I was unaware of the F280's guide number differences between cameras.
After reading the user's manual and your two links a couple of times I
still haven't a clue. The implication as that when used on the OM-707
that the flash actually puts out more power. I dunno why but that's the
only thing I can think of.
Anyhow, your questions got me interested enough to go play with my Metz
52-AF for 4/3 and m.4/3 as well as the Neewer CN-LUX 360 LED thingies
mentioned here recently by Moose and me.
The Metz 52-AF also has FP mode. The 52-AF is a zoom capable flash and
at 28mm equivalent (the coverage angle of the F280) the 52-AF has a
guide number of 30 vs. the F280's 28... pretty close. Therefore I
conclude that the power outputs of both units doing FP mode repetitive
flashes is probably pretty close.
I wanted to visually check the brightness of the 52-AF's FP mode flash
but discovered that you can't put the flash into FP mode unless it's
mounted on and communicating with the camera. But then I remembered its
modeling light option. It appears that the modeling light is nothing
but the manual version of the FP mode. When activated it flashes at a
very fast rate for 2 seconds.
I then decided to visually compare the brightness of the modeling light
in a semi-darkened room (mid-morning day light with blinds closed) with
the light produced by the 35 LED Neewer CN-LUX 360. Visually, they are
pretty much the same except that the LED light is constant.
Conclusion: The FP mode of the F280 likely has no brightness advantage
over the Neewer LED.
Next question: How does the Neewer do as a substitute for macro flash.
Answer: Not very well. At best it might be used as a fill light in
shade. It is totally overpowered by daylight but in mid-morning shade
and up very close to the subject (maybe 6") it increased the exposure by
1/3 to 2/3 stops. In the specific case it raised shutter speed from
1/200 to 1/250-1/320.
The Neewer lights can be physically joined together to produce more
light but it's not very useful for a macro subject since the lighting
unit becomes much larger and much of the light no longer strikes the
subject when up close. Making it more useful would require some gadget
to concentrate the light... a white funnel or a fresnel lens or ???
Chuck Norcutt
On 8/16/2016 7:24 PM, Mike Gordon via olympus wrote:
Yes, on topic. ;-)
The flash has always been a bit of a mystery. As best I can tell and
confirmed by Tim, in Super FP mode the output seems fixed. So why are
the GN's different
for the OM -77AF and a 4T??????????
http://www.mir.com.my/rb/photography/hardwares/classics/olympusom1n2/shared/flash/f280.htm
http://olympus.dementix.org/esif/om-sif/flashphotogroup/f280.htm
The write ups imply that the flash is metered--perhaps if it strobes
fast enough it should be. A Flash bulb should be "meterable" too, but
John H never recommended using anything but manual mode for flashbulbs.
If one wishes to use a given aperture, seems one has to use distance
alone to modulate ambient/fill flash ratio with the F280. The shutter
speed might change a tad due to the flash and thus the GN but the effect
should be minimal, I would think, unless quite close.
I have not read many compliments from list members about the 77AF
body--no manual mode to start. I wonder how it compares to the little
LED gizmos in terms of GN for use in fill. I do like the faster synch
speed of the 77AF.
My recent flutterby chasing with OM gear got me a thinkin' and a
ponderin' about it again.
Mike
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