D90 Nikon : Video bad sweep effect !

A

archi3d

New member
Hi there,
I am exploring the Video mode of D90.

And i checked that some bars "sweep" on the screen (light flicker) when you shot
on interior scenes, with artificial lights.
The problems doesn't exist outside, with exterior/natural lights.

Please check my sample here : http://www.vimeo.com/2590559

Did you notice that ?
Do you know how to avoid this ?
Thanks for your help !
 
Last edited:
You can avoid the strobing effect of fluorescent lights. In my student short I just finished, I had a scene outside in a parking lot that was filled with fluorescent-based fixtures. I did the best I could to lock exposure just right to prevent noticeable scan lines. When I got the footage into post, I had noticed that I did in fact have scan lines! However, they were really slow moving scan lines so upon normal viewing it would be practically invisible. But if the video was fast forwarded, the scan lines would show up in all their unattractive glory.

It's a strange dance with the D90. Frustrating at times but straightforward most of the time. But when it comes to fluorescents, try to avoid them at all costs, otherwise you'll really have to start playing with that AE/L button.
 
it likes fluorescent lights than it does sodium vapor. I work in an office and there are no scrolling lines, but outside, where there are sodium vapor, it's almost impossible to get rid of, but still possible.
 
many flos are high frequency and those are less of a problem than even tungsten lights, which also create a bit of roll at least here in the 50hz world.

/matt
 
you know I watched the video. I posted on another thread that I was having the same problem. The wierd part is that my screen would show exactly the same lines...and I recorded that way..but when i play them back thru my computer or editor...the lines are not there at all
 
It actually says in the manual that live view and movie mode don't like flouresent lights:

Banding or distortion may be visible in the monitor and in the final movie under fluorescent,
mercury vapor, or sodium lamps or if the camera is panned horizontally or an object moves at
high speed through frame. Bright light sources may leave after-images when the camera is
panned. Jagged edges, false colors, moiré, and bright spots may also appear. When recording
movies, avoid pointing the camera at the sun or other strong light sources. Failure to observe
this precaution could result in damage to the camera’s internal circuitry.
Click to expand...

(From page 51)

It's a shutter speed issue, I think. Seeing as how you can't really adjust shutter speed on the d90, don't know how you should fix it... just avoid shooting under fluorescent I guess.
 
there's been at least 3 threads going over this already. it works fine under fluorescent lights...i guess you need some footage then? i'll post it tomorrow when i get back from the office, with flourescent lights. just lock the exposure when the lines disappear. i've gone over this like a dozen times. it's the same for sodium vapor. the lines will disappear when you lock the expsore to the correct shutter speed, though you may not know what that speed is, you can still get rid of it, but simply....LOCKING EXPOSURE...when the lines disappear.
 
does it really work "fine" if it requires a workaround method? i'm well familiar with the workaround yet i think it's a major hassle and something i'd like to see fixed in a firmware update before all other problems. but i've always been more interested in workflow than results since i'm a content person before all. i'd rather get the shot with lines than not get the shot without lines, if you know what i'm saying.

/matt
 
i dunno if fine is the right word for others, but it's fine for me. But at work, i don't even have to use exposure lock, the lines don't even show up...not sure what hz the lights are at, but those specific lights don't have scrolling lines....i understand in pal land this would be much easier to have manual shutter, but some of the people are misinforming others of something they aren't aware of.

yeah, i agree. if you need the shot and there's nothing you can do, then go for it. at least you got something.

i'll post some video tonight of fluorescent and sodium vapor lights. best solution i have so far.
 
Car3o said:
...just lock the exposure when the lines disappear...the lines will disappear when you lock the expsore to the correct shutter speed... but simply....LOCKING EXPOSURE...when the lines disappear.
Click to expand...

I played with different apertures, exposure compensations, pointed at several lightness... no success in finding the right shutter speed - here in Europe 1/50. At no point in time the waves, stripes... disappeared...
 
i'm in europe too and i've shot several hours of footage, no roll. you need to *slowly* move the camera across the scene, you'll see the change in the number of lines and their speed as you go along and the exposure is adjusted one "click" at a time, then lock focus at the very right moment. it's annoying but it works every time.

/matt
 
also, super8 has pointed out that even though you see "some" lines on your lcd screen it doesn't always show up on your videos. unless you speed it up and then it'll be noticeable.
 
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