Nikon F4 Flash-Sync Problem

[GarysChickens]

I picked up an F4 a few months ago that was in excellent shape. I wanted to start experimenting with some flash photography, so I bought the SB-24 flash. I've since been unable to get the flash to fire (without film). I know that the flash and camera are syncing to some degree, as the red flash icon is displayed through the viewfinder and the aperture reading on the flash changes as I rotate the aperture ring on the camera. 

I was considering buying a sync cable to bypass the hotshoe and link the camera and flash using an alternative method. Is this a viable option? If so, what would be the best sync cable?

Thanks, everyone. This is my first post!

Colin

[John Seaman]

You really need to pinpoint the cause of the problem before buying any more kit. It could be an issue with the flash, camera or with the connection between them. Try cleaning the main central flash contact on the camera, it looks OK but they can acquire a film of dirt, oxidation or whatever.

Does the flash fire off camera via the test button? If not it's faulty. If it fires, can you check it on another camera? Or just short the main central contact to the side contact with a piece of wire.

The camera hot shoe may not be working, sometimes they do fail, perhaps from being used with a flash with high sync voltage. Test it with a different gun (if available).

 

[joseph_smith3]

This link might help you. 

http://www.mir.com.my/rb/photography/hardwares/classics/nikonf4/flash/index.htm

[rodeo_joe1]

I know that the F4 locks out manual or Auto selection of slow shutter speeds until the frame counter reaches 1. Now whether it also locks out flash firing before frame 1, I don't know, but it wouldn't surprise me. 

I also see that the camera appears to be set to A mode in the picture. You could try setting the shutter speed to 1/60th manually and then see if the flash fires. Or override the lockout with a roll of film or by depressing the film sensor switch. 

FWIW, the F4 is my least favourite of all the Nikons I've owned or handled. A heavy beast that performs well below its weight class. 

Edited January 15, 2023 by rodeo_joe1

[Jay M]

First of all I verified with my F4 and SB-24 that dry-fire of camera with flash hotshot mounted should work without issues regardless of M or A mode or frame counter being set and even higher shutter speed than 250 in manual mode would still fire. Then I'd suggest to remove the DP-20 viewfinder from camera to inspect the contact pins (refer to the diagram below) especially a and b are clean and moving properly with a multimeter if possible to check connections, try again. If DP-20 and F4 seem good to you, likely the culprit is the flash (test fire or another good flash to verify). Also, check the ISO setting dial that should not be in DX mode by accident which will cause flash out of order in "Err" mode as shown on flash panel. Hope this helps.

Edited January 15, 2023 by photomemory

[rodeo_joe1]

The SB-24 hotshoe connection can be tested by shorting the centre pin to the 'earth' contacts hidden between the plastic hotshoe foot and the lock-down screw. 

These sideways contacts are often overlooked when it comes to checking for dirt or corrosion. They can also get pushed in, such that they don't make proper contact with the side of the camera's metal hotshoe slide. 

The test fire button on the flash is no guarantee of connection between camera hotshoe and flash foot. 

[GarysChickens]

Thanks for all the advice everyone. 

It turned out that it was a connection issue with the DP-20 and F4. Thanks for the direction @photomemory

It's a simple yet annoying fix: push on the back of the DP-20. Anyone know why this connection isn't tight enough?

Cheers,

Colin

[Greg M]

After as long as 34 years and who knows how many different owners/users, the cause could be just about as varied and unknown by now.

[hjoseph7]

I'm not sure if this is the problem, but sometimes the little metal clips inside the Hot-shoe get smashed so that they lay flat at he bottom of the Hot-shoe and you lose contact. What I do is to use a thin blade so they spring back up. 

[Rick Helmke]

I have an F4s that was heavily used before I got it and apparently there is not a good tight connection between the prism and the rest of the body because at times I have to push a bit forward on the back of the prism to get it to make an exposure. I have two others in much better condition and they all seem to work fine on the SB 24 and 25. As I often do I disagree with Joe about the F4, it’s the only camera I ever liked as well as a motor driven F2. Weighs less and quieter and fits my hand. A lot of pros disagreed at the time. 
 

Rick H.

[rodeo_joe1]

10 hours ago, Rick Helmke said:

As I often do I disagree with Joe about the F4, it’s the only camera I ever liked as well as a motor driven F2.

But unlike the F2, and every single-digit F series Nikon before it, it has a plastic top plate. This is my main beef with it, and quite possibly a reason for the fit of the prism working loose; because plastics aren't as dimensionally stable as metal. 

[mike_halliwell]

12 hours ago, Rick Helmke said:

apparently there is not a good tight connection between the prism and the rest of the body

Sounds like a design flaw as that gap will allow all manner of crap and water into a very vulnerable area!

No rubber seals/gaskets? 

What were they thinking....?   🤔

🤣

[Rick Helmke]

Actually Joe if I put a viewfinder from another F4 on this body it runs fine. I had the shutter replaced but this camera either got used very heavily, got dropped or got used as a hammer. 
 

Rick H.