What is a good 85mm choice: Sigma or Zeiss?50mm Sigma or sony 1.8?

Hi alla

So i wanna buy the 85mm but sam is too dark , minolta too old ( I whant some warranty ) and the only lenses are the Zeiss and Sigma . I will use it few because i have an a77 and i think 85mm is too long for portraits and my small indoors .

Actually i have 50mm sony 1.8 sam and if i need tele i use 70-200 sigma hsm II but i found it too heavy and fat for little travels.

Question is :what 85mm buy between sigma and zeiss?

Other question is the 50mm .

If i buy the 85mm sigma (700€ vs 1200€ for zeiss) i can buy the 50mm sigma (400€) but i need your help.

Infact Sam is very light and fun but has into lense some dust .I think that my a77 need more quality 50mm so i wanna ask : The sigma 50mm is better than 50mm sony? I will see really difference ?

Last question aboute both sigma: They are compatible with a77 (No AF problem) and a99 (No crop) ?