A720IS and a flash gun with slave mode?

[Changeling]

Hello to all, this is a question as well as a recommendation, so please keep that in mind when you reply. Please explain in your responses like you are talking to a real newbie, cause that is exactly what I am. However, I pick up on things very fast.

NickC in another post talked about using a " Flash gun with a slave mode" attached to a Canon A720IS to get awesome lighting that far surpassed the internal flash unit, and his shots definitely prove that.

Question: 1. Can someone please explain the relationship between the camera and a flash slave unit. From his comments I surmised what he said, the slave unit is evidently the external flash connected to the camera (how on a A720IS), that receives it's signal when the main unit (camera button) is actuated, but I don't know understand the connection, is there a wire/connection port between the two devices, or what?

2. What is a really cheap way to go on getting one of these "slave units" and is there a preferred brand direction I should follow for some reason?
The need for a unit of this type would be limited to the home atmosphere, not outside ( I think). Futher use would be for macro use and that would probably be it.

Any and all responses concerning this subject would be very much appreciated.

Changeling

[Changeling]

Additional info: I searched on Ebay for "Flash guns with slave mode" and there was a seller that "said" there was a difference between regular and "Digital" flash units and his unit was for digital flash units. I have no idea what this really means (lack of experience)!

Changeling

[msowsun]

Slave flashes have no connection to your camera. All they do is flash when they sense another flash go off. So you must use your own camera's flash to fire the slave flash.

Most modern cameras fire a pre-flash a split second before the main flash fires. This is used to meter the amount of flash needed.

Older slave flashes will fire during the pre-flash and your photo will be dark because the pre-flash is fired before the shutter is actuated.

Most slave flashes you buy now are "digital". What they really mean is that the newer models of slave flash have custom circuitry that will disregard the pre-flash and only fire during the main flash. You may have to select a button on the slave flash to match your camera's pre-flash.

[CRE@TE]

I believe it's an optical slave.

[Changeling]

Slave flashes have no connection to your camera. All they do is flash when they sense another flash go off. So you must use your own camera's flash to fire the slave flash.

Most modern cameras fire a pre-flash a split second before the main flash fires. This is used to meter the amount of flash needed.

Older slave flashes will fire during the pre-flash and your photo will be dark because the pre-flash is fired before the shutter is actuated.

Most slave flashes you buy now are "digital". What they really mean is that the newer models of slave flash have custom circuitry that will disregard the pre-flash and only fire during the main flash. You may have to select a button on the slave flash to match your camera's pre-flash.


First off msowsun thank you for answering the post.

If the new slave "digital" flashes disregard the pre-flash (as you said), how do you know/figure out which slave flash to get for your camera among the various brands, using the A720IS as an example? I want to do this cheaply.

[Nick_C]

Don't worry yourself too much with the preflash, if you put the A720IS into full manual mode (M) it doesnt fire any preflash & this is the mode I use.

The Sigma EF500 DG Super flashgun has a built in optical slave, it works incredibly well, it fires even with my hand over the sensor, I tried putting the flash in another room & it still sensed, its VERY sensitive but at the same time I have never had a false trigger from it.

Ive had the best results from using this combination, infact I use it more than my 5D due to the higher DOF on the A720.

[Changeling]

Nick, I read up on the Sigma flash and it does seem to be very capable probably because Sigma reverse engineered Canon's flash to design it. However that is a pretty expensive flash at about the same cost as the Canon A720 IS, I would like to find something a little cheaper.

[msowsun]

I have never used one of the newer optical slave flashes. But from what I have read, there is a multi position switch and the instructions will tell you which position to use for your particular camera.

[maxmarengo]

If you want to get in to this a cheaply as possible and have an old flash unit, you can buy an optical triggered hot shoe. Then provided you have the camera flash set to manual, the remote flash will be triggered correctly. Total cost £10 and a good way to use old kit.
Example here
http://www.7dayshop.com/catalog/product_info.php?cPath=777_1&products_id=7850

[Changeling]

If you want to get in to this a cheaply as possible and have an old flash unit, you can buy an optical triggered hot shoe. Then provided you have the camera flash set to manual, the remote flash will be triggered correctly. Total cost £10 and a good way to use old kit.
Example here
http://www.7dayshop.com/catalog/product_info.php?cPath=777_1&products_id=7850



maxmarengo, I have been doing some investigating on my own, very hard when you have no experience, but anyway, I sorta know what you are talking about.
I found this web site that talks about a "flash trigger" and provides the plans for what evidently is an extraordinarily good product. This unit has evidently been built with excellence in mind and not really making a fortune. Check it out and let me know what you think if you have the time.
http://www.pbase.com/sinoline/sft_kit

Actually I am really interested in everyones opinion of this "flash trigger". One of the ladies that live with me left a message, but she hasn't heard anything back yet.

Changeling

[Nick_C]

maxmarengo, I have been doing some investigating on my own, very hard when you have no experience, but anyway, I sorta know what you are talking about.
I found this web site that talks about a "flash trigger" and provides the plans for what evidently is an extraordinarily good product. This unit has evidently been built with excellence in mind and not really making a fortune. Check it out and let me know what you think if you have the time.
http://www.pbase.com/sinoline/sft_kit

Actually I am really interested in everyones opinion of this "flash trigger". One of the ladies that live with me left a message, but she hasn't heard anything back yet.

Changeling

Yes I was going to suggest making your own, but I didnt like to say as not everyone is capable.

That circuit looks simple enough, its the sort of thing I would have done if I didnt have one already built in my flashgun, if you know how to print out on film & etch the PCB etc.. then go for it... I find its more fun making things than buying them!

[Nick_C]

Just had another look, they are using a pic chip, so unless you have access to a pic programmer you wont be able to make this.

[msowsun]

Changeling,

Do you have an external hotshoe flash now? If so, then an optical trigger would be a good idea.

If not then a economical alternative is something like this: http://cgi.ebay.ca/Compact-Slave-Flash-for-CANON-A610-A620-G3-G6-S50-NEW_W0QQitemZ170235888447QQihZ007QQcategoryZ48515Q QssPageNameZWDVWQQrdZ1QQcmdZViewItem

http://38.105.141.10/images/IBP-Images/DigitalFlash.jpg

[Changeling]

msowsun Thanks for the link. A (flash trigger/flash) is not something I would need a lot, therefore the reluctance to spend a lot.
The link I gave sounded like a unit that could be used with current equipment and tomorrows equipment. However I spent the last hour trying to find the guy's email address to no avail, therefor I consider the link I posted above to be worthless. Sorry if I inconvenienced anyone.

Changeling

PS. This equipment is for use on the Canon A720 IS.
However it is always a good idea to consider equipment one may own the road and buy accordingly.

[Nick_C]

Whatever you decide you will ideally need the slave flash to have adjustable power, many of the cheapo ones dont!

[menehune]

Here's a cheap slave flash (http://www.ritzcamera.com/product/531660769.htm) for only $20. I know, it's a Quantaray, but some people have been using it as hair/accent light with pretty decent results. It doesn't sense preflash. You'll have to shoot in M or go up a model.

[Changeling]

Just had another look, they are using a pic chip, so unless you have access to a pic programmer you wont be able to make this.

Nick, thanks for the reply, sorry it has been a while I've been extremely busy. The camera (A720IS) came and I haven't even had a chance to read the instructions/manuals yet!

One of the women that live with me informed me she was buying the "Flash Trigger" that I described above with the address. I thought the guy had closed up shop but Lola went to the web site and found his email address and has been talking to the guy about him building one for me, very nice gesture on her part.

Whats a Pic chip, I have no intentions of programing it, I'll find out if that is done before she buys it, I hope! If not it won't do me any good, I don't need any more confusion in my life right now!! Please explain about the chip, will the program stay in the chip? Confusing.

[Nick_C]

Nick, thanks for the reply, sorry it has been a while I've been extremely busy. The camera (A720IS) came and I haven't even had a chance to read the instructions/manuals yet!

One of the women that live with me informed me she was buying the "Flash Trigger" that I described above with the address. I thought the guy had closed up shop but Lola went to the web site and found his email address and has been talking to the guy about him building one for me, very nice gesture on her part.

Whats a Pic chip, I have no intentions of programing it, I'll find out if that is done before she buys it, I hope! If not it won't do me any good, I don't need any more confusion in my life right now!! Please explain about the chip, will the program stay in the chip? Confusing.

A PIC chip is an IC which can be programmed using a Pic Programmer, I use them in some of my other projects that ive made in the past, if your buying the completed board ready to use then the guy selling it would definantely have already programmed the Pic chip, otherwise it simply wouldnt work!

It will stay programmed, you dont have to do anything other than use the gizmo ;)

[menotomyhunter]

After reading these threads, I resurrected my Sigma EF-500 Super, not a DG model, and read the instructions. To my surprise, I discovered that it had a slave mode; amazing what's in the owners manual! I have tried it with my A720IS in the manual mode and it performs extremely well. I use CHDK and shoot RAW plus JPG. I'll play around with the Sigma more to explore exposure control for indoor use. Prior to this discovery, I used the Sigma on a Pentax ZX-5n 35mm film camera with the ABBC (A Better Bounce Card) accessory for bounce lighting. I still use the ABBC for digital photography on the Canon P&S. Gorgeous lighting indoors!

Cheers,
mh

[Changeling]

A PIC chip is an IC which can be programmed using a Pic Programmer, I use them in some of my other projects that ive made in the past, if your buying the completed board ready to use then the guy selling it would definantely have already programmed the Pic chip, otherwise it simply wouldnt work!

It will stay programmed, you dont have to do anything other than use the gizmo ;)

Thanks for the reply Nick, as usual you are exactly right!
Lola said he is doing all of the things you suggested and is going to also build a cable with a hot shoe so just any old/new flash can be used ! In short, it will accept "any" flash! I am definitely no expert on any of these matters, but this is AWESOME!!

It, the design is all his and he controls the rights to it, she said he was an elderly gentleman with vast knowledge in the electronics and photography field.
I would be willing to bet that there will be companies knocking on his door about buying the rights when it's capabilities become known. I was worried I was going to have to spend a whole lot of money on this lighting situation witch everyone seems to agree is the major problem in photography, but his slave flash triggering system is going to solve my lighting/money worries.

I like going to yard sales and those giant ones they have around here in parking lots, I've seen tons of old flash units that used to probably cost a heck of a lot, but now because no one can use them are for whatever reason they are really cheap, maybe a couple of bucks!
But with this mans "gizmo" it's like having an expensive flash, if the flash breaks, trash it and buy another.

Nick, with all your knowledge (actual, not BS) you are the guy I thought would be really worked up about an item like this.

Changeling

[Changeling]

All that and I forgot to ask, What is/was a really good flash in it's day with power and capabilities that are no longer what anyone wants, read that as cheap? A few if you have the time and remember off the top of your head?

[Nick_C]

Thanks for the reply Nick, as usual you are exactly right!
Lola said he is doing all of the things you suggested and is going to also build a cable with a hot shoe so just any old/new flash can be used ! In short, it will accept "any" flash! I am definitely no expert on any of these matters, but this is AWESOME!!

It, the design is all his and he controls the rights to it, she said he was an elderly gentleman with vast knowledge in the electronics and photography field.
I would be willing to bet that there will be companies knocking on his door about buying the rights when it's capabilities become known. I was worried I was going to have to spend a whole lot of money on this lighting situation witch everyone seems to agree is the major problem in photography, but his slave flash triggering system is going to solve my lighting/money worries.

I like going to yard sales and those giant ones they have around here in parking lots, I've seen tons of old flash units that used to probably cost a heck of a lot, but now because no one can use them are for whatever reason they are really cheap, maybe a couple of bucks!
But with this mans "gizmo" it's like having an expensive flash, if the flash breaks, trash it and buy another.

Nick, with all your knowledge (actual, not BS) you are the guy I thought would be really worked up about an item like this.

Changeling

Thanks for your kind comments, im glad that its all worked out well in the end for you, its nice to leave on a high note as I will no longer be posting on this forum in future (dont ask why).

So good luck with it all & im glad my advice/comments have been helpful to you.

PS, as for an old flash, I cant think of any actual models, but I do have an old practika flashgun which works well, you might be able to pickup something from the old film days on ebay, look for the "guide number" larger the number the more powerful the flash is.

[Changeling]

Thanks for your kind comments, im glad that its all worked out well in the end for you, its nice to leave on a high note as I will no longer be posting on this forum in future (dont ask why).

So good luck with it all & im glad my advice/comments have been helpful to you.

PS, as for an old flash, I cant think of any actual models, but I do have an old practika flashgun which works well, you might be able to pickup something from the old film days on ebay, look for the "guide number" larger the number the more powerful the flash is.

Thanks for all the information and kind responses to my questions Nick, guys like you and msowsun have really helped me a lot.
I am truly sorry there is some sort of problem that makes you want to leave this forum if there is anything I can do or if you need to talk about it later, just let me know.
It seems to me you have always been very courteous and helpful to everyone.

Take care, Changeling.