I've searched for this problem but little seems to have come up for a specific answer, so I wondered if anyone could help me here. After doing my first test render I noticed horrendous noise in my photon illumination, in the Brazil tutorials on Global Photon And Regathering tutorial the example has the same problem but it corrected by 'undersampling'. But what exactly is undersampled?
If I set the QMC quality to say -4, -4 then there's barely any difference and then if I change Image Sampling to say -3, -2; then as you would expect I start losing details everywhere. Any suggestions? Thanks in advance.