void msm_start(void) {
if (status.msm_count > 0) {
status.msm_active = TRUE;
tv_t tv = ev_normalize(status.msm_tv / status.msm_count);
av_t av = ev_normalize(status.msm_av / status.msm_count);
av_t av_max = DPData.ef_lens_exist ? DPData.avmax : AV_MAX;
av_t av_min = DPData.ef_lens_exist ? DPData.avo : AV_MIN;
msm_ae_return = DPData.ae;
send_to_intercom(IC_SET_AE, AE_MODE_M);
msm_tv_return = DPData.tv_val;
msm_av_return = DPData.av_val;
send_to_intercom(IC_SET_TV_VAL, CLAMP(tv, TV_MIN, TV_MAX));
send_to_intercom(IC_SET_AV_VAL, CLAMP(av, av_min, av_max));
enqueue_action(beep);
}
}
void qexp(void) {
int weight;
ec_t diff, ec_tmp;
av_t av = status.measured_av;
tv_t tv = status.measured_tv;
ec_t ec = status.measured_ec;
av_t av_max = DPData.ef_lens_exist ? DPData.avmax : AV_MAX;
av_t av_min = DPData.ef_lens_exist ? DPData.avo : AV_MIN;
if (status.measuring) {
// Set lens to maximum aperture
diff = av_min - av;
av += diff;
ec -= diff;
// Set shutter to 1/60
diff = settings.qexp_mintv - tv;
tv += diff;
ec -= diff;
// If under-exposing, increase shutter speed
if (ec < 0) {
diff = MAX(tv + ec, TV_MIN) - tv;
tv += diff;
ec -= diff;
}
// If over-exposing, split the blame
if (ec > 0) {
ec_tmp = ec;
switch (settings.qexp_weight) {
default:
case QEXP_WEIGHT_NONE: weight = 2; break;
case QEXP_WEIGHT_AV : weight = 3; break;
case QEXP_WEIGHT_TV : weight = 1; break;
}
diff = MIN(av + weight * ec_tmp / 4, av_max) - av;
av += diff;
ec -= diff;
weight = 3 - weight;
diff = MIN(tv + weight * ec_tmp / 4, TV_MAX) - tv;
tv += diff;
ec -= diff;
}
// If still over-exposing, one of Av / Tv reached a maximum
if (ec > 0) {
diff = MIN(tv + ec, TV_MAX) - tv;
tv += diff;
ec -= diff;
diff = MIN(av + ec, av_max) - av;
av += diff;
ec -= diff;
}
send_to_intercom(IC_SET_AV_VAL, ev_normalize(av));
send_to_intercom(IC_SET_TV_VAL, ev_normalize(tv));
enqueue_action(beep);
}
}
tv_t tv_sub(tv_t ying, tv_t yang) {
tv_t tv = ev_normalize(ying - yang);
return MAX(tv, TV_MIN); // 30s
}
tv_t tv_add(tv_t ying, tv_t yang) {
tv_t tv = ev_normalize(ying + yang);
return MIN(tv, TV_MAX); // 1/4000s
}
av_t av_sub(av_t ying, av_t yang) {
av_t av = ev_normalize(ying - yang);
av_t min = DPData.ef_lens_exist ? DPData.avo : AV_MIN;
return MAX(av, min);
}
av_t av_add(av_t ying, av_t yang) {
av_t av = ev_normalize(ying + yang);
av_t max = DPData.ef_lens_exist ? DPData.avmax : AV_MAX;
return MIN(av, max);
}