Bent Propeller....? - UK Vintage Radio Repair and Restoration Discussion Forum

ms660 · 25th May 2016, 4:23 pm

Why with modern TV's are the propellers bent when showing clips of aircraft?....I've not Googled it yet.

Lawrence.

ukcol · 25th May 2016, 4:32 pm

Because as the picture is scanned in lines, each time the next line is scanned the propeller has rotated a bit further.

With film it's different because the whole scene is taken in each frame, this leads to strobe effects like wheels that rotate backwards when a vehicle is moving forward.

ms660 · 25th May 2016, 4:37 pm

That sounds plausible, wonder why I've only noticed it in relatively recent years.

EDIT: Found this as well:

http://www.discoverdigitalphotograph...asics-shutter/

Lawrence.

paulsherwin · 25th May 2016, 4:44 pm

The effect will vary depending on which cameras are used, how they are set up, how the video is transferred to the studio, what the transmission system is etc.

dseymo1 · 25th May 2016, 4:57 pm

You see a similar effect with stills cameras using a focal plane shutter, hence the cartoon convention of leaning, oval wheels, for instance, to suggest speed.

ms660 · 25th May 2016, 5:02 pm

Electronic rolling shutter...Explanation here, shows a bent propeller in the video:

https://www.thebroadcastbridge.com/c...-camera-part-1

Lawrence.

vidjoman · 25th May 2016, 7:46 pm

Bit like the wagon wheels going backwards in old western films.

25th May 2016, 4:23 pm	#1
ms660 Dekatron Join Date: Apr 2011 Location: Cornwall, UK. Posts: 13,454	Bent Propeller....? Why with modern TV's are the propellers bent when showing clips of aircraft?....I've not Googled it yet. Lawrence.

25th May 2016, 4:32 pm	#2
ukcol Rest in Peace Join Date: May 2003 Location: Harlaxton, Lincolnshire, UK. Posts: 3,944	Re: Bent Propeller....? Because as the picture is scanned in lines, each time the next line is scanned the propeller has rotated a bit further. With film it's different because the whole scene is taken in each frame, this leads to strobe effects like wheels that rotate backwards when a vehicle is moving forward. Last edited by ukcol; 25th May 2016 at 4:33 pm. Reason: spelling

25th May 2016, 4:37 pm	#3
ms660 Dekatron Join Date: Apr 2011 Location: Cornwall, UK. Posts: 13,454	Re: Bent Propeller....? That sounds plausible, wonder why I've only noticed it in relatively recent years. EDIT: Found this as well: http://www.discoverdigitalphotograph...asics-shutter/ Lawrence. Last edited by ms660; 25th May 2016 at 4:43 pm.

25th May 2016, 4:44 pm	#4
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,957	Re: Bent Propeller....? The effect will vary depending on which cameras are used, how they are set up, how the video is transferred to the studio, what the transmission system is etc.

25th May 2016, 4:57 pm	#5
dseymo1 Retired Dormant Member Join Date: Dec 2007 Location: Shropshire, UK. Posts: 3,051	Re: Bent Propeller....? You see a similar effect with stills cameras using a focal plane shutter, hence the cartoon convention of leaning, oval wheels, for instance, to suggest speed.

25th May 2016, 5:02 pm	#6
ms660 Dekatron Join Date: Apr 2011 Location: Cornwall, UK. Posts: 13,454	Re: Bent Propeller....? Electronic rolling shutter...Explanation here, shows a bent propeller in the video: https://www.thebroadcastbridge.com/c...-camera-part-1 Lawrence.

25th May 2016, 7:46 pm	#7
vidjoman Dekatron Join Date: Jun 2013 Location: East Sussex, UK. Posts: 3,326	Re: Bent Propeller....? Bit like the wagon wheels going backwards in old western films.