TimeLapse Photography
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2012
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11
pages
Français
Documents
2012
Le téléchargement nécessite un accès à la bibliothèque YouScribe Tout savoir sur nos offres
TimeLapse Photography Time-lapse lets you see the natural progressiotnim oef, while not having to wait through the actual length of it. Pictures are taken at regulara lisn.te rWv hen replayed at normal speed, time appe ars tobe moving faster and thus lapsing. For exam pilme,a gaen of a scene may be captured once every second, and then played back at 25 frames perd .se conThere are some things to keep in mind and caolcnusl atoi be done while setting up a time lapse shoot. • Usually the length of the project changes how ey oguo’ring to shoot it. • Your final movie can end up two ways: blocky oort hs manod seamless. • Usually for a smoother transition you drag youtrt esrh speed when you’re shooting, This will produce some blur and the images would bnle nsdm oither. • Time-lapse compilations are commonly rendered a t o2r 430 (fps) frames (photos) per second. Time-lapse Interval • What do you want to capture and how long is tnhte? eve• How fast is the action taking place? • How long do you want your time-lapse compilati obne ,t oand how long to shoot? • Your interval MUST exceed your exposure time. Ad grouole of thumb is to keep your exposure at about 60% – 80% of your interval teo ygoivur camera enough time to clear the image buffer before the next frame is taken. • Based on how long we want the movie to be wel ccualant ec ahow many shots we would need. For a 20 second timelapse movie at 2 4w ofpusl dw neeed 24 x 20 = 480 frames.
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TimeLapse Photography
Time-lapse lets you see the natural progression of time, while not having to wait through the actual length of it. Pictures are taken at regular intervals. When replayed at normal speed, time appears to be moving faster and thus lapsing. For example, an image of a scene may be captured once every second, and then played back at 25 frames per second.
There are some things to keep in mind and calculations to be done while setting up a time lapse shoot.
·Usually the length of the project changes how you’re going to shoot it. ·Your final movie can end up two ways: blocky or smooth and seamless. ·Usually for a smoother transition you drag your shutter speed when you’re shooting, This will produce some blur and the images would blend in smother. ·Time-lapse compilations are commonly rendered at 24 or 30 (fps) frames (photos) per second.
Time-lapse Interval
·What do you want to capture and how long is the event? ·How fast is the action taking place? ·How long do you want your time-lapse compilation to be, and how long to shoot? ·Your interval MUST exceed your exposure time. A good rule of thumb is to keep your exposure at about 60% – 80% of your interval to give your camera enough time to clear the image buffer before the next frame is taken. ·Based on how long we want the movie to be we can calculate how many shots we would need. For a 20 second timelapse movie at 24 fps we would need 24 x 20 = 480 frames. ·To know how often we need to take a shot (interval between shots) we need to know the duration that our event is going to take. For example if the event is for 4 hours i.e. 14400 seconds then we need a 30 second interval between shots. (14400 / 480). ·Shutter interval time = Total shooting time in hours x 3600 / Movie duration in seconds * Movie frame rate
Some common intervals
o o o o o o o o
Fast moving clouds: 1 second Slow moving clouds: 10 seconds Sun moving across a clear sky: (wide) 20-30 seconds Stars moving across the sky: (wide) between 20-60 seconds Sunsets close up: 1-2 seconds Crowds of people: 1-2 seconds Plants growing eg cucumber vines: 2 minutes Shadows moving across the ground: 10-20 seconds
Camera Settings.
·All standard settings should be set manually Make sure auto focus is off o Manual ISO. Set your ISO to its lowest if shooting in daylight without ND filters. o Manual Exposure o Manual aperture. Deciding upon the aperture setting depends on two things – how o much depth of field do you want and how fast (or slow) you want your shutter speed to be. The latter of these two will probably be your bigger concern in the beginning. Manual Shutter. Shutter speed in time lapse films is a very important factor. If you o shoot with a fast shutter speed (eg. 1/100th second), the movement in your final film will tend to look less realistic than if you shoot at a slower speed (eg. 1/2 second). Manual White Balance. Pick one appropriate for your situation and keep it there for o the entire shoot. Manual Sharpness o Manual Contrast o Manual Color Saturation o It’s important to try and anticipate what is likely to happen to the available light o during the time lapse. If it’s likely to get brighter, then you need to set your initial exposure to be a little darker than you might if taking a single image. If you don’t allow some headroom, and the Sun comes out from behind clouds for example, then the image will become overexposed and you’ll lose detail in the highlights. Likewise if it’s likely to get darker, set your initial exposure to be quite bright (without overexposing, of course). ·Long shutter speeds are the best 1/2 second is the minimum shutter speed o 1 second to 30 second shutter speed are optimal depending on the event o oUse a neutral density filter to achieve low shutter speeds during the day. The increased exposure time will significantly reduce the battery life of the camera, o this is worth considering particularly since a time lapse film may potentially consist of thousands of photos. Roughly speaking, your shutter speed should be just under half that of your interval. o So, for a 3 second interval, a 1.3 second exposure is great. At longer intervals this rule ceases to apply. You may need to get some Neutral density filters (ND filters) so that you can o maintain a longer shutter speed while taking a picture under daylight conditions. ·Use a sturdy tripod lock all tripod latches o sa g your c bration might be an issue oif wind/vindba amera
Tips.
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Slowly zoom in or out at times to create a variation. Pan the camera slowly to bring some movement into the scene.
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Check that your memory card has sufficient free space for your images. Shoot with a battery pack or external power source where possible if you are shooting over a long period of time.
Putting it all together.
Creation of a Time Lapse moving using Freeware tools
Tools used
1) Irfanview 4.30 (http://www.irfanview.com/) 2) VirtualDub-1.10.0 (http://www.virtualdub.org/) a. Donald Graft’s DeFlicker plugin (http://neuron2.net/deflick/flick.html) b. Donald Graft’s Zoom filter (http://neuron2.net/zoom.html) c. Donald Graft’s Pan filter (http://neuron2.net/pan.html) d. Deshaker plugin (http://www.guthspot.se/video/deshaker.htm) 3) XVID Codec (http://www.xvid.org/Downloads.15.0.html) 4) MPEG Streamclip 1.2 (http://www.squared5.com/) 5) QuickTime Alternative 1.81 (http://www.filehippo.com/download_quicktime_alternative/2615) 6) Rename Master (http://www.joejoesoft.com/cms/showpage.php?cid=108)
Preparation, resize and cropping of your images.
To save time resize your photographs to the size you are going to create your video for display. In this example I am creating a video of 1920x1080. This is in the ratio of 16:9. Your images most likely are in the ratio 4:3. We will need to first resize the images tom match the width of 1920 and then crop them to 1920x1080. This means you are going to loose pixels on the top and bottom of your image.
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Select all the images you need to process in Irfanview. Keeping the images selected, click on ‘File’ – ‘Start batch dialog with selected files’
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Select ‘Batch conversion – Rename result files’ Output format is JPG. Use the ‘Options’ button to make changes to the image quality etc. Select ‘Use advanced options (for bulk resize…..) and click on ‘Advanced’. We will first resize the images.
·Click ‘OK’ when done. ·Under ‘Batch rename settings’ and use a name like ‘image-####”, the #### will be replaced by an incremented number. ·Set the ‘Output directory for results files’, to the location you want the resized files to be stored. ·Click on ‘Start Batch’ when ready to start resizing. ·Once complete we will need to crop the images so that they are in the ratio 16:9, to do this follow the previous process except remove the tick from RESIZE and select CROP instead.
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My images were in the format 4:3 so I used 0 for X-pos and 100 for Y-pos, the width and height are 1920x1080. Start left top and click ok.
Reselect the resized images and select a new output folder. Click on ‘Start Batch’ when ready to start cropping. Once this is done you are ready to begin creating your Video.
Creating the Video with VirtualDub
·VirtualDub requires the photos used for a time-lapse be in their own folder and numbered sequentially without gaps between number. ·Open VirtualDub.
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Click on ‘File’ -> ‘Open Video File’ Navigate to your images and select the first image in the sequence.
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Make sure ‘Automatically load linked segments’ is selected and click ‘Open’. Right click on the screen and set the zoom to a convenient setting for your monitor.
·When you do this for the input video and output video, you will see both videos on the screen.
·Next you set the frame rate normally this would be 24fps for PAL.
·Flicker occurs when each frame of a video has a different overall brightness. Click on ‘Video’ and select Filters.
·Select the deflicker filter and accept the default values.
·Select Video..Filters (or ctrl-F) and add... you should have deshaker on the list. When selected, press configure. Basically you make sure the Pass 1 button is selected, close the dialog, reset the play position to the start if it isn't, and and press Play O to run through the pass 1 stage. You'll see a load of dots on the footage as it works out the motion vectors to compensate for. ·You then repeat the excercise by going back into the deshaker filter config, press the Pass 2 button, and Play through again, and this time it deshakes the footage. When it's done you'll see the dramatic difference, and you can save the clip as an AVI. ·Select Video - Compression, If you want to export to QuickTime select uncompressed then Select File – Save as AVI and save your video, then follow the directions in the next step to create the video. ·You can export the video to XVID format, Select Video – Compression and from the list of codecs select XVID MPEG-4 Codec then click on File – Save as AVI to save your video.
Encoding a H.264 video in QuickTime MOV format.
·To create QuickTime MOV video you can use the Squared 5 MPEG Streamclip software combined with KL QuickTime Alternative. Both are freeware. ·Launch MPEG Streamclip and open the video you want to convert.
·Click on ‘File’ – ‘Export to QuickTime…’
·The following screen appears.
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From the Compression dropdown select the H.264 Encoder. Set the quality between 60 to 80% If your video does not contain sound select ‘No Sound’ from the dropdown. Select 24fps for PAL or 30fps for NTSC. Select 1920x1080 (HDTV 1080i) and click ‘Make Movie’ That’s it your movie would soon be encoded.
