AlanU wrote in post #18143386
The thing about photography is that everyone has different shooting styles and personal preferences.
I do find that as the noise control gets better at high iso I will change my shooting style. This is regarding keeping high image quality in terrible light before the RAW file falls apart. This is where I would love to have a 5dmk4, Nikon D810 or lower res A7s(mk2)to have clean images before they fall apart. As you can see this has nothing to do with full frame. This totally has to do with maintaining clean images at high iso. It just so happens that the full frame sensor excels in this criteria.
OK.......on the other hand the image quality of the fuji is great! the newer 24mpx sensors just improves noise control even higher in ISO. However I do feel that if your a zoom shooter the full frame f/2.8 zooms can produce excellent IQ as well as more shallow dof (almost like your shooting a prime dof ) heck of alot easier than a crop sensor with f/2.8 zooms. This is where I find some nikon/canon crop shooters just loving the 18-35 sigma f/1.8 for that zoom running and gunning photography.
If your a crop sensor guy be it mirrorless or traditional dslr I think if your a prime shooter you can love shallow dof. With a zoom your going to have less "pop" in your images than a larger sensor format. This is physics and nothing to do with emotional debate.
I recently looked at a wedding album online. The team of photographers used 5dmk3's and 24-70Lmk2 for a large portion of the wedding documentation. I was thinking "wow" considering it was a simple camera/lens combo but the images turned out stellar with "almost" prime like qualities with very good shallow dof.
NOW we are benefiting with the recent technology in crop sensor mirrorless bodies. I fine that a mirrorless system can effortlessly achieve ridiculous sharpness with the simple path of light hitting the sensor without sharing light with the viewfinder/penta-prism in a dslr.
I know when I shot crop sensor only with f/2.8 zooms I though it was an INCREDIBLE treat to use a full frame with f/2.8 zoom in achieving effortless 3d "pop" with zero effort.
Now that I'm using a fuji crop and 80D crop I can see a difference in my casual photos with f/2.8 limitations. This is where I prefer primes with my crop sensor formats.
Since camera's are tools I look at them for specific reasons with no emotional attachments. I grab what I need in the toolbox.........
For paid events photography I'd feel more comfortable with camera capable with extremely high ISO performance to give you the utmost quality in all situations. Yes the 5dmk4 is on my shortlist at the moment but I'll also be buying a X-T2 as well. Comfort zone for me I'd probably still grab the 5dmk4 for those photos where I need to shoot available light and still get incredible high IQ. At this moment my 5d3 is my current tool for high iso.
Everyone has specific reasons to use certain tools. This is where people use tools to achieve exactly what they need to do.
Your f/2.8 zoom point is a good one, imo. The thing I do miss most about using the 6D was having that 24-70 f/2.8ii. Gave me the convenience of not having to switch lenses. For equiv DOF, on APS-C you'd need something like a constant f/1.8 zoom, and for M4/3 you'd need a constant f/1.4 zoom. AFAIK, these do not exist for the mirrorless cameras, and if they did would probably be too big to use satisfactorily with the bodies.
Fuji has the 16-55 f/2.8, and Panasonic has the 12-35 f/2.8, but obviously you lose DOF control and would have to shoot at the same ISO as on the FF camera to get the same exposure, and thus the FF camera will always have the advantage there in terms of performance at the same high ISO.
However, one thing I've noticed in practice is there are diminishing returns as you go higher in ISO. So if I want FF f/2.8 DOF at say 50mm, I could use the Fuji 35mm f/2, or the Panasonic 25mm 1.4. So for same exposure, if I need ISO 6400 on the FF, I could go with 3200 on Fuji, or 1600 on Panasonic. Now I used to think the sensor size compensated for this, meaning I thought ISO 6400 on a FF would look just as good as 3200 on Fuji or 1600 on Micro43. I found though this is not the case. There is not a huge difference in my eyes, but I do find at the higher ISOs (say 1600 and up) images look cleaner using lower ISO even on smaller sensors.