Guide no, 121 specifications – Canon 550 EX User Manual
Page 121
121
Specifications
● Guide No.
[Normal Mode]
(At ISO 100 in meters)
[High-Speed Sync (FP Flash) ]
Flash Coverage (mm)
17
24
28
35
50
70
80
105
Normal (full) Flash Guide No.
15
28
30
36
42
46
50
55
Quick Flash
Same as for manual flash from 1/2 to 1/6.
1/1
15
28
30
36
42
46
50
55
1/2
10.6
19.8
21.2
25.5
29.7
32.5
35.4
38.9
1/4
7.5
14
15
18
21
23
25
27.5
1/8
5.3
9.9
10.6
12.7
14.8
16.3
17.7
19.5
1/16
3.8
7
7.5
9
10.5
11.5
12.5
13.8
1/32
2.7
4.9
5.3
6.4
7.4
8.1
8.8
9.7
1/64
1.9
3.5
3.8
4.5
5.3
5.8
6.3
6.9
1/128
1.4
2.5
2.7
3.2
3.7
4.1
4.4
4.9
Manual Flash Guide No.
Shutter Speed
Flash Coverage (mm)
17
24
28
35
50
70
80
105
1/125
10.6
19.8
21.2
25.2
29.7
32.5
35.4
38.9
1/160
9.4
17.5
18.8
22.5
26.3
28.8
31.3
34.4
1/180
8.8
16.5
17.7
21.2
24.7
27.1
29.5
32.4
1/250
7.5
14.0
15.0
18.0
21.0
23.0
25.0
27.5
1/320
6.6
12.4
13.3
15.9
18.6
20.3
22.1
24.3
1/350
6.3
11.8
12.7
15.2
17.7
19.4
21.1
23.2
1/400
5.9
11.1
11.9
14.2
16.6
18.2
19.8
21.7
1/500
5.3
9.9
10.6
12.7
14.8
16.3
17.7
19.4
1/640
4.7
8.8
9.4
11.3
13.1
14.4
15.6
17.2
1/750
4.3
8.1
8.7
10.4
12.1
13.3
14.4
15.9
1/800
4.2
7.8
8.4
10.1
11.7
12.9
14.0
15.4
1/1000
3.8
7.0
7.5
9.0
10.5
11.5
12.5
13.8
1/1250
3.4
6.3
6.7
8.0
9.4
10.3
11.2
12.3
1/1500
3.1
5.7
6.1
7.3
8.6
9.4
10.2
11.2
1/1600
3.0
5.5
5.9
7.1
8.3
9.1
9.9
10.9
1/2000
2.7
4.9
5.3
6.4
7.4
8.1
8.8
9.7
1/2500
2.4
4.4
4.7
5.7
6.6
7.3
7.9
8.7
1/3000
2.2
4.0
4.3
5.2
6.1
6.6
7.2
7.9
1/3200
2.1
3.9
4.2
5.0
5.9
6.4
7.0
7.7
1/4000
1.9
3.5
3.8
4.5
5.3
5.8
6.3
6.9
1/5000
1.7
3.1
3.4
4.0
4.7
5.1
5.6
6.1
1/6000
1.5
2.9
3.1
3.7
4.3
4.7
5.1
5.6
1/6400
1.5
2.8
3.0
3.6
4.2
4.5
4.9
5.4
1/8000
1.3
2.5
2.7
3.2
3.7
4.1
4.4
4.9
(Multiply by 3.3 to convert to feet)
08. F073-E (99~) 02.4.1 2:16 PM Page 121