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01-17-2013, 07:37 AM   #1
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P-TTL capable radio flash triggers?

Looks to me that there are none.

Anyone know better?

01-17-2013, 07:52 AM - 1 Like   #2
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There is only one that I know of:
Aokatec - Products
01-17-2013, 09:45 AM - 1 Like   #3
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QuoteOriginally posted by elliott Quote
There is only one that I know of:
Aokatec - Products
Thanks for the original question and for the followup about Aokatec. I've been wondering about this myself. Apart from the demo on their site, this may be useful:

Better Family Photos: Cheap Wireless TTL? Aokatec AK-TTL Review
01-18-2013, 05:14 AM   #4
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aokatec works 100 % ok for pentax, there is a thread somwhere on aokatec if you search

01-18-2013, 12:38 PM   #5
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Question : why do you want PTTL? If you're using off-camera flash, chances are that you're shooting in a specific context, like a studio, where a nicely averaged light output is likely to serve little purpose. In a studio, you generally want your lights set in specific and different ways.

If you use flashes to light, say, a large room, then again PTTL will serve little purpose.

Just my two cents.
01-19-2013, 01:35 AM   #6
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Thanks for the Aokatec advice. Much appreciated.

They even ship to HK in only 2 days!
01-19-2013, 01:51 AM   #7
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QuoteOriginally posted by bdery Quote
Question : why do you want PTTL? If you're using off-camera flash, chances are that you're shooting in a specific context, like a studio, where a nicely averaged light output is likely to serve little purpose. In a studio, you generally want your lights set in specific and different ways.

If you use flashes to light, say, a large room, then again PTTL will serve little purpose.

Just my two cents.
Quite simply because I'm clueless about off-camera flash!

I've been reading that I can use the built-in flash as a controller, and set it so low that it doesn't affect the exposure. I guess I had better pull out the manual!

I'm looking to having two off-camera flashes, at different power levels, playing nice with each other and the ambient light too, and, in combination, get a correct exposure. I am assuming the camera has to communicate the P-TTL information wirelessly with the flashes in order to achieve that?
01-19-2013, 09:49 AM   #8
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You might actually find manual easier. What I find with PTTL is I try to make an adjustment eg increase key light and reduce the fill, then the PTTL system kicks in trying to maintain an even exposure!

I have PTTL flashes controlled via the onboard flash for when I need it to do that. I'm buying some radio triggers for when I want manual control. Also means ill be able to use an old Jessops Nikon TTL flash for xperiments / hair lights.

01-21-2013, 09:09 AM - 2 Likes   #9
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QuoteOriginally posted by Unsinkable II Quote
I'm looking to having two off-camera flashes, at different power levels, playing nice with each other and the ambient light too, and, in combination, get a correct exposure.
You won't get that with PTTL. A PTTL flash (or flashes, but I don't think the PTTL system is designed for multiple flashes) will fire at the power it feels is needed to get a correct exposure. You won't get a simple way to control the light output of each flash short of filtering one and hoping the other will compensate.

What you really want is a simple manual setup. It may sound scary but it's actually much easier to get the results you want with manual flashes. Just get a wired or wireless trigger that does only that. Then switch your camera to manual, set your flashes at one given power each, and test. Then adjust as needed. Once you're set, you never have to change anything for that session, and chances are you will be able to use roughly the same settings in future venues.

As for the camera, here is what you ned to know:

Aperture is for flash illumination (wider = more flash-made light on your picture)
Speed is for ambiant (faster speed = less ambiant light, better for, say, dark backgrounds or exotic lighting schemes)
ISO influences both

Pretty straightforward. Try it!

Last edited by bdery; 01-22-2013 at 05:41 AM.
01-21-2013, 11:51 AM - 1 Like   #10
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Theoretically, you can set ratios between flashes, and use different exposure compensations on the different flashes, but I've never had a great deal of luck with it. The best use of wireless TTL is to bounce with a flash off the camera, or set up flashes to give an even, shadowless effect. It is quite effortless at that, IMO.
01-21-2013, 10:07 PM   #11
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QuoteOriginally posted by bdery Quote
As for the camera, here is what you ned to know:

Aperture is for flash illumination (wider = more flash-made light on your picture)
Speed is for ambiant (faster speed = less ambiant light, better for, say, dark bagrounds or exotic lighting schemes)
ISO influences both

Pretty straightforward. Try it!
I'll certainly try, thanks!
01-22-2013, 06:06 AM   #12
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I would add that I find it pretty easy to use wireless P-TTL with multiple flashes, but I would agree with Bdery that it is often easier to use manual for portraits where you want a specific key and fill light direction. One of the biggest improvements digital photography made in our lives is to allow quick, cheap, chimping. Once you have set up your lights a few times, it just takes a few minutes to take enough test shots to get what you want.

I still use my 30 year old Vivitar 283s on cheap wireless triggers for setting up portrait lighting where studio flashes are impractical. My one small nit with modern Pentax flashes is that I don't find an easy and reliable way to use a non-illuminating, "controller" flash from the on-camera unit as a to trigger the flashes in something other than wireless P-TTL mode. It may be buried in the manual somewhere (and I think there have been other threads on this), but the wireless triggers are easier to figure out.
01-26-2013, 10:00 AM - 1 Like   #13
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A follow up. I did some experiments, and I was able to set up two wireless P-TTL slave flashes triggered by the on-camera to be key and fill lights, and get a directional effect. Steps were:

1) Make sure the on-camera flash is set to controller only. (Lots of ineffective tries before I noticed this)
2) Set key light to overexpose by desired stops by which key and fill are differentiated
3) Set fill light to underexpose by same amount as key light is overexposed
4) Fine tune resulting total exposure with camera exposure compensation.

If the Key light was not set to overexpose by the same amount as the underexposure of the fill light, I got an underexposed shot when the camera balanced things out.

All in all it, I think it is still usually easier just to set up manual flashes for this purpose. Set the ratios and chimp a few times and it is done. All these exposure adjustments to the slave flashes will have to be undone when they go back to their usual uses as dedicated flashes. I am sure I would forget and wonder why the exposure is off. If I just set the power (1/2, 1/4, etc.) when used in manual mode, it won't affect later use in P-TTL. The only reason I can see to use the wireless P-TTL method is if you are trying different apertures for the shot.
01-27-2013, 06:13 AM   #14
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QuoteOriginally posted by GeneV Quote
A follow up. I did some experiments, and I was able to set up two wireless P-TTL slave flashes triggered by the on-camera to be key and fill lights, and get a directional effect. Steps were:

1) Make sure the on-camera flash is set to controller only. (Lots of ineffective tries before I noticed this)
2) Set key light to overexpose by desired stops by which key and fill are differentiated
3) Set fill light to underexpose by same amount as key light is overexposed
4) Fine tune resulting total exposure with camera exposure compensation.

If the Key light was not set to overexpose by the same amount as the underexposure of the fill light, I got an underexposed shot when the camera balanced things out.

All in all it, I think it is still usually easier just to set up manual flashes for this purpose. Set the ratios and chimp a few times and it is done. All these exposure adjustments to the slave flashes will have to be undone when they go back to their usual uses as dedicated flashes. I am sure I would forget and wonder why the exposure is off. If I just set the power (1/2, 1/4, etc.) when used in manual mode, it won't affect later use in P-TTL. The only reason I can see to use the wireless P-TTL method is if you are trying different apertures for the shot.
Thanks for both testing and posting! This will definitely be my reference once I get my 2nd flash next week.

Much appreciated.
01-27-2013, 07:59 AM   #15
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Just so everyone knows, this is not a tried and true technique that I have been using for years, but the results of an afternoon of experimenting. I will be interested to see what kind of luck others have with this.
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