A
Abbazz
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Epson RD1/RD1S.BTW, I am not aware of any digital cam that uses a mechanical shutter. Those hand cranked gizmos are history.
Cheers!
Abbazz
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Epson RD1/RD1S.BTW, I am not aware of any digital cam that uses a mechanical shutter. Those hand cranked gizmos are history.
I understand that ... but I think you'll find that in the time that the shutter plane is moving along that it has to pulse a few times on a single charge ... this causes the GN to be revised down ... did you not read what I explained? If you have an alternative mechanism to explain it I would be interested to read it, but to my knowledge it works as I explained.Pellicle, The Nikon SB-24, for example can do >1/10,000 s flash at its lowest power. BTW, with the D70, at high speeds, the whole sensor is exposed. No clippings occur.
There are others that can do even higher.
Not true Vivek. focal plane shutters get their fast shutter speeds by releasing the second curtain before the first curtain has travelled to the bottom of the sensor, a stip of light travels down the sensor. For faster shutter speeds the strip of light is narrower for slower ones it's wider.Pellicle, The Nikon SB-24, for example can do >1/10,000 s flash at its lowest power. BTW, with the D70, at high speeds, the whole sensor is exposed. No clippings occur.
There are others that can do even higher.
This is where High Speed Sync comes into play and why it is so important to TriCoast’s wireless flash technique. When you have your High Speed Sync button set on your flash and you click the shutter to take an image, everything works the same with the curtains, however now the flash fires for a longer period of time and keeps firing as the stripe between the two curtains runs across the chip or sensor. So even though the shutter was never completely all the way open, all of the chip or sensor gets the light of the flash on it. However there are drawbacks to this technique in that the faster the shutter speed is the less time the flash can “fire” on the chip or sensor. The end result will be less light on your image. Due to this effect your light source needs to be closer to your subject the faster the shutter speeds are to get more light on them
or use the system pioneered by Olympus (iirc) which essentially high frequency pulses the flash for the duration of the shutter operation....The only way you can get all the sensor to be exposed at high speeds is to use a copal shutter built into the lens, this is impractical on any camera that can change the lens hence the use of focal plane shutters on DSLR's.
one of the few advantages of being old is that I lived through this ... so I actually remember it rather than need to research it.This is what gives Olympus engineers their clue. Instead of just one flash emission per discharge, the F280 produces thousands of pulses, perfectly timed so that the level of illumination remains constant from start of finish.
Then we are back to the limited GN of the flash.or use the system pioneered by Olympus (iirc) which essentially high frequency pulses the flash for the duration of the shutter operation....
yep remember the old GE flashbulbs?Then we are back to the limited GN of the flash
GN 200 ... man ... stick that in your pipe and smoke it ;-)When used with ISO100 B&W film, they give a guide number of about 200 at 1/100s shutter speed.
He has a smoke detector in his workshop, good to see He's safety minded!!!yep remember the old GE flashbulbs?
GN 200 ... man ... stick that in your pipe and smoke it ;-)
http://graflex.org/flash/ge-5.html
http://www.darklightimagery.net/flashbulbs.html
watching this video was enough to make me sigh ..
http://www.youtube.com/watch?v=x9Pn8AUwmHQ
just how dumb are some people?
Chris, Search p.net for Frank Skomial's posts. AFAIK, he is the one who found this feature and expounded on it. He also knows a thing or two about flashes and flash sync and such.Not true Vivek.
Chris
real interesting ... reading Edward Ingolds discussion on the only thread I could find much detail on he says:Search p.net for Frank Skomial's posts. AFAIK, he is the one who found this feature and expounded on it.
I'm not entirely across the system, although Frank says in this post:The D70 has a CCD sensor with an electronic (gate) shutter that supplements the mechanical shutter. It appears that the mecanical shutter is fully open at all shutter speeds, and does not exceed 1/250 second. The electronic shutter takes over above 1/250 second and affects the entire image area at one time. Therefore, you can use an SB-800 at any shutter speed if you sync from a PC port rather than from the hot shoe. You may find an adapter you can place between the SB-800 and the hot shoe to either eliminate the "TTL" connections or provide a PC port. If necessary to prevent shorting, insulate the foot (or accessory shoe) of the SB-800 with Scotch Magic Tape.
its interesting that they apply an electronic gating method, but it seems that the flash operation is more or less as described above (pulsing).This requires to place FP flashes very close to the subject, - (due to FP/HSS loss of power/or rather spread of power over longer time - thus making it "thin"),
which kind of implies that the shutter is open less than 250th ... hmmmTo prove that I was right with D70 and SB800 FP operation at 1/4000 and my understanding was correct about this sharade, I performed test with D70 set in manual at 1/4000. On purpose I used a non-FP flash, notably great flash Sunpak 555, and expected partially exposed frames.
Using non-FP flash at 1/4000 I expected to obtain partially exposed frames, but to my surprise ! entire frames were exposed correctly, end the recorded picture data stated 1/4000 shutter speed. I just could not believe my eyes. The only explanation is that Sunpak 555 flash slowest duration is 1/200 and that is certainly long enough to cover narrow shutter slot (1/4000) travelling across the sensor that only needs 1/500 sec to complete the journey.
The bottom line is that D70 shutter speed faster than 1/500 can be used with FP flash, or any flash with longer duration than 1/500 sec, but results are not quaranteed by anyone. You are responsible for setting appropriate flash output level to obtain correct exposure.