Hello
P
Bestflowers
It's nice to have a new member of the forum. Welcome.
As for your photo... there's room for improvement. Especially in terms of the sharpness of the image. As you took the photo at ISO 160 and it shows very visible grain, I assume you've done a big crop. A slightly smaller fly on the screen wouldn't be bad either...
As for the sharpness itself, there are two possibilities. Weren't you just a little bit closer than the minimum focusing distance of your zoom? Also, for macro / proxi photography, it's rarely a good idea to work in autofocus. The best solution is often to use manual focus. Do a coarse focus with the focus ring, then leave it untouched. Then focus finely by moving your chest slightly forwards or backwards.
I also frequently take photos of insects with a 300mm f/4 L IS. Mostly dragonflies. To be able to get as close as one metre, I often use extension rings and more recently a NISI close-up lens.
This forum is the right place for you to make rapid progress. I look forward to your next photos.