Using hotshoe flash on vintage coldshoe camera

lotech · 04-22-2023, 01:49 AM

Most of the vintage camera has coldshoe instead of hotshoe, I wonder how to use a modern hotshoe flash on it. I ask because the coldshoe short-circuit the hotshoe contacts so the flash my not function normally even with PC cord attached. I found some 3rd party flash does not work properly on my K3 even with hotshoe, that the flash will self-fire completely lost control, but original Pentax flash and newer 3rd party models worked fine, so that older flash with far more simpler design will not know how to adapt to the camera with coldshoe.

Lord Lucan · 04-22-2023, 02:29 AM

Perhaps this linked article will help. Beware that older flash units often had a high trigger voltage which can derange a modern electronic camera (not just digital ones), if not damage it.

Hotshoe Configurations

lotech · 04-22-2023, 03:54 AM

Originally posted by Lord Lucan

Perhaps this linked article will help. Beware that older flash units often had a high trigger voltage which can derange a modern electronic camera (not just digital ones), if not damage it.

Hotshoe Configurations

Thanks for the detailed info., I'm just wondering if the coldshoe will shortcircuit the flash prevented it to work properly, I got couple of sensor flash that I planned to use on the vintage RF.

kypfer · 04-22-2023, 04:24 AM

In my experience, if a "hot-shoe" flash also has facility for a cable connection, the cable connection will isolate the hot shoe connection once it's plugged in … that's how my Nissin 360TW works.
Alternatively, there were available cold-shoe to hot-shoe adaptors, they fit into the cold-shoe and have a hot-shoe on the top and a connection cable to go to the camera.

titrisol · 04-22-2023, 07:28 AM

If the flash can;t take a cable, there used to be a hotshoe-adapter, it connected to the camera X-terminal and you put your flash on it
BH still has it

lotech · 04-22-2023, 09:23 AM

Originally posted by kypfer

In my experience, if a "hot-shoe" flash also has facility for a cable connection, the cable connection will isolate the hot shoe connection once it's plugged in … that's how my Nissin 360TW works.
Alternatively, there were available cold-shoe to hot-shoe adaptors, they fit into the cold-shoe and have a hot-shoe on the top and a connection cable to go to the camera.

As far as I understand the PC cable only has 2 contacts, which simply act as electrical switch that short/close circuit to trigger the flash, and the cable is fixed to the flash no need to plug in, so I don't know how it can carry 'control signal' to the flash which trigger to use hotshoe or PC, unless there's a switch on the flash to select.

titrisol · 04-22-2023, 10:16 AM

Originally posted by lotech

As far as I understand the PC cable only has 2 contacts, which simply act as electrical switch that short/close circuit to trigger the flash, and the cable is fixed to the flash no need to plug in, so I don't know how it can carry 'control signal' to the flash which trigger to use hotshoe or PC, unless there's a switch on the flash to select.

Not necessarily, many "universal" flashes (Inlcuding Metz, Sunpak, Vivitar, Achiever, etc) used to have a detachable cable with a small plug that looked like the earphones plug.
These cables were not always interchangeable though, diameters and lengths varied by manufacturer

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Lord Lucan · 04-22-2023, 12:23 PM - **1 Like**

Originally posted by lotech

As far as I understand the PC cable only has 2 contacts, which simply act as electrical switch that short/close circuit to trigger the flash, and the cable is fixed to the flash no need to plug in, so I don't know how it can carry 'control signal' to the flash which trigger to use hotshoe or PC, unless there's a switch on the flash to select.

Some cables between the camera and flash (usually called "sync cords") are entirely detachable and some are fixed to the flash. In the case of detachable ones, there is often a microswitch inside the flashgun socket that detects if the sync cord is plugged in, and if it is plugged in the contacts in the foot are electrically isolated. It is like the loudspeaker of a portable radio being disconnected when you plug an earphone cable in.

In the case of non-detachable sync cords, a common arrangement was that they had a slot/groove to stow them when not in use, as they would be when the flashgun was being used in a camera hot shoe. The flashgun foot contacts were only made electrically live when the sync cord was in its slot, and otherwise were dead when the cord was pulled out to connect to the camera PC socket. The picture below is an example ("Fig 42"): the foot contacts lead up only to a PC socket in the flash body (visible just above the cross-head screw in the foot). When stowed in its slot the cord plugs into this socket and makes the foot contacts live, and when not stowed (as in the photo) the contacts are dead.

Originally posted by titrisol

Not necessarily, many "universal" flashes (Inlcuding Metz, Sunpak, Vivitar, Achiever, etc) used to have a detachable cable with a small plug that looked like the earphones plug.

Indeed, there was a large range of plugs, and not only of audio jack type - and even those could be 2.5mm, 3.5mm or something else, and of different lengths. Some makers (eg Sunpak) often used a two, three or more pronged plug, and by the 1990's they were using multi-core sync cords with a plug that slid into the camera hotshoe at one end and had a multi-pin plug at the flashgun end, to carry the proliferation of signals that flash units were using by then. Here is a selection of cords ("Fig 40") :

kypfer · 04-22-2023, 02:00 PM

Originally posted by lotech

As far as I understand the PC cable only has 2 contacts, which simply act as electrical switch that short/close circuit to trigger the flash, and the cable is fixed to the flash no need to plug in, so I don't know how it can carry 'control signal' to the flash which trigger to use hotshoe or PC, unless there's a switch on the flash to select.

Much like a headphone socket on a portable radio … plug in the headphones and the speaker goes silent

**TwoUptons** · 04-22-2023, 03:53 PM

Those are some good examples...

I'll add a couple of things...

There may be a weird plug on the camera to try and plug into on some vintage stuff... pre-1960s PC sockets were not universal; finding adapters for those is challenging and/or expensive these days.

My experience with PC-hot shoe adapters has not been terribly positive. Most of them are terrible... loose, wobbly, likely to fall out of the shoe. Better to have a flash with a cord.

In my experience, it is better to use a modern flash with a modern camera. I save the old ones for the old cameras, generally, unless I am confident of the trigger voltage.

The Pentax flashes I've used from the 80s and on are fine. AF280 is almost always the right answer for something with a hot shoe

though I also use AF160s for their small size on occasion.

If an old flash gets confused and won't work properly, use another one...

-Eric

lotech · 04-22-2023, 05:14 PM

Originally posted by Lord Lucan

...In the case of non-detachable sync cords, a common arrangement was that they had a slot/groove to stow them when not in use, as they would be when the flashgun was being used in a camera hot shoe. The flashgun foot contacts were only made electrically live when the sync cord was in its slot, and otherwise were dead when the cord was pulled out to connect to the camera PC socket. The picture below is an example ("Fig 42"): the foot contacts lead up only to a PC socket in the flash body (visible just above the cross-head screw in the foot). When stowed in its slot the cord plugs into this socket and makes the foot contacts live, and when not stowed (as in the photo) the contacts are dead...

Right, that's simple very neat design that I missed ha ! without the PC cord in it's own place the 'shoe' can do nothing.

womble · 04-24-2023, 01:51 AM

If you are really worried about it, cut a small square of film from the leader of a developed roll and slip it between the shoe and the contacts.

04-22-2023, 01:49 AM	#1
lotech Pentaxian Join Date: Apr 2012 Posts: 1,312	Using hotshoe flash on vintage coldshoe camera Most of the vintage camera has coldshoe instead of hotshoe, I wonder how to use a modern hotshoe flash on it. I ask because the coldshoe short-circuit the hotshoe contacts so the flash my not function normally even with PC cord attached. I found some 3rd party flash does not work properly on my K3 even with hotshoe, that the flash will self-fire completely lost control, but original Pentax flash and newer 3rd party models worked fine, so that older flash with far more simpler design will not know how to adapt to the camera with coldshoe.

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04-22-2023, 02:29 AM	#2
Lord Lucan Pentaxian Join Date: Sep 2017 Location: South Wales Photos: Gallery Posts: 2,961	Perhaps this linked article will help. Beware that older flash units often had a high trigger voltage which can derange a modern electronic camera (not just digital ones), if not damage it. Hotshoe Configurations

04-22-2023, 03:54 AM	#3
lotech Pentaxian Join Date: Apr 2012 Posts: 1,312 Original Poster	Originally posted by Lord Lucan Perhaps this linked article will help. Beware that older flash units often had a high trigger voltage which can derange a modern electronic camera (not just digital ones), if not damage it. Hotshoe Configurations Thanks for the detailed info., I'm just wondering if the coldshoe will shortcircuit the flash prevented it to work properly, I got couple of sensor flash that I planned to use on the vintage RF.

04-22-2023, 04:24 AM	#4
kypfer Pentaxian Join Date: Jan 2018 Location: Jersey C.I. Posts: 3,593	In my experience, if a "hot-shoe" flash also has facility for a cable connection, the cable connection will isolate the hot shoe connection once it's plugged in … that's how my Nissin 360TW works. Alternatively, there were available cold-shoe to hot-shoe adaptors, they fit into the cold-shoe and have a hot-shoe on the top and a connection cable to go to the camera.

04-22-2023, 07:28 AM	#5
titrisol Pentaxian Join Date: Dec 2007 Location: In the most populated state... state of denial Photos: Gallery \| Albums Posts: 1,852	If the flash can;t take a cable, there used to be a hotshoe-adapter, it connected to the camera X-terminal and you put your flash on it BH still has it

04-22-2023, 09:23 AM	#6
lotech Pentaxian Join Date: Apr 2012 Posts: 1,312 Original Poster	Originally posted by kypfer In my experience, if a "hot-shoe" flash also has facility for a cable connection, the cable connection will isolate the hot shoe connection once it's plugged in … that's how my Nissin 360TW works. Alternatively, there were available cold-shoe to hot-shoe adaptors, they fit into the cold-shoe and have a hot-shoe on the top and a connection cable to go to the camera. As far as I understand the PC cable only has 2 contacts, which simply act as electrical switch that short/close circuit to trigger the flash, and the cable is fixed to the flash no need to plug in, so I don't know how it can carry 'control signal' to the flash which trigger to use hotshoe or PC, unless there's a switch on the flash to select.

04-22-2023, 12:23 PM - 1 Like	#8
Lord Lucan Pentaxian Join Date: Sep 2017 Location: South Wales Photos: Gallery Posts: 2,961	Originally posted by lotech As far as I understand the PC cable only has 2 contacts, which simply act as electrical switch that short/close circuit to trigger the flash, and the cable is fixed to the flash no need to plug in, so I don't know how it can carry 'control signal' to the flash which trigger to use hotshoe or PC, unless there's a switch on the flash to select. Some cables between the camera and flash (usually called "sync cords") are entirely detachable and some are fixed to the flash. In the case of detachable ones, there is often a microswitch inside the flashgun socket that detects if the sync cord is plugged in, and if it is plugged in the contacts in the foot are electrically isolated. It is like the loudspeaker of a portable radio being disconnected when you plug an earphone cable in. In the case of non-detachable sync cords, a common arrangement was that they had a slot/groove to stow them when not in use, as they would be when the flashgun was being used in a camera hot shoe. The flashgun foot contacts were only made electrically live when the sync cord was in its slot, and otherwise were dead when the cord was pulled out to connect to the camera PC socket. The picture below is an example ("Fig 42"): the foot contacts lead up only to a PC socket in the flash body (visible just above the cross-head screw in the foot). When stowed in its slot the cord plugs into this socket and makes the foot contacts live, and when not stowed (as in the photo) the contacts are dead. Originally posted by titrisol Not necessarily, many "universal" flashes (Inlcuding Metz, Sunpak, Vivitar, Achiever, etc) used to have a detachable cable with a small plug that looked like the earphones plug. Indeed, there was a large range of plugs, and not only of audio jack type - and even those could be 2.5mm, 3.5mm or something else, and of different lengths. Some makers (eg Sunpak) often used a two, three or more pronged plug, and by the 1990's they were using multi-core sync cords with a plug that slid into the camera hotshoe at one end and had a multi-pin plug at the flashgun end, to carry the proliferation of signals that flash units were using by then. Here is a selection of cords ("Fig 40") :

04-22-2023, 02:00 PM	#9
kypfer Pentaxian Join Date: Jan 2018 Location: Jersey C.I. Posts: 3,593	Originally posted by lotech As far as I understand the PC cable only has 2 contacts, which simply act as electrical switch that short/close circuit to trigger the flash, and the cable is fixed to the flash no need to plug in, so I don't know how it can carry 'control signal' to the flash which trigger to use hotshoe or PC, unless there's a switch on the flash to select. Much like a headphone socket on a portable radio … plug in the headphones and the speaker goes silent

04-22-2023, 03:53 PM	#10
TwoUptons Loyal Site Supporter Join Date: Nov 2015 Photos: Albums Posts: 4,213	Those are some good examples... I'll add a couple of things... There may be a weird plug on the camera to try and plug into on some vintage stuff... pre-1960s PC sockets were not universal; finding adapters for those is challenging and/or expensive these days. My experience with PC-hot shoe adapters has not been terribly positive. Most of them are terrible... loose, wobbly, likely to fall out of the shoe. Better to have a flash with a cord. In my experience, it is better to use a modern flash with a modern camera. I save the old ones for the old cameras, generally, unless I am confident of the trigger voltage. The Pentax flashes I've used from the 80s and on are fine. AF280 is almost always the right answer for something with a hot shoe though I also use AF160s for their small size on occasion. If an old flash gets confused and won't work properly, use another one... -Eric

04-22-2023, 05:14 PM	#11
lotech Pentaxian Join Date: Apr 2012 Posts: 1,312 Original Poster	Originally posted by Lord Lucan ...In the case of non-detachable sync cords, a common arrangement was that they had a slot/groove to stow them when not in use, as they would be when the flashgun was being used in a camera hot shoe. The flashgun foot contacts were only made electrically live when the sync cord was in its slot, and otherwise were dead when the cord was pulled out to connect to the camera PC socket. The picture below is an example ("Fig 42"): the foot contacts lead up only to a PC socket in the flash body (visible just above the cross-head screw in the foot). When stowed in its slot the cord plugs into this socket and makes the foot contacts live, and when not stowed (as in the photo) the contacts are dead... Right, that's simple very neat design that I missed ha ! without the PC cord in it's own place the 'shoe' can do nothing.

04-24-2023, 01:51 AM	#12
womble Pentaxian Join Date: Apr 2010 Location: Hertfordshire Photos: Gallery Posts: 4,324	If you are really worried about it, cut a small square of film from the leader of a developed roll and slip it between the shoe and the contacts.