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what are focus-assist lamps?

 
 
=?ISO-8859-1?Q?BenOne=A9?=
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      01-29-2004
Hi all,

Recently saw some people mention these, but don't know how they work.

I assume they are most useful in low light where the camera can't see what it
has to focus on, but the light isn't bright enough to affect the exposure.


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Melbourne, Australia

 
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Phil Stripling
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      01-29-2004
ISO-8859-1?Q?=A9? <(E-Mail Removed)> writes:

> I assume they are most useful in low light where the camera can't see
> what it has to focus on, but the light isn't bright enough to affect the
> exposure.


That's it. Mine turns off after focus is achieved, if I recall correctly,
but whatever.
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David Dyer-Bennet
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      01-29-2004
BenOne© <(E-Mail Removed)> writes:

> Hi all,
>
> Recently saw some people mention these, but don't know how they work.
>
> I assume they are most useful in low light where the camera can't see
> what it has to focus on, but the light isn't bright enough to affect
> the exposure.


The light turns on during focusing, and then turns off before the
exposure, so it's not an issue.

Originally they were in flash units for auto-focus slrs. They've
spread since then, and some bodies now also have them. Often they
project a pattern of parallel lines (often in red) to provide some
detail to focus on if the target is featureless. They help a *lot*.
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RKBA: <http://noguns-nomoney.com> <http://www.dd-b.net/carry/>
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=?ISO-8859-1?Q?BenOne=A9?=
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      02-01-2004
David Dyer-Bennet wrote:
> BenOne© <(E-Mail Removed)> writes:
>
>
>>Hi all,
>>
>>Recently saw some people mention these, but don't know how they work.
>>
>>I assume they are most useful in low light where the camera can't see
>>what it has to focus on, but the light isn't bright enough to affect
>>the exposure.

>
>
> The light turns on during focusing, and then turns off before the
> exposure, so it's not an issue.
>
> Originally they were in flash units for auto-focus slrs. They've
> spread since then, and some bodies now also have them. Often they
> project a pattern of parallel lines (often in red) to provide some
> detail to focus on if the target is featureless. They help a *lot*.


Can you buy manual ones that don't connect to the camera?

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Ben Thomas
Melbourne, Australia

 
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David Dyer-Bennet
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      02-02-2004
BenOne© <(E-Mail Removed)> writes:

> David Dyer-Bennet wrote:


>> The light turns on during focusing, and then turns off before the
>> exposure, so it's not an issue. Originally they were in flash units
>> for auto-focus slrs. They've
>> spread since then, and some bodies now also have them. Often they
>> project a pattern of parallel lines (often in red) to provide some
>> detail to focus on if the target is featureless. They help a *lot*.


> Can you buy manual ones that don't connect to the camera?


Not that I've seen. If they weren't switched on and off
automatically, they'd be a lot less convenient to use. You could, of
course, mask a gridded lighting instrument to get roughly the same
effect.
--
David Dyer-Bennet, <(E-Mail Removed)>, <http://www.dd-b.net/dd-b/>
RKBA: <http://noguns-nomoney.com> <http://www.dd-b.net/carry/>
Photos: <dd-b.lighthunters.net> Snapshots: <www.dd-b.net/dd-b/SnapshotAlbum/>
Dragaera/Steven Brust: <http://dragaera.info/>
 
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=?ISO-8859-1?Q?BenOne=A9?=
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      02-02-2004
David Dyer-Bennet wrote:
> BenOne© <(E-Mail Removed)> writes:
>
>
>>David Dyer-Bennet wrote:

>
>
>>>The light turns on during focusing, and then turns off before the
>>>exposure, so it's not an issue. Originally they were in flash units
>>>for auto-focus slrs. They've
>>>spread since then, and some bodies now also have them. Often they
>>>project a pattern of parallel lines (often in red) to provide some
>>>detail to focus on if the target is featureless. They help a *lot*.

>
>
>>Can you buy manual ones that don't connect to the camera?

>
>
> Not that I've seen. If they weren't switched on and off
> automatically, they'd be a lot less convenient to use. You could, of
> course, mask a gridded lighting instrument to get roughly the same
> effect.


What colour light would you need to use so that the exposure wouldn't be affected?

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Ben Thomas
Melbourne, Australia

 
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George Preddy
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      02-02-2004

"BenOne©" <(E-Mail Removed)> wrote in message
news:2fqjvb.51c.ln@192.168.11.2...
> David Dyer-Bennet wrote:
> > BenOne© <(E-Mail Removed)> writes:
> > Originally they were in flash units for auto-focus slrs. They've
> > spread since then, and some bodies now also have them. Often they
> > project a pattern of parallel lines (often in red) to provide some
> > detail to focus on if the target is featureless. They help a *lot*.

>
> Can you buy manual ones that don't connect to the camera?


Yes.

Sigma's "Super" flash units continuously pulse their built in AF assist
lamps when put into slave mode, right up until the shot happens, then they
turn it off to fire, then they start pulsing it again. They also come with
thier own stand (like a hot shot with feet) which has a tripod screw in the
bottom. This would be compatible with any camera that can produce a flash
to trigger them, or if your camera can use S-TTL, E-TTL, D-TTL, or P-TTL,
the SA-N models will also comunicate in via radio transmitter for full TTL
operation without the need for a light trigger.

Concievably, even if your camera doesn't support one of those TTL modes you
could use one or more "Supers" in slave mode as an AF assit lamp only, on
your hot shoe or as a stand alone unit. Flash power is fantastic.

Here are some pictures of the DG Super, the front IR window is where the AF
assit beam originates, and the rear shot shows the backlit control panel...

http://www.pbase.com/image/23256593
http://www.pbase.com/image/25688089

The flashes shown there were actually fired for the pics using slave mode,
so their AF assist lights were firing right up until they were triggered.








 
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George Preddy
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      02-02-2004

"George Preddy" <(E-Mail Removed)> wrote in message
news:bvkdph$rqb$(E-Mail Removed)...
>
> "BenOne©" <(E-Mail Removed)> wrote in message
> news:2fqjvb.51c.ln@192.168.11.2...
> > David Dyer-Bennet wrote:
> > > BenOne© <(E-Mail Removed)> writes:
> > > Originally they were in flash units for auto-focus slrs. They've
> > > spread since then, and some bodies now also have them. Often they
> > > project a pattern of parallel lines (often in red) to provide some
> > > detail to focus on if the target is featureless. They help a *lot*.

> >
> > Can you buy manual ones that don't connect to the camera?

>
> Yes.
>
> Sigma's "Super" flash units continuously pulse their built in AF assist
> lamps when put into slave mode, right up until the shot happens, then they
> turn it off to fire, then they start pulsing it again.


I double checked mine, in slave mode the DG Super fires its AF assist lamp
about once per second for about a half second.

> They also come with
> thier own stand (like a hot shot with feet) which has a tripod screw in

the
> bottom. This would be compatible with any camera that can produce a flash
> to trigger them, or if your camera can use S-TTL, E-TTL, D-TTL, or P-TTL,
> the SA-N models will also comunicate in via radio transmitter for full TTL
> operation without the need for a light trigger.
>
> Concievably, even if your camera doesn't support one of those TTL modes

you
> could use one or more "Supers" in slave mode as an AF assit lamp only, on
> your hot shoe or as a stand alone unit. Flash power is fantastic.
>
> Here are some pictures of the DG Super, the front IR window is where the

AF
> assit beam originates, and the rear shot shows the backlit control

panel...
>
> http://www.pbase.com/image/23256593
> http://www.pbase.com/image/25688089
>
> The flashes shown there were actually fired for the pics using slave mode,
> so their AF assist lights were firing right up until they were triggered.
>
>
>
>
>
>
>
>



 
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George Preddy
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      02-02-2004
"George Preddy" <(E-Mail Removed)> wrote in message
news:bvkdph$rqb$(E-Mail Removed)...

> Here are some pictures of the DG Super, the front IR window is where the

AF
> assit beam originates, and the rear shot shows the backlit control

panel...
>
> http://www.pbase.com/image/23256593


As shown in the picture above - 10.3MP SD9 body, with Power Pack and 8 x AA
PowerEx 2200mahs inside, 600mm mirror lens, DG Super Flash, and tripod...

$1350, before any package discounts.

($150 less than a blurry Canon 10D body alone)


 
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Paul L
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      02-02-2004

"George Preddy" <(E-Mail Removed)> wrote in message
news:bvkf0v$si7$(E-Mail Removed)...
>
> ($150 less than a blurry Canon 10D body alone)
>
>


Were you bored so you figured you'd knock Canon to stir something up? It
was quiet here for awhile, like I'd been on vacation or something. Sigh.


 
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