If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
Thread Tools | Display Modes |
#1
|
|||
|
|||
"16-bit" mode.
First I thought it was strange when I found out that Photoshop's 16-bit
mode was actually 15-bit. Then, I though it was stranger still when I found out there was one additional level (32768; it was explained that this made certain types of math faster). Now, this evening, I was writing an applet to extract RAW data from the uncompressed output of the DNG converter, and decided to create a raw greyscale bitmap 256*256, containing every possible 16-bit value, to see what PS would do with them. I assumed that PS would make 0 and 1 0, 2 and 3 1, 4 and 5 2, etc, but it does not. This is a sample of what it does: real 16-bit PS values data 0 0 1 0 2 0 3 3 4 3 5 3 6 3 7 3 8 3 9 5 2044 19128 2045 19131 2046 19131 2047 19131 2048 19131 2049 19131 2050 19131 2051 19134 2052 19134 4085 32762 4086 32762 4087 32766 4088 32766 4089 32766 4090 32766 4091 32766 4092 32766 4093 32768 4094 32768 4095 32768 Does anyone have any idea why they posterize the data even more than the 15-bit limitation? This is basically about 13.5 bits of level-resolution. -- John P Sheehy |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Sony Cybershot P100 VX '640x480' movie mode is fake | Mark Elkington | Digital Photography | 17 | November 2nd 04 01:24 AM |
What's the D300's "Close-up mode" for? | Darryl | Digital Photography | 10 | September 23rd 04 05:11 PM |
Q-Confused about which picture record mode to use in a digital camera. | Mr. Rather B. Beachen | Digital Photography | 1 | July 13th 04 01:50 AM |
What image quality mode to use? | Mr. Rather B. Beachen | Digital Photography | 2 | July 13th 04 01:21 AM |
wireless 550EX in manual mode with 420EX | danny | Other Photographic Equipment | 1 | February 15th 04 03:35 PM |