Vivitar Flash?

[606photo]

Hello,

I am very new and am still learning a lot. What I have figured out very quickly is that the built in flash on my 300D sucks. The shadows are always too sharp and directly behind the subject. I have a flash that I bought years ago for my rebel x. Here is a pic of it and do you think it is worth fooling with on my new camera? I would like to get a 420ex but am short on funds at the moment. Just looking for some pointers on maybe using this flash...so far everything looks WAY blown out.

[robertwgross]

Power the Vivitar on. With a DC voltmeter, measure the trigger voltage (where it fits to the camera). If you see any voltage above 5-6 volts, then it stands a very good chance of burning up parts of your camera. However, if it passes that test, then you might be able to get only flash on manual mode of the camera.

In general, the solution is any Canon -EX flash unit.

---Bob Gross---

[PacAce]

If you check here, the table shows that the Vivitar flash you have has a very high trigger voltage. I have the Vivitar 2800 and when I checked it with the cheap VOM I usually have lying around, it only showed around 3 or 4 V. But the table says the trigger voltage could be as high as 140! :shock: Puzzled by the discrepancy, I took out my digital VOM and measured the voltage across the hot shoe pins and sure enough, 140V is what I got (although the voltage was constantly decreasing)! I then checked the voltage with two other analog VOMs that I have and they each showed a voltage of just over 100 V. :shock: :shock: :shock:

In short, I wouldn't be using your old Vivitar 2000 with the DRebel if I were you, at least not without some kind of "safe sync" gizmo between the flash and the camera.

And a word of caution to other who are contemplating checking the trigger voltage of their old flash units, make sure you use a very reliable VOM for measuring the voltage. Better yet, get a second "opinion" from another VOM if you have one handy. :)

[Edit: Oops! :o Forgot to include the link:

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

[Mark H.]

Thanks for the answers above!! I bought a digital Rebel last Tuesday and I have been playing around with an old Vivitar 2600 I use with a manual Pentax I own. I didn't have clue it could damage the camera. I just found this site this morning and I've learned something new and potentially saved myself some repair $$$.

Thanks again for the shared knowledge and I look forward to participating in the forums.

[robertwgross]

It's a good thing that you caught that, Leo.

Personally, I cannot function right on a week-to-week basis without using a multimeter for something. Normally, I keep one good one and one cheap one on hand.

Somebody will ask the question of why I keep a cheap one around if I have a good one. Simple. When I am going to drop the leads onto something completely unknown, I would rather sacrifice the cheap one first. They don't make meter protection like they used to.

---Bob Gross---

[MTalley]

I have an old Vivitar 2000 that looks exactly like the one in the picture, above. Same story, bought mine several years ago to use with my old Pentax K1000 film camera.

I bought a Wein SafeSync to use with it now. It is usable, but you'll have to learn how to manually meter everything. I put the 2000 in the "M" mode, take a few test shots to figure out what aperature to use at the distance I'm shooting, and then I'm good to go.

For variable distances and general walking around needing a flash, though, I'd agree with others that recommend you purchase a Canon flash. That way, the camera will fire the flash correctly for you using the built-in metering, etc.

[sjprg]

I have the opposite problem. I would like to use my 550EX on my old cold shoe Mamiya C22. I have tried the various cord manufactures but no joy on a hot shoe female to old fashioned PC connector. It would be even better if I could find an single piece adapter that would have a cold shoe on the bottom, a hotshoe on the top, and a short PC connector cord out the side, than I coudl use my ST-E2 to trigger the 550EXs.
Any ideas???

[PacAce]

I have an old Vivitar 2000 that looks exactly like the one in the picture, above. Same story, bought mine several years ago to use with my old Pentax K1000 film camera.

I bought a Wein SafeSync to use with it now. It is usable, but you'll have to learn how to manually meter everything. I put the 2000 in the "M" mode, take a few test shots to figure out what aperature to use at the distance I'm shooting, and then I'm good to go.

For variable distances and general walking around needing a flash, though, I'd agree with others that recommend you purchase a Canon flash. That way, the camera will fire the flash correctly for you using the built-in metering, etc.
You did know that you can work that flash in auto-thyristor mode, right? It's got two auto modes which uses two different aperture values. Sometimes the aperture value to use needs to be tweaked to get the best flash results but once set, you can get some pretty darn good flash exposures.

BTW, I forgot to mention, there should be a GN/distance/aperture table somewhere on the flash (usually on the back) which tells you what aperture to use for subjects at a certain distance and ISO setting so that you don't have to figure it out by trial and error like you're doing.

[MTalley]

Yeah, I knew it had the two auto modes (green and red scales on the back), but it's been a while since I've seen the manual for the thing. I did a Google search on using those modes, but didn't pursue it far enough or didn't enter any good search terms.

Yes, I know it has a table, but dragging out the tape measure at our house takes longer than just snapping a few pics to see how they are coming out. Out in the field, though, I do guesstimate the distance, set the manual settings appropriately and work from there.

[PhotosGuy]

I've used Vivitars for over 30 years & they're almost indestructible, not to mention cheap enough that it doesn't break the bank to have 2 or 3 of them in a lighting kit! Here's a few threads that might help you out.

Simple "every-day-emergency" location lighting (http://photography-on-the.net/forum/showthread.php?t=66358)

Fill light at sunset (http://photography-on-the.net/forum/showthread.php?t=66353)

[DocFrankenstein]

Unless it's a very advanced voltmeter that gives you the top of the voltage spike only, I would not trust anything but an oscillograph to measure the voltage on the flash.

[MTalley]

True. I was using a combination Oscilloscope/Meter in regular meter mode. Still, 86V is definitely higher than 6V, so trying to find the peak voltage is rather a moot point.

[PacAce]

Unless it's a very advanced voltmeter that gives you the top of the voltage spike only, I would not trust anything but an oscillograph to measure the voltage on the flash.
The voltage across the flash terminals is DC, so where does the voltage spike come into play here? An oscilloscope is a little overkill, I would think. A good digital VOM should be all one needs if one doesn't want to trust the anolog VOMs.

[DocFrankenstein]

One can't really trust the analog VM at all for measuring the flash voltage. You have a very short spike when the capacitor is discharging, followed by maybe a very small leg on the graph. Analog VM won't be able to react to the spike at all, so the needle will jump up to say 3 volts when the actual voltage is 300V

With digital voltmeters, it's also shaky grounds and you have to be really confident in yout VM then. Yeah, it's DC, but when the pulse is so short, it may not be accurate at all. Your VM would have to take a 10000+ readings every second to be accurate.

And I don't think many voltmeter manufacturers actually publish the way their VM works... so you're never really sure if it's accurate or not.

With an oscilloscope, you can tell for sure: "yeah, ok... the top of the spike is at 9 volts"

[PacAce]

One can't really trust the analog VM at all for measuring the flash voltage. You have a very short spike when the capacitor is discharging, followed by maybe a very small leg on the graph. Analog VM won't be able to react to the spike at all, so the needle will jump up to say 3 volts when the actual voltage is 300V

With digital voltmeters, it's also shaky grounds and you have to be really confident in yout VM then. Yeah, it's DC, but when the pulse is so short, it may not be accurate at all. Your VM would have to take a 10000+ readings every second to be accurate.

And I don't think many voltmeter manufacturers actually publish the way their VM works... so you're never really sure if it's accurate or not.

With an oscilloscope, you can tell for sure: "yeah, ok... the top of the spike is at 9 volts"
Again, what spike are you referring to. When you initially start to charge up an "empty" capacitor, yes, there's a spike as the current rushes through the capacitor. Then, after that inital spike, the capacitor starts to charge at a steady rate until it is almost fully charged. At the point you are testing the flash voltage, the assumption is that the flash has been on for a while and hence, the capacitor will be at its full charge. No spike to worry about at that point. Depending on the impendance of the testing equipment you are using, the capacitor may start to slowly discharge through the test equipment and you'd see a gradual decrease in the voltage as you are measuring it but again, you're not going to see a spike anywhere unless the test equipment is of such a low impedance that the current just surges through the equipment, but usually that's not the case unless there's something wrong with the test equipment.

[sjprg]

Whoh!
The flash capacitor itself is charged to 300 to 900 volts depending on the flash tube and is actualy discharged through either a transistor or SCR. A good design of the trigger control would probably use at least a couple of transistors to completely isolate the high voltage. The older original circuits just dumped the high voltage through the shutter contact. (circa 1960s). I haven't seen the curcuitry of a modern flash tube but I would suspect that the shutter contact is controling the base of a transistor through a resistive divider from the battery supply. From what I have read of the specs of my 550EX the internal batterys must be installed even if you use the external high voltage connector. Which leads me to believe that the base current is controlled by the installed AA batteries. A lot of the older (and cheaper) units used a voltage divider from the high voltage supply. A good digital voltage should be able to measure the base voltage accurately. Any capacitor across the base would probably be small and only there to control the response time of the transistor, as the whole object is to reduce the current through the shutter contact. Some where "lost in my possesions" is an original design curcuit written by "Edgerton" who did a lot of the original design of strobe lights. I think there is a chapter on this in my old ITT engineering handbook also.

[TylerOxendine]

Sorry for bringing a thread dated 3 years ago, but I was given this flash and have a Rebel XTI. I was going to use this flash for a halloween party coming up. Im rather new to the Rebel and i'm pretty confused on the anwser's, but would this flash at any way possible hurt the camera and would it work?

[PhotosGuy]

The link in Post #3 will give you the flash trigger voltage.

From http://dpanswers.com/canon_flash.html#tv I found:

However, an email from Chuck Westfall (Director, Media & Customer Relationship, Canon USA), posted in this thread in DPreview's Canon EOS 350D/300D forum in April 2005 by Doug Kerr had the following to say about trigger voltages:

The EOS Digital Rebel XT [350D] uses a modified version of the EOS 20D's shutter unit. Consequently, acceptable trigger circuit voltage for both cameras is the same, i.e., 250 volts. Except for the original Digital Rebel [300D], all current EOS digital SLRs (i.e., EOS-1Ds Mark II, EOS-1D Mark II, EOS 20D and EOS Digital Rebel XT) generate their X-sync signals electronically rather than mechanically. This is why they have higher acceptable trigger circuit voltage ratings than earlier models like the D30, D60, 10D and original Digital Rebel [300D]. These older models cannot be modified to achieve a higher trigger circuit voltage rating, since such a modification would require a different shutter mechanism as well as a complete redesign of the supporting circuitry.

I take this to mean that all Canons DSLRs newer than the 350D, as well as all the professional models, can use flash with trigger voltages up to 250 volts in their hot-shoe. However, 6 volts is the safe limit for the D30, D60, 10D and 300D.

[TylerOxendine]

still pretty confused....

[DavidSR]

Go here and look for the flash..
http://www.botzilla.com/photo/strobeVolts.html

it looks like people have recorded volt readings anywhere from 50V - 202V

I take this to mean that all Canons DSLRs newer than the 350D, as well as all the professional models, can use flash with trigger voltages up to 250 volts in their hot-shoe. However, 6 volts is the safe limit for the D30, D60, 10D and 300D.

It looks like we can use flashes all the way up to 250 volts so you might be safe, but I wouldn't risk it since the flash volts are so close to what our cameras can tolerate. It's last minute, but the safe sync. is the safest way to go to put that flash on camera. You probably won't be able to get it in time for your party though.

[Wilt]

Hello,

I am very new and am still learning a lot. What I have figured out very quickly is that the built in flash on my 300D sucks. The shadows are always too sharp and directly behind the subject. I have a flash that I bought years ago for my rebel x. Here is a pic of it and do you think it is worth fooling with on my new camera? I would like to get a 420ex but am short on funds at the moment. Just looking for some pointers on maybe using this flash...so far everything looks WAY blown out.

Apart from the warning about too high of a trigger voltage (reports are 54-202v trigger voltage measured with the Vivitar 2000, so not safe for Canons pre-dating the 350D/XT and 20D, such as the OP's 300D), a hotshoe flash will drop the shadow down a tiny amount, but the size of the source is the only thing which affects shadow edge, and you only alter that with optional flash modifiers (some of which are overpriced!)

[DavidSR]

Apart from the warning about too high of a trigger voltage (reports are 54-202v trigger voltage measured with the Vivitar 2000, so not safe for Canons pre-dating the 350D/XT and 20D, such as the OP's 300D), a hotshoe flash will drop the shadow down a tiny amount, but the size of the source is the only thing which affects shadow edge, and you only alter that with optional flash modifiers (some of which are overpriced!)

I was responding to the person below, not the O.P. :)

Sorry for bringing a thread dated 3 years ago, but I was given this flash and have a Rebel XTI. I was going to use this flash for a halloween party coming up. Im rather new to the Rebel and i'm pretty confused on the anwser's, but would this flash at any way possible hurt the camera and would it work?

[Wilt]

I was responding to the person below, not the O.P. :)

And I was responding to the OP question about lighting benefit of a hotshoe flash over built in flash, but also responding to the safety for the 350 and later, of the later post.

[DavidSR]

Than I appoligize, but I thought your statement was directed at me since you posted right below me.

[Wilt]

Than I appoligize, but I thought your statement was directed at me since you posted right below me.

That's exactly why I quote the statement that I am reply to! :D I should have quoted the later one from Tyler, too!

[DavidSR]

I saw that, but yet ignored it..still thought it was directed at me..haha..I will shut my mouth and go back to taking pictures.