Commons:Featured picture candidates/File:Strip photo of San Francisco Cable Car 10.jpg

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File:Strip photo of San Francisco Cable Car 10.jpg, featured[edit]

Voting period is over. Please don't add any new votes.Voting period ends on 15 Aug 2017 at 06:28:54 (UTC)
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Strip photo of San Francisco Cable Car 10
  • There is some slight colour fringing because the line scan camera I'm using actually has two lines, one with alternating red and green pixels and one with alternating green and blue pixels. It is possible to digitally correct for this offset, but I haven't implemented this yet since this is my first day shooting with this camera. Perhaps in the next few weeks I will write a program to do it. In any case, the effect is very minor in this photo. Another limitation of this technique is that this is essentially a high speed camera; each column of pixels has a very short exposure time. As such, the photo may be slightly noisy. dllu (t,c) 07:17, 6 August 2017 (UTC)[reply]
  •  Comment - Thanks. The effect doesn't seem minor to me, but the composition is good, and I may after deliberation vote for this photo on the basis of the composition and pure novelty. -- Ikan Kekek (talk) 08:38, 6 August 2017 (UTC)[reply]
  • The best way to understand how strip photography works is to imagine that you are standing with your camera in a fixed position behind a door that is only open a very small crack. You rapidly take photos of what you can see through the crack from that point of view. At first nothing happens so your photos will all be a very thin vertical line that looks the same in each frame. Then something, a streetcar, passes by the crack and you get a small piece of the vehicle in each of your photos. When it has passed by the opening, the scene may go back to what it was before and once again all the photos you take of the crack will look the same. After shooting this sequence, you take all the photos and crop away all the black around the crack in the doorway, leaving you with lots of photos of just the crack and you paste them side by side in chronological order. As you do this a photo of the streetcar as it passed the crack will start to appear. If you were taking photos at the same time-interval during the shooting session and the car moved at a constant speed, you'd end up with a photo like the one here. Imagine if the car had slowed down, then you would have got more photos with it in the crack towards the end of the session and the back of it would have been sort of "drawn out". And if it had stopped in front of the crack all your photos until the end of the session would have had a bit of streetcar in them that looked the same until the end. Now this is done with a special camera that shoots only a slit that is two pixels wide and the photos are taken in an automatic fashion to make sure the time between shots is the same and the shots are merged into a photo with software, but the principle is the same as photographing through a crack in the doorway.
All this said, it would be very useful if the creator of this photo could mention in the description on the file's page, what camera and/or gadgets plus software (and the usual facts about camera settings) were use to make this photo since there is no EXIF on this photo. --cart-Talk 15:39, 6 August 2017 (UTC)[reply]
  •  Follow up question out of sheer curiosity: After looking very carefully at the photo, I noticed that the lines on the right side of the streetcar are a bit wobbly. Is this the ground shaking from the passing streetcar or did you accidentally record a small earthquake? Or is it just heat turbulence in the air after the car? --cart-Talk 22:06, 6 August 2017 (UTC)[reply]
  • @PumpkinSky: Yes, strip photography is often used for photo finishes. It is different from panning though. Most regular video cameras don't have sufficient framerate for this type of photo. For example, most video cameras do 24 to 60 frames per second whereas this type of photo requires around 2000 frames per second (the fast-moving cable car took only a few seconds to pass by). Prior to digital line scan cameras, this type of photo was made using a film slit scan camera, such as [1], for which it's possible to use a wider slit as long as you move the film to match the speed of the subject exactly. dllu (t,c) 21:41, 7 August 2017 (UTC)[reply]

* Support by all means --Martin Falbisoner (talk) 06:55, 7 August 2017 (UTC)[reply]

Confirmed results:
Result: 24 support, 0 oppose, 0 neutral → featured. /PumpkinSky talk 23:40, 12 August 2017 (UTC)[reply]
This image will be added to the FP gallery: Objects/Vehicles/Land vehicles#Rail vehicles
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