old flash compatibility

<p>I don't have it with me or I'd say exactly what is is, but I have an old flash from my ME Super (manual distance switches, fixed 90 degree bend pointing forward). Will this be compatible with my K-x? I had heard I shouldn't use it on my Olympus E-510 because of voltage differences that could fry the camera. Would I be taking the same risk with my K-x? Thanks!<br>

Matt</p>

<p>Yes, all Pentax dslrs are sensitive to trigger voltage. I think all dslrs are. This is the voltage across the sync terminals of the flash when it is fully charged. Some old flashes can have trigger voltage of 300 volts or more. A modern dslr doesn't do well with more than about 25 volts. Even less is better, if possible.</p>

<p>The reason is that, in your old ME Super and most film slrs, the sync mechanism is a simple metel-to-metal contact. This can take pretty high voltage with no damage. On a dslr, the sync is all electronic, which likes things in the ten volt or less range.</p>

<p>It is easy to check the voltage of your flash. All you need is a simple digital multimeter. You can pick these up for $10-15 and they're handy to have around the house, so its a good investment. Simply charge the flash until the ready-light comes on. Then touch the meter leads to the hotshoe contacts. These will be the center pin and a metal contact on the side, in the slot that engages the lip of the hotshoe. If the voltage is more than about 25 volts, I wouldn't use it.</p>

<p>On the other hand, Wein makes a little device called a "Safe-Sync" which fits onto the camera's hotshoe and provides a new hotshoe for the flash. In between, there is circuitry that steps the voltage down to a safe level.</p>

<p>Paul Noble</p>

<p>I have a multimeter so I'll check that out.<br>

Thanks Paul!</p>

<p>Even if the voltage is ok, it is still a rather "crippled" situation, unless your flash has its own "Auto" mode independent of any TTL mode, or you always shoot your flash shots in the flash's manual output, using an external light meter. Otherwise, your flash would have to be P-TTL compatible as mandated by recent Pentax DSLR design, in which case it would not be a very old flash.</p>

<p>Here's a <a href="http://www.botzilla.com/photo/strobeVolts.html">link</a> I found while researching about old flash guns' compatibility with my K100D Super.<br /> The info's slightly outdated, but worth perusing for a basic guideline.<br /> <br /> Hope that helps, good luck.</p>

<p>I use an old Pentax flash on my K10D, it's the <a href="http://www.bdimitrov.de/kmp/flashes/TTL/AF200T.jpg">AF200T. </a> It's useful because you can manually vary the light output, so when I use it I simply shoot in full manual mode. Old TTL flashes that don't have adjustable power settings are pretty much useless, even if the trigger voltage is OK.</p>

<p>Manual flash is not such a bad thing with digital. I shoot with older nikon flashes on my k20d, or more often radio triggered from the k20d. I don't use a meter, I guess, then fire a test shot to check the effect and the histogram for exposure. Make a quick adjustment to the manual output of the flash and then fire away. Its not quite as fast as pttl, but way more reliable. Really with some practice its very fast. If you shoot in program mode then you probably want a program flash, but if you don't mind being in control of the camera, you won't mind being in control of the flash.<br>

Nikon film era flashes are a great deal, they won't ttl, but most have a decent auto mode, and all have good manual adjust from 1/1 1/2 1/4 1/8 1/16. I have two sb27s and an sb28, these three flashes cover just about every situation I'm likely to find, and I paid less than $50 for each one.</p>

<blockquote>

<p>If the voltage is more than about 25 volts, I wouldn't use it.</p>

 

</blockquote>

<p>Most cameras are o.k. up to 250 volts - check your manual.</p>

<p>This low sync. voltage nonesense for DSLRs is mainly paranoa.</p>

<p>Is there any difference if you work the old flash off rhe X-sync socket rather than the Hot Shoe?</p>

<p>It's a AF200S. There are three pins. The voltage between the center and one side pin is 5.4v, to the other side it's 3.2. So it seems like it might work.</p>

<blockquote>

<p>Is there any difference if you work the old flash off rhe X-sync socket rather than the Hot Shoe?</p>

</blockquote>

<p>I would say no. I think most of the warnings about using high voltage flashes on hotshoes are worries about fitting a fully charged flash to the shoe and shorting the sync. pin out to another data pin. The actual sync connection will be the same circuit (parallel connection) or an identical circuit - either PC sync. or hot shoe.</p>

<p>Modern cameras use opto-triacs or thyristors to trigger the flash. It is not possible to buy one of these which is only rated at 6 volts (which is an often quoted maximum) or even 25 volts. They are all specified at 200 + volts.</p>

<p>Also, only an idiot of a camera electronics designer would create a camera flash sync. circuit which was incompatible with every flash made over the last thirty years and which would be damaged if used with such a flash.</p>

<p>I think it's a combination of paranoa and manufcturers perpetuating a myth in order to sell their 'compatible' flashguns.</p>

<p>However: ********* Experiment at your own risk! ****************</p>