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Reference Manual ATOM one SSM500
16.2 aec_weight <index> <weight>
By default the AEC uses an optimized algorithm to determine the needed exposure which
also takes into account back light lighting conditions. This algorithm should work fine for
most use cases, but some might require manually tweaking the auto exposure. To do this
use the aec command and set the “useCustomWeights” flag (see chapter 16.1 for more
details).
Value
Minimal
Maximal
Description
index
1
25
Index of the field which weight shall be changed
weight
1
25
Weight of the field at the given index
In custom mode the auto exposure uses a 5x5 grid which is equally split across the image.
In each field of the grid the average brightness is measured. For each field a weight can
be specified, which determines how strong the average brightness of this field is taken into
account by the auto exposure algorithm.
The following table shows the index of each field of the grid:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
By default all fields are weighted equally (with a factor of 1). If, for an example, the top-
right corner of the image is the most important part of the currently filmed scene, but it is
over- or underexposed with the default setting, a solution is to increase the weight of the
fields 4,5, 9 and 10 to a higher value, e.g. 5:
aec_weight 4 5
aec_weight 5 5
aec_weight 9 5
aec_weight 10 5
This will take the average brightness of those fields more into account, leading to this
parts being correctly exposed, at the cost that the rest of the image will not be perfectly
exposed.
16.3 stat_ae
Dump auto exposure statistics
Example:
