As much as I wish there was a solution to fix spider issues around cameras, there just isn't one solution that works for all. Spiders are just too persistent.

The problem:

Spiders are attracted to the IR light and heat the camera produce, and so are all the insects they eat. 

The solution/Workaround:

The best long term solution is to turn the camera's IRs off and use an external IR that has a little distance between it and the camera. This won't guarantee spiders stay off the camera but should draw them away. Some of the Hikvision cameras with EXIR IR can sometimes have less issues than the bullets and domes with IR surrounding the lens as well. Though there isn't much distance between the lens and IR. 

Other options would be to find a residual surface spider repellent that you can spray all around the camera. We suggest not to spray it on the dome or lens of the camera though.These usually last months and will require to re-spray periodically. A pest control specialist would be a great source to ask for a product you can use. Most spider sprays in the store are not good for this situation. The right product might only need to be sprayed a couple times a year. 

Another thing we hear some people use are Mothballs. They repel insects including ants. But they do smell so keep that in mind. The idea is to just put one or two as close to the camera as possible.