Host Mark Bennett has a cold, but still plows on into explaining the functions and effects of apertures, so you'll have to look into that! He looks into the Sigma 100-400mm F5-6.3 DG OS HSM | C lens and finds an admirable performer, sorta regardless of the price, but it's got a really good price! Peter Ensenberger keeps looking to improve our composition skills, Mark suggests you look squinty (a request, not a comment on your looks), and a cluster of quotees look at light from both sides now.