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External flash on Canon S1...?

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Anonymous
December 9, 2004 8:01:08 PM

Archived from groups: rec.photo.digital (More info?)

I wonder...
i have an old flash (it used to be very good at the times) and a possibility
to make a circuit with a photosensor in order to trigger this flash via
built-in S1. So, what do you guys think - will i gain anything? This old
flash is good up to 5-6 metres, while built-in S1 is good only for up to 3.5
m. So, theoretically, i would gain some light. The question is what will the
camera do with settings - will i have under- or overexposed pics?--

So, any comments or experiences on this...
THX

More about : external flash canon

Anonymous
December 9, 2004 8:01:09 PM

Archived from groups: rec.photo.digital (More info?)

"SleeperMan" <SleeperMan@too.sleepy> writes:

> I wonder...
> i have an old flash (it used to be very good at the times) and a possibility
> to make a circuit with a photosensor in order to trigger this flash via
> built-in S1. So, what do you guys think - will i gain anything? This old
> flash is good up to 5-6 metres, while built-in S1 is good only for up to 3.5
> m. So, theoretically, i would gain some light. The question is what will the
> camera do with settings - will i have under- or overexposed pics?--

In any of the programmed modes, you'll be dumping light into the scene
that the camera isn't expecting based on it's pre-metering, so you'll
either get lucky and it'll work out (the camera might be able to
respond quick enough to reduce output to the on-camera flash), or
(more likely), you'll have overexposed pics.

Opitcal slave sensors are available commercially and are dirt
cheap--so no need to reinvent the wheel there. For example here's one
for $29:
http://www.bhphotovideo.com/bnh/controller/home?O=produ...

And since it's digital, it doesn't cost anything to play around with
it.

Best Regards,
--
Todd H.
http://www.toddh.net/
Anonymous
December 9, 2004 8:01:09 PM

Archived from groups: rec.photo.digital (More info?)

SleeperMan wrote:
>
> I wonder...
> i have an old flash (it used to be very good at the times) and a possibility
> to make a circuit with a photosensor in order to trigger this flash via
> built-in S1. So, what do you guys think - will i gain anything? This old
> flash is good up to 5-6 metres, while built-in S1 is good only for up to 3.5
> m. So, theoretically, i would gain some light. The question is what will the
> camera do with settings - will i have under- or overexposed pics?--
>
> So, any comments or experiences on this...
> THX

Note that since the S1 does use a pre-flash to set exposure, you'll need
a "digital" slave that is designed to ignore the pre-flash.

Lisa
Related resources
Anonymous
December 9, 2004 11:47:46 PM

Archived from groups: rec.photo.digital (More info?)

Lisa Horton wrote:
> SleeperMan wrote:
>>
>> I wonder...
>> i have an old flash (it used to be very good at the times) and a
>> possibility to make a circuit with a photosensor in order to trigger
>> this flash via built-in S1. So, what do you guys think - will i gain
>> anything? This old flash is good up to 5-6 metres, while built-in S1
>> is good only for up to 3.5 m. So, theoretically, i would gain some
>> light. The question is what will the camera do with settings - will
>> i have under- or overexposed pics?--
>>
>> So, any comments or experiences on this...
>> THX
>
> Note that since the S1 does use a pre-flash to set exposure, you'll
> need a "digital" slave that is designed to ignore the pre-flash.
>
> Lisa

That is not a problem, since that circuit is made so that i can set number
of pre-flashes...
It's overexposure i'm worried about.
But, since material for it is cheap, maybe i'll just try it out and see.
Anonymous
December 9, 2004 11:53:06 PM

Archived from groups: rec.photo.digital (More info?)

Todd H. wrote:
> "SleeperMan" <SleeperMan@too.sleepy> writes:
>
>> I wonder...
>> i have an old flash (it used to be very good at the times) and a
>> possibility to make a circuit with a photosensor in order to trigger
>> this flash via built-in S1. So, what do you guys think - will i gain
>> anything? This old flash is good up to 5-6 metres, while built-in S1
>> is good only for up to 3.5 m. So, theoretically, i would gain some
>> light. The question is what will the camera do with settings - will
>> i have under- or overexposed pics?--
>
> In any of the programmed modes, you'll be dumping light into the scene
> that the camera isn't expecting based on it's pre-metering, so you'll
> either get lucky and it'll work out (the camera might be able to
> respond quick enough to reduce output to the on-camera flash), or
> (more likely), you'll have overexposed pics.
>
> Opitcal slave sensors are available commercially and are dirt
> cheap--so no need to reinvent the wheel there. For example here's one
> for $29:
>
> http://www.bhphotovideo.com/bnh/controller/home?O=produ...
>
> And since it's digital, it doesn't cost anything to play around with
> it.

you have the point here... :-)

Maybe i could compensate more light with manual lowering something, .like
either closing aperture a bit or set faster shutter.
I guess that at the end of year i'll have some free days and (if i'll feel
happy) will just make this thing and see...

BTW...i wonder why that slave sensor on the link is not compatible with
Canon's...since most (if not all) do have pre--flash for measuring needed
settings...
Anonymous
December 9, 2004 11:53:07 PM

Archived from groups: rec.photo.digital (More info?)

"SleeperMan" <SleeperMan@too.sleepy> writes:

> BTW...i wonder why that slave sensor on the link is not compatible with
> Canon's...since most (if not all) do have pre--flash for measuring needed
> settings...

FWIW, preflash for metering is a relatively new thing in the past
years. For instance, My Elan doesn't preflash except (maybe) with
bounce flash. My Pentax TTL flash system never preflashed (circa
early 90's). And studio setups don't have to deal with preflash....

That's why it's a feature that's not universal on those optical
slaves. I hadn't thought of the preflash when I posted a link that
cheapie


--
Todd H.
http://www.toddh.net/
Anonymous
December 10, 2004 12:05:23 AM

Archived from groups: rec.photo.digital (More info?)

On Thu, 9 Dec 2004 17:01:08 +0100, "SleeperMan"
<SleeperMan@too.sleepy> wrote:

>I wonder...
>i have an old flash (it used to be very good at the times) and a possibility
>to make a circuit with a photosensor in order to trigger this flash via
>built-in S1. So, what do you guys think - will i gain anything? This old
>flash is good up to 5-6 metres, while built-in S1 is good only for up to 3.5
>m. So, theoretically, i would gain some light. The question is what will the
>camera do with settings - will i have under- or overexposed pics?--

SleeperMan,

depending on the way the camera controls flash exposure, you may
be able to correct by setting the camera for underexposure. It's
tricky though and may not always work with the same numbers.

Hans-Georg

--
No mail, please.
Anonymous
December 10, 2004 12:08:22 AM

Archived from groups: rec.photo.digital (More info?)

Hans-Georg Michna wrote:
> On Thu, 9 Dec 2004 17:01:08 +0100, "SleeperMan"
> <SleeperMan@too.sleepy> wrote:
>
>> I wonder...
>> i have an old flash (it used to be very good at the times) and a
>> possibility to make a circuit with a photosensor in order to trigger
>> this flash via built-in S1. So, what do you guys think - will i gain
>> anything? This old flash is good up to 5-6 metres, while built-in S1
>> is good only for up to 3.5 m. So, theoretically, i would gain some
>> light. The question is what will the camera do with settings - will
>> i have under- or overexposed pics?--
>
> SleeperMan,
>
> depending on the way the camera controls flash exposure, you may
> be able to correct by setting the camera for underexposure. It's
> tricky though and may not always work with the same numbers.
>
> Hans-Georg

That is what i fear...that even if i do find correct setting, it won't be
good for next photo, so result will be that i will have to make several
photos of each scene.
I guess that external flash units made for digital cameras can handle two
shots when pushing the shutter, right? Not like these old ones, which take
5-10 seconds to refill after one single shot.
Anonymous
December 10, 2004 12:25:04 AM

Archived from groups: rec.photo.digital (More info?)

Todd H. wrote:
> "SleeperMan" <SleeperMan@too.sleepy> writes:
>
>> BTW...i wonder why that slave sensor on the link is not compatible
>> with Canon's...since most (if not all) do have pre--flash for
>> measuring needed settings...
>
> FWIW, preflash for metering is a relatively new thing in the past
> years. For instance, My Elan doesn't preflash except (maybe) with
> bounce flash. My Pentax TTL flash system never preflashed (circa
> early 90's). And studio setups don't have to deal with preflash....
>
> That's why it's a feature that's not universal on those optical
> slaves. I hadn't thought of the preflash when I posted a link that
> cheapie

Aha...i didn't know that since i have digital camera for about 2 years
only...my first was Olympus C300 (which was quite OK), now i have S1 and the
only problem i see is long distance shooting with flash. That's why i
thought of this. Oh, well...
Anonymous
December 10, 2004 1:07:52 AM

Archived from groups: rec.photo.digital (More info?)

On Thu, 9 Dec 2004 21:08:22 +0100, "SleeperMan"
<SleeperMan@too.sleepy> wrote:

>Hans-Georg Michna wrote:

>> depending on the way the camera controls flash exposure, you may
>> be able to correct by setting the camera for underexposure. It's
>> tricky though and may not always work with the same numbers.

>That is what i fear...that even if i do find correct setting, it won't be
>good for next photo, so result will be that i will have to make several
>photos of each scene.
>I guess that external flash units made for digital cameras can handle two
>shots when pushing the shutter, right? Not like these old ones, which take
>5-10 seconds to refill after one single shot.

SleeperMan,

just a few statements.

I believe if you get one well exposed shot in a certain
situation, the next shot will be just as well exposed. To get
the first one right is the problem.

I think that external flash units fire all of their energy at
once if they have to, depending on their setting. If they don't
have to, they can fire a second shot almost immediately and
continue until their capacitors no longer have enough energy for
the next shot.

Hans-Georg

--
No mail, please.
Anonymous
December 10, 2004 8:57:19 PM

Archived from groups: rec.photo.digital (More info?)

Hans-Georg Michna wrote:
> On Thu, 9 Dec 2004 21:08:22 +0100, "SleeperMan"
> <SleeperMan@too.sleepy> wrote:
>
>> Hans-Georg Michna wrote:
>
>>> depending on the way the camera controls flash exposure, you may
>>> be able to correct by setting the camera for underexposure. It's
>>> tricky though and may not always work with the same numbers.
>
>> That is what i fear...that even if i do find correct setting, it
>> won't be good for next photo, so result will be that i will have to
>> make several photos of each scene.
>> I guess that external flash units made for digital cameras can
>> handle two shots when pushing the shutter, right? Not like these old
>> ones, which take 5-10 seconds to refill after one single shot.
>
> SleeperMan,
>
> just a few statements.
>
> I believe if you get one well exposed shot in a certain
> situation, the next shot will be just as well exposed. To get
> the first one right is the problem.
>
> I think that external flash units fire all of their energy at
> once if they have to, depending on their setting. If they don't
> have to, they can fire a second shot almost immediately and
> continue until their capacitors no longer have enough energy for
> the next shot.
>
> Hans-Georg

Thanks for your comments. I'll see what next...
!