Contents
This information in this post is a bit beyond the normal New To Photography member which is why it has been placed in an appendix.
It is something you should consider as your photography skills progress.
We advised you to use JPEG (JPG) mode while working through the Learning Plan.
But at some point you should change to raw mode; and we don't mean being naked
BTW: raw is a word not an acronym; so even though its done a lot on the Web 'RAW' is incorrect and 'raw' is the correct way to write it.
Every time you squeeze the shutter, your camera takes a picture and saves it in a file.
The file format is either a high-quality JPEG or raw.
JPEG is a lossy format due to the compression algorithms used and that throws away the data that you can’t see in order to
give you smaller file sizes. Raw on the other hand is lossless.
Raw keeps every piece of data your camera captures; even if it is not required.
This results in larger file sizes, and slower time to copy to your memory card.
Raw files have to be converted by special software on your computer and processed in order to be suitable for print or web publishing.
Various brands of cameras have differing raw formats: Pentax = PEF, Nikon = NEF, Canon = CR2 etc.
There is also an industry standard called DNG from Adobe that my K20D and K-7 can use instead of PEF.
Some other brand cameras can also produce DNG.
The native raw files are often smaller then DNG format files.
[hide][top]Why should I use raw format?
There are pros and cons to using either raw or JPEG formats.
Many people choose to shoot in JPEG because it is a universal format that they can be taken right off the cameras and shared via email or published to the Internet.
Raw requires an additional processing step on a computer.
Raw images need to be processed in a program Lightroom or Adobe Camera RAW (Photoshop) or with the software supplied with your camera.
But the two main reasons to use raw are much more creative control (white balance) and more dynamic range (more data bits)! (and you are a control freak aren't you?
)
You are in control of what happens to your image.
You control the white balance see:
Whitebalance, and the #1 reason to use RAW
and a host of other controls over the image being loaded onto your computer.
The raw image file has more data to use (JPEG is an 8 bit format, raw is a 16 bit (usually 12 or 14 effective bits)).
You also have better control of colour space.
Colour Temperature
http://en.wikipedia.org/wiki/Colour_temperature (measured in Kelvins) is sometimes
used loosely to mean "white balance". In practice this means setting your camera so that pictures look natural when
taken under various lighting conditions. You can also obtain interesting effects by varying the colour temperature
setting on your digital camera. Most camera's have an automatic setting that sorts out colour temperature,
but often this automatic setting does not work well with some lighting such as tungsten lights; this is when you should use the manual setting.
Using raw mode and post processing using software like Lightroom and Photoshop lets you get better
control of the white balance, especially for low light work.
Lighting Source |
Kelvins |
Match Flame |
1700 |
Candle Flame |
1850 |
40-Watt Incandescent Tungsten Lamp |
2650 |
75-Watt Incandescent Tungsten Lamp |
2820 |
100-Watt Incandescent Tungsten Lamp |
2865 |
500-Watt Incandescent Tungsten Lamp |
2960 |
Professional Tungsten Photo Lamp |
3200 |
Color Photography Studio Tungsten Lamp |
3350 |
Photoflood or Reflector Flood Lamp |
3400 |
Daylight Blue Photoflood Lamp |
4800 |
Daylight (Sunlight is the light of the sun only. Daylight combines sunlight and skylight.) |
Sunlight: Sunrise of Sunset |
2000 |
Sunlight: One Hour After Sunrise |
3500 |
Sunlight: Early Morning or Late Afternoon |
4300 |
Average Summer Sunlight at Noon in the Mid-latitudes |
5400 |
Direct Mid-Summer Sunlight |
5800 |
Overcast Sky |
6000 |
Daylight Fluorescent Lamp |
6300 |
Average Summer Sunlight (plus blue skylight) |
6500 |
Light Summer Shade |
7100 |
Average Summer Shade |
8000 |
Summer Skylight (varies) |
9500 – 30,000 |
See:
Rick's raw processing tutorial.
[hide][top]When should I start using raw mode?
We suggest you stay in JPEG mode for at least the first half of the learning plan.
So after you have got a good handle on both Av (aperture priority), Depth of Field and Tv (shutter priority) and are starting to
deal with ISO sensitivity is probably a reasonable time to start using raw. If you wait a bit longer it will be no harm and
in fact you may decide never or rarely to use raw - it is up to you.
Raw will give you more control in the Post Processing part of photography; but also a bit more work.
If you take indoor, night or other low light photographs that needs a change to the white balance
then you will need to either use raw mode or manually set the white balance in your camera.
The information in the following schematic diagram explains what is going on inside your camera when you take a photograph and the difference between raw and JPEG images.
The following image shows the primary light paths in a DSLR camera. THe above diagram shows what happens after the light is captured by the sensor.
Cross-section view of SLR system.
1 - Multi-element lens
2 - Reflex mirror
3 - Focal-plane shutter
4 - Sensor
5 - Matte focusing screen
6 - Condenser lens
7 - Pentaprism
8 - Eyepiece