Opening in the lens Aperture fnumber or stop focal lengthAperture diameter Each stop represents either half or double the amount of light exposing the film or chip The circle of confusion is defined as the largest blur spot that is indistinguishable from the point source that is being rend ID: 245988
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Aperture
Opening in the lensAperturef-number or stop= focal length/Aperture diameterEach stop represents either half or double the amount of light exposing the film or chipSlide2Slide3
The circle of confusion is defined as the largest blur spot that is indistinguishable from the point source that is being rendered.
Stated more simply, it is the limit at which we start noticing that things are getting blurry. Based on this definition, the circle of confusion should more appropriately be called the circle of “maximum” confusion (or “least” confusion if you are a glass half full person).Slide4
Where to Focus
If you are focused on a subject you will have roughly twice as much depth of field behind the subject than in front of it
A rule of thumb when shooting is to focus on the subject one third the distance from the closer to the farther object
w
here to focus Slide5
Exposure Range/Contrast Range
Our eyes adjust to scenes way better than video In video you have to either choose between detail in the shadows or detail in the highlight areaVideo anywhere between 5 to 45 stops of contrast range Slide6
GAMMA SETTING
Was used to compensate for the difference between a CRT monitors which were incapable of linear image reproduction—in which output brightness was directly proportional to input signal level. Gamma was needed so that shadow areas wouldn’t be too dark and bright areas wouldn’t wash outThis isn’t necessary with digital monitors
Gamma curves can be used to capture a greater range of scene brightness than was possible in analogSlide7
Gamma
In photography and motion picture film gamma is a number that expresses the contrast of a recorded image as compared to an actual scene1:1 contrast would be if the scene was re-created perfectly .55:1 Motion Picture Negative2:1 is the final projection—twice what is seen in nature
In video gamma can be used as a creative tool to capture a greater range of a scene High gamma setting: Can compress and stretch the blacksLow gamma setting can create a super high contrast imageSlide8
Contrast: Gamma Slide9
Adjusting the kneeSlide10
HistogramSlide11Slide12
Waveform Monitor Slide13
Reflective vs. Incident Light Meter Slide14Slide15
Gray Card Slide16Slide17
Pixels and Resolution
The digital video frame is made up of a lattice or grid of pixelsHD Formats have a higher resolution (more pixels)Our ability to judge resolution is related to how large the image appearsHow big is the screen? From how far away are you viewing it?In most living room viewing conditions consumers can’t always see the difference between 1080p and 720p
In theatrical distribution it is debatable whether audiences can see a difference between 1080p 2k about 2048X1080 and 1080p 4k 4096X2160. This depends on the screen size and the audience member’s distance from the screen Slide18
Bit Depth
Resolution can be improved by measuring the brightness of each pixel more precisely Eight bit systems can distinguish between 256 different brightness values for each pixel256 shades of red, green and blue—millions of colors16 bit systems yield 65,536 gradations of each color. The more gradations, the finer the detail.
Greater bit depth allows better color correction and the ability to recover shadow and highlight detail. Slide19
Resolution and Sharpness
The resolution of a video image refers to its ability to reproduce fine detail. Often this allows an image to look sharp to the eye.Slide20
Still image and Video
DPI or PPI (dots per inch and pixels per inch) refer to the size of a single digital image. This is irrelevant in Video. The numbers in video only refer to the dimensions. 1,024 × 576 pixels | 1,280 × 720 pixels.
Full resolution (1,920 × 1,080 pixelsSlide21
Different formats
Quicktime: Apple MPEG-4: container file format from Quicktime. H.264Windows Media: Microsoft container format
MXF: Material Exchange Format: Used in cameras and editing systemsAAF and OMF: Advanced Authoring Format: open exchange between different applications or systems
XML Interchange format: a tool used to describe data using plain text, so that it can be transferred from one NLE to another
DPX: Digital Picture exchange is a nonproprietary container file for uncompressed images Slide22
Data Exchange
A digital movie file is made up of video audio and metadata packaged inside a container or wrapper The video may be uncompressed or compressed with one of many possible codecs H.264, DV, DVCPRO, HDSlide23
Artifacts
A compression artifact (or artefact) is a noticeable distortion of media (including images, audio, and video) caused by the application of
lossy data compression.Slide24
What is Moiré
Moiré pattern occurs when a scene or an object that is being photographed contains repetitive details (such as lines, dots, etc) that exceed the sensor resolution. As a result, the camera produces a strange-looking wavy pattern as seen
Read more: http://photographylife.com/what-is-moire#ixzz2hFKzfPFsLooks like vibrating of the actual image
A mathematical error that occurs when you are down sampling—not using all of the sensorSlide25
Compression
intraframe: Compressing within a frame: DCT: discrete cosine transform or waveletInterframe: compresses several frames in a groupSlide26
Constant and Variable Bit Rates
CBRVBR: efficient data It provides more data when you need it and less when you don’t. This can result in fewer artifacts and smaller file sizes. Slide27Slide28Slide29Slide30Slide31Slide32Slide33Slide34Slide35Slide36Slide37Slide38Slide39