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04-18-2008, 03:45 PM   #16
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I thought the camera would use the pop up flash as a focus assist?

04-18-2008, 03:51 PM   #17
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QuoteOriginally posted by yeedub Quote
I thought the camera would use the pop up flash as a focus assist?
You can... but it's 'strobe' effect is very annoying to most subjects.

And when you do press the shutter they're likely to have either looked away or shut their eyes.

Some form of non-visible light (like most flash unit's AF assist beams) would definately be preferable.

So... how much would we pay for a non-visible AF only lamp to mount in the flash shoe?
04-18-2008, 03:56 PM   #18
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QuoteOriginally posted by ftpaddict Quote
Isn't the SAFOX module protected by an IR filter as well? Correct me if I'm wrong. (in this case, I really do hope I'm wrong)

Take a look at the Pentax AF-540 FGZ and AF-360 FGZ flash units. Both emit a nearly invisible infrared beam to assist focusing in low light or low contrast conditions and both are fully compatible with the latest Pentax cameras.

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04-19-2008, 12:39 AM   #19
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QuoteOriginally posted by stewart_photo Quote
Take a look at the Pentax AF-540 FGZ and AF-360 FGZ flash units. Both emit a nearly invisible infrared beam to assist focusing in low light or low contrast conditions and both are fully compatible with the latest Pentax cameras.

stewart
Does the focus assist beam work in all lighting conditions? Or does the camera get to decide when it turns it on?

04-19-2008, 04:59 AM   #20
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QuoteOriginally posted by ftpaddict Quote
Does the focus assist beam work in all lighting conditions? Or does the camera get to decide when it turns it on?

I believe it is like my Pentax Z-1P SLR, the red assist light is only emitted when AF is having trouble in very low light.
04-19-2008, 04:02 PM   #21
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QuoteOriginally posted by ftpaddict Quote
Does the focus assist beam work in all lighting conditions? Or does the camera get to decide when it turns it on?

Sune is probably right. Referring to just those two flash units, I doubt it would be on all the time. After all, bright sunlight, for example, completely overwhelming the infrared beam would render it virtually useless. But, to be honest, I don't know since the beam is nearly impossible to detect in those lighting conditions.

Update: after reading the manual again, it does say the focus assist beam on the AF-540 FGZ only comes on when needed - low-light or low-contrast conditions.

stewart


-

Last edited by stewart_photo; 04-19-2008 at 06:45 PM. Reason: added update
04-19-2008, 04:18 PM   #22
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stewart
so we can use only the focus assistant beam (no flash i mean), if we want (when we use 540 or 360)???
btw i started the same topic in dpreview.com and Brad99 explained how to build a focus assistant:
If you're into DIY electronics then it should be possible as one of the contacts, the single one nearest the front, has a solid 3.9v signal there when a half-shutter press occurs, and stays there for some 20 or 30 seconds. There's also the normal centre contact pulse that would normally fire the flash, I presume that's a low going current sink for the flash's trigger voltage. I saw a brief 0.6v on a DVM but of course that's without a flash connected to provide a pull up voltage. So, the small contact could initiate the laser, and the beginning of the large centre contact pulse would turn the laser off. This centre pin signal would have to be latched. One CMOS logic chip like a 4001 or 4011 might do it, plus a transistor to switch the laser.

I nearly embarked on this quest myself, but a lack of a spare Pentax hot shoe mount with the necessary contacts, plus a lack of time put me off, so I weakened and got a Sigma EF-500.
04-19-2008, 06:42 PM   #23
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QuoteOriginally posted by hll Quote
stewart
so we can use only the focus assistant beam (no flash i mean), if we want (when we use 540 or 360)???

Yes, page 56 of the flash manual for the AF-540 FGZ explains the four steps needed to do this...

1. Set the power swicth to the (ON) position.
2. Press the flash mode button (MODE) to select (SB).
3. Set the camera to an autofocus mode.
4. Press the shutter release button halfway down to let the AF spotbeam fire.

The note below says, "The flash does not fire when using the AF540FGZ spotbeam exclusively as a focusing aid."


QuoteQuote:
btw i started the same topic in dpreview.com and Brad99 explained how to build a focus assistant:
If you're into DIY electronics then it should be possible as one of the contacts, the single one nearest the front, has a solid 3.9v signal there when a half-shutter press occurs, and stays there for some 20 or 30 seconds. There's also the normal centre contact pulse that would normally fire the flash, I presume that's a low going current sink for the flash's trigger voltage. I saw a brief 0.6v on a DVM but of course that's without a flash connected to provide a pull up voltage. So, the small contact could initiate the laser, and the beginning of the large centre contact pulse would turn the laser off. This centre pin signal would have to be latched. One CMOS logic chip like a 4001 or 4011 might do it, plus a transistor to switch the laser.

Interesting. Obviously several ways to accomplish this. My goal was to keep it simple for those without electronics skills. Simply changing a bulb or adding an infrared filter to an existing device clearly meets that goal.

stewart

04-19-2008, 09:40 PM   #24
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You could also try the CameraBright series of focus assist modules that attaches to the tripod mount of your camera...

CameraBright! X1-ER+



It's bright enough to reach 20ft and gives you the ability to compose and focus your shot in near darkness. It's a neat little gadget to have!

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04-20-2008, 02:32 AM   #25
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QuoteOriginally posted by stewart_photo Quote

Interesting. Obviously several ways to accomplish this. My goal was to keep it simple for those without electronics skills. Simply changing a bulb or adding an infrared filter to an existing device clearly meets that goal.

stewart
but, don't you want to stop the asist light when you press the shutter??
i mean i don't like a laser beam or a led light beam in my photos, the light must turn off after the focus is locked.
stewart and AlexM, thank you very much for informing us!!!
04-20-2008, 02:43 AM   #26
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QuoteOriginally posted by hll Quote
but, don't you want to stop the asist light when you press the shutter??
i mean i don't like a laser beam or a led light beam in my photos, the light must turn off after the focus is locked.
stewart and AlexM, thank you very much for informing us!!!
The assist light does not get in the photo. It helps the camera for a brief time, and then stops as the photo is taken. It is also not very intrusive, as it is a thin patterned veil of red light emitted.

My Pentax Z-1P SLR had it included, but with DSLR you have to buy one of the flashes to get it. Maybe they should make a small one to put on the hot shoe (without a flash attached), but I doubt they'll do it.
04-20-2008, 03:18 AM   #27
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i was talking about CameraBright!™ X1-ER+, it gets in the photo.

"Maybe they should make a small one to put on the hot shoe (without a flash attached), but I doubt they'll do it."

this is exactly what i need....
04-20-2008, 04:47 AM   #28
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QuoteOriginally posted by hll Quote
but, don't you want to stop the asist light when you press the shutter??
i mean i don't like a laser beam or a led light beam in my photos, the light must turn off after the focus is locked. (snip)

Are you talking about my infrared focus assist idea or something else? In you're talking about my idea, infrared is outside the visible light spectrum and also filtered from the camera sensor. In other words, it wouldn't show in the final image.

stewart
04-20-2008, 04:56 AM   #29
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wow, i wasn't aware of it, i thought that IR is something visible like laser.
i think it is easier to do one!!
i will think about that one..
thanks
halil

Last edited by hll; 04-20-2008 at 06:04 AM.
04-20-2008, 05:00 AM   #30
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QuoteOriginally posted by Jonson PL Quote
The assist light does not get in the photo. It helps the camera for a brief time, and then stops as the photo is taken. It is also not very intrusive, as it is a thin patterned veil of red light emitted. (snip)

I believe she ("hll") is talking about my manually on/off focusing assist beam idea described on the previous page, Sune. It is not turned off or on by the camera, but that's not really needed since it's infrared outside the visible light spectrum.

stewart
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