All Things Mopar wrote in news:Xns9591984A5BA6ReplyToken@
216.196.97.135:

bob commented courteously ...

As I said, I don't see an "auto" or "TTL" control or any
control on the Vivitar 728. So, I'd expect that the 1/16"
diameter sensor on the 5700's built-in Speedlight is being
used to measure the reflected light and make all the
exposure decisions.

Are you saying there are NO controls on the back of the vivitar flash?
Other than the power switch and the test button, that is... If there are no
controls, then you could not have tested the flash in manual mode (the
flash, not the camera) as you previously indicated!

Does the front of the flash say 728AFNi?

Yeah, but if you are in full manual, you do need to be
fairly accurate with the distance given the fact that flash
light falls off as the square of the distance and you want
to get something at least mid-range in the exposure so
highlights aren't blown out nor are mid-range and shadows
turned into mud, resulting in digital noise.

With a flash in auto mode, it knows how you set the camera, and it takes
care of the exposure. The flash has a sensor on the front that measures the
light. You don't need to be accurate, because the flash is. If your flash
only has TTL mode and doesn't have auto mode, then you wouldn't be able to
try that out.

Its when you have a flash in manual mode that you need to be accurate,
because then nothing is doing any metering, but if your flash doesn't have
a manual mode, then you can not try that either.


I wouldn't be playing with full manual in the first place if
I could get the 5700's "auto" to work. For now, I'll have to

If your flash doesn't have a manual mode, then using manual settings on the
camera aren't going to help.


cool my heels until I get the blankety-blank thing back
around Thanksgiving to see if they fixed it, said "no
problem found", or as Richard Thomkins suggested (based on
exposure variability he's also seeing), live with the fact
that it's a design flaw.

I would guess that the flash system on my 5000 and your 5700 are the same.
My 5000 handles the external Sunpak flash I use really well. If all else
fails, you can sell your vivitar on ebay and buy a Sunpak. Since the Sunpak
has TTL, auto, and manual, you can get really good flash pictures with any
camera.

Besides -- all you need to do is leave the monitor on and
review the shots with the histogram and you will know
strait off if the exposure is OK or not! It's not like
cars
in museums are action shots ;-)

The 5700 has a nifty feature where it shows the picture it
just took for 3 seconds and gives me a chance to delete it.
So, I *know* right then if it is OK, sorta OK, or crap. Of
course, there's an ancillary problem where the viewfinder
and/or LCD display looks considerably brighter than what I
see on three different PCs when looking at the actual JPEGs.

But if you put it into play mode and roll the dial two clicks clockwise, it
will show you the histogram, and then you will know exactly what the
exposure looks like, regardless of the condition of the LCD.


But, that's not the issue. The issue is what to do about
lousy exposure once I see that it's 6 stops under, while the
picture I took 5 feet away 2 minutes ago looks perfectly
fine.

We still haven't figured out how your flash operates. If it only has TTL
mode and if it isn't working right, then you probably just need a new
flash.

If the flash has an automatic mode, it's only going to be 6 stops under if
you are too far away. If the flash has a manual mode, it will only be 6
stops under if you are way too far away.


I can't speak competantly of the flash(es) you've used nor
what your experience has been with digitals in a museum
environment, so I'm hardly arguing with you, just commenting
on what I see and what Nikon has told me.

Most people in tech support don't know how to use the products they support
-- they just read scripts. It's pretty clear that the guy you talked to
didn't know how to use your flash. That seems to be the real issue --
figuring out how to use the flash, and then determing which settings on the
camera to use to support the flash.

Bob


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