What should I look to photograph in the future that could help confirm S. vitripennis?

Microscopic details of the microtrichia on the wings; close-up of the eyes to make sure if there are hairs on the eyes; close-up of hind femora to check the colour of hairs at the tip at the anterior surface.
Syrphus vitripennis has the eyes bare but eye hairs are sometimes difficult to see, especially in females. S.vitripennis has the second basal cell clear of microtrichia on the anterior part and anterior tip of hind femur with yellow hairs.
I can`t see any eye hairs but you need good resolution close-up pictures as they can be difficult to see. This is almost certainly Syrphus vitripennis.
S.torvus has hairs on eyes; S.ribesii female has the hind femora yellow/orange, black at extreme base only.
The British Columbia distribution fits too and it is common.

Thanks! Probably too difficult for my photographic abilities (and abilities to sneak up to the insect), but I'll see what I can do in the future.