8Bit or 16

[alpine62uk]

Could someone please explain to me how to take atvantage of the 16 bit format my shots come in RAW.

Once in PS I can only do some alteration whilst in 16bit mode and have to change to 8bit before I can save a Jpeg.

I understand that 16 bit has more info but clueless as to how to take advantage of it

Thanks

[Jesper]

Here are some links:

The High-Bit Advantage (http://www.creativepro.com/story/feature/7627.html)
Tonal quality and dynamic range in digital cameras (http://www.normankoren.com/digital_tonality.html)

Your camera records images with 12 bits per channel (red, green and blue). That means the camera is able to record 2^12 = 4096 different light intensity levels for each channel. So for all the three channels that's 3 x 12 = 36 bits per pixel, which means your camera can record 2^36 = 68,719,476,736 different colours.

The JPEG file format is limited to 8 bits per channel, or 3 x 8 = 24 bits per pixel, 2^24 = 16,777,216 different colours. So if you use JPEG or any other format limited to 8 bits per channel, you've already thrown away some of the information that the camera recorded.

In RAW mode, all the information that the sensor records (all the 12 bits per channel, not just 8) is stored. In your RAW conversion software, you can convert the RAW file to a standard file format such as TIFF. The TIFF format does not support 12 bits per channel directly, but it does support 16 bits per channel. So you convert your RAW image to a 16 bit per channel TIFF file (in which the lower 4 bits for each channel are not used).

So the main benefit is that it enables you to use ALL of the information, the full 12 bits per channel, and not just 8 bits.

Note that (practically) all output devices (monitors and printers) can only display 8 bits per channel. That means that when you work with 16 bit per channel images in Photoshop for example, they will look exactly the same as 8 bit per channel images. You will not suddenly see more or better colours.

The benefit is in the editing: you can for example stretch the contrast of a 16 bit per channel much more than that of an 8 bit per channel image without getting strange effects such as banding.

If you're not going to do much editing on your images, and you're going to print your images more or less straight out of the camera, there's little advantage in using 16 bits per channel. But if you're going to do a lot of editing it has its advantages.

A disadvantage is that the image files will get at least twice as large and that you also need a lot of memory in your computer.

[cmar]

Shoot raw, adjust levels and color while in 16bit mode, then convert to 8 bit to do the rest of the adjustments.
That is one of the big advantages of PS 7 or above, increases support for 16bit files

[ecobo]

Shoot raw, adjust levels and color while in 16bit mode, then convert to 8 bit to do the rest of the adjustments.
That is one of the big advantages of PS 7 or above, increases support for 16bit files

The shortest and the most complete explanation I've ever read about 8/16 bit color modes! Congrats CMAR!!!