New Metz HSS Flashes

greenspun.com : LUSENET : Pentax 67 SLR : One Thread

The latest CameraArts includes a new product blurb about the Metz 54 MZ-3. Features of interest to 67 shooters are film format designation for the auto flash zoom and high-speed flash sync capability. Since the 67 doesn't have a HSS flash mode there's no way to use this with TTL flash metering, but I'd be curious to see how it might work in auto mode. Does the 67 generate a flash trip signal to the X terminal with the shutter set faster than 1/30th? I know you're supposed to set the shutter to X, but I sort of assumed the body generated a bare trip signal every time the shutter was tripped, whether or not the dial was set to X or B. I can't see any reason to lock out the flash trip for speeds above 1/30th other than extreme idiot-proofing.

-- Bill Baker (wab@well.com), March 14, 2001

Answers

It will not work. If I understand correctly you are wondering if the P67 will work with high speed sync by using the normal sync signal. The P67 generates a sync signal for any shutter speed (at least the P67II does) but this is of no use for high speed sync (or as its otherwise known focal plane high speed sync). The problem is that the camera generates the normal sync signal only after the first curtain reaches the end of travel (i.e. shutter fully open). If the shutter speed is higher than 1/30 then by the time the first curtain stops traveling the second curtain is already on it way (somewhere in the frame depending on shutter speed) otherwise known as slit exposure. This will result in a partial flash exposure (flash banding). What is required is for a signal that occurs even before the first curtain has left. If after this signal there is a constant flash source for longer than 1/30 of a second then the exposure will be even at any shutter speed. The P67 happens to have such a signal, the FP sync. Its a shame Pentax left this feature out in the P67II. Now there is no way of using high speed sync without modifying the camera. I've heard comments stating that the FP sync was removed because its outdated since its useful only with flash bulbs. Wrong! Its been prety much usless only because pentax has not designed a high speed sync flash to make use of it. But if you know a little about flash systems you can adapt other high speed sync flashes to the camera. Also some high power studio strobes have the ability to generate long flash pulses in the order of 1/40 which could give the ability for the P67 to sync at all shutter speed (there is also a way of modifying these strobes to lengthen the pulse lentth). I've been tempted many times to purchase a P67 in addition to my P67II for this reason alone. Granted the FP sync has limited usefulness and requires making your own flash adapter not to mention the flash exposure compensation hassles. Still there will come a time in every camera's life when this feature is indispensable.

-- M.B. (mbarroca@americasm01.nt.com), March 14, 2001.

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