How to shoot screen images?


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kiwi2

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Has anyone tried shooting their PC screen while it's on? I notice there'll be some thin black bands that appear quite randomly at the side of the images. It's an interesting physical phenomena but is there a way to prevent or at least reduce it? Thanks!
 

GeEkMaN

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kiwi2 said:
Has anyone tried shooting their PC screen while it's on? I notice there'll be some thin black bands that appear quite randomly at the side of the images. It's an interesting physical phenomena but is there a way to prevent or at least reduce it? Thanks!
this only happens with CRTs because that's the way the image is updated on the screen.

you can correct that by using a slower shutter speed, say 1/20s or slower, and that will capture the entire screen without those black bars.
 

kiwi2

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GeEkMaN said:
this only happens with CRTs because that's the way the image is updated on the screen.

you can correct that by using a slower shutter speed, say 1/20s or slower, and that will capture the entire screen without those black bars.
Thanks! Yah, I tried to shoot at slower shutter speed. It does eradicate the thicker black line on the screen. But I'm referring more to the smaller ones at the side.... It's like a diffraction pattern that we learn in our Physics class. But it comes about randonly depending on when I press the shutter. I guess it's hard to prevent these?
 

roygoh

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kiwi2 said:
Thanks! Yah, I tried to shoot at slower shutter speed. It does eradicate the thicker black line on the screen. But I'm referring more to the smaller ones at the side.... It's like a diffraction pattern that we learn in our Physics class. But it comes about randonly depending on when I press the shutter. I guess it's hard to prevent these?
What resolution is your screen setting and what resolution is your camera?

The CRT screen image is made up of discrete pixels which our eyes normally cannot resolve at normal viewing distance. The camera should have higer resolution than our eyes thus the pixels on the screen will "beat" with the pixels on the CCD and create what is referred to as "moire".
 

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