what are focus-assist lamps?

Discussion in 'Digital Photography' started by =?ISO-8859-1?Q?BenOne=A9?=, Jan 29, 2004.

  1. 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.


    --
    --
    Ben Thomas
    Melbourne, Australia
     
    =?ISO-8859-1?Q?BenOne=A9?=, Jan 29, 2004
    #1
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  2. ISO-8859-1?Q?=A9? <> 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.
    --
    Philip Stripling | email to the replyto address is presumed
    Legal Assistance on the Web | spam and read later. email to philip@
    http://www.PhilipStripling.com/ | my domain is read daily.
     
    Phil Stripling, Jan 29, 2004
    #2
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  3. BenOne© <> 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*.
    --
    David Dyer-Bennet, <mailto:>, <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/>
     
    David Dyer-Bennet, Jan 29, 2004
    #3
  4. David Dyer-Bennet wrote:
    > BenOne© <> 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?

    --
    --
    Ben Thomas
    Melbourne, Australia
     
    =?ISO-8859-1?Q?BenOne=A9?=, Feb 1, 2004
    #4
  5. BenOne© <> 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, <mailto:>, <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/>
     
    David Dyer-Bennet, Feb 2, 2004
    #5
  6. David Dyer-Bennet wrote:
    > BenOne© <> 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?

    --
    --
    Ben Thomas
    Melbourne, Australia
     
    =?ISO-8859-1?Q?BenOne=A9?=, Feb 2, 2004
    #6
  7. RE: Flashes Re: what are focus-assist lamps?

    "BenOne©" <> wrote in message
    news:2fqjvb.51c.ln@192.168.11.2...
    > David Dyer-Bennet wrote:
    > > BenOne© <> 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.
     
    George Preddy, Feb 2, 2004
    #7
  8. Re: Flashes Re: what are focus-assist lamps?

    "George Preddy" <> wrote in message
    news:bvkdph$rqb$...
    >
    > "BenOne©" <> wrote in message
    > news:2fqjvb.51c.ln@192.168.11.2...
    > > David Dyer-Bennet wrote:
    > > > BenOne© <> 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.
    >
    >
    >
    >
    >
    >
    >
    >
     
    George Preddy, Feb 2, 2004
    #8
  9. Total cost (Re: Flashes Re: what are focus-assist lamps?)

    "George Preddy" <> wrote in message
    news:bvkdph$rqb$...

    > 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)
     
    George Preddy, Feb 2, 2004
    #9
  10. =?ISO-8859-1?Q?BenOne=A9?=

    Paul L Guest

    Re: Total cost (Re: Flashes Re: what are focus-assist lamps?)

    "George Preddy" <> wrote in message
    news:bvkf0v$si7$...
    >
    > ($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.
     
    Paul L, Feb 2, 2004
    #10
  11. Re: Total cost (Re: Flashes Re: what are focus-assist lamps?)

    "Paul L" <> wrote in message
    news:qTkTb.37705$...
    >
    > "George Preddy" <> wrote in message
    > news:bvkf0v$si7$...
    > >
    > > ($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.


    If price quotes knock blurry Canon DSLRs, so be it.
     
    George Preddy, Feb 2, 2004
    #11
  12. Re: Total cost (Re: Flashes Re: what are focus-assist lamps?)

    "Paul L" <> wrote in message
    news:qTkTb.37705$...
    >
    > "George Preddy" <> wrote in message
    > news:bvkf0v$si7$...
    > >
    > > ($150 less than a blurry Canon 10D body alone)
    > >
    > >

    >
    > Were you bored so you figured you'd knock Canon to stir something up?


    Oh and I kept the wrong link in that message, it is actually this set up,
    where everything shown including the extra batteries and tripod, that is
    cheaper than a blurry 10D Canon DSLR body alone...

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

    But wait a minute... this set up is only $1475, so it is still less than
    the blurry 10D body alone even with Sigma's best-in-class 15-30 EX DG, Power
    Pack, DG Super Flash, and 8 x Powerex 2200mah AAs inside...

    http://www.pbase.com/image/23256593
     
    George Preddy, Feb 2, 2004
    #12
  13. BenOne© <> writes:

    > David Dyer-Bennet wrote:
    >> BenOne© <> 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?


    Can't be done; that's not how they work. They turn off during the
    exposure. Hence my point about a disconnected one not being useful.
    --
    David Dyer-Bennet, <mailto:>, <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/>
     
    David Dyer-Bennet, Feb 2, 2004
    #13
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