photographing modern monitors, tablets, screens, phones

removed account4 · Mar 3, 2014

does anyone here have any experience photographing modern stuff as mentioned in the thread title
( computer monitors, tablets or phones ) ? tv's and OLD monitors have a refresh rate and i remember if didn't get the shutter speed just right
you'd get half a screen &c ... does modern technology have a refresh rate that is the same like ac current 60c/s?

thanks in advance for your expert help
john

benjiboy · Mar 3, 2014

I know with TV's John it's 1/30 sec. or longer if you want to avoid the scan lines., I've never tried the other two.

Thomas Bertilsson · Mar 3, 2014

I am quite certain the refresh rates of modern screens is much higher than the AC current rate. I remember in the 90s having a TV, over in Sweden, that was twice the rate of the 50Hz frequency, 100Hz.

I have seen figures for the iPhone 5S being 120Hz, but can't find evidence for it.

benjiboy · Mar 3, 2014

You are probably right Thomas it's a long time since I did it, and all TV's were CRT in those days.

snapguy · Mar 3, 2014

Don't know

Have no experience with modern stuff. I do know in 1970 I used to have to go over to ABC News in New York and photograph TV monitors (for stills from video footage of the war in Vietnam). With a Nikon F you would have to hold the camera in the vertical position and with a Nikkormat, in the horizontal position, due to a difference in the way the shutters worked. Can't remember now if we used 1/30th of a second or 1/60th because of the refresh rate.

MDR · Mar 3, 2014

Depends on the screen not all LCD screens have the same refresh rate. The Hz number is also more marketing than true speed. Furthermore LCD do not refresh like old screens if you don't change the image the refresh rate is zero. They flicker though.

Good luck

WetMogwai · Mar 4, 2014

I just did an experiment with the d... to make sure I was right before I said anything. LCD screens do typically refresh at 60Hz, but because they draw the whole screen at once, they aren't a problem at any speed. The problem with the old CRT screens was that they only drew half the screen on each pass and then, only one line at a time. The problem with photographing them came from that, not the refresh rate itself. You had to shoot at half the refresh rate so that you captured all the lines in both fields. With a modern LCD or OLED screen, just expose for the amount of light and account for any movement on screen to get or avoid motion blur. The refresh rate doesn't really matter.

removed account4 · Mar 4, 2014

you folks are great, thanks for your help !

Alan Klein · Mar 4, 2014

How do you get rid of the Moire patterns?

removed account4 · Mar 4, 2014

Alan Klein said:
How do you get rid of the Moire patterns?

LOL i don't plan on it ...

Chan Tran · Mar 11, 2014

Alan Klein said:
How do you get rid of the Moire patterns?

I tried a few shots last night and can't get rid of it

removed account4 · Mar 11, 2014

the last 4 images in my apug blog
(there was a url link here which no longer exists)
were taken directly off my tablet,
no moire patterns that i am worrying about ...
but others i didn't post, well they were
looking kind of miore-ee ...

mrred · Mar 11, 2014

WetMogwai said:
The problem with the old CRT screens was that they only drew half the screen on each pass and then, only one line at a time.

That would only be true in interlace mode. As an IT person (and former radio & tv repair), I would always set them up in non interlace mode to prevent noticeable flickering. However in the later years, they did have 120 hz interlace available.

The flat screens are made, as a default, to accept 60 hz as a standard. The better ones are double-buffered (internal memory for screen buffer), which would make the actual screen independent. The back lighting bulbs should have a greater influence on flicker.

I would test before making a critical shot.

photographing modern monitors, tablets, screens, phones

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