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The article mentions that this is true of cheaper digital cameras, but in fact SLRs have a similar effect. At high shutter speeds, the back curtain closes short
by teilo 17y ago
The article mentions that this is true of cheaper digital cameras, but in fact SLRs have a similar effect. At high shutter speeds, the back curtain closes shortly after the front curtain opens, causing the exposure to happen as a slit of light that passes across the sensor or film.
- rimantas 17y agoActually I am not sure you can get this effect on cheap camera. Which cheap camera uses curtain shutter? And I would be extremely surprised to see that kind of shutter on the cameraphone.
- zefhous 17y agoThat was taken on an iPhone. It happens in camera phones not because of a physical shutter, but because the entire frame isn't captured at once.
- thmz 17y agoTrue, I think it has something to do with the burst mode used in most sensors. The sensor will transmit the picture, but the iPhone is not ready to process all of it. So the next burst is processed later but is used for the same image.
- Terretta 17y agoTwo examples of deliberately abusing this effect on a static subject (house and church) by pivoting the iphone while taking the shot: http://farm4.static.flickr.com/3158/2421813332_3c36b3b808.jpg http://farm4.static.flickr.com/3158/2421813332_3c36b3b808.jp... http://farm4.static.flickr.com/3187/2421813434_dbdc309901_b.jpg http://farm4.static.flickr.com/3187/2421813434_dbdc309901_b....
- teilo 17y agoThere are two different effects here. One, as in the iPhone and all similar devices, is a scanning phenomenon caused by the fact that cheap or very small sensors are usually CCDs. Since such cameras do not actually have real shutters, the equivalent effect of a shutter is achieved by delaying the time that each line is exposed and read. Because cheap CCDs do not have multiple channels, the lines are read one at a time in sequence. The maximum speed that the lines may be read sequentially is the maximum "shutter speed" of the camera. The other is the traditional curtain shutter of an SLR. Even a high-end CMOS multi-channel sensor will still see a slit of light on any speed upwards of 250, even though the data is not necessarily read a line at a time. Thus, whereas the sensor in an SLR is exposed via a slit of light at higher shutter speeds, cheaper non-SLR cameras are always exposed one line at a time. Thus this effect is more likely to be seen on a camera phone than on an SLR.
- defdac 17y agoAs a sidenote this only happens with faster shutter speeds than about 1/250 sec, which also happens to explain why "high speed synchronization" of flashes is needed and visualized here: http://webs.lanset.com/rcochran/flash/hss.html http://webs.lanset.com/rcochran/flash/hss.html