The "recommendation of keeping the ambient one-stop lower than flash"
was not a specific exposure recommendation, only an example to indicate
that when using TTL flash the flash must be the main light. One stop is
probably a good rule of thumb but it could certainly be something else.
I think your comment about the Minolta A-series being the only cameras
to use focusing distance for flash exposure control is incorrect. The
Minolta DSLRs incorporate the "Advanced Distance Integration" system as
well when used with D series lenses although, as you say, this is not
pure distance info but also integrates the pre-flash. I assume the Sony
follow-ons do the same since they use the same lenses and flash units.
Canon and Nikon also use distance data. Nikon has apparently used it
for a long time and Canon more recently with its E-TTL II which also
requires specific lenses with distance encoders. As to why distance
alone is not the sole exposure determinant I point you to this excellent
article on Canon flash and the logic (or illogic) behind it. See the
sections on E-TTL and E-TTL II near the middle of the page.
<http://photonotes.org/articles/eos-flash/index.html>
I guess I would be very surprised if E lenses do not also provide
distance data to the camera for flash power computation.
Dr. Flash
Ken Norton wrote:
> Dr Flash, thank you for that report on Will Crockett's DVD as well as your
> experiential notes.
>
> First of all, his recommendation of keeping the ambient one-stop lower than
> flash is an outstanding one. Depending on other factors, I will do either
> one or two stops. With the OM system, this was always a breeze as you would
> stick the camera in auto mode and adjust the aperture till the scale
> indicated 1/30 of a second. With a dedicated flash, the OM (except for first
> generation OM-2) would fire at 1/60 which would automatically underexpose
> the ambient background one stop. NO other camera did it that well. By
> keeping the ambient this close, you would get far fewer big variences in
> exposure between shots.
>
> The ONLY camera I know of that would nail fill-in flash perfectly every time
> was my IS-3 with G40 flash. It set the flash exposure based on
> focus-distance. (it assumed the focus was set on the subject). and the
> background (ambient) was set according to the surround metering. It REALLY
> did work and I used that setup for many an outdoor portrait session.
>
> As to the IR and daylight, I agree. I'm an RF kinda of guy, and I suspect
> that this is one reason why Olympus chose to not use an IR trigger on their
> "R" flash models.
>
> I am reminded, again, why the OM system is such an incredible thing. It
> truely represents the absolute maturity of design. With the exception of
> autofocus and a few more cupholders, the OM system--especially in auto-flash
> control, is lightyears ahead of current systems. We took a HUGE step
> backwards with not only digital, but most PASM cameras. PASM with
> nonsensical digital readouts in the viewfinder have solely set back the
> camera-photographer interface by 50 years. And then the camera
> manufacturers have to try and fix the error of their ways with preflash, IR
> and a host of other things that were previously solved. Other than the
> Minolta A-series, there has been NO digital camera made that truely
> calculates flash exposure based on subject distance (and that was poorly
> implemented and usually defeated by preflash). Why is distance calculation
> so important? Because it works 100% of the time and is completely
> independant of ambient lighting conditions. After all, when you use a flash
> in manual-exposure mode, you are totally tied to the distance calculation.
> This is lighting 101.
>
> That also goes a long ways to explain
>> my travails with the T-32 last week in an auditorium where 99% of what I
>> was shooting was way outside that range. As I said, I'd have been
>> better off shooting manual.
>>
>
> Chuck, this is one of those "been there, been doing that" things for me
> too. I've been chasing flash exposures around like a mother with an ADHD
> child. It ain't working sometimes. Yes, this is one reason why I'm
> drifting back to the OM system. The trevails of film pale in comparison to
> the trevails of flash exposure control. But I will say the Vivitar 285HV's
> sensor does a far better job at great distances than any other auto-flash
> I've used. (speaking of such, I had to teardown and repair one of mine
> tonight).
>
>
>> Finally, manual flash (and focus) is for static setups. He gave as an
>> example shooting portraits of 160 corporate managers on the golf course
>> with Gary Player. Fixed distance, fixed setup, change subjects and
>> shoot. Of course, Dr. Flash has no digital TTL so shoots manual in
>> almost all cases. But now I think I understand where TTL might actually
>> be useful and also where it wont.
>>
>
> Back in the day when I used to shoot Little League team/individual shots, we
> lived by manual flash exposure. Those 160 corporate managers? Try 600+
> kids in an evening. I did the individuals, the chief photographer did the
> groups and he'd assist in matching names with roll and frame number. How
> two of us were able to do 600+ in an evening, night after night, is beyond
> me. Nowadays, with digital, it takes teams of people to pull off the same,
> and our margins are worse than ever. Those packages were nearly pure profit
> 20 years ago. The boss told me one time how much they made on team pictures
> alone, and I quickly learned about the economics of mass production and NO
> post-processing. Get it right in camera, NEVER force the lab to correct.
> Anyway, we'd measure the "set", I used a Canon T90, with Tokina AT-X 35-70
> Zoom, and some decent-sized flash powered by an external battery pack. One
> verifying exposure with the lightmeter and off we went. I was never so glad
> that the T90 would auto-rewind the film. :)
>
> AG
>
>
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