Aux flash for P&S

Getting acquainted with my new Canon Powershot A720 and digital photography after some decades of not being involved with photography..

My first question is, other than the Canon Auxiliary Flash HF-DC1 what aftermarket brands and models of flash will work with a point and shoot? I really dont want to invest in the Canon dedicated unit, I would rather invest in a flash like Metz or Vivitar or what ever brands are current in the market so that later on it is useable equipment with a DSLR. Ideally, I would want full swivel capablilty for bounce flash horizontal and vertical. It doesn't make sense to spend the money on a fixed position filash like the dedicated Canon or the Metz made for P&S. By the way, how do the Canon and the Metz compare?.

I read some older literature on auxiliary flash with these cameras. They suggest that you can cut the flash on the camera off with a piece of exposed SLIDE FILM so that only IR light passes through, and this will trigger the slave sensor on your auxilary..

If this is true what other media can I use to block the on camera flash? I am sure I have some exposed ends on some color negatives that I have (I MAY have some exposed ends from some old b+w stuff) I reallly don't want to purchase a roll of slide film (do they still make the stuff? ) and bang off some totally overexposed shots to get a piece of exposed transparency..

Perhaps I dont need to block the light from the camera completely but diffuse it down enough so that it just reaches the slave trigger on the bracket mounted auxiliary flash..

I am sure I will be getting into this as I move along with learning the settings and use of the A720.

For now I am getting the canon aux lens adapter and a haze filter..

We are going on vacation in a few weeks and will be doing a day tour of the National Seashore on Cape Cod. I dont want to get sand in this camera and the lens drive is VERY VULNERABLE TO THIS..

I notice that with flash there will be some SHADOW in the center area caused by the protruding lens adapter that the filters connect to, so when I get into some in depth fill in flash outdoors I might be able to invest in a nice auxiliary flash with some versatility for future camera purchases..

(and not to complicate the inquiry any further, but here goes. I assume that if I can utilize such a set up as above, the auxilary flash would then trigger another non camera mounted flash with a green dome or other. If I am able to use a versatile aftermarket flash with the P&S that swivels is there a way to get into a wireless trigger? hope this added question doesnt complicate any answers).

As you can see I'm on a budget at this time but chomping at the bit..

I have seen reasonably priced watertight bags for point and shoots where one is shooting right through the front plastic which is said to be "optically clear" but wonder how much this degrades picture quality and I can see that fill in flash may not be practical with these bags..

I am not sure if a fogged piece of film will do the job of blocking or cutting down the flash but triggering a slave, and I am sure there are those knowledgable here that can offer schemes..

I have even thought of blocking the flash exept for a piece of fiber optic stuck on the front and piped to the slave sensor of the auxilary but I think this is too elablorate and overkill. Perhaps just a cardboard deflector taped to the flash on the camera will diirect the flash to the slave sensor and not noticeably affect the subject..

Any wisdom submitted for my project is welcome. thanks very much..

I have little idea yet how flash exposure is determined with these cameras, such as TTL monitoring of flash off the camera and from an aux so I am theorizing all this at this point. the manual does leave a bit to be understood with the various flash settings and how they work relative to the cameras exposure.

I may not need any fill in flash for my sand dune pictures unless there are some people in it, but I certainly want to protect the delicacy of the lens mechanism but have the freedom to have fill in capability and also I want to plan for expansion and make investment for flashes a long term investment for the future..

I have thought about using a uv haze and taking a zip lock bag and cutting a circle out for the lens and taping the BAG to the FILTER and affixing the fliter to the front of the lens with BLUTAK as someone here suggested. then I could cut out a section for the flash and tape down the bag to the camera at that point allowing the flash lens to be unobstructed..

I APOLOGIZE FOR THE LENGTH OF THIS. hope I made it clear enough..

Comments (6)

Sunpak makes a grip with a slave sensor that can work with your camera. You mount whatever flash makes you happy on the grip, although it is really best with something like a Vivitar or Sunpak auto-thyristor unit. There is no TTL flash control with these units, of course..

I'm not familiar with your particular camera, so I don't know if you can set the flash so that it only fires one burst. Most of the new cameras use multiple bursts, for both metering and red-eye reduction. The Sunpak grip has a slave sensor that understands these pre-flash bursts and will trigger the man flash at the appropriate time..

I believe Wein also makes an optical trigger that understands pre-flash systems..

If your camera has any sort of flash control, you may be able to dial down the flash to bare minimum, letting that trigger the main flash and not affecting the exposure so much..

Crime Scene PhotographyA small gallery of personal work:

Comment #1

Thanks for this info..

That sunpack grip for the price looks like a good thing although I see that there is a Digi-Slave Deluxe 3000 Flash that works as a slave for P&S and also as a hot shoe flash. A bit over $100 but looks like it is worth the chance pending my emailing them for some more complete specs..

Seems I have some options here. I still want to experiment with a length of fiber optic cable from the flash to the slave sensor if the slave sensors prove to be not so reliable..

By the way the Powershot A720 seems to use the auto focus light for red eye preconditioning, the flash fires once..

Thanks again!..

Comment #2

J45 wrote:.

By the way the Powershot A720 seems to use the auto focus light forred eye preconditioning, the flash fires once..

Red eye reduction and the flash pre-burst are two separate things. With digital, the flash fires a pre-burst for the flash metering then fires the real burst - these bursts may occur so close together that one can't see that there are two bursts happening..

From my research back when I was looking into doing something similar to what your asking, I found that the Canon A5xx and A6xx allowed one to not only switch the flash to manual (therefore no pre-flash), but could one adjust the power to low, medium, or high. Don't recall if the A720 has this option..

I eventually though decided on a Fuji F20 which unfortunately on the negative side doesn't allow one to dis-able the pre-flash. I knew about the Sunpack battery sensor grip and the Wein digital ready optical slaves, but never got around getting either one. I'd read negative comments of both and had doubts as to there consistency of operation..

Also I eventually figured that if I'm going to take an external flash, and various othere accessories (like a flash bracket) etc., then the size advantage (versus a DSLR) of a pocket-size P & S would be somewhat negated and so I might as well take my DSLR..

Anyway as it turned out though I was able to get a Sunpack flash I already had to work with the Fuji F20. The Sunpack flash I have is a Sunpack PZ 5000 AF which I bought off ebay for $50 and has a built-in (dumb - ie. non-digital) optical slave..

What happens is that the Sunpak, because it isn't digital ready will trigger on the pre-flash, recycle, then fire again with the main bust from the on-camera flash. As long as the Sunpack doesn't have to fire at full power then it can recycle fast enough..

That's basically I believe how any non-digital ready flash will behave..

If the A720 doesn't allow you aperture control then you need a flash that offers a variety of apertures for which it can work in auto..

The external flash must have it's own sensor (auto-thyristor) which it uses to tell it when to cut-off it's flash burst..

Meter the scene with you camera, take note of what aperture it has chosen then dial that same aperture in on the external flash. You can intentionally mis-match the camera and external flash apertures which then is a form of flash exposure compensation..

I placed a piece of aluminum foil over the F20 on-camera flash to direct/reflect it off to the side (towards the off-camera external flash held in my left hand) so that none of the flash from the on-camera flash illuminated the subject, but was only used to trigger (optically) the external flash which is itself angled to bounce off the ceiling/walls..

I knew about the un-exposed slide film trick, but had no slide film laying around and didn't feel like buying a roll just for this purpose..

Example pics.

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Good Day,Roonal.

'Money doesn't buy happiness, but it makes for an extravagant depression' by golf tournament sportscaster..

Comment #3

Great information and great pictures (and a great cat!).

The camera does have on and auto flash settings, at aperature preferred it has on or off. it is difficult to tell if the flash is double firing or not especially on the "on" setting of aperature preferred..

Also it does have various flash levels manually selectable..

Worth some experimentation..

I suppose that what ever flash device I choose, if it doesn't work it could be returned..

Your information is very helpful, thanks so much..

Comment #4

Happened to come across this today - if it works, then could use any hotshoe type external flash..

Sunpak Digital Slave Unit with Preflash Cancellation, Multi Flash & Sync Socket.

@ Adorama $40

Good Day,Roonal.

'Money doesn't buy happiness, but it makes for an extravagant depression' by golf tournament sportscaster..

Comment #5


Thanks for spotting this!!!!.

Most interesting I found some fiber optic cable online from a surplus supplier that caters to the 'display' industry and there was one item and at about $2.50 a foot it is worth fooling with. fiber optic cable directly to the sensor would solve most problems anyway you and others have been extremely helpful here as usual!.

I think I will give this a try. I will look for a flash bracket for my 720 hopefully one that isnt too massive and does allow me to flip it for verticle camera holding shots..

I will post a question regarding flash units perhaps on the lighting section..

Thanks again, all, for your attention...

Comment #6

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This question was taken from a support group/message board and re-posted here so others can learn from it.


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