Non-Pentax off-camera flashes with K100D?

Hi

I wonder if someone could give me some advice, please. I recently decided to switch to digital and bought the K100D. I now want to take some off-camera flash pictures with it, but I’m not sure if I can use my existing flash units. In the past, with my film Pentaxes (e.g. the Z-1), I would simply attach any old hot shoe adapter (such as a Hama) to the camera, plug one end of any sync cable into the PC socket of the adapter and the other end into whatever flash gun (I’ve been using a National, some small Vivitars and two Electra studio flashes lately), and all’s been fine.

But I’m cautious about doing this with the K100D with its, presumably, more intricate electronics (and, of course, the manual only recommends Pentax flashes). What should I do? Can I use, say, the National flash (it’s a PE-357S) attached to the camera via a non-Pentax sync cable and a non-Pentax hot shoe adapter, or must I buy a Pentax flash, cable and adapter or some other dedicated flash (apparently Sigma makes one)?

I’m not too concerned about the studio flashes. I wouldn’t like to risk connecting one of them with the K100D, but once I’ve got a smaller flash gun going that’s connected to the camera, I’ll simply use that to fire the studio flashes via their slave units.

Any responses would be much appreciated.

Errol

Hi Errol, welcome the the forum.

Why cant you use the pop up flash on the camera to fire the slaves on the studio flash? or are they "slave" via cables?

Hi Errol, welcome from me too.

The popup flash is P-TTL and fires a pre flash.

This topic was cover not so long ago, have a look at this thread https://www.pentaxuser.com/forum/viewtopic.php?t=3312

Hi

Many thanks for the replies and the welcomes.

Impotentspider, thanks, yes, but as Brian says, there's the problem of the pre-flash, and I haven't yet found a way to turn it off (though the manual suggests you can). But, even if I could turn it off, it of course adds another light to my lighting set-up, which I might not always want (e.g. in backlit shots) and would introduce an unwanted extra catch light in portraits.

However, that still doesn't help me in cases where I want to use a separate small flash gun in a portable arrangement, say handheld or attached to the camera via one of these angle brackets. This would be specifically to avoid the dead-in-line flat lighting of the pop-up. Any ideas about this?

Thanks Brian. I've seen the discussion in that thread, and it was quite interesting, but unfortunately it doesn't really solve my problem as mentioned in the previous paragraph. The radio slave might be a possbility to look into for the studio flashes, but the idea of an older Pentax flash that doesn't do P-TTL sounds good. Getting one to South Africa through the post in one piece is another problem! But I'll have a look on eBay. Could you perhaps suggest some model numbers of suitable ones, please?

I'm still wondering whether getting the dedicated Sigma isn't the answer. After all, the guy's got it in the shop down the road, but at around R3000 (about £200), it's not cheap. And then it may still have a red-eye reduction that you can't turn off.

Now if only I could be sure that I can connect my National flash that would be the end of my problems!

Many thanks for the replies.

Regards,
Errol

The solution is to buy a very cheap, very small, manual flashgun, and mount it on the hotshoe. This will then trigger an external very cheap but somewhat more powerful flashgun located to the side.

No reasonably modern flashgun is going to damage the camera, and if you are at all worried, measure the voltage across the terminals with a
voltmeter.

G

This link might be of use:

http://www.botzilla.com/photo/strobeVolts.html

Dan

Hi George and Dan

Many thanks for the replies. George, yes thanks a lot, I didn’t know that all it boils down is measuring the voltage across the terminals of the hot shoe adapter, and if it’s high it’s risky, and if it’s low it’s fine. However, how low is low enough for this camera?

I used my digital multimeter to measure the voltages for the flashes I mentioned above and got some interesting results.

The big studio flashes were 10,9V and 13,4V. The medium-sized National (which runs on four penlight batteries) was 12,8V. And, believe it or not, the small, innocent looking Vivitars (operated by two penlights) built up to more than 200V! One was 205V and the other 215V.

So I certainly won’t be connecting the Vivitars directly to the K100D. But I see myself more and more driven to buying the Sigma, which I’m told is compatible and presumably is safe. As you said, one can get a small flash to fire the larger ones, which would be fine, but even so how does one know any small one is safe? After all, I would’ve thought that of all mine the little Vivitars would be the safest, but now they don’t seem to be so at all. And while in a studio set-up one could set a little flash up off-camera and then turn its light away from the subject, it would be a nuisance to have two flashes attached to the camera while carrying it around outdoors. Alternately I’ll try to find one of the smaller, older Pentax flashes, as Brian said. That should work fine with the studio flashes.

Many thanks for your comments.

Dan, thanks a million for that link. There’s a great deal of valuable information there, and now for the first time I’m a bit more au fait with what it’s actually all about. Unfortunately they don’t mention my camera or any of my flashes, but I’ll be going back there to learn more about it all. I will also send in the readings that I took for my flashes, as they may be of use to someone.

At present, it looks as if my best bet will be the dedicated Sigma flash. That will work well for outdoors or fill-in flash. Hopefully it won’t produce those annoying pre-flashes, in which case it will work well in the studio set-up too. If not, I’ll have to start hunting for an older Pentax flash, or perhaps the Wien adapter.

Thanks a lot for your reply.

Regards,
Errol

Errol,

I was assuming, perhaps wrongly, that you were on a bit of a tight budget. If so, the cheap manual route is the way to go. But if you can afford the Sigma, or, better still, one of the Pentaxes, then that would be the best solution.

G

I bought a multimeter from Argos yesterday, and used it to measure the trigger voltages of my two, and my Dad's two flashguns.

Mine are an old Jessop 270 TBZ (bounce, zoom, GN27), which I've had for approaching 20 years, and a Braun 320 BVC (bounce, swivel, GN32), which is probably even older since I bought it second hand not long after the Jessop one.

My Dad's ones are a big monster Cobra (twin head, GN 55) and a Braun 260 BC (auto, no bounce).

My two and the Cobra were all under 10V.

But the littlest one, the Braun 260 BC had a trigger voltage of, wait for it...

... 210 Volts !!!!

I guess it pays to measure.

Hi George

Thanks for your note. Yes, well, the budget is always a problem, but having spent nearly R7500 (that's about £530) on the camera less than a year ago (and I was led to believe that's a good price), my first consideration is not to blow it up by connecting the wrong flash. So, even if I have to wait a while to save up the money, I'd prefer to get something like the Sigma (the Pentaxes will obviously cost more, and seem to be in short supply out here) if I can be sure it's safe. But, after all that, I'm still not sure whether one can turn off those darn pre-flashes on the Sigma (or on the Pentaxes, for that matter). Because if they're so amazingly dedicated, won't they do everything that the camera does, including the pre-flashes? A possibility that sounds feasible to me, but I'm just guessing at this stage, is to use a flash like the Sigma, but when I don't want the pre-flashes, just to use it with a simple non-Pentax hot shoe adapter and sync cable. But, again, I'd have get confirmation about whether this will be safe.

Hi Chris. Thanks for the comment. Yes, it seems you never can tell. Imagine how surprised I was when I read over 200V for my innocuous-looking little Vivitars. At first I was sure the meter was faulty.

The main question, however, is how low is low enough for any particular camera? In my case, especially the K100D?

Regards,
Errol