Photos of plasma screen

[beanster]

Why oh why when i take a picture of my plasma does the image of the screen look covered in an oil slick.


My canon a95 could do it fine but not my canon 30d. wierd.

Any explanations more than welcome because I have no idea and it's bugging me.

[munchy]

example? Let's see!

[beanster]

I'll post a shot up when i get home, i'm at work at the mo (hey it's a slow friday ).

[KCMO Al]

I don't know about plasma or computer screens, but I know to take a photo of a CRT tv screen the shutter speed has to match the scan rate. It used to be that 1/30th sec would give you a reasonably good image. Try changing the shutter speed.

[beanster]

here we go, shutter 1/200. but thank you KCMO Al a shutter speed of 1/60 does give me an image with correct color (taa ) :

[TMR Design]

Interesting. There is no refresh rate to deal with so I would think it should be like taking a picture of an LCD display which is easy and comes out pretty good. I don't understand the plasma technology enough but it looks like there is something about the screen (plasma) that reflects the light differently.

[surfologist]

Sweet!!

[CyberDyneSystems]

Originally Posted by TMR Design

Interesting. There is no refresh rate to deal with

But, these are moving pictures so there is "redraw" which will pretty much behave like refresh rate to a certain extent as far as taking a photo is concerned (though they exist for totally different reasons)
A static image on an LCD screen on you laptop is not comparable, but a movie on that laptop would be,.. and the movies frame rate would come into effect.

[deadpass]

plasma screens still have the response rate which is similar to the refresh rate of a CRT

[lostdoggy]

Plasma=small little fluorescent bulbs linked together to form an image by igniting a charged gas to created plasma (hence the name plasma) that causes the phosphers to glow its respective color.

[beanster]

for what it's worth...@ 1/60 the colors come out fine, the faster the shutter the more the colors go. Could it be that the camera stops the plasma technolgy's "refresh" in action?

edit: like a less technical version of what lostdoggy said

[lostdoggy]

Back to Op's question.

P&S uses alot of noise reduction and sharpen and color&saturation boosting and DSLR uses moderate amount.

I think the noise reduction is smoothing out the oily swirls.

[lostdoggy]

Just curious, doesn't PAL and SECAM (I think) sync at 50hz w/ respective AC service. Here the TVs syc at 60hz.

I don't know much about HDTV but regular TV broadcast is interpolated and requires a full sec to fully draw the screen. So it would take 2 pass to fully draw one frame.

[Wilt]

Originally Posted by lostdoggy

Just curious, doesn't PAL and SECAM (I think) sync at 50hz w/ respective AC service. Here the TVs syc at 60hz.

I don't know much about HDTV but regular TV broadcast is interpolated and requires a full sec to fully draw the screen. So it would take 2 pass to fully draw one frame.

lostdoggy, you're on the right trail but following the wrong scent!

US TV (and a few other countries, too) refreshes at 60Hz to do one pass, and it takes two passes (alternating odd lines, then even lines) in an interlaced display to make a single image. So 30 frames per second.

PAL and Secam TV refreshes at 50Hz to do one pass, and it takes two passes (alternating odd lines, then even lines) in an interlaced display to make a single image. So 25 frames per second.