A photo of the computer screen -- what causes vertical lines

[Vrbic]

https://www.dropbox.com/s/be52pax3jezv3cb/IMG_20170128_170143.jpg?dl=0 https://www.dropbox.com/s/be52pax3jezv3cb/IMG_20170128_170143.jpg?dl=0 I have question what causes vertical lines on the photo of the screen of my laptop?
But I would like to find out it alone. Could someone lead me?
I know the screen works with some frequency and it "blinks". Something around 75Hz I guess. But why it makes such vertical lines...I don't have any idea. Maybe problem is I don't know how works camera in my phone. Please advise.
Thank you for your posts.
Picture is here: https://www.dropbox.com/s/be52pax3jezv3cb/IMG_20170128_170143.jpg?dl=0

 

[lewando]

Interesting question. Lines are horizontal when my phone is horizontal--vertical lines when phone is vertical. Investigate how your laptop updates its screen image AND investigate how your camera digitally processes an image.

 

[Buffu]

https://www.dropbox.com/s/be52pax3jezv3cb/IMG_20170128_170143.jpg?dl=0 https://www.dropbox.com/s/be52pax3jezv3cb/IMG_20170128_170143.jpg?dl=0 I have question what causes vertical lines on the photo of the screen of my laptop?
But I would like to find out it alone. Could someone lead me?
I know the screen works with some frequency and it "blinks". Something around 75Hz I guess. But why it makes such vertical lines...I don't have any idea. Maybe problem is I don't know how works camera in my phone. Please advise.
Thank you for your posts.
Picture is here: https://www.dropbox.com/s/be52pax3jezv3cb/IMG_20170128_170143.jpg?dl=0

Does it happen only with laptop ? did you try that on TV or other screen ?

 

[Vrbic]

Does it happen only with laptop ? did you try that on TV or other screen ?

Investigation in progress :)
Summary:
My laptop Lenovo
portrait mode: https://www.dropbox.com/s/f2pd2u5g8jyq277/2017-01-28 17.01.44.jpg?dl=0
landscape mode: https://www.dropbox.com/s/87mcwucmjgxu135/2017-01-30 17.17.04.jpg?dl=0
laptop Asus
portrait mode: https://www.dropbox.com/s/8idk18q5c6uzi9q/2017-01-30 17.18.17.jpg?dl=0
landscape mode: https://www.dropbox.com/s/lb6nrd9y6z1gvrc/2017-01-30 17.18.22.jpg?dl=0
LCD TV
portrait mode: https://www.dropbox.com/s/8ghu71pwzwo5nq3/2017-01-30 17.40.18.jpg?dl=0
landscape mode: https://www.dropbox.com/s/e56bg6uczfxfcgk/2017-01-30 17.37.58.jpg?dl=0
old TV
portrait mode: https://www.dropbox.com/s/rpp1i4gji5lol22/2017-01-30 17.25.17.jpg?dl=0
landscape mode: https://www.dropbox.com/s/sznywsqp2zym13j/2017-01-30 17.26.04.jpg?dl=0

 

[Vrbic]

Investigation in progress :)
Summary:

It is very interesting. Asus and LCD TV don't have any lines. And old tube television in portrait mode produces oblique lines :-D Landscape photo of old TV produces horizontal lines...don't understand anything :-)
Any idea, why sometimes there are lines and sometime not? What can be different in these screens?

 

[Buffu]

It is very interesting. Asus and LCD TV don't have any lines. And old tube television in portrait mode produces oblique lines :-D Landscape photo of old TV produces horizontal lines...don't understand anything :-)
Any idea, why sometimes there are lines and sometime not? What can be different in these screens?

Try changing the refresh rate of the monitor.
Then click the pictures.

 

[Vrbic]

Try changing the refresh rate of the monitor.
Then click the pictures.

50Hz: https://www.dropbox.com/s/g6u263kyyqcwybj/2017-01-31 10.11.15.jpg?dl=0
60Hz: https://www.dropbox.com/s/b62u0zjic3mgnj1/2017-01-31 10.12.26.jpg?dl=0
It seems it is same, but if you look closer on blue word "english" on both photos, you find out that space between shadows lines is for 60Hz a bit bigger. Unfortunately, I have no other options for this frequency.

 

[Buffu]

50Hz: https://www.dropbox.com/s/g6u263kyyqcwybj/2017-01-31 10.11.15.jpg?dl=0
60Hz: https://www.dropbox.com/s/b62u0zjic3mgnj1/2017-01-31 10.12.26.jpg?dl=0
It seems it is same, but if you look closer on blue word "english" on both photos, you find out that space between shadows lines is for 60Hz a bit bigger. Unfortunately, I have no other options for this frequency.

Did you try clicking pictures with another camera ?

 

[Vrbic]

Did you try clicking pictures with another camera ?

No doesn't matter. Do you have any idea what is happaning with my camera?

 

[rcgldr]

The effect is related to the camera. I tested a Note 4 camera with a CRT monitor. The camera is sensitive to refresh rate and brightness. At 60 hz or 120 hz, at normal brightness I don't see lines, but if I dim the brightness somewhat, I see thick moving darker lines, but if I continue to dim below some threshold, I don't see lines. At 70hz or 85hz, there are always lines present. I see moving darker lines that change speed and generally get thicker as the image on the CRT monitor gets dimmer. At normal brightness levels, the lines are thin similar to the images posted earlier. On a very dim setting the darker lines are so thick that the effect is like thin brighter lines. At 70hz / 85 hz, normal brightness: if the camera is horizontal (landscape) I see horizontal lines; if the camera is vertical (portrait), I see angled lines; if the camera is held about 30 degrees counter-clockwise from vertical, I see vertical lines on the camera.

The Note 4 uses a IMX240 EmorRS CMOS sensor.

http://en.wikipedia.org/wiki/Exmor#List_of_Exmor_RS_sensors

The CMOS sensors have an effective scan rate, which causes the artifacts you see with moving objects, or objects like a CRT monitor where the phosphors fade until refreshed by the sweeping beam. This website includes a video animation of the effective scanning across then down rows, comparing CMOS versus CCD sensors.

http://www.popphoto.com/clever-animated-videos-explain-how-cmos-and-ccd-camera-sensors-work

More info:

http://electronics.howstuffworks.com/cameras-photography/digital/question362.htm

http://www.teledynedalsa.com/imaging/knowledge-center/appnotes/ccd-vs-cmos

 

[Vrbic]

The effect is related to the camera. I tested a Note 4 camera with a CRT monitor. The camera is sensitive to refresh rate and brightness. At 60 hz or 120 hz, at normal brightness I don't see lines, but if I dim the brightness somewhat, I see thick moving darker lines, but if I continue to dim below some threshold, I don't see lines. At 70hz or 85hz, there are always lines present. I see moving darker lines that change speed and generally get thicker as the image on the CRT monitor gets dimmer. At normal brightness levels, the lines are thin similar to the images posted earlier. On a very dim setting the darker lines are so thick that the effect is like thin brighter lines. At 70hz / 85 hz, normal brightness: if the camera is horizontal (landscape) I see horizontal lines; if the camera is vertical (portrait), I see angled lines; if the camera is held about 30 degrees counter-clockwise from vertical, I see vertical lines on the camera.

The Note 4 uses a IMX240 EmorRS CMOS sensor.

http://en.wikipedia.org/wiki/Exmor#List_of_Exmor_RS_sensors

The CMOS sensors have an effective scan rate, which causes the artifacts you see with moving objects, or objects like a CRT monitor where the phosphors fade until refreshed by the sweeping beam. This website includes a video animation of the effective scanning across then down rows, comparing CMOS versus CCD sensors.

http://www.popphoto.com/clever-animated-videos-explain-how-cmos-and-ccd-camera-sensors-work

More info:

http://electronics.howstuffworks.com/cameras-photography/digital/question362.htm

http://www.teledynedalsa.com/imaging/knowledge-center/appnotes/ccd-vs-cmos

Great. Thank you, I will study your links :)

 

[newjerseyrunner]

I think you are getting this kind of effect from the refresh rate of the screen.

My guess is that the screen changes in brightness during each refresh for a moment, and the scan-rate of the camera is catching that.

 

[Vrbic]

I think you are getting this kind of effect from the refresh rate of the screen.

My guess is that the screen changes in brightness during each refresh for a moment, and the scan-rate of the camera is catching that.

Could you be more specific please? What is name of this effect. Honestly, I'm not sure what is exactly happening at your picture. Could you send some link with description of this effect or something like that?

 

[f95toli]

The effect is seen in many different systems. A good example would be an old fashioned (mechanical) strobe tuner for a guitar.
See


The "lines" you see is because the two systems (your laptop and your camera) are "out of tune" (not synchronized).

 

[newjerseyrunner]

Could you be more specific please? What is name of this effect. Honestly, I'm not sure what is exactly happening at your picture. Could you send some link with description of this effect or something like that?

Oh damn, I thought I was posting a gif. Here's the source.

https://www.google.com/amp/www.popu...ropellers-look-so-weird-explained-in-one-gif/

 

[Vrbic]

Thank you all! I hope I understand ;-)