Get Photo Abilities

requesttype=0x24

I think this replaces the Get Camera Photo Abilities command. The response block for this command is longer, but contains a similar list of image type names, resolutions, and compression types.

Command: 0x50 bytes

00000000  10 00 00 00 01 02 00 00 00 00 00 00 00 00 00 00  ................
00000010  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000020  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000030  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000040  02 00 00 00 24 00 10 12 10 00 00 00 f0 df e4 00  ....$...........
      

Camera response: 0x474 bytes (EOS 20D)

00000000  34 04 00 00 01 03 00 00 00 00 00 00 00 00 00 00  4...............
00000010  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000020  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000030  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000040  02 00 00 00 24 00 10 22 34 04 00 00 f0 df e4 00  ....$.."4.......
00000050  00 00 00 00 20 04 75 01 00 80 43 61 6e 6f 6e 20  .... .u...Canon 
00000060  45 4f 53 20 32 30 44 00 00 00 00 00 00 00 00 00  EOS 20D.........
00000070  00 00 00 00 00 00 00 00 00 00 07 00 00 00 4c 61  ..............La
00000080  72 67 65 3a 46 69 6e 65 00 00 00 00 00 00 00 00  rge:Fine........
00000090  00 00 20 09 00 00 b0 0d 00 00 02 00 00 00 4c 61  .. ...........La
000000a0  72 67 65 3a 4e 6f 72 6d 61 6c 00 00 00 00 00 00  rge:Normal......
000000b0  00 00 20 09 00 00 b0 0d 00 00 03 00 00 00 4d 69  .. ...........Mi
000000c0  64 64 6c 65 3a 46 69 6e 65 00 00 00 00 00 00 00  ddle:Fine.......
000000d0  00 00 a0 06 00 00 f0 09 00 00 02 00 00 00 4d 69  ..............Mi
000000e0  64 64 6c 65 3a 4e 6f 72 6d 61 6c 00 00 00 00 00  ddle:Normal.....
000000f0  00 00 a0 06 00 00 f0 09 00 00 03 00 00 00 53 6d  ..............Sm
00000100  61 6c 6c 3a 46 69 6e 65 00 00 00 00 00 00 00 00  all:Fine........
00000110  00 00 80 04 00 00 c0 06 00 00 02 00 00 00 53 6d  ..............Sm
00000120  61 6c 6c 3a 4e 6f 72 6d 61 6c 00 00 00 00 00 00  all:Normal......
00000130  00 00 80 04 00 00 c0 06 00 00 03 00 00 00 43 52  ..............CR
00000140  57 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  W...............
00000150  00 00 20 09 00 00 b0 0d 00 00 04 00 00 00 00 00  .. .............
00000160  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000170  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000180  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000190  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000001a0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000001b0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000001c0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000001d0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000001e0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000001f0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000200  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000210  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000220  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000230  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000240  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000250  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000260  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000270  00 00 00 00 00 00 00 00 00 00 00 00 00 00 70 00  ..............p.
00000280  00 00 00 00 00 00 9f 00 00 00 07 00 00 00 0f 00  ................
00000290  00 00 00 80 00 00 00 80 00 00 00 80 00 00 00 80  ................
000002a0  00 00 00 80 0f 00 00 80 00 00 00 80 00 00 00 80  ................
000002b0  00 00 00 80 03 00 00 80 21 00 00 80 00 00 00 80  ........!.......
000002c0  00 00 00 00 00 00 00 80 00 00 00 80 00 00 00 00  ................
000002d0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000002e0  50 00 00 00 01 c0 00 00 01 80 00 00 00 80 0b 00  P...............
000002f0  00 80 00 00 00 80 00 00 00 80 00 00 00 80 00 00  ................
00000300  00 80 00 00 00 a0 00 00 00 80 00 00 00 80 00 00  ................
00000310  00 00 00 00 00 80 00 00 00 80 00 00 00 80 00 00  ................
00000320  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000330  00 80 00 00 00 80 00 00 00 00 00 00 00 00 00 00  ................
00000340  00 80 00 00 00 80 00 00 00 90 00 00 25 a0 00 00  ............%...
00000350  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000360  00 00 00 00 00 00 00 00 00 fc 00 00 00 00 00 00  ................
00000370  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000380  00 80 00 00 00 00 00 00 00 a0 00 00 00 80 00 00  ................
00000390  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000003a0  00 00 00 00 00 00 00 00 00 00 00 00 00 80 00 00  ................
000003b0  00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000003c0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000003d0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000003e0  00 80 00 00 00 80 00 00 00 00 00 00 00 00 13 00  ................
000003f0  00 80 13 00 00 80 00 00 00 00 00 00 00 00 00 00  ................
00000400  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................

00000440  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000450  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000460  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000470  00 00 00 00                                      ....
      

Table 4.4. Fields in photo abilities response

offsetbytesvalue
0x50:4status code
0x54:2?Length of structure (here 0x420=1056)
0x56:2?unknown (here 0x175=373, 2236/6 rounded to nearest integer)
0x58:2unknown (here 0x8000=32,768)
0x5a:32camera identification (ASCII)
0x7a:4Count n-1 where n is the number of entries in image-quality table
0x7e:n*32Table of image quality levels allowed

Each entry in the table seems to be

struct {
  char imageType[20];   /* ASCII name of this image type */
  long imageHeight, imageWidth;
  long compressionType; /* 2:Fine 3:Normal 4:RAW */
} tableEntry;
        

So we can see that the EOS 20D can produce the following image types:

Table 4.5. EOS 20D image formats reported

HeightWidthCompressionName
22363504JPEG fineLarge:Fine
22363504JPEG normalLarge:Normal
16962544JPEG fineMiddle:Fine
16962544JPEG normalMiddle:Normal
11521728JPEG fineSmall:Fine
11521728JPEG normalSmall:Normal
22363504RawCRW

I suspect that the remaining bytes after 0x15d are garbage.