Can I use an old Vivtar 550FD on an XTi body?

I have a friend who just recently purchased an XTi but would like to experiment with flash. Will this flash pose

any harm to the XTi?

It should be fine. The camera can tolerate up to 250V at the hotshoe whilst the flash has been variously measured as producing between 4 and 10V. You'll find it listed here:

 

http://www.botzilla.com/photo/strobeVolts.html

Thanks Mark. The chart says its "your call" which is somewhere between yes and no. But 4-10V is a long way from

250V. That is a really helpful chart- I also have an ancient minolta auto 132x and it looks like I can use that

one as well. I love finding this kind of info. Thanks a lot!

The chart is made with cameras that only tolerate around 6V at the hotshoe in mind (e.g. the original Digital Rebel) - unlike the XTi. However, you will only be able to use it on one of its auto aperture settings or M mode: TTL will not work, as the camera has no TTL flash sensors - only E-TTL sensors. The difference is that TTL sensors are in the mirror chamber (of film cameras) and measure the flash during exposure, whereas the E-TTL sensors are in the pentaprism, and meter a preflash before exposure.

Mark, I had thought of that and figured I would guide her as you have said. Can you guide me to a good tutorial

on TTL flashes? Thanks so much in advance.

-- "The chart is made with cameras that only tolerate around 6V at the hotshoe in mind (e.g. the original Digital Rebel)"

 

And even my original 300D, albeit not specified for higher voltages, survived a lot of use with a Metz 30 ... which I measured with about 160volts. I'm not saying this isn't bad for the camera, I probably was just lucky.

 

-- "a good tutorial on TTL flashes?"

 

http://photonotes.org/articles/eos-flash/

 

Its very EOS specific but is worth reading.

Since the XTi has no TTL sensor, and the 550FD is not TTL flash anyway, you will have to use the flash's auto sensor. Set the flash's ISO (ASA) to whatever you are using on the camera. Set the camera to manual, and set the lens aperture to whichever auto aperture range you choose to use on the flash, and then set the shutter speed to anything 1/200 or lower. That should get a decent exposure. If you want to use a different aperture, choose a different auto aperture range on the flash. If you need to adjust the exposure up or down use a different aperture than what the auto aperture range suggests. It's all pretty simple, but can be confusing and slow to adjust until you get the hang of it.

 

TTL, and E-TTL is simpler, but far more expensive and are not really any better for most things.

See the photos of a 550FD c/r (Canon Ricoh) here:

 

http://www.eos-numerique.com/forums/f18/avez-vous-deja-utilise-ce-flash-vivitar-550fd-37068/

 

They plainly show a TTL setting (which you should not use), and two auto aperture settings (marked A1 and A2), and a manual setting (marked M) on a switch on the back of the flash. The front of the flash has a sensor that measures the flash in the autoflash settings (circled in blue). There is also a slider on the rear of the flash for setting ISO.

 

First set the ISO to the same as you are using on the camera. If you set a higher ISO on the camera it will increase the maximum range of the flash. If you are using the M setting, the aperture you should use will appear in between the distance scales in metres and feet - set the aperture that corresponds to the subject distance from the flash (this assumes you are using the flash directly pointing at the subject). If you work with the camera in M exposure mode you can use any shutter speed of 1/200th and slower: using slower shutter speeds will increase the contribution of ambient light to your picture (particularly the more distant background), while leaving the flash contribution constant. You can increase or decrease the contribution of the flash by using a wider or narrower aperture.

 

To use the A settings, select one: the aperture at which it works for your ISO will be displayed, along with a range of subject distances at which flash will be automatically set to approximately the right level provided the sensor on the front of the flash is pointing at the subject. This saves having to measure or estimate the flash to subject distance, and it can also be used with the flash set to bounce off the ceiling or a convenient white wall - which will give more even lighting without the harsh shadows of direct flash. If you bounce the flash you will probably need to use a somewhat higher ISO (try 400 to start) to allow for the extra distance from the flash to the bounce surface and then back to the subject, along with some absorption of light by the bounce surface. Again, you can change the contribution of the ambient light by varying the shutter speed, and of the flash by changing the aperture you are using on the camera. The choice of apertures allows different depth of field, and also a choice of maximum range.

 

Experiment with the interplay between ISO, aperture and shutter speed to help familiarise yourself with what you can achieve.

Wein HSHS - an flash adapter that will filter any voltage spikes to protect your camera.

 

After I burnt out the circuitry on my 20D I've got to be very nervous about sending high voltages through my camera. As I understand it (and as I think some of the links above may actually say) damage can be cumulative rather than immediately disastrous. Why gamble?

 

On the other hand, maybe there's even more to be said for buying a new flash that is made to work with the Canon cameras.

When I emailed Canon about what they called a safe sync voltage for my XTi they replied that it was safe up to 250 watts. [scratch my head] I emailed them back, asked if they meant volts instead of watts, they said 'oh no, its only rated for 6 volts' [paraphrasing]. Dont listen to anyone telling you that its rated at 250 volts, its not. If you dont believe me, contact Canon directly. They are very accomodating with that information, just pay attention to volts vs watts.

The issue of safe hotshoe (and PC connection, where available) voltage has been covered many times in this forum. I prefer to rely on answers from Chuck Westfall of Canon over those from Canon techs who lack his degree of knowledge. The most comprehensive answer he has given is here:

 

http://www.digitaljournalist.org/issue0703/tech-tips.html

 

From that is is quite clear that both the 20D and the XTi support 250V at the hotshoe. The 10D and original Digital Rebel/300D are the last 6V only DSLRs. It is also clear that there are a number of older flashes that can exceed this level (just read through the table at Botzilla) and are therefore capable of burning out a 20D. Among these are some models with a wide range of hotshoe voltages (e.g. the Vivitar 283 which has been sold over many years), where checking the voltage with a voltmeter is advisable - which is also the case with older models not listed there. However, the Vivitar 550FD is not one of these: at 10V a Wein safesync would simply be a waste of money (they're not cheap, priced at a several hundred (?thousand) percent markup over a couple of dollar cost components to prey on people's sometimes unjustified fears).

 

http://www.carlmcmillan.com/Optoisolated_Adapter.htm

Hey Mark, That picture really does show a TTL setting for the 550FD. I thought sure it didn't have one. Still, since the digital can't do TTL, manual or an auto range has to be chosen, and they all work about the same.

 

And yes, we've gone round & round about the safe sync voltages of Canons, and some people continue to disbelieve all the new hotshoes are safe to 250 volts. And of course, some flash units exceed even that limit.

Get yourself a Wein Safe-Synch to be sure, and you can experiment away.

Why waste $50+? If you have any concerns at all, start by measuring the hotshoe voltage (instructions at Botzilla). If the hotshoe voltage does exceed 250V then $50 may be better spent on a different flash that doesn't have a high hotshoe voltage - especially if you add in another $25-30 from selling the flash. Or you could make your own optoisolator/SCR circuit for under $5 if you have the skills in electronics. The Wein safesync really only makes sense if you have a powerful old potato masher that is worth rather more. Besides, Wein's safe syncs are only built with 400V SCRs:

 

http://www.weinproducts.com/safesyncs.htm

 

so if you do have a flash with a 600V hotshoe voltage you can expect the safesync to fail after a while - whereas you could buy a 600V SCR for you own homebuild version and expect a good service life.

"Why waste $50+? " Yes why would you want to waste $50 on a camera that would take more than $50 to replace (if you bought new)?

 

But seriously, "If the hotshoe voltage does exceed 250V then $50 may be better spent on a different flash that doesn't have a high hotshoe voltage - especially if you add in another $25-30 from selling the flash." isn't bad advice. Although I would change the 250V to 12V or whatever you felt comfortable with. Canon states 6 volts, Chuck says 250 volts. Thats a hell of a difference. But in the end its your camera, your call.

 

Incidently high trigger voltages (over 50 volts or so) are a problem with radio triggers as well if you wanted to use this flash off camera. Optical triggers seem to be unaffected, but I'm sure they have a limit as well. And an optical trigger costs less than a safe sync.

 

Regards

Did you check who Chuck Westfall is? I think he is a much more reliable voice of Canon than some junior employee answering emails, since he actually has the clout to ask Canon Japan for real answers. As a Director of Canon USA (previously, Technical Director, now Director of Customer and Media Relations), Chuck's statements carry much weight. If they were incorrect, it could provide a basis to sue the company in a class action. Junior employees will be instructed to give cautious answers unless they know and can quote the correct answer.

 

The voltages that can be handled by radio triggers clearly depend on the design of the trigger. While some of these may be designed with particular studio strobes in mind (e.g. Elinchrom Skyport system, or even Pocketwizards limited to 200V) and thus not be engineered for the general case, some may use 400V or higher SCRs - clearly you have to check that the unit is adequately specified. However, if you don't intend to use a radio trigger, the issue doesn't arise, neither does it if your flash is low voltage anyway. Optical slave triggers are essentially the same kind of device as a safe sync - the difference being that they miss the front half of the opto-isolator (i.e. a camera connected flash in the case of the slave, rather than an LED in a packaged opto-isolator). The disadvantage with optical slave triggers if you are relying on the XTi camera popup for triggering is that they need to be devices that ignore the camera pre-flash or you have to use one of these techniques:

 

http://www.eosdoc.com/manuals/?q=blankFEL

In previous discussions about this Canon USA technical employees that had listed the safe voltage as 6 volts, when challenged have later responded, "if Chuck Westfall said it's good for 250 volts, it's good for 250 volts." You're not going to get a more reliable answer.