I had something similar. A Braun Ultrablitz. The battery was two cell (lead acid), clear plastic construction. with 4V and the voltage inversion by a vibrator (just like the car radios at the time). The battery, etc. was in a pack that you carried around with a shoulder strap. The flash part was connected to the pack with a spiral coiled cable. A powerful brute. John ----- Original Message ---- From: Peter J Nebergall <iusar4s@xxxxxxxx> To: rollei_list@xxxxxxxxxxxxx Sent: Friday, January 11, 2008 8:42:23 AM Subject: [rollei_list] Re: Rollei Flash My first strobe was an old "Braun Hobby," unit with a pack that held huge caps and what appeared to be a motorcycle battery. I think it was so bright it gave subjects a sunburn. Yes it was noisy, like a slap to the face. Used it with first TLR, my Yashica "A", then my Cord V... Gone many years ago P.J. Nebergall On Thu, 10 Jan 2008 22:37:49 -0600 Don Williams <dwilli10@xxxxxxx> writes: > Richard Knoppow wrote: > > The difference isn't the caps so much as the circuits used. > > Modern stobe units have some sort of impedance in the discharge > > path through the lens which lengthens the duration of the > > discharge. The old Kodatron lamps, which were I beleive the first > > > commercial strobe units, sounded like pistol shots when they went > > > off from the sudden mechanical change in the capacitors. These had > > > very short duration times, on the order of 1/50,000th second in > > order to get motion stopping effect. Both duration time and > > strobotron life is increased by lengthing out the duration time. > > This also gets rid of the noise. > > I measured my Vivitar flash for duration and found that at > > maximum power it was on the order of 1/400th second, at minimum > > power something like 1/20,000 second. Evidently the unit varies > the > > length of the flash to change its effective exposure. > > I am not convinced about there being a radical difference in > the > > appearance of strobe vs: flashbulb pictures particularly if the > > flash reflectors are approximately matched for size and location > > relative to the camera. I have a means for testing this but won't > > > be able to get to it for a time. > > I believe the difference in flash duration with output power setting > > has used two different methods- > > The early variable power units just integrated the light (photocell > > sensor for those that measured the reflected light) until the > desired > value was reached and then just dumped the capacitor with an > electronic switch. > > Very quickly new designs were produced which somehow opened the > circuit when the desired total output was reached. > > In both versions the flash duration decreased as the power setting > decreased. > > My old 283 is of the newer design and the capacitor remains partially > > charged after a "small" flash. I can run it at 2-3 flashes per > second (as a test) when flashing light colored objects close up. > Fun > but not a practical thing except for close subjects and motor drive > cameras. > > Thyristor was the operative word, I think, for both versions. > > DAW > > > > > --- > Rollei List > > - Post to rollei_list@xxxxxxxxxxxxx > > - Subscribe at rollei_list-request@xxxxxxxxxxxxx with 'subscribe' > in the subject field OR by logging into www.freelists.org > > - Unsubscribe at rollei_list-request@xxxxxxxxxxxxx with > 'unsubscribe' in the subject field OR by logging into > www.freelists.org > > - Online, searchable archives are available at > //www.freelists.org/archives/rollei_list > > > --- Rollei List - Post to rollei_list@xxxxxxxxxxxxx - Subscribe at rollei_list-request@xxxxxxxxxxxxx with 'subscribe' in the subject field OR by logging into www.freelists.org - Unsubscribe at rollei_list-request@xxxxxxxxxxxxx with 'unsubscribe' in the subject field OR by logging into www.freelists.org - Online, searchable archives are available at //www.freelists.org/archives/rollei_list --- Rollei List - Post to rollei_list@xxxxxxxxxxxxx - Subscribe at rollei_list-request@xxxxxxxxxxxxx with 'subscribe' in the subject field OR by logging into www.freelists.org - Unsubscribe at rollei_list-request@xxxxxxxxxxxxx with 'unsubscribe' in the subject field OR by logging into www.freelists.org - Online, searchable archives are available at //www.freelists.org/archives/rollei_list