to enhance a mood for the audience and video is the last thing considered.
I just shot a performance where the stage was rather dark (the orchestra had stand lights for their music) and the overhead lights were dark in color (blue). There were two vocal soloists out front that were lit with white spots so they were very bright.
My resulting video of that piece has the orchestra actually looking quite good, but the soloists looking completely overexposed and washed out. I'm shooting on a Sony HXR-NX5U camera and while I can't remember my exact settings for this show, it was likely on an automatic setting as I don't have time to mess with much when I'm mixing.
Being new to the video world, how would I deal with this situation in the future to keep all the objects in the picture looking good?
Thanks for any help you can provide.
August 7th, 2010, 12:30 AM
Doing video isn't that much different than doing audio. You know you can't fix a hard clip in audio. Well the same is true in video. If you let the signal clip (pure white blowout) you can't fix that later. So you have to make SURE to not lose the highlights. That means the blacks are going to fall off into oblivion. You don't have much latitude.
An analogy for these consumer cameras is that you are recording 128Mbps mp3 level quality instead of 24bit or even 16bit PCM. The video equivalent of 24bit PCM is called RAW, and you don't see that on video cameras under $50k. So you just have to do the best you can with what you have.
Job one is to learn enough to take the camera off "auto" mode. You wouldn't mix with your levels controlled automatically, so don't shoot the video that way. If you want to be "income producing" with this, you're going to need to invest the time. No one is going to pay you for "garbage". And well they shouldn't.
August 7th, 2010, 01:04 AM
You've just described something that is hard do with a single camera and most NLEs. Actually, a situations like this first pushed me to manual mode multi-cam shooting back in the Hi-8 dark ages of the last century.
The basic problem is that video still has limits to its dynamic range. If you ramp down the exposure so that the soloists are not blown-out by the spots, your orchestra gets very dim or, if you expose for the orchestra, the soloists are blown out. It is the same kind of thing as using your camera in a shaded room with window opening onto bright sunshine on a snow field.
The simplest thing to do is to go into the camera menu and set the spotlight function to "on." This will mostly keep the images of your soloists from being blown out by the spots, but it can make your orchestra pretty dim.
If I were shooting this with a single NX5, I'd use manual controls, assuming that the video is for spectators. I would turn start by turning off the steady shot. This is partly habit for me (on older Sony cameras back in the previous century, the stablization could affect exposure settings -- doesn't happen particularly with the NX5 but old habits persist.) The main reason to do this is that it prevents motion artifacts when you pan the camera. (You are shooting on a tripod, right?) The next thing I would do is switch to manual focus. (Switch to manual, then zoom as far as you will during the performance, press the focus zoom button to get an enlarged picture in the LCD, get the focus sharp and then pull to a full stage view.) This keeps the focus steady for everything else you will be doing. I don't rely on auto focus in this situation because the darkness can really throw it off. Next, I'd probably set the shutter speed to 1/60th (this being NTSC land) and would switch on the manual Iris. Use the ring to adjust down for the brightness when aiming at the soloists and the adjust wider when aiming for the orchestra. Expose for the soloists when they sing, expose for the orchestra when they play an overture, intros, instrumental passages and such. When shooting the orchestra, I'd try to get the brightly lit soloists as much out of the frame as I can. Another thing I've tried that can work okay in a pinch is exposing for the soloists and then kick the gain up as I pan down to the orchestra when I aim at them. Before trying this during a performance, go into the camera settings menu and set "smooth gain" to "medium." So far, the NX5 does nice job of smoothing out gain changes.
I still go through this even though I am equipped for multi cam shooting. What I do now is set my NX5 camera in manual mode for close ups on the soloists and the orchestra as above, set another cam at medium zoom for the soloists with the focus and exposure locked down, and set a third camera in semi-wide mode to see the orchestra and the soloists but with exposure and focus locked down for the soloists. This allows me to avoid showing zooms or pans except when I want them, and allows me to edit between the views later.
August 7th, 2010, 11:42 AM
The issue of exposure is exactly the reason why it took so many years to bring my photography setup into the digital age. With film I could fudge some of those issues, but with digital, it became that much harder to do.
I'm aware of the issues of compression and the limitations of the AVCHD files. The $50K cameras will never happen for me as I have no desire to get into that realm of video work. I'll hire the pros when that is needed. This particular concert was for test footage for me- camera was a week old and I needed material to practice with. The piece in question was an unstaged one act contemporary opera. The rest of the festival went off really well and I was quite impressed at the image quality under low light. Client wasn't being charged and they weren't expecting anything so the majority of what is being delivered will be great for their needs.
The vast majority of the work I'll be doing is just documentary or under very cntrolled situations. The whole reason I am getting into video is because of the part of my business doing college demos for young musicians. The schools are requiring single camera shoots on DVD of their performances because of the amount of audio editing going on out there. Since I have the camera, I'll do a stationary documentary/archival shoot, but I'm not a large operation.
Perhaps someday I'll have multiple cameras and then those suggestions are perfect (thanks! I wouldn't have thought of doing things that way). I'll also examine those settings on the camera and see what they do for me.
Ultimately, it sounds like I need to get better at using manual settings.
Thanks for the help and if anybody else has any tips, I'm all ears...
August 7th, 2010, 01:11 PM
Two observations, first are you shooting the orchestra or the soloist? You won't get both in good exposure under those lighting conditions... make a choice, and frame accordingly, that will help (see below).
Second, even when framed accordingly, you may have blown highs, Sonys will tend to overexpose, use the spotlight comepensation feature, OR set the AE shift between -2 and -4, OR manually pull the exposure back to prevent blown highs, or a combination as needed, depending on how harsh the lighting is. You should be able to leave the AE shift ON and then use the other functions - my AE shift is almost always set to the range I mentioned, with manual exposure being my second adjustment... for fine tuning.
The CMOS equipped cameras have better lattitude, but you still have to remember that "auto" exposure will try to balance the ENTIRE FRAME, which means if there are extremes, it will cause you to lose somewhere, usually the bright end of the spectrum because the camera will try to make the majority of the frame "usable brightness", and if most of that frame is dark or nearly black... guess what the camera "brain" does...?