Safe or no? Pentax K-x & Ricoh XR Speedlite 300P flash

Hi all,

I'm hoping the flash-gurus here can shed some light (ho-ho) on a compatibility issue I'm having.

I've got a 20-year old Ricoh XR Speedlite 300P flash unit which was great in its time - 0-90 degree tilt, auto/manual mode, low/high power modes, etc. I'm loathe to simply bin it, even though it is old, and I doubt it has much resale value.

Meanwhile, I have recently bought a new Pentax K-x dSLR with which I am in love. Its on-board flash does plenty of good work, but I'm still keen to know whether I can safely use my Ricoh flash too, for those occasional moments when I'd rather bounce a flash off the ceiling than point it in someone's eyes. You know the drill, I'm sure...

Trouble is, despite emailing the supposed Ricoh UK official source, as guided by the Ricoh website, I cannot find out the hotshoe pinouts, nor can I get them to commit to answering whether it would even be safe to connect to my Pentax K-x. The best they'd offer by way of advice is to tape over all but the centre pin connection. They couldn't, however, even tell me what those connections were on the Ricoh unit (despite repeated asking in various different ways) - so I'm assuming they've lost the service manuals/design blueprints way, way down the back of the sofa, or they just can't be bothered to go looking for a 20-year old bit of paper in a drawer somewhere. C'est la vie, I guess.

I have managed to find some useful info by myself and on the net, but I'm still no nearer a real answer.

http://www.bdimitrov.de/kmp/technology/hot-shoe/index.html tells me the Pentax hotshoe pinouts are (excuse the mis-aligned ASCII drawings, please):

(Lens-mount side)
X   --- Trigger
x x

^ ^
|  Ready
|
Mode

And by measuring (with a voltmeter) the signals on my Ricoh flash, I've deduced the following:

(Lens-mount side)
X --- Trigger (5.9v when fired/charging, down to 4.9v when charged)
x x

^ ^
| Not sure - zero volts at all times, seemingly. Poss XR auto/mode?
|
Ready (2.9-volt when charged, 0-volt when discharged)


As such, looking at all the above, I *think* the flash is basically safe, in terms of 'zappable' voltages (sub 6v on the trigger is okay for pretty much all dSLRs, from what I've read). However, I'm not sure whether the other two contacts being 'backwards' are likely to cause (a) operational problems (b) damage over the longer term.

I've even considered opening up the Ricoh flash unit and swapping the wires to the two Ready and Unknown contacts (they're just soldered on to a board the other side of the hotshoe base) - but I'm not sure if this is a good idea until I definitely know what the unknown pin does.

Does anyone have any advice/experience here that can help me? I'd be indebted to you, if you do.

And would you:
(a) bin the flash and buy a new one (in which case, replacement recommendations would be great, thanks)
(b) use the flash but only as a remote slave unit (in which case, what recommendations have you for how to connect it to the Pentax K-x & trigger it?)
(c) sell the flash on Ebay (in which case, what's it worth, do you think?)
(d) give the flash to a charity shop
(e) part-exchange it for some candles and a box of matches.
(f) none of the above - insert inventive and humorous solution here!

Thanks in advance for any and all ideas!
Regards
--
Neil

By the looks of it the Ricoh XR Speedlite 300P has the same mount/contacts as Pentax.

I would just pop it on to see what it does, but that's me though and I'm known not to be too careful with my equipment.

You have checked the voltage, and it's low.

The centre contact is always the flash trigger, so that will be compatible.

The other contacts carry a very low current because they are simply sending signals.

In your shoes, I would try it, but if it blows up I regret you will get condolences from me, but no more.

G

Hi Guys - thanks for responding.

@Stefan - the hotshoe contacts are in the same places, yes - but only the back two make contact on the flash unit. Worse, they appear swapped: Ready and (presumably) Mode. I'm guessing it probably won't matter... but I'm wondering whether I should shield them, just in case.

I'll confess that I *have* already given it a try, and it seems to work. At least, it'll flash, and the camera hasn't blown up yet. I'm not entirely sure whether it's working correctly, mind - possibly I haven't set the sync shutter speed right? The camera seemed to want 1/180th sec, and the flash manual talks about 1/125th, so I'm not entirely sure what to use! It's been so long since I've used that flash (and it used to work at 1/125th on my old film SLR, I think).

The other mildly annoying thing is that the K-x can't tell when the flash is fully-charged - but I guess that's down to the 'ready' line being on the wrong contact on the hotshoe. It's no biggy - but it does mean I have to keep taking my eye away from the viewfinder in order to check the ready lamp on the back of the flash itself.

I can live with that - as long as it's not going to do any major damage in the long run. My gut tells me it's *probably* okay... but having just bought the camera, I'm loathe to cook it already!

Thanks for the input, guys. Of course, if anyone's got any further input, advice, warnings or solutions, please do let me know! I'm all ears!

Regards
Neil

Glad to hear it didn't blown up.

If the ready and the info are switch then why not turn them around and see if it works?

Like George says it's the shutter inside the camera that determine the flash sync.
In manual mode you can't set it to 1/180 I believe with such a flash so 1/160 is then the option.
Slower is always good but not faster wan then you can get the shutter inside your shot.

I use an old Ricoh Speedlite 240P with a Pentax K200D occasionally. Use the K-x in manual. Set the flashgun to auto and aperture to whatever the chart on the back of the flashgun tells you is OK for the ISO the camera is set to. Set the shutter speed to anything less than 1/180sec (the 1/125 in the manual was the fastest flash synch speed for the Ricoh KR10 Super SLR so you can ignore it). Works fine for me.

Andrew

Thanks again, gentlemen - you've all been most helpful.

I think I may possibly have confused myself about the camera's 1/180th requirement - I went looking in the manual again, to substantiate what I thought I'd seen, and I can't find it again! All I can find is a reference to the built-in flash having a flash sync range of 1/180th and slower (my bold) and a reference to using the Pentax own-brand external flashes in 'High Speed' mode, which it considers to be speeds above 1/180th (and those proprietary Pentax flashes do this when they're in a special 'HS' mode).

So... I'm not entirely sure whether I was right about the camera's 'requirement' to sync at 1/180th, after all. Maybe the 1/125th that the flash is wanting, will do after all! I will, of course, give both a try and see what happens!

@Stefan - the Ricoh flash has an auto mode which self-monitors the light reflected back from the scene/subject, so I'm hoping it might still work at 1/180th. I probably won't be using the flash in its full manual mode, because it seems such a headache to work it all out! Apart from anything else, I can't work out what the Guide Number would be at some of the higher speeds that the Pentax K-x can do!

The Ricoh manual lists the follow film speeds and guide numbers:

Film speed - Guide Number (m, ft)
25 - 15 (49)
50 - 21 (69)
100 - 30 (98 )
200 - 43 (141)
400 - 60 (197)
1000 - 95 (312)

The problem I have (apart from my own ignorance and stupidity, no doubt!) is that I can't work out what the Guide Number would be at, say, ISO 800, 1600 or 3200. The GNs don't seem to double as the film speed doubles, and (despite having played around with the numbers in a spreadsheet), I cannot work out what the mathematical series is!

So - the Auto mode looks like it will have to do for now (if it works). The Ricoh purports to 'beep' if it gets enough light, but I'm not qiute sure how it can know that the film/sensor is also getting enough. Even the auto mode requires the lens aperture f-stop to be set according to a table (which also doesn't go quite fast enough, but I reckon I can wing this one more easily). It shows:

Film speed (ISO/ASA) - F-stop
25 - f2.8
50 - f4
100 - f5.6
200 - f8
400 - f11
1000 - f16

I'm reckoning that at the higher speeds (3200, 6400 and 12800, we're talking f22, f28 and f32 or thereabouts! Even I can guess those from the preceding sequence! At least, I hope I've got that right!

As for Stefan's idea of swapping the hotshoe contacts around - that's next on my agenda (I mentioned in my first post that I was considering it). Unfortunately, I can't seem to get the flash unit fully apart (I get the freeling I haven't yet found all the screws, or there's something hidden inside the hinge)... so there isn't a lot of room to wield a hot soldering iron yet! But once I've found out how to properly disassemble the flash body, I will give it a go!

And to Andrew - thanks for the update on using your 240P. I couldn't find this one at the Butkus manual site, so I'm not entirely sure whether this is the one with just the 'ready' contact, or the 'ready and mode'. They have a 260P there, and a straight 240 (with no P)... so I'm still playing a tad cautious (in case yours didn't have the 'mode' contact too - and that's the one which is worrying me most, at the moment) Any further light you can shed on your exact model (or the number of contacts it's got) would be really handy.

And do you see the 'ready' light in your K200D's viewfinder? If not, that confirms my findings about which side the 'Ready' contact is on, too. If you do, then I'm back to the drawing board!

Thanks again to everyone for all your input and advice. I'm feeling a lot safer about using it, and having a good experiment this evening when the light drops a bit!

HS is a special mode, it actually fires multiple flashes very fast continuously to evenly lit the whole sensor.
I believe it even times the flashes according to the shutters and how fast they move.


What I meant was is that 1/180th isn't a natural shutterspeed for the camera to come on since it use 1/3th of stops. Just set you camera on Tv or manual, you get 125 - 160 - 200, there is no way you can set it on 180.
So the camera need to know a flash is on the camera to make it stop there. Sadly I believe you've a dumb flash which doesn't tell anything against the camera so it won't stop.
The only way to get it then on 1/180 is the use the X-sync mode, that's the flash sync and set the shutter permanently on 1/180th.
It's the red X on the same dial where you find Av & Tv, ect.

Maybe if you get the ready signal working it might actually stop on 180.

What do you mean with the guidenumber and speed?
If you mean shutter speed then actually it doesn't have any effect at all on the guide number. If you mean ISO speed then a doubling in the ISO/ASA means a doubling in the guidenumber.

You use the guide number to know what kind of aperture, ISO speed and/or flash power you need to use at a given flash distance.

Shutter speeds controls the amount off ambient light in your photo and it does not effect the flash power or guide number because the flash duration is 1/6400th of a second or something like that at least it's extremely fast, so you always get the full flash in your photo.

If I'm not clear enough please say so

Mmm ... I was tryping from (defective) memory. Just had a look. It is a XR Speedlite 240 - exactly as the manual on the Butkus site.

Andrew

That's useful to know - thanks, Stefan. I guess (for me) that'll have to wait until one day in the future when I get a native Pentax flash! For now, this Ricoh will have to suffice (and I don't think it can do anything as sophisticated as HS mode!)


Indeed, you're quite right. I hadn't noticed that. Still - I don't think it matters... I'll try 1/160 and 1/125 and see what I get!


I believe when paired with its original Ricoh XR camera in P mode, it would do that 'flash squelch', but with the Pentax K-x, I think it's almost a certainty that it won't! Even if I swap the contacts over. However, the flash isn't entirely dumb... and (according to its manual) if I get the right aperture set, it'll monitor the exposure through its own sensor, and shut down accordingly when *it* thinks there's enough light. It's just that it won't be TTL, or measured off the film plane (as it would have been on a Ricoh camera in days gone by).


The K-x doesn't have an X-synce mode that I can see. Certainly, there's nothing on the dial selector such as you describe. I will check the manual though, just in case...


That's a possibility. As soon as I can open the &$%£ing flash unit without breaking it - - I'll give that a try!


I meant FILM speed (ISO/ASA) not shutter-speed. Thing is, if you look at the numbers in the first table above, they clearly DO NOT simply follow the pattern of 'double-the-ISO-means-double-the-GN'. I've not been able to quite work out the pattern, but it's looking like if the ISO is QUADRUPLED, then the GN is doubled. Hence, ISO 25 = GN 15, ISO 100 = GN 30, ISO 400 = GN 60, and so on. Still - the interim figures don't look *quite* right to me (and this is taken from the Ricoh flash manual, remember), but I think I might be able to suss out ISO 1600 now.. my guess is the GN would be 120! I can guestimate the inbetweens now, I reckon!

Thanks for the pointers... it has definitely made me think, and as a result, I may have cracked at least some of the problem!


Thanks for checking, Andrew. In that case, yours is missing the extra 'P' connector (which I've worked out communicates to/from the Ricoh XR-P camera body about the mode/sync/etc). It's actually this signal I'm most worried about, because it will be connecting to the Pentax K-x's 'Ready' input, and I'm not sure whether it'll do anything bad, in the long run.

Conversely, I'm pretty sure that the Ricoh flash's 'Ready' indicator hitting the Pentax K-x's 'Mode' input probably won't hurt the Pentax, because (a) the voltage is only about 3v at worst, and (b) the Pentax probably won't take any notice of it, if the 'real' Ready input is inactive. And so far, I've not measured any voltage activity at all on the Ricoh 'P' contact which is touching the Pentax's 'Ready' input. I'm presuming (hoping) that the 'P' contact is actually FROM the Ricoh camera TO the Flash - in which case it'll be safe... but I can't be certain, yet! Hence the mild worry.

Cheers again for taking another look at your flash. Decent of you.

No there is hardly any difference so don't worry.
With the K10D it actually stop firing the flash when you set the shutterspeed at 1/200 or above, don't know if that's true with the K-X but if you can get your flash to fire that might be the problem.


I'm sure you're right about the Ricoh camera, I've never hold one so can't share any experience about that.
The flash indeed isn't dumb but it's dumb for the Pentax since they don't speak the same language, I hope the ready signal is the same with both

About TTL, Pentax only supported that with the ist DSLR cameras (and some film) but with the current DSLR and a bit older only P-TTL works. So your hopes to get a TTL flash working on the K-X is non.


Yes you're right was looking at my camera and didn't came up in me the K-X might not have it.


Yes you are quite right, found this.
The higher the sensor’s sensitivity is, so the efficiency of the flash will increase. Doubling the ISO will increase the GN by 1.4 and after ISO 100 will double the GN.



No problem if you want to know more there are some good articles on the web that can help you and even video clips.

Manual does sound taunting but you've instant feedback how your photos are with the K-X so if you're trying some still life's at home just take you time and experiment with the flash on manual.

Hehe - dunno whether it was bravery or stupidity, but I took my life into my hands and partly disassembled the flash, and swapped the 'ready' and 'p' cables around.

Took a bit of doing, because I still wasn't able to get the whole flash apart neatly (which is probably a good thing, actually, because I means I wasn't able to accidentally touch the flash capacitor and get a big zap!)

But with a fair bit of wiggling and prising, I was able to get the hotshoe base out, just enough to get a 25w soldering iron with a point-tip bit onto the pink and white wires. Desoldered them, swapped 'em over, and soldered them back on, then put the unit back together.

Moment of truth... and yippee! We have 'flash ready' light working on the K-x now. Seems to be perfectly normal - steady 'lightning' lamp in the viewfinder when the flash is charged and ready to fire, switching to flashing whilst it recharges. Nice.

Haven't quite worked out whether the 'P' line is doing anything useful, or whether the Pentax is actually 'saying' something down that line which the flash is interpreting (I guess it depends what the Pentax 'mode' commmands are, and I haven't found these out yet).

But certainly the flash works fine enough in M mode on the K-x. In fact, the shutter-speed automatically sets itself to .... 1/180!! Even though I can't normally dial that in! Go figure! But it means I can just set up an appropriate ISO and aperture f-stop from the scale on the back of the flash unit, and I get a nicely exposed shot with no blown highlights and a decent histogram.

Not quite sure whether Av mode is working right (in these low-light conditions indoors, it was offering a faster shutter-speed with the flash unit on and ready, than it did without, but it was still far too slow for a good exposure. Maybe I'd better read up Av mode + external flash settings a bit more before drawing a conclusion, though.

Thanks again for the help and encouragement. If nothing else, you've inspired me to get physical with the soldering iron!