[rollei_list] Re: Rollei Flash
- From: Peter J Nebergall <iusar4s@xxxxxxxx>
- To: rollei_list@xxxxxxxxxxxxx
- Date: Fri, 11 Jan 2008 08:35:46 -0800
At this time almost all my flash work is with my little Nikon SBs, used
in TTL. I know TTL adjusts by flash duration (it is an amazing product,
and justifyably so) -- are you saying some of those short durations can
produce reciprocity failure?
P.J. Nebergall
On Thu, 10 Jan 2008 17:58:11 -0600 Don Williams <dwilli10@xxxxxxx>
writes:
At 03:13 PM 1/10/2008 -0800, you wrote:
These figures look more realistic. Early strobes used higher voltages and
achieved shorter flash durations however this resulted in short duration
reciprocity failure, leading to colour imbalance with colour emulsions
and underexposure with BW emulsions. Modern flashes use larger capacitors
with longer discharge times leading to a safer and more usable product.
My memory is that Bron flashes can still do very short duration stuff.
All the best
Laurence Cuffe
All the best
Just for the heck of it I did a Google search on reciprocity failure and
by far the most citations were for long exposure, but there were some for
short exposure failure.
There are even Kodak sites with correction values and recommendations for
minimum exposure times for various Kodak films.
Bottom line, however, is that emulsions were changed some time back to
better handle the short duration failures, and of course, as mentioned
above, strobe flash durations have become longer with larger capacitors.
On this same subject, Carlos mentions that he still uses a Vivitar 283,
and I do also. Mine is very-very old, and has the high-voltage
high-current trigger for the flash contacts and I feel sorry for the
contacts every time I use it. There are low level adapters but since
nothing in a camera has failed yet I just continue to use my old model.
DAW
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