Taking Videos At Concerts: how can I improve the clarity and zoom and are there any zoom lenses that would improve my results?

[Loopylumia]

Taking Videos At Concerts, Please Help

Hi,
I'm new to the forum and would really appreciate some help please.

We like to go to concerts, but due to disabilities are often seated in the disabled seating way back from the stage and the distance can vary quite a bit from venue to venue. I like to capture the whole concert and then my partner edits it all together on a macbook. My partner gets really stressed attending concerts, but having our own home movies to play back later is brilliant and it helps to create only positive memories and is something to help us through difficult times . We don't share them on youtube or any other sites.

I love my 1020 and it was chosen for the camera, in fact I use it for little else other than using it to text and make calls or surf the net. I don't do apps or social media as such.

Since getting my 1020 last June and losing Pro cam to Lumia cam I'm sure the results have suffered. The zoom and clarity don't seem as good and whilst taking a video the focus fluctuates for no apparent reason. I have both the camera grip and the nokia portable charger.

So my questions are,

How can I overcome the focus problem and are there any tips to improve the clarity and zoom ?

Are there any zoom lenses that would improve my results without spending too much ?

Do you have any general tips ?

Thanks to all who respond. I really want to get the best from this camera.