Lesson 3 - Bridge, Raw and Metadata

Lesson 3

Metadata

Two Types of metadata:
1/ The unchangable information that is recorded by the camera
2/ Personal info eg keywords/tags/author

Industry standard of metadata so the data is the same and readable across all programs. It can be editied in programs such as bridge and lightroom.

Importing: Rename - back Up - Add metadata

Raw Files

- All cameras capture raw files
- Camera sensor types = CMOS

- CMOS : Comlementory Metal Oxide Semi Conductor
- CCD : Charged Coupled Device
- Foveon : Multilayer CCD (Not Common)
- 3CCD : Dichroic Prisms (Used in Movie Cameras)

- The sensor consists of photoreceptors (photosite)
- Each photo receptor has a green, red or blue filter
- During each exposure each photoreceptor collects photons
- Photons are converted to an electrical current (analogue) which is proportional to the number of photons
- Electrical current is converted to numeric calue (analogue to digital conversion)
- These brightness values are the RAW image data

What is in the RAW file?

- A brightness value for every photoreceptor (pixel) in the image
- Specification mapping the correct colour (ie. R,G,B) to each photoreceptor
- The pixel dimensions of the image
- Image metadata
- Other camera specific information

Wavelenghts of the following colours:

Red - 620-750 nm
Green - 495-570 nm
Blue - 450-475 nm
Cyan - 476-495 nm
Magenta - 380-450 nm
Yellow - 570-590 nm