More About Appropriate D850 Lenses

I've gotten a fair amount of pushback on my D850 lens list, mostly about lenses that weren't on the list, or ones that I've indicated that I'm going to examine more closely. 

My belief is this: if you're going to be buying at the front edge of the pixel wars (now basically 42mp+ for full frame), you really need to think about what you're trying to achieve and why. More sampling (more pixels) should result in more accuracy to the underlying scene. Some call this resolution, but I think it's simply better if you stay in the digital realm with the terminology: more sampling means more accuracy to the thing you sampled. 

But lenses are also part of the overall equation. 

Think of it this way: if you have retinal issues, it's not going to matter a lot what eyeglasses you put in front of your eyes. If you have a perfect retina, it does make a difference as to what eyeglasses (or cornea adjustment/replacement) you put in front of it. Well, we're getting better "retinas" in our cameras, we need a great lens in front of it. 

We're also in a realm now where we have only a narrow band between fully-achieved acuity versus aliasing caused by diffraction. If you're shooting with f/5.6 lenses or worse, you're losing some of the benefit gained at the sensor by bending some of the light before it hits it. 

A common question led me to my current thoughts on the subject: A7rII or D810 (D850)?

Handled poorly, I'd say you're better off with the A7rII. 

Oh dear, don't open up your email to fire off a response to me just yet...

If you're not into best-possible shot discipline and don't know how to get dead-on focus out of a phase detect autofocus system with tons of options and tricky bits, I'd argue that you're better off with the A7rII for two reasons (1) it has sensor-based IS to deal with the bad camera handling, no matter what lens you put on it; and (2) it follows up its initial focus guess with a contrast-based verification. In AF-S mode with mostly non-moving subjects (especially faces), most people handling the camera somewhat casually are going to get "better looking" images out of an A7rII with the 24-70mm f/4 than they would out of a D810/D850 with the 24-70mm f/2.8E. Whoa. That 24-70mm f/2.8E is a better lens. How's that happen?

It happens because the person in question here was never going to achieve all that the D8xx/24-70mm combo could provide them, while the Sony A7rII/24-70mm combo could. Even though the Sony is a lesser lens overall, the camera's achieving everything that lens can provide. 

Which gets me to why I'm being critical with lens selection in the high-pixel Nikon cameras now: I think you're buying the D850 to try to achieve everything it can produce. I sure hope so, otherwise you're spending too much money (buy the D750). 

Trying to come up with an arbitrary bar over which we get best-possible-performance and below we get okay-but-not-up-to-camera's-potential is a task fraught with hazards. I took on that task knowing the hazards. 

One area of disagreement others have with my placement of that bar has to do with center versus edge performance. 

No doubt most Nikkors perform admirably in the very central region of the frame on a D850. Nikon really doesn't make a dud FX lens in that respect, though a lot of the zooms get into the less-than-admirable level at the telephoto end of their focal range (e.g. 80-400mm, 28-300mm, etc.). Plus they're often at the start of diffraction impacts wide open in telephoto use, so stopping down doesn't really pull in more useful acuity. 

But why did you buy a 46mp in the first place? For better center-of-image? Not likely. More likely is that you want to print bigger. And that means that you're using edge pixels. 

This is where it gets real tricky and I'm willing to have the debate/discussion: if I print at 27" (D850) versus 20" (D750), are you going to look at that print at the same distance or will you step back further from the D850 print? ;~) If you pick the latter, then maybe the edge performance isn't as important as I make it out to be. If you pick the former, those edges are going to get more revealing of what my lens is up to.

This isn't the only hazard in my defining a bar above and below which lenses do and don't work so great on the D850, but it's indicative of the kind of thinking I went through in trying to establish my own standards here. I'm comfortable that the lenses on my list perform as I expect with the added sampling. Lenses not on the list, I'm not so comfortable with.

I will say this: the 200-500mm f/5.6 is one lens I got a lot of pushback on. After all, I reviewed it positively. I should re-evaluate both those things, and will. But note that in my review I found 500mm doing that thing the other non-f/2.8 zooms tend to do: get soft and lose edge acuity. In thinking about this some more and looking back at some of my D810 shots with the lens, I think that it's right below my bar. It might get just above the bar if I only shot in DX crop on the FX bodies. So how you're using this lens plays a part in how you'd evaluate it.

Look, no list from anyone using any criteria is perfect. That includes mine. But I can tell you this, my list is indicative of the lenses I'll be using on my D850. You're not going to see me wandering around the canals of Venice with a 28-300mm sitting on the front of my D850 and me proclaiming this is the perfect travel combo. Not my style, and not the level of quality I want to produce. Your mileage may vary. But make sure you know how and why it varies.

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