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Old Aug 28, 2006, 11:32 AM   #181
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Ira-

That would work with safety. Thanks for sharing.

MT/Sarah
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Old Aug 29, 2006, 9:31 PM   #182
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Our Flash Thread has been one of the busiest threads on the Pentax Forum. However, while flash remains a very good alternative for lighting your photos, it will take always take some practice, it is not an automatic thing. You have to learn a few new photo techniques, to make it work effectively.

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Old Aug 30, 2006, 6:56 AM   #183
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Quote:
Here is the 285 on my DL, trigger voltage was about 10V BTW.
Ira, you say you are only using the flash as a slave so, at 10v would it be too powerful for the istD or not.


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Old Aug 30, 2006, 8:48 AM   #184
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What should I look for in a shoe slave unit so I can use my soon to be retired Vivitar flash as a slave for "studio" lighting?

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Old Aug 30, 2006, 11:11 AM   #185
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Hi nlp,

From what I've read on various fora, there has been some discrepancy between replies from Pentax Tech depending on the country. Answers have varied from 6v to 300v, so take your pick. I would prefer to be on the safe side, and a number of users owning multiple flash units have had no problems up to 30v, so I personally use that number when considering a flash. This is what works for me -- be as conservative as makes you comfortable. I would think that 10v would be a very conservative limit.

BTW, Wein makes a Safe-Synch hotshoe to hotshoe module which will regulate any flash down to safe levels for any camera:

http://www.bhphotovideo.com/bnh/cont...ughType=search

I believe there are others, but the Wein is probably the least expensive and most well known.

Scott


nlp239 wrote:
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Quote:
Here is the 285 on my DL, trigger voltage was about 10V BTW.
Ira, you say you are only using the flash as a slave so, at 10v would it be too powerful for the istD or not.

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Old Aug 30, 2006, 11:36 AM   #186
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Hi fghouse,

It actually depends on what your planning on triggering the slave with. The onboard flash on all the Pentax DSLRs use P-TTL for any lens allowing full exposure automation. This mode requires a pre-flash, so if you are planning on using the onboard or a P-TTL external flash to trigger the slave, then you have to get a slave that will ignore the pre-flash and fire on the main flash. These are usually designated "digital" in some way to distinguish them from standard optical slaves which would fire on the pre-flash and give you no extra light for the exposure, and would fool the camera into thinking that there is more ambient light and cause significant underexposure.

If you have a D or DS and are using a TTL external flash to trigger the slave, then you want the standard slave that just fires off a single flash.

Here's a link to B&H's selection of optical slaves:

http://www.bhphotovideo.com/bnh/cont...Q=&ci=1736

My tendancy would be towards a hotshoe to hotshoe slave since a lot of newer and less expensive flash units don't have a pc connection.

One other tip. If you just want to have the slave as the sole light source, but want to fire it from the onboard flash, find an end piece of exposed, developed color film (the black part from the lead-in end, not the orange clear part) and cover your onboard flash with it (I bend it around from top to bottom and use a rubber band). This will block the visible light coming from the flash, but will allow enough infra-red through to fire the slave.

Scott

Scott



fghouse2000 wrote:
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What should I look for in a shoe slave unit so I can use my soon to be retired Vivitar flash as a slave for "studio" lighting?

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Old Aug 30, 2006, 1:04 PM   #187
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nlp239 wrote:
Quote:
Quote:
Here is the 285 on my DL, trigger voltage was about 10V BTW.
Ira, you say you are only using the flash as a slave so, at 10v would it be too powerful for the istD or not.

I believe the Pentax is capable of handling much higher trigger voltages than a Canon (which can be literally fried by as little as 8 or 9 volts. Search around, I don't remember where the info came from but I recall some notice that the *istD series could handle a fairly substantial amount of voltage (about 50V I believe). Do not trust this figure and do not quote me I merelymentionit here because someone here may be able to verify the exact figure. Personally I wouldn't trust more than 10V.


BTW http://www.botzilla.com/photo/strobeVolts.htmllists trigger voltages, they say the 285 is 350V, mine tested around 10V, they also say the 285HV is 12V, haven't tested mine yet, don't have a digital meter on hand.

Ira

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Old Aug 30, 2006, 4:49 PM   #188
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Roy

Did you get your HSS sorted out?

Been trying mine, and up to 1/1000 seems ok, from 1/1000 to 1/4000 seems to be 0.5-1.0 under-exposed. No proper test, just camera in M mode, AV 8.0 (my fav aperature), and no diffuser.



Darren


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Old Aug 30, 2006, 5:07 PM   #189
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f8 seems to do good. it's the higher f-stops when i start getting off results. i'll hook up the rig tomorrow and try for some macros. temps here are finally easing..

roy.

oh darren. tell us why your handle is FRED????
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Old Aug 30, 2006, 5:52 PM   #190
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robar wrote:
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f8 seems to do good. it's the higher f-stops when i start getting off results. i'll hook up the rig tomorrow and try for some macros. temps here are finally easing..

roy.

oh darren. tell us why your handle is FRED????
It started several years ago on some dubious sites (incl warez etc) as Fred Bloggs ie Anonymous, then changed to Fred666 (sign of the devil when I did online gaming (Unreal tournament etc) and it just stuck.

I wasn't sure about this forum initially, so used Fred666 to sign in, not realising it can't be changed. Suppose it would be easier to set up a new login, but I'm used to Fred666.

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