DaveyDitzer Loc: Western PA

Using a shoe mounted flash on my D850 I experience intermittent failures of the camera to trigger the flash. I have cleaned the contacts on both the flash and the hot shoe. I have tested three different flash units (one a Nikon). I have tested the flash units on my D500 without a problem. Is there possibly some menu setting I have missed?
Please offer helpful suggestions before I pack the D850 up and off to Nikon service.

larryepage Loc: North Texas area

From your description, this sounds most like an internal problem in your D850. I had a similar problem several years ago. It was repaired under warranty, but would have been expensive as a paid repair. Has your camera been dropped or handled roughly, by chance? There's lots going on in the space between the viewfinder prism and the hot shoe. There are also two circuit boards (main board and flash control board) that control the flash. I suggest a call to Nikon Service.

DaveyDitzer Loc: Western PA

Thank you. This body has experienced no shocks, drops or even vigorous use. I normally use other bodies and use the 850 when I want more resolution. It has only a few thousand shutter clicks.

chuckrem Loc: Katy, Tx

Is there a menu setting where Flash may be in the off setting by any chance?

DaveyDitzer Loc: Western PA

Not likely because the flash fires intermittently

MJPerini

Stick with the Nikon Flash for testing, because I have seen very small variations in flash shoe thickness or shape cause issues. The most common cause of what you describe is when people leave the flash mounted while transporting the camera. Even a small bump can break internal contact---the flash acts s lever, nd the flash shoe is a weak spot on most cameras.
Your description of camera use suggests that that is probable not your problem, but it only takes one time.
How old are the other flashes? Because older flash units had very high trigger voltages that can damage the contacts. If the other flashes are modern , that is not an issue.
With the nikon flash mounted , Try flashing while attempting to move the flash Be gentle look for any plat in the hot shoe. If The D850 has a PC terminal try connecting a flash that way. If that works reliably and the shoe doesn't you have proof of internal damage. If you don't have a PC cord, try a local camera store that has any modern flash with a PC cord or connector
If all this is inconclusive, call Nikon and arrange to ship Your camera and Nikon Flash
Good Luck

tcthome Loc: NJ

Flash Sync Speed possibly?

DaveyDitzer Loc: Western PA

on manual at 125th

larryepage Loc: North Texas area

Just for grins, have you tried it at 1/60?
And do you know for sure that the flash you are using is recharging quickly enough? I know that it works fine on the other camera, but something different could be going on with the D850.

Also..those times that it doesn't flash...what is the result? Dark images? Proper exposure?

DaveyDitzer Loc: Western PA

Shutter speed at 1/60 does not change the behavior. The images are just grossly underexposed due to lack of light.

DaveyDitzer Loc: Western PA

OP: I have an SB11 speed light but is syncs through a hot shoe attachment.

E.L.. Shapiro Loc: Ottawa, Ontario Canada

Troubleshooting for misfires or synchronization issues involves isolating the problem. First, remove the FLASH unit for the camera and see if it operates reliably and normally using the open flash button or shorting out the center pin on the foot to the contact on the perimeter of the foot. If it works consistently the defect is in the camera or the connection in the hot shoe. Make sure you are allowing for adequate recycling time when you are testing the Speedlight. If the Speedlight works independently and the contact between the foot and the shoe is positive, the issue is probably in the camera.

Next- If you have another speedlight in working order, mount it atop the camera and see if the problem recurs.

Modern digital cameras have more complicated synchronization circuitry than their ancestors with simple shutters and internal (mechanical) synchronization contacts. The old mechanical cameras have circuit boards where the flash is triggered by a switch-like contact. These contacts are known to carbonize, bun out, wear out, or seize up and short out. I imagine that your camera has a more complex circuit board where the "switching" occurs in a chip, semiconductor, or some kind of circuit that is "way above my paygrade. and therefore may be a costly repair.

Modern Speedlights are supposed to have LOW trigger voltages but a defect in the unit can cause the voltage to increase and still work, however, it can damage the camera's synch circuitry.

Sorry for the worst-case scenarios- try the simple tests first and you may be able to isolate and solve the problem. If you have access to a simple multimeter, you can verify the voltage across the center pin of the foot and the outside contact on the perimeter of the foot. With the ohmmeter r setting on the multimeter, you can probe the center content and the end of the hot shoe to check the continuity of the synch circuit.
These tests do not require disassembly or exposure to dangerous voltages.

BebuLamar

Well you have the SB-11 and although it's a Nikon unit it may have too high sync voltage. It can damage the flash but sometimes it doesn't but solid state switch in the camera (perhaps an SCR) continue to conduct after it fires the flash because the voltage from the flash doesn't drop low enough for it to realease. So if you have a meter, measure the sync voltage and also try to remove the flash, turn it off, then reattach the flash and take a shot. Do it with every shot and if that works fine then what I thought was the reason.

larryepage Loc: North Texas area

I received verbal confirmation from Nikon several years ago that the old higher trigger voltages on consumer flash units are not harmful to the higher-tier Nikon SLRs, including the D300/s, D500, and D8xx models. I cannot say whether this is still considered to be true.

Since the flash(s) in question work perfectly on the OP's other camera, which is very close in design to his D850, I have been convinced from very early on that this is a camera problem (similar to one I experienced a few years ago). I was simply considering some other questions that might be helpful to include with the repair request to Nikon, since this is reported to be an intermittent problem.

Bubbee Loc: Aventura, Florida

Your P setting is not recognizing the flash in the hot shoe and is giving you an ambient light reading. I don t use P but if I use A priority on my D7100 and SB 800 flash, it puts the shutter at 1/60.
I prefer Manual, especially with flash. But your P should be reverting to 1/60th when a flash is in the hot shoe