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[OM] Solution for slow synch speed for OM2 with fill-in flash

Subject: [OM] Solution for slow synch speed for OM2 with fill-in flash
From: usher99@xxxxxxx
Date: Thu, 11 Aug 2005 19:10:07 -0400
Chuck and Andreas,
Thanks for your input.  I have read the T20 manual many times and alot of thing 
are implied and never 
stated.  It was never clear there was an "auto"
mode without TTL.  There are two auto settings as you mention and I had assumed 
they controlled the 
max output and that the suggested f stops were not mandatory for it to work.  
(wrong)  It appears that if the camera is in manual mode
and the T20 in one of the auto modes, that this is non TTL auto.  It sounds 
like if this fill-in with bright light is doable, I will have to be very close.
I do have a large Vivitar flash with a thyristor that does not talk with the 
OM-2.  It has approx  twice the GN of the T20, but states should be used in 
manual mode for fill-in.
I supose one could calculate the appropriate distance for full manual and use 
the zoom to frame the picture properly, if possible.  I also lost you on 
changing the ISO of the flash---does the OM-2
contol this?   Thanks,  
Mike
usher99@xxxxxxx wrote:
> Wondered what people do with bright light where there are harsh shadows with 
> OM-2.  Do neutral density filters work OK for this problem??  I usually only 
> lug around the small T20 flash.  With 400 film at max speed of 1/60 there is 
> not much leeway.  Thanks for any suggestions.
----------------------------------

No matter how you do it you've got to get the exposure to the point 
where 1/60th is OK.  If you're facing sunny 16 conditons in the 
foreground (meaning the main subject) you don't have any choice but to 
accept sunny 16.

The first thing to do is dump the ISO 400 stuff.  Just use some 
Kodachrome 25... oops!  Guess they don't make that anymore :-)  OK, 
let's assume you've got some ISO 100/125 stuff.  Even with that you're 
already at f/22 in full sun.  Even an ND8 only cuts this by 3 stops to 
f/8.  This is a bit more like it but would be even better if you had ISO 
64 film and could open up to f/5.6.

Your next problem is to make your flash punch through this same ND8 
filter at one to two stops less exposure.  If you were shooting the 
camera at f/8 you would want the flash to believe that the camera is at 
f/4 or f/5.6.  Since the T-20 has normal auto range settings at f/4 and 
f/8 I'd choose f/4.  This will give you a two stop lesser exposure by 
itself and you could adjust the ISO setting on the flash downward to 64 
to make only a one stop difference.

This assumes that you're shooting the camera in manual mode at 1/60th 
and have the flash in "normal auto" mode vs TTL.  John Lind has posted 
instructions several times here on doing TTL fill flash but it's all too 
complicated for me.  I'd rather not give the camera a chance to make the 
wrong decision.

In a related condition you may be shooting in the shade with a bright 
sunlit background.  Here you have to make an ambient light exposure for 
the bright background and use flash power to bring the subject up toward 
the background brightness.  I don't think everyone would agree with me 
but, in this case as long as the total sunlit area isn't too large, I 
believe it's OK to let the sunlit background be a stop or so overexposed 
if you really can't close the gap on brightness range.  When looking 
from shade into sun I think it's normal for us to expect the background 
to be a bit overly bright.

I think I may forever hold onto my Minolta A1 since it can sync with 
flash at 1/500th or possibly much faster.  It's a great tool for 
overcoming these bright sun situations.  Some of the Nikon DSLR's go to 
1/500th also but this great advantage gets negated by a minimum ISO 
setting of 200.

Chuck Norcutt


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