10x42 anything smaller than 40mm kinda stinks in low light.
Yes to a POINT. The point being, if you raise the power too much you end up defeating the larger objective lens' ability to transmit light. It all goes back to the ratio of objective lens size to power. A 10 x 42 is really not muchbetter than an 8 x 32. A 7 or 8 X 40 transmits much more light.