Pansonic Lumix G7 -Adapter Ring Question (To Use My Canon EF-S Lenses)

Are your referring to the Sigma 10-20 f/4-5.6 lens?

If so, I might rather prefer to spend some US$100 (a brand new de-kit lens) for a 12-32 f/3.5-5.6 pancake lens for the excellent AF speed, ultra light weight (67~70g depending on your version), compactness (24mm in length) and quite good IQ.

It has IQ very compatible to 14-42 (assume you have the Mk-II version), wider start of 12 instead of 14 (the 32mm vs 42mm is of no material meaning IMHO, but quite significant on the 2mm different on the wide end), and much more compact. The only draw back, no focus ring for MF. BTE the accurate AF of Pany camera making MF fine tuning be rarely needed.

Trade in the 14-42 (if possible, should in the same money as 12-32) and replace it with a 12-32 can hardly go wrong (at least to me).

I always do not think it is worth to spend the extra money (more than US$100) for a focal reducer. As the particular Sigma lens concerned does not have an aperture control ring, you at least have to spend some more money (than a cheap dummy adapter) for a smart adapter, plus the extra weight of the adapter itself... It would only be an advisable option if you have some very expensive L lenses.

My 2 cents.

Ok so you're bsically saying its better to go with fresh lenses for my LUMIX G7.

My G7 application is only video usage. My only requirement is to go wider to cover interiors of rooms properly. Say a 10x10 room from the room corner.

I think ill need at 7mm on this M43 camera ? because i understand even though its 7mm, on this DSLM it will give a me only a same FOV as my Sigma @10mm gives on my Canon 550d.

I only use my trusty old 550d for photography (Because already invested a little in lenses / attachments / multiple flashes for strobist work / flash triggers etc).