[Concerned about moving from DSLR to Fuji again!]

I use a Fujifilm XT20. I love it! It is light, silent (with focus beep turned off and electronic shutter) and fun to use with the different dials. AF is good, photos are good. I really just enjoy using it a lot!

 

I also use a Canon 5D Mark IV. I also love that one. The low light performance is better. The dynamic range is better. Granted this could just be a matter of my opinion, but I like the images and the sharpness produced from this one better.

But it is heavy, cumbersome, and not nearly as fun to carry or use.

 

 

I have and love both for different reasons. I use both for different reasons. 

[xt20 Bulb Mode only takes for 1 second]

That's pretty much my question there.... If I set my XT20 on bulb mode it will appear at the bottom of the display as 1" and then if I press and hold the shutter button down there will be a counter that goes from 1 to 0 and then the exposure stops. 

[Samyang 12mm F2.0 NCS CS X Mount]

I'm very close to getting this lens. Has anyone ever used filter step up rings with it? I currently have 77mm filters. How bad would vignetting be with a 63 to 77mm step up ring?