Nikon D850 auto-focusing issue

Hi all,

 

I'm encountering a very strange issue with my nearly 1-year-old Nikon D850, one that I have never experienced with my D800. Using back-button autofocus, continuous servo (AF-C) mode and various f1.8 Nikon primes, I find that the focus point(s) in the viewfinder inexplicably disappears in any of the various AF-Area modes including Single-point, 9-point Dynamic, Group and and 3d tracking. And when the focus point(s) disappear, the camera appears to shift into some sort of auto focusing mode in which the camera controls where to place the focus point boxes. I have no control over their placement.

 

I've run this issue across the local pro shop and they're stumped too.

 

Any ideas or theories?

 

Thank you!

Andrew

What are your taking a pictures of? D850 I hear (although I do not own) have face recognition with subject eye tracking. Might this be interfering?

It's news to me - mine seems to behave. (I might be having problems with the invisible "helper" AF points trying to focus on things when I'm trying to focus precisely with a specific point, but that seems separate from your issue.)

 

I'd do a full reset just to see whether some setting has been hit by a cosmic ray. The only deliberate way I can think of to get the behaviour you have is to have one of the control points set to override the AF mode (+ focus) - under some circumstances, for example, I have the Fn button set to area AF + AF On. I don't think I've hit them accidentally, but I've been known to press the AF mode button next to the lens mount when trying to review images, and wonder why it stopped the camera responding. If your lens has any control points, that might be worth checking too.

ChrisSpeaker is thinking about the auto focus meny option A4 (3D-tracking face-detection). My understanding of that option is that it only comes into play when in 3D-tracking mode.

 

To elaborate on what Andrew Garrard wrote about control points:

If you look further down, under F1 (custom control assignment). Double check that AF-ON is set to AF-ON only. It can be se to AF-ON and AF-area mode (which may be preset to Auto-area AF) among other options. Same goes for the Sub-selector (thumb joystick), so double check that pressing it does not change AF-area mode either. Personally, I use the Sub-selector to change to single point for better precision when shooting perched birds while still in group-area AF or D9/25 for birds in flight.

 

Please note that these settings are saved independently for each custom settings bank.

The answer to your question, grasshopper, is in the manual. Any time you engage automation, it comes at the price of control. Choose wisely.

The answer to your question, grasshopper, is in the manual. Any time you engage automation, it comes at the price of control. Choose wisely.

 

And in my experience, bear in mind that when you lend the camera to someone, they might have done something weird to the settings. :-)

What are your taking a pictures of? D850 I hear (although I do not own) have face recognition with subject eye tracking. Might this be interfering?

 

Good thought! Alas, I've got it set to 3d-tracking face-detection - off.

 

This issue is surfacing when I shoot people.

It's news to me - mine seems to behave. (I might be having problems with the invisible "helper" AF points trying to focus on things when I'm trying to focus precisely with a specific point, but that seems separate from your issue.)

 

I'd do a full reset just to see whether some setting has been hit by a cosmic ray. The only deliberate way I can think of to get the behaviour you have is to have one of the control points set to override the AF mode (+ focus) - under some circumstances, for example, I have the Fn button set to area AF + AF On. I don't think I've hit them accidentally, but I've been known to press the AF mode button next to the lens mount when trying to review images, and wonder why it stopped the camera responding. If your lens has any control points, that might be worth checking too.

 

Good thought about a reset. I will give that a try. Regarding camera control points, I confirmed that I've got the AF-ON button set to AF-ON only. The sub-selector is set to Focus point selection.

 

I'm not clear about your comment concerning lens control points. I haven't heard of that before. What are you referring to?

 

Thanks!

And in my experience, bear in mind that when you lend the camera to someone, they might have done something weird to the settings. :)

 

So true, but this thing hasn't left my paws since purchase!

Lens control points are buttons on some longer lenses that can be assigned to certain functions.

The answer to your question, grasshopper, is in the manual. Any time you engage automation, it comes at the price of control. Choose wisely.

 

Actually, "control" is exactly what I'm seeking and have lost. Single-point AF selector mode is from the 1800's. It's definitely not an auto mode.

ChrisSpeaker is thinking about the auto focus meny option A4 (3D-tracking face-detection). My understanding of that option is that it only comes into play when in 3D-tracking mode.

 

To elaborate on what Andrew Garrard wrote about control points:

If you look further down, under F1 (custom control assignment). Double check that AF-ON is set to AF-ON only. It can be se to AF-ON and AF-area mode (which may be preset to Auto-area AF) among other options. Same goes for the Sub-selector (thumb joystick), so double check that pressing it does not change AF-area mode either. Personally, I use the Sub-selector to change to single point for better precision when shooting perched birds while still in group-area AF or D9/25 for birds in flight.

 

Please note that these settings are saved independently for each custom settings bank.

 

Right, agreed. I just checked those custom controls and have confirmed that AF-ON is set to AF-ON only. The sub-selector is set to change single-point only. 3d tracking is not set to face detection. Good ideas.

Right, agreed. I just checked those custom controls and have confirmed that AF-ON is set to AF-ON only. The sub-selector is set to change single-point only. 3d tracking is not set to face detection. Good ideas.

 

Oh dear. So much for the logical conclusion. I'd do a reset anyway, since sometimes corrupted settings can cause effects that aren't reported obviously through the menu system, but there certainly isn't a smoking gun.

 

(And yes, Heimbrandt knew what I meant - if you had, say, the latest 70-200 and were accidentally pressing its buttons while holding it, something odd could be happening. Likewise the controls on the battery grip.)

 

I could believe a loose contact causing one of the buttons to be "pressed" when you weren't doing so, and for this to activate an AF mode, but if the menu says that's not something you've configured, it seems unlikely. I'm confused. If you do work it out, I hope you'll report back.

Well, after 10 hours of shooting, it looks like this issue has gone away. Resetting the camera appears to have done the trick. It's nice to have focus point control again!

 

Thanks everyone.

And in my experience, bear in mind that when you lend the camera to someone, they might have done something weird to the settings.

 

And how.

Although sometimes the idiot who reset something is yourself :(

 

 

For more complex equipment, I usually carry a pdf copy of the manual on my phone, just in case you are standing at the dock in Puerto Rico and everything is screwed up.

Oh yes, the local copy of the PDF is important. Even then it didn't save me when I was trying to work out why I couldn't enable electronic VR in video mode while standing at Skookumchuck rapids, but it would have done if I'd been better with search terms, hadn't been dehydrated into incoherence, and it had occurred to me that having focus peaking turned on even though it doesn't do anything in autofocus mode would possibly have had an effect.

 

By way of reporting back, I've not done an exhaustive test yet, but I've now set my Pv button to "single point focus + AF-On" and I think it's doing a better job of focussing on the thing I'm actually pointing at, rather than the nearest thing in the surrounding area (as 3D tracking seems to do). I'll be interested in feedback from anyone else with one of the D500/D850/D5 triumverate with the same AF module. I should probably see whether Thom Hogan has already covered this in his book (since I don't dare ask him until I've bought it...)

I had the same problem where the AF point would inexplicably change. It would always happen when I lift the camera to take a picture after a period of inactivity. I found the culprit to be custom setting a7: "store by orientation". It's a function that stores your selected AF point separately for horizontal and vertical composition, so that for example if you are taking portraits, the selected AF point will be close to the subject's eye as soon as you flip the camera over from one orientation to the other. However, when the meter and the LCD turn off after a few seconds (whatever you have it set to), the next time you hold the camera to your eyes, the previously selected AF point will be highlighted, regardless of whether you are holding the camera horizontally or vertically. But as soon as you wake the camera up, the focus point will switch to the one you had previously selected in that orientation. So if I had been shooting vertically for a few frames, then stopped shooting, the next time I hold the camera to my eye horizontally, the previously selected AF point will still be highlighted, until I push a button, when it suddenly jumps to the one I last selected in the horizontal orientation. It took a while to realize what the "problem" was.