Suggestions on using old flash kit with K100D

Hello

I've been browsing the forum for enlightenment (pardon the pun) and am still in the dark (couldn't help it) about whether or how I can use my old flash gear with my Pentax K100d. I hope someone here can advise me.

I only want the capability to shoot manual exposures with the old kit, and am trying to establish if this is viable or if I need to save my pennies for expensive flash gear. Please say I don't have to!!

My old gear (which still gets used on a Ricoh XR-X) comprises two Vivitar 550FD flash guns - with TTL dedication contacts for Ricoh and Canon cameras - plus a Ricoh dedicated cable allowing use of one flash off camera and another on camera.

1 - I gather I must first work out whether or not the flashes operate at safe trigger voltages, but I am not 100% sure what classes as safe for the K100d. Info appreciated.

2 - Assuming safe voltage, I will need to mask off or disable the dedicated contacts in some way. That should just leave the central trigger contact exposed. With everything on the flashes set to manual, will the camera try to trigger a pre-flash? What camera settings will avoid a pre-flash?

3 - Will the rig I mention work, or am I missing anything obvious?

All responses will be gratefully received - although derogatory comments about my branching to Ricoh when my main kit was Pentax may not go down too well.

Welcome to the board

I've just checking this list of measurements and it would seem the Vivitar 550FD will be just fine.

I can't remember the voltage limit on the Pentax dSLRs, but I'm sure the Pentax was higher than most other brands

Since your guns are Ricoh and Canon dedicated (:shock you should be able to get some kind of hotshoe adapter that will mask the contacts off. Are the Ricoh ones in the same format as the Pentax? (I know that Ricoh used the K-mount... maybe they used the Pentax flash configuration too?? ) EDIT: Just seen that the 550FD does Canon & Ricoh in one configuration, so forget that idea!

You could connect using PC-connectors and a cheap little hotshoe-to-PC-connector adaptor.

Preflash won't come into it. You just need to connect the flash to the Pentax hotshoe and it'll work just fine

I'll see if I can dig anything else up off the 'net....
Matt

Just looked some bits up...

"Hama 6952" will provide a PC cord to centre pin
"Kaiser 1300" will create a PC socket for the Pentax.

You could put the two together... but it'd be a bit wobbly!
Probably the best suggestion is to use the Kaiser 1300 (or equiv) to make a PC socket on the Pentax, and get an angled flash bracket with PC cord to plug in.

Also, see this thread: https://www.pentaxuser.com/forum/viewtopic.php?t=2620&highlight=safe+flash+v...
HTH!
Matt

Hi Matt

Thanks for that swift reply. Plenty of useful detail.

You know, I used to have an off-camera flash angle bracket with a hot shoe linked to the pc socket on my ME Super - so all I'd need to follow your suggestion would be a hot shoe to PC socket converter. If I can find that bracket and connector - could be in my loft, or anywhere in my parents' house!

On the plus side, replacing that rig would be a lot cheaper than buying two new flash guns.

Time to go hunting.

And I'm open to any further suggestions people might have.

For information - I got hold of a multimeter at the weekend and checked the voltages on my two Vivitar 550FD flash guns.

NOTE: I was using NiMH rechargeable batteries, haven't tested with alkalines.

The readings came in at 6.5 and 7 volts respectively after I waited for the readings to stabilise. I noticed that they were climbing slowly after they reached about 6v, so it may be that they will go a bit above those figures. if left charging. However, I don't see them exceeding 10 volts at any time, so I shall make use of them with my K100d.

Additional Information and a request for suggestions...

The hotshoe adapters look problematic
- my Vivitar 550FD flashguns have 4 dedication contacts as well as the centre pin.

All the adapters I can find have metal fittings all but surrounding the centre contact, and the metal seems to be touching (or even part of) the negative contacts which form the gripping parts of the hotshoe.

This means the dedication contacts will all be in contact with each other and with the negative pole of the flashgun. I am worried that there could be some sort of electrical interaction of the "oops, that didn't work" variety.

Anyone know enough about all this to pass comment?

If it helps, the reason for 4 dedication contacts is that the flash was designed to give TTL function and dedication with Ricoh XR series cameras, and also dedication with Canon (and I think Minolta) cameras.

My ideal would be to find an adapter which would let me plug a flash gun into it and only have the centre pin and side rails making contact to form an electrical circuit.

As always, enlightenment would be appreciated! Ho! A Pun.

Andrew

Andrew,
I understand what you mean - and yes, it's probably an issue (the Pentax AF540 misbehaves if one of the dedicated pins is shorted).

However, I'm sure I have seen adapters that are plastic except for the centre pin contact. Just can't remember where on earth I've seen them

If I can find any current ones I'll reply on this thread. However, you may get better results if you phone round second hand camera shops (e.g. mxv.co.uk , clocktowercameras.co.uk etc). If you explain that you need plain-old-PC connection for a dedicated flash they may just have something lying around in a junk box

Matt

A Camera Fair might be a good place for one of these adapters. They can be quite useful.

Greetings! If I understand the discussion correctly, I should be able to use any Pentax branded flash in manual mode with my Pentax dslr. My specific interest is connecting my auto strobonar 772 (circa 1972) to my ist* ds. In order to do this I would need a hot shoe to pc adapter. The question of the trigger voltage has me in an uncertain state. How is this measured? Are there instructions somewhere? Is this even an issue with this old of a flash? I would appreciate any thoughts, info, or leads you would care to share.

Dave Bauer

The trigger voltage is measured using a volt meter (digital or analogue) between the centre pin and the ground contact in the side of the mounting slot.

And do this carefully... without touching the meter probes or contacts with your fingers
Matt

Thanks for the info and advice!! It turned out not to be a shocking experience for me and the unit had a 1.65 trigger voltage.