My current setup is: Canon 40D with Nikon-fit Cosina lens attached with an adapter, connected to dragonframe on my mac. The lights I use are (primitive I know, but what's a poor student to do!) fairly ordinary desk lamps. One would have thought I would not be getting any flicker, but alas, I am. I think it must be the desk lamps (unless I'm missing something else!), so wondered if there was a way of not getting flicker through lamps you plug right in to a plug socket? I'm sure I've seen something before but I just can't remember what it is. Any ideas?
The best alternative would be to scrap the desk lamps and buy some proper film/work lamps, but that doesn't seem likely in the near future.
10 points to anyone who can solve my problem!!!
Have you figured out how to set all the functions of your camera to full manual? You need to not allow it to auto-control any of them - exposure, shutter speed, and color balance. I had to spend some time with the manual learning the various menus before I figured it all out. And is the Cosina lens also manual?
If it is actual lighting level fluctuations, it could still be due to several different things. One of the most common is light reflecting off of the animator and the animator moving around between frames. You could be either blocking light or reflecting light onto the set at various times. You need to make sure you aren't standing anyplace where you can do that.
It could be something else blocking/reflecting light too - I remember Isomer saying he had a colored lighting filter (or was it a reflector or a flag or something?) that was moving aroundwhen he walked past it and doing funky things to the light You might also have a fan moving things around and changing light levels.
Or it could be some big appliance like the dryer or the furnace kicked on. Ok, probably more likely the air conditioner if you live in my hemisphere - but you know what I mean. If it's this you'll see the overall lighting get dimmer and stay that way for a little while, then suddenly get brighter again when the appliance stops using so much juice.
I have used a 40d with Nikon manual lenses for 5 or 6 years. I had everything on manual, but still got flicker which turned out to be caused by the AC power in my area fluctuating by a volt or two. That actually made the lights go brighter and dimmer by a tiny amount. I could make it happen by switching my oven on and off, but it was really being caused by other properties in the area using more or less power. At midnight to 5 AM it was much steadier, but I wasn't too keen on doing all my animating in the wee hours. If it is light levels, it is probably not the fault of your lights, they are responding to the AC voltage.
My solution was an expensive one, I installed an Eatonware power conditioner, called a Double Conversion UPS, that converts the mains power to DC, stores it in a battery, then converts back to AC and puts out steady power at a couple of volts lower. A plug-in unit at 1500 AH was around $1500, my wired-in one at 5000 AH was $4500 plus $500 for the electrician to install it. (I already had a special overhead lighting circuit with ceiling power points for my movie lights, so it had to be hard wired or I had got that built for nothing.) Go with the small one if you go this way!
Recently I have switched to a Canon 7d for pro work (because of a couple of hot pixels and dirt on the sensor with the 40d), and I started getting some occasional flicker again, despite everything being sorted out for the 40d. I searched through the manual and menus and found a couple of functions I had missed. They still made auto adjustments even though the camera was set to M for manual and white balance was manually set to 3200k, and the lenses were manual. (One was Peripheral Illumination Correction, the other Auto Lighting Optimizer. I don't think the 40d has those which is probably why I missed them.) But you do have to be thorough, these cameras are sneaky and want to help you get the best exposure for each image, without regard for whether it matches the last one, or whether you told it to bugger off and let you handle the settings thanks very much.
I'll just check my 40d and see what I have my camera set to. Not all of these will make a difference, but if I wasn't sure I did them just in case. It does work for me, I can get flicker-free shots. So looking at the lcd screen on the back:
1st menu - red square on top left of the rear screen, with white camera icon and one white dot: Switch red-eye off.
Across to 2nd menu - 2 dots - going down the list from top to bottom: AEB, Auto Exposure Balance? I have it set to 0. Don't know if that matters. White Balance - I have it set manually, but the tungsten (lightbulb icon) is fine too for halogen desk lamps. Anything except auto. WB SHIFT/BKT - I have it on 0, but it probably only comes in with auto WB set. Picture Style - I have it set to Standard, but it depends on which looks best to you under your lights. I wanted minimal processing and correcting, but I think there is always some.
3rd menu, blue with 1 dot - nothing here I can see.
4th menu, blue with 2 dots - nothing that should affect exposure. I have AF Point disp disabled, since I never use AF.
5th menu, yellow with wrench and one white dot. I have Auto Power Off set to Off so it doesn't turn itself off when it takes me longer to do a frame, but that's nothing to do with flicker.
6th menu, white with yellow wrench and 2 dots - nothing.
7th menu, white with yellow wrench and 3 dots - nothing.
8th menu, orange with white camera, custom functions. 1st item, C. Fn I: Exposure - click on it and it says Exposure Safety Shift, I have it set to 0: Disable. C FnII Image: Long Exposure Noise Reduction - I have it set to Off. At ISO 100 or 200 I don't get noise. C FnIII:Auto Focus Drive Mirror Lockup - I have it disabled. Mirror goes up anyway when connected to Dragonframe. C FnIV: Operation/Others - Live View exposure simulation. I have this set to 1.Enable (simulates exposure), since it only affects the live view and I need it to be bright enough to see what I am doing. I set the actual amount in Dragonframe.
9th Menu, green with white star, My Menu Settings. I haven't actually used this.
That's all the menus on the back screen.
Obviously, the dial on the top of the camera, left side, is set to M for Manual. I have set my exposure time with the wheel on the top right, near the shutter button. Currently it is at 1.5 sec, it is usually between 1/2 sec and 2 sec.
The lens should have the aperture set by turning the ring on the lens. The adapter means the Canon body should not be able to change it.
I did get flicker once from the computer monitor facing the set, with me standing in front of it but in a different position every frame, so a reflective car model in the foreground was flickering.
Sometimes I suggest compact fluorescent lights if you have unstable power, because they do not normally respond to small changes in voltage. You can't dim them, they stay the same until you turn the dimmer too low, then they go out. But I picked up a product lighting kit with a translucent cube tent thing and 3 lights using those coiled fluoro lightbulbs, and when I was testing with a dimmer, I found they did dim slightly when the voltage was reduced a tiny amount. Turn the dial down a bit more and they turned into strobe lights and visibly flash on and off, a bit lower and they went out. (Fluoros do flicker anyway, but very fast, so a 30 sec exposure will smooth it out.) That very small difference in current is what causes the problem, so these ones would not be a solution for that. But my long fluoro tubes in the ceiling don't change brightness with small voltage changes. I haven't tested coiled fluoro bulbs from the supermarket with my dimmer yet.
Thanks a lot to both of you. Strider - I tend to wear black t-shirts while i animate and stand back from the action as the frame is taken, so i'm certain it's not me. Small power fluctuations seem quite probable. After reading how much you spent on a power conditioner Nick, i was a bit scared!!
I went through the menus on my camera and 99% of it was set to the same as yours, and the remaining 1% i'm sure has nothing to do with flicker - but i have changed it now so we will see! I'll animate a couple more shots this week to check, and if the flicker's still there i'll have to start investigating other options like the fluoro tubes you suggested. Thanks
Another things that can work good is to use 12V halogen lamps, if you avoid the cheapest ones and get one in the middle price range they usually have a voltage regulator that keeps to 12V very accurate even if the main voltage move around a lot.
Typical spotlights you put in the bookshelf or over the kitchen sink model can work good.
Just check if they have a true voltage regulator, but might not be so easy to find out.
A nice thing about traditional stop motion (in response to Marnik) is that you can get away with wearing black T-shirts. Clay animators used to wear white shirts because in addition to hiding dirt, a black T-shirt would get noticeable lint on the puppets. White lint was less visible on set, especially if it was close to camera.