I really love my EA-50s but im having a couple things I want to work on. 1. Low light and 2. auto functions (auto focus,Irris stuff) I have a couple questions1. I noticed the Speed booster is now Ultra I wonder whats the difference between that and the one I bought 3 years ago? I have a sigma 17-50 and it vingettes it looks like the new ones are better? Also I was looking at the Sigma 17-35 I notice they have a MC-11 adapter. Does that give me auto Iris/focus? I notice they have a version Canon to NEX and Sigma to NEX which one would work better?

https://www.bhphotovideo.com/c/product/1264120-REG/sigma_18_35mm_f_1_8_50_100mm.html
https://www.bhphotovideo.com/c/product/967343-REG/sigma_18_35mm_f1_8_dc_hsm.html
https://www.bhphotovideo.com/c/product/1234035-REG/sigma_89s965_mc_11_mount_adapter_for.html



Thanks