Is there a standard for hot shoe center contact?

Pasto · Jun 1, 2023

I bought the Kaiser PC to Hot Shoe Adapter with cable to use my Nikon SB-30 with a Hasselblad SWC. The adapter does not work. It appears that the center pin on the flash is not at the right place for the adapter. If I slide the flash only partly into the adapter then it does fire. I attached a picture of the flash hot shoe. I also attached a picture of the bottom of a wireless trigger I have (FlashQ trigger). You’ll note that the center pin of the FlashQ is in a slightly different location. I tested both on my other flashes with these results:

Nikon SB-30, Kaiser does not work, FlashQ does
Nikon SB-15, both FlashQ and Kaiser work
Sunpak Auto 221 and Auto 131, Kaiser works, FlashQ does not

It's strange that both work well with SB-15. Maybe it's more than the center pin location that is responsible for the differences. Are there different standards for flash hot shoe center contacts, and maybe physical size front to back?

wiltw · Jun 1, 2023

The center contact function for any conventional flash hot foot is always the Trigger...the Ground is the contact on the side of the hot foot. I am not aware of positional (dimension) deviations of the placement of the Center contact for different brands, although that might have occurred. Minolta and Sony, and now Canon for reecent mirrorless cameras, have adopted a multi-pin configuration for their flash units.

Some flash units (the older ones) may present too high of a Voltage to be safe for use with the newer (since about 1990) cameras hot shoe, which might only tolerate 5V (or is that 12V ?!), although dSLRs mostly have tolerance for higher Voltage than the film cameras of the 1990s.

The issue arises by the additional contacts...even if the contact position lines up, the Function of that contact is not standardized. So newer cameras might not trigger an external flash if the camera does not detect a mounted flash via its additional contacts. But that should not be true of a Hasselblad simple mechanical hotshoe.
It appears, from your description, that a Nikon SB-30 differs enough from the SB-15 hotfoot for the SB-30 to not work...instead it might be simply that the SB-30 has stopped functioning...Have to you tried to fire the SB-30 to verify its functionality by

pressing its own 'open flash' or 'test' button
shorting its center pin on hot foot to the side Ground, using wire or paper clip

Pasto · Jun 1, 2023

Thanks for the detailed response wiltw. IMHO it's not related to flash voltage. It could be the Kaiser adapter that's not completely to spec. The center contact on "modern" flashes is a pin rather than a metal strip like found on older flash units, and probably needs tighter tolerances. I ordered the Impact SCS-MPC PC Male to Hot Shoe Sync Cord to see if it works better. I will report back.

RalphLambrecht · Jun 1, 2023

Pasto said:
Thanks for the detailed response wiltw. IMHO it's not related to flash voltage. It could be the Kaiser adapter that's not completely to spec. The center contact on "modern" flashes is a pin rather than a metal strip like found on older flash units, and probably needs tighter tolerances. I ordered the Impact SCS-MPC PC Male to Hot Shoe Sync Cord to see if it works better. I will report back.

it could also be that the Kaiser has an electrical fault(broken wire or such) I'd send it to Kaiser and complain or a replacement.

Pasto · Jun 1, 2023

Good point....

Sirius Glass · Jun 2, 2023

Pasto said:
I bought the Kaiser PC to Hot Shoe Adapter with cable to use my Nikon SB-30 with a Hasselblad SWC. The adapter does not work. It appears that the center pin on the flash is not at the right place for the adapter. If I slide the flash only partly into the adapter then it does fire. I attached a picture of the flash hot shoe. I also attached a picture of the bottom of a wireless trigger I have (FlashQ trigger). You’ll note that the center pin of the FlashQ is in a slightly different location. I tested both on my other flashes with these results:

Nikon SB-30, Kaiser does not work, FlashQ does
Nikon SB-15, both FlashQ and Kaiser work
Sunpak Auto 221 and Auto 131, Kaiser works, FlashQ does not

It's strange that both work well with SB-15. Maybe it's more than the center pin location that is responsible for the differences. Are there different standards for flash hot shoe center contacts, and maybe physical size front to back?

You may be able to find a Nikon hot shoe adapter that is compatible with the SB-30.

Pasto · Jun 2, 2023

I'll have a look, thanks

MattKing · Jun 2, 2023

The variation that I've sometimes noticed is in the shoes - some permit the flash to slide in a different distance than others do.

Chan Tran · Jun 2, 2023

I see the the hot shoe on the left would short out the 2 pins on the SB-30. Tape all the pins except the center pin on the SB-30 and try.

Sirius Glass · Jun 2, 2023

Chan Tran said:
I see the the hot shoe on the left would short out the 2 pins on the SB-30. Tape all the pins except the center pin on the SB-30 and try.

That could [would] block out the strobe to camera messages thus eliminating the advanced features of the SB-80.

Chan Tran · Jun 2, 2023

Sirius Glass said:
That could [would] block out the strobe to camera messages thus eliminating the advanced features of the SB-80.

may be it has nothing to do with the trouble the OP has.

neilt3 · Jun 2, 2023

RalphLambrecht said:
it could also be that the Kaiser has an electrical fault(broken wire or such) I'd send it to Kaiser and complain or a replacement.

A simple multi-meter would confirm if there's a fault with the Kaiser adapter before starting to complain it's broke .
I would say the first thing to do is to try the Nikon flash on a Nikon body to check it works correctly , and then try a basic flash with built on PC cord on the Hasselblad to confirm it isn't the connection on the camera at fault .
Probably take the lot into a camera shop to try things out .

Sirius Glass · Jun 2, 2023

Chan Tran said:
may be it has nothing to do with the trouble the OP has.

Why chain up a good working strobe and hobble all the features that come with it. You have suggested a poor idea.

Chan Tran · Jun 2, 2023

Sirius Glass said:
Why chain up a good working strobe and hobble all the features that come with it. You have suggested a poor idea.

I tried to explain why the SB-30 won't work with some hot shoe adapter. I only suggest to tape the contact to see if it would fire. As for using such a dedicated flash on a camera without hot shoe let alone compatible with all the feature is not my idea. It's the OP that wanted to do that.
I have an SB-30 and I never use it. It's rather a useless strobe.

Sirius Glass · Jun 2, 2023

Chan Tran said:
I tried to explain why the SB-30 won't work with some hot shoe adapter. I only suggest to tape the contact to see if it would fire. As for using such a dedicated flash on a camera without hot shoe let alone compatible with all the feature is not my idea. It's the OP that wanted to do that.
I have an SB-30 and I never use it. It's rather a useless strobe.

I rarely use my SB-800 stroke but I would not call it useless, it sits without batteries unused. It has zoom features and automatic exposure capabilities that can even be used with bounce flash.

reddesert · Jun 2, 2023

These PC to hot shoe adapters are not really guaranteed to work with a TTL-era flash that has extra pin contacts for camera to flash communication. It is clear that as Chan Tran pointed out, the extra metal on the ground part of the adapter would short some of the pins to ground, and this may be one reason the flash isn't firing. Taping over the extra pins on the flash (or taping over the extra metal on the adapter) would avert this. You aren't going to get the extra camera to flash communication through a PC to hot shoe adapter anyway.

maltfalc · Jun 4, 2023

reddesert said:
These PC to hot shoe adapters are not really guaranteed to work with a TTL-era flash that has extra pin contacts for camera to flash communication. It is clear that as Chan Tran pointed out, the extra metal on the ground part of the adapter would short some of the pins to ground, and this may be one reason the flash isn't firing. Taping over the extra pins on the flash (or taping over the extra metal on the adapter) would avert this. You aren't going to get the extra camera to flash communication through a PC to hot shoe adapter anyway.

there are tons of accessories out there with a single central contact and all the major camera brands knew that when they designed their current hot shoe pin arrangements. shorting ttl pins to ground shouldn't cause any problems.

Sirius Glass · Jun 4, 2023

maltfalc said:
there are tons of accessories out there with a single central contact and all the major camera brands knew that when they designed their current hot shoe pin arrangements. shorting ttl pins to ground shouldn't cause any problems.

Except blocking the use of the focal length adjust communication and distance communication between the strobe and the camera. One could greatly improve on shorting the pins by putting a burlap bag over the strobe.

Pasto · Jun 4, 2023

neilt3 said:
A simple multi-meter would confirm if there's a fault with the Kaiser adapter before starting to complain it's broke .
I would say the first thing to do is to try the Nikon flash on a Nikon body to check it works correctly , and then try a basic flash with built on PC cord on the Hasselblad to confirm it isn't the connection on the camera at fault .
Probably take the lot into a camera shop to try things out .

Everything checked out OK.

Pasto · Jun 4, 2023

Sirius Glass said:
I rarely use my SB-800 stroke but I would not call it useless, it sits without batteries unused. It has zoom features and automatic exposure capabilities that can even be used with bounce flash.

Not sure if you mean SB-30?? I think it's a great flash for the right conditions. My SWC stays put at f11, whatever shutter speed conditions warrant, and the focus at 1m. The SB-30 with it's wide flash coverage and minuscule size and weight, and 4 auto apertures if I ever need them, is just about the best I found for this context and I've tried many over the last 2 decades

Chan Tran · Jun 5, 2023

Sirius Glass said:
Except blocking the use of the focal length adjust communication and distance communication between the strobe and the camera. One could greatly improve on shorting the pins by putting a burlap bag over the strobe.

When the OP uses the flash with a camera that doesn't even have a hot shoe how can he expect any communication between the strobe of the camera. He uses the adapter just to fire the flash.

Pasto · Jun 5, 2023

This thread went in different, and sometimes funny, directions. Thanks to all for their contribution....

Sirius Glass · Jun 5, 2023

Chan Tran said:
When the OP uses the flash with a camera that doesn't even have a hot shoe how can he expect any communication between the strobe of the camera. He uses the adapter just to fire the flash.

It also helps others who later look at the thread for advice on that or a similar problem. Each thread helps more than just the OP, their are others who will read it later.

kl122002 · Jun 5, 2023

I have been told some morden, computerized flash are not working well with the old single-pin hot shoe. Those E-TTL pins have contacts with the ground metal holder on the hot shoe body, which causing them short circuited. The flash then prevents operating for safety purpose.

Is there a standard for hot shoe center contact?

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