Canon, Nikon or Sony..etc

Canon and Nikon both have great lens options...Sony less so.  Nikon lenses can be adapted to Canon bodies but Canon lenses can't be adapted to Nikon.  Well you can with an adapter that has another lens in it, which would be much like using a teleconverter.  If you were adapting Nikon to a Canon body, there's no added lens, just an added spacer.  You won't want to go the Canon lens to Nikon body route. 

Other Lens Makers

There are several lens makers that make them for other cameras.  Sigma, Samyang and Zeiss for instance make lenses made for different camera brands, without using an adapter.  Many of these are better than the Nikon or Canon focal range equivalent.  For my Canon 6D I have 2 Samyangs, 2 Canons and 1 Sigma.  I've had a Zeiss in the past. 

Sony Sensors Rule...Nikon Uses Them

Sony's sensors dominate Canon's when it comes to dynamic range and shadow noise when boosted.  It is truly silly what they can do that Canon cannot.  But the situations where you'd need it or see it is extremely small.

The crux of this topic is largely here right now.  If you shoot a sunset for instance and keep the Sun very much in check, your shadows will be rather smashed near black.  Once you lifted such shadows in post-processing, the Sony sensors will simply do things the Canons can't dream of.  And most of Nikon's bodies are using them now. 

This said, I haven't jumped to Nikon yet.  My Canon 6D produces amazing images.  The shadow banding potential is far less than it was on the Canon 5D II I had before.  Most of the examples of the Sony sensors doing voodoo magic compared to the Canon is when pushed like 5 stops.  Which is very very excessive. But it is voodoo magic what it can do and so impressive.  It is hard not to want access to that.  Especially so if you shoot mostly dynamic scenes and don't want to mess with multiple exposures.  Really no need on the Sony's.  Keep the highlights in check then open the magic shadows. 

If I was starting off new right now I would want a Sony sensor in my camera.  Sort of like more megapixels.  Very few reasons to need them, but we all figure why not.

Autofocus

I never use autofocus. The rare times I need it the center point on my 6D works fine for me.  Some are just better in low light than others.  You have to pay more to get systems that are more capable at tracking focus, often while blazing out super fast frames per second.  If you don't require that you can simply get by with base systems.  If you are just shooting landscapes then using live view 10x and doing it manually just makes more sense.  And in that case you really don't have need for expensive beefed up cameras geared towards fast frame rates and crazy tracking autofocus abilities. 

One thing you might consider is the ability to do microfocus adjustments.  Not all bodies will have that.  A body and lens combination might be back or front focusing, that is focusing too far out or too close in from where you have the focus point.  This feature lets you set offsets so those hit more right on.  The camera makers are sticking this in more and more bodies now.  Even for the casual bird shooter like myself, that feature could would actually be rather dang useful.  Could make the difference between consistently off and consistently on.

Under $1,000

My Pick: Nikon D5300

24 megapixels, 5 frames per second, 39 focus points, 9 high precision cross type, no autofocus microadjustment.

The Nikon D5300 is worth the extra $100 or so over the Nikon D3300 as you get some better focusing. You can also go up to the Nikon D5500 but to me the added touch screen isn't worth the money difference.  You of course get the Sony sensor capabilities the Canon won't have(if seldom useful).  If you need weather sealing(I'm a storm chaser and have never had it on a body) and autofocus microadjustment, spend more on the Nikon D7200.

Alternative: Canon T6i

24 megapixels, 5 frames per second, 19 focus points, 19 high precision cross type, no autofocus microadjustment.

Quite similar to the Nikon D5300 and still a ways under $1,000.  The T6s just adds a top LCD and a back control wheel.  If you need weather sealing(I'm a storm chaser and have never had it on a body) and autofocus microadjustment, spend more on the Canon 70D.

$1,000 - $1500 Crop Frame

My Pick: Nikon D7200

24 megapixels, 6 frames per second, 51 focus points, 15 high precision cross type, has autofocus microadjustment.

You begin to get more focus ability and frame rates in this area but only on crop frames. Full frames in this range usually don't have fast frame rates or their top focusing abilities yet.

It is a pretty easy choice here. I'd go with the Nikon D7200. It's near $1,000 and you get quite a capable camera. You again get the great Sony sensor traits over Canon alternatives. It is worth spending more on this one than the D7100 as that one actually can show shadow banding, being the only one I've seen from them evidently not using the great Sony sensors.

Alternative: Canon 7D II

20 megapixels, 10 frames per second, 65 focus points, 65 high precision cross type, has autofocus microadjustment.

If you have to go Canon, I'd probably go 7D II. A super capable autofocus system and a blazing 10 frames per second shooting rate. Or for quite a bit less the Canon 70D would be a good option. 7 frames per second and a still great but not as great focusing system.

$1,000 - $1500 Full Frame

Toss Up: Canon 6D

20 megapixels, 4.5 frames per second, 11 focus points, 1 high precision cross type, has autofocus microadjustment, -3 EV low light focusing.

This is the section I favor. I don't need frame rates or crazy tracking focus abilities. I just want cleaner images and the ability to occasionally use higher ISO settings and paying for it less than you do on crop frame sensors.

These two are priced super similar.  The Canon edges the Nikon out in really high ISO use.  It also beats it at low light autofocusing.  Loses on frame rate and overall focus, neither of which I care about here. 20 vs 24 megapixels, meh, will never notice it.  I'd give it to the Canon if it weren't for again Sony's sensor ability in the Nikon.  So I'm just going to call this class a toss up. 

Toss Up: Nikon D610

24 megapixels, 6 frames per second, 39 focus points, 9 high precision cross type, has autofocus microadjustment -1 EV low light focusing.

If I was to switch to Nikon right now I'd probably do so to this camera.  But the D750 now out is so close in price and more capable as far as low light focusing and overall focusing, I'd be tempted to fork out a bit more.  Even if I don't really ever need or use autofocus.   Actually thinking more about it, no I wouldn't even bother.  I'd use that difference on some lens. 

$1500-$2500 Full Frame With Focusing

My Pick: Nikon D750

24 megapixels, 6.5 frames per second, 51 focus points, 15 high precision cross type, has autofocus microadjustment -3 EV low light focusing.

The Nikon D750 would be an easy choice for me. It comes in near the bottom of that price range while the 5D III is only now squeaking in at the top of it. Like all the other Canon compared to Sony sensors in the Nikons, you just have some ability with the Nikon's dynamic range you don't with the Canon. And obviously you will surely rarely ever need it or see it. But there are dynamic scenes that can most certainly use it, let alone any user error in exposure on something.

Alternative: Canon 5D III

22 megapixels, 6 frames per second, 61 focus points, 41 high precision cross type, has autofocus microadjustment -2 EV low light focusing.

The price difference combined with the better Sony sensor would just make me pick Nikon again with the D750.  If you need to use Canon lenses though, you obviously have to go Canon camera.

$3000+ Here Comes The Resolution

My Pick: Canon 5Ds-R - Barely

50 megapixels, 5 frames per second, 61 focus points, 41 high precision cross type, has autofocus microadjustment -2 EV low light focusing.

The 5Ds-r version of the 5Ds is sharper as it cancels the optical low pass filter.  There's then an added risk of images ending up with moiré patterns on repeating pattern objects like fabric or bricks etc.  It is noticeable sharper.  If one is clearly going this much for resolution I think they may as well go the 5Ds-r route. 

The resolution of this thing is just insane.  It also includes a super good autofocus system and is managing 5 frames per second even with the massive files 50 megapixels is pushing out.  It's really just impressive.  You'll obviously need good glass to get to that resolution. 

Alternative: Sony A7R II

42 megapixels, 5 frames per second, 399 focus points, 25 contrast type(completely different focus system with mirrorless...on the sensor), -2 EV low light focusing.

This is an entirely different camera to the Canon.  It's mirrorless and far smaller.  It is cheaper.  You can adapt Canon and Nikon lenses to it.  If holding a smaller body isn't a huge deal, this one to me really competes with the Canon.  20 compared to 24 megapixels isn't going to really ever jump out to a person.  24 to say 50 obviously will.  But again, 42 to 50 difference I don't think is going to really jump out to anyone. 

Besides price and well being smaller if one wanted that, the Sony uses a Sony sensor which will have more dynamic range than the Canon.  The Sony holds out better at higher ISO settings.  It like most all of its other sensors in the Nikon bodies, really shine if shadows need lifting(like if the exposure was held down to bright sun areas in a scene).  The thing is though they do need quite a lot of lifting before that is ever going to be that evident.

Lens Selection

Ultra-wide - 14mm

My Pick: Samyang 14mm - Bower 14mm - Rokinon 14mm

There is a lot to love about Samyang(Bower and Rokinon are the same lens just rebranded). They general correct for coma really well, instead of having big wings on light sources towards the edges when used more wide open. They are more affordable than most. They deliver. They are made for several camera makers. See my comparison to Canon 14 F2.8.

Medium wide - Samyang/Bower/Rokinon 24mm

My Pick: Samyang 24mm - Bower 24mm - Rokinon 24mm

I may swap to the new/out in November Sigma 20 Art....to be determined

Much like the 14 the 24mm is really great. Much like 14 you really don't need autofocus, which these don't have. They are made for several camera makers. See my comparison to Canon 24 F2.8.

Normal - 50mm

My Pick: Sigma 50mm Art F1.4

Plenty of offerings in the 50mm realm. The Sigma 50mm Art is simply amazing. Yet a much cheaper F1.8 Canon or Nikon will be great for most uses too. If you want to use it more wide open with light sources like at night, say city lights or stars, well most of the 50mm offerings out there just don't do well with them. Especially on full frame, like always. Maybe not even a real issue if you are using a crop sensor camera. The Sigma 50mm Art is fairly pricey but it also compares to a new $4,000 Zeiss 55 Otus. I don't yet own the Sigma 50 Art but it is my next lens goal. See my overview of 3 50s and a partial of the Sigma 50 Art.

85mm

No Idea

I've never owned an 85mm nor shot portraits, which it is often preferred for. That said, it might be worth watching for the surely coming Sigma 85 Art, given what they've been doing lately.