Buy lens with fix aperture & stay clear from the sliding one. Ex:f3.5-5.6 Sigma 24-70 f2.8 macro Tamron 28-75 f2.8 Tamron 17-50 f2.8 no vc Tokina 11-16 f2.8 Canon 17-40 f4L Canon 70-200 f4 Canon 70-200 f2.8 L Canon 85 f1.8 Canon 135 f2 Canon 50 f1.8 or f1.4.
If you're talking Canon and can afford it, the 70-200f4L IS is a must have. If that's out of your reach I recommend you look at the Canon 85f1.8. Great for portraits even on a crop and an excellent medium telephoto lens. I have both.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.