ATtiny 85 to trigger Canon camera using IR LEDs and laser tripwire

Excellent!

Because there are only 128 steps in the OSCCAL value 1, in the worst case, you call not be able to get better than 1/128*100 = 0.78% 2. The goal is ±1%. Anything better than that is just good luck.

1 Tiny Tuner 2 uses the full range; 256 values.
2 The actual value is a bit lower because the relationship between OSCCAL and the frequency is not linear.