funny lines from my LED light

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    • #97163

      I am new to filmmaking and am attempting to teach myself the basics using as much DIY gear as possible.

      One site I visited suggested using a Husky task light from Home Depot for beginner lighting rigs.  Picked one up for $50, as best as I can tell it's 30w, 120 volts, 60 HZ and 1500 lumens.  I set my DSLR on Aperture priority to do some practice shoots and I have two black horizontal lines that scroll from bottom to top on my display screen.  What the heck is going on?  When I set camera to shutter priority they disappear.  When I turn this light off they disappear.

      Can anyone explain to me what is going on?  Any solutions to how I get rid of this and still be able to shoot in aperture priority.

      thanks for your help.

      Rob

    • #278578
      RockyRocky
      Participant

      Rob, what you are describing sounds like 60cps hum on the video, you can confirm this, by checking, out the TV screen effect in first thirty seconds of a YouTube video titled "Ground Loops and Hum" by TheOnLineEngineer.  Most probable cause is no or poor AC filter circuit in the Husky light (Flouresent lights habitually cause the problem). This can normally be eliminated with a 60cps in line AC filter (sometimes found in multi outlet powerboards). To avoid the problem altogether suggest a 192 (or greater) LED on camera mount battery opertaed light with almost the same specs as Husky (1500 lumen v 1350 lumen). Total cost should be less than US$50 and it comes with additional features for video/photography. Trust this assists.

       

       

    • #278586
      Avatarpaulears
      Participant

      Your camera is effectively open to light input for a very specific amount of time each second – and your different modes capture the correct amo8unt of light by adjusting sensitivity and the amount of time the sensor is active. They often very, very quickly scan the chip, so on high shutter speeds, in a similar way to the old film cameras, there's a kind of electronic shutter. It's this that also give propeller blade on aircraft a strange bent shape, as the scan is done progressively through the frame. Your LED lights are also constantly flickering at the same speed as your mains (60Hz in the US, 50Hz in the UK), so at some point your camera is receptive to light at the exact time your LEDs are off!. The movement you see is the two things being extrenely close, but not quite, in sync.

      I have to report that LED lighting comes in two types. Lighting for quality of light, and lighting for quantity of light. Whoever recommended work lights for video lights has never used real video lighting. They are bright, the reflectors create very strange shadows and the light is harsh and blends very poorly with other light sources. You can soften them up with some diffuser taped to the front, but they are simply crude brute force lights. I bought two and they got given away to my colleague to use in his workshop for work light – absolutely no use to me for video lighting. Video light have specific qualities, apart from brightness. Beam quality, beam angle, half-peak angle, hardness and softness. Position is also important and work lights rarely go high enough. Video lighting usually requires soft or semi-soft lighting. We used to say Fresnels were key lights and created hard shadows – that was until small source LED came along and created VERY hard lighting – so Fresnel lenses are considered to be the shadow creators, and the softboxes and LED arrays are the softligh shadowless lights. Many of these are still not soft enough. Light people with those worklights and the look is pretty horrible, unless really deep shadows and very distinct edges are wanted for effect.

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