Re: A7s or GH4 - which for you?
 

I use the olympus 12mm f2.0 for my wide shots, works well and if I want fish eye wide I use a 7,5mm rokinon lens.

Re: A7s or GH4 - which for you?
 

12mm on M4/3 is 24mm.

Re: A7s or GH4 - which for you?
 

Is that not wide enough for you?

Re: A7s or GH4 - which for you?
 

12mm is indeed a decent wide, using a tight bedroom as your example concern, if it's that tight than adding just a few watts of extra light would solve that issue along with the 7-14 or other ultrawide of your choice.

Available samples aside, you just have to wait till it's in the wild to see what it's fully capable of. those photosites are twice the size of the average full frame camera these days, so yea, 50,000iso may very well be the new 6400iso, or even better. the rx10 i see as being on par or a smidge better in lowlight than the 5d2, huge difference in size and yet the significantly newer tech shows its strength. always fun to see what the latest tech will do.

And i'm in the same boat wedding/event wise, there are plenty of times i struggled with available light(hate the on camera light look), and cringed the few times i pushed 6400 on the 5d2, with the c100 i put a lot of 12,800 to use to get some manageable DOF. With the a7s, it might be the first camera you can achieve short distance hyperfocal with in unreasonable light :)

Re: A7s or GH4 - which for you?
 

How experienced are you with full frame cameras? Have you owned/used one quite a bit so far?

Re: A7s or GH4 - which for you?
 

Sometimes it isnt really. I suppose I'm also at fault for not getting one of those 12mm 2.0's leaving me limited to my 14 2.5, which again just doesn't cut it for me sometimes. I work around it and all, but sometimes I wish I had a bit more options. I then quickly remember that my equipment cost a 1/4th of my associates canon stuff.

Ive toyed around a bit with a friend of mines 5d. If the FF route wasn't so much more expensive I'd have probably went that way from the get go.
The affordability really pushed me into m4/3, my wedding work isn't full time (haven't made it that big yet). I'd like it to be. Heck I'd like a FS700 and a bunch of other gear if I could! :)

Re: A7s or GH4 - which for you?
 

I have worked with aps-c sensor camera before and there a 14mm was sufficient for my needs but once I invested into m4/3 I too saw the 14mm f2.5 was not wide enough so I do understand where you are coming from. :)

I now have a olympus 12mm f2.0 and that one is just ok for my wide angle needs, Olympus will be working on a 7-14mm f2.8 coming for m4/3 and I guess it will be a expensive one but maybe worth the wait and investement, I have read that it will be released in 2015.

Re: A7s or GH4 - which for you?
 

I used the Panasonic 7-14mm lens when I had my GH2 & it is a really great wide angle lens(14-28mm FF equivalent). The F/4 maximum aperture wouldn't be such a limitation on the OM-D, G6, GH3 or GH4 which all have better low light capability than the GH2.

Re: A7s or GH4 - which for you?
 

I fail to see why you are thinking in Full Frame terms then, when your experience with full frame is very limited. Are you sure 12mm for a normal sized room is not wide enough?

Re: A7s or GH4 - which for you?
 

Ive watched quite a few videos shot by people online in which they breakdown and explain their lens choices for given moments, so it gives me an idea. That said, I do realize I lack experience so who knows for certain.

Re: A7s or GH4 - which for you?
 

Do you really need experience with full frame? a gh3 has a 2x crop compared to full frame, so a 12mm is a 24mm on full frame, you just multiply by 2 to have a reference. Fact is that you can go much wider on a full frame and have faster lenses available. Eventhough 12mm on m4/3 is wide enough for me for most purposes I have had occasions where I wished I had the 7-14mm on my gh3, I only find the f4 a bit too slow, I will see what the Olympus 7-14 f2.8 will cost but if it's not too expensive that lens will be on my wishlist.

Re: A7s or GH4 - which for you?
 

Not a lot of affordable f0.95 lenses for full frame, last I checked.

I've had very good luck using a SpeedBooster with the Tokina 11-16/2.8 and Sigma 10-20/3.5 UWA zooms on MFT... that yields very useable ~8-12/2 and 7-14/2.5 lenses (not to mention other good options). That they become manual focus only doesn't bother me with a UWA, just set it hyperfocal and go.

Re: A7s or GH4 - which for you?
 

Not sure if this lens is for full frame but in order to get the same field of view of a Sigma 20mm f/1.8 would require a 10mm f1.8 for the same field of view on m4/3, can you use this len swith a speedbooster and how much would you gain? Also, would this lens on a canon or panasonic camera with speedbooster retain it's autofocus functionality?

Re: A7s or GH4 - which for you?
 

tokina 11-16 and speedbooster, best solution.

Re: A7s or GH4 - which for you?
 

Unless you happen to like your image quality. Focal reducers are not new, and yet they haven't come into wide use. Also, there is no such thing as a free lunch. So test it first. I have used one on an FS700 and did not like the results at all.