New Vivitar 285HV suitable for Canon Rebel T2 and Bessa R3A?

Discussion in 'Lighting' started by Edimilson, Dec 30, 2008.

  1. Edimilson

    Edimilson Member

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    Hello all!

    Sorry in advance for this newbie question!

    I own a Canon Rebel T2 (also known as EOS 300V) as well as a Voigtländer Bessa R3A. I have decided to buy a flash unit and have come across the Vivitar 285 HV. I have done some research at APUG and elsewhere and people seem to agree that it's a good choice considering its price.

    Problem is: after being around for decades, the new Vivitar 285 HV is now being produced in such a way as to be fit for modern digital cameras. This has to do with volts and electricity, a field in which my ignorance is boundless. I quote (http://www.popphoto.com/lighting/3983/vivitar-285hv-review.html):

    "The biggest change to the latest incarnation -- and the reason for reintroducing it -- is the sync voltage: Many modern DSLRs and advanced compact digitals sync up with external flash units using six volts or less in the sync circuit. Unknowing 35mm film converts, upon switching to digital, have hooked their old reliable flashes up to their new cameras only to find the sync circuits fried quickly. The older Vivitar 285 and 283 both had sync voltages between 200 and 260 volts, high enough to give modern six-volt circuits a heart attack. The new 285HV model syncs at under six volts, perfectly safe for today's digital cameras."

    My question is: would the new Vivitar 285HV be adequate for use with my film cameras?

    Thanks!
    Edimilson
     
  2. brofkand

    brofkand Member

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    Absolutely. The Rebel T2 is like digital cameras, it can't handle flash sync voltages that are very high. At least my Rebel 2000 couldn't.

    I have a Vivitar 283 I got from Goodwill for a few bucks about 6 months ago, and it's a great flash. I'm sure the 285hv is no exception.
     
  3. Edimilson

    Edimilson Member

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    Thank you, Brofkand. I understand the new model would work just fine with the Rebel then. But what about the Bessa R3A? Any thoughts?
     
  4. eric

    eric Member

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    I'm not sure about the 285's but I have an army of 283's. I don't chance it on my Xti. I got a Wein safe sync.
     
  5. Steve Smith

    Steve Smith Subscriber

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    Whilst the newer 285 HV does have a lower sync. voltage, the HV designation has nothing to do with this. It actually stands for High Voltage and refers to the high voltage connector (for a separate power supply).

    Of the older 285s, some were high voltage. According to this website: http://www.aljacobs.com/ultimate_vivitar_285hv_page.htm

    The flashes marked 'made in Japan' are high voltage whereas the rest are low.


    sTEVE.
     
  6. Edimilson

    Edimilson Member

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    I'm sure now the Vivitar 285HV I bought will suit my Bessa. I've already acquired a Vivivtar 2800 for my older film cameras. Thank you all.
     
  7. donbga

    donbga Member

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    If you own a volt meter you can measure the d.c. voltage accross the contacts. My old 285 reads about 7.5 VDC and I've used it safetly on DSLRs. However it's best to measure what your own unit charges to or use the Wein Saftey sync for suspected/unsafe high voltage units - cheap insurance.
     
  8. tim_walls

    tim_walls Member

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    Should work fine.


    For an understanding of the problem:

    The standard flash sync connection is just a switch. The outside of the hotshoe and the pin the middle are connected together when the shutter is open, and open when the shutter is closed.

    On many cameras - any all-mechanical camera, like an old 35mm or a brand new LF shutter - this is just a simple mechanical mechanism; two contacts that come together when the shutter is opened.

    On 'simple' flashes, in very simplistic terms you can think of the recharging circuit as being a battery connected to a capacitor which charges the cap up to a nice high voltage - e.g. 250 volts. The capacitor is also connected through a switch to the flash gun; close the switch, and the capacitor discharges all its stored energy through the flash gun in an instant.

    The problem with old flashes is the 'switch' is just the hotshoe. I.e. one of the high-voltage outputs of the capacitor is connected directly to the centre pin, and the flash bulb is connected directly to the outside of the hotshoe. When the shutter connects the two together, the capacitor discharges (through the centre pin, via the shutter, back to the hotshoe and into the flash bulb.)


    This all works fine. It even works fine with electronic cameras that use a Thyristor to replace the mechanical switch with an electronic switch (I believe high-end professional electronic cameras probably still use thyristor switching.) Thyristors can handle large voltage/current switching easily.

    The trouble with thyristors is principally that they are physically quite large, which obviously doesn't fit with the miniaturise-everything approach of camera manufacturers. So many modern consumer level cameras use a transistor instead. Except, of course, stick 250 volts through a small transistor and the thing will probably blow up. (In a sad, life expiring fizzle kind of way, so don't try and replace your fireworks display with this.)

    The solution is to move the thyristor into the flashgun - so you present only the low battery voltage through the hotshoe, and instead of hooking the hotshoe directly up to the capacitor/flash, you connect it to a thyristor in the flashgun which then connects the capacitor to the flashbulb.



    So, to cut a long story short:
    Old flashguns with high-voltage hotshoe - work fine on old cameras, should be on professional new cameras but check, will blow the switching transistor on modern compact cameras.

    New flashguns with low-voltage hotshoe - work fine on any camera.



    Edit: Just for the pedants/curious, I missed one component out of my 'simple flashgun' circuit, which is the inverter which uprates the DC battery power to the 250V to charge the capacitor - this is just a simple oscillator & transformer circuit, and it's this bit that creates the whining noise as the flash charges.

    You can actually still buy brand-new flash units that still operate this way - I have three dead-cheap (10 buck type cheap) fixed-output flash units bought new last year which forgo a thyristor inside.

    A Wein Safesync type device, incidentally, is simply a thyristor inside a small box :smile:.
     
    Last edited by a moderator: Jan 11, 2009
  9. DBP

    DBP Member

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    The only issue I can see would be the size of the Vivitar on the Bessa. I use a cheap little Sunpak 1600A for better balance.
     
  10. Edimilson

    Edimilson Member

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    Thank you Donbg, it's good to know I may use the new Vivitar with older cameras. The degree of control you can have on the 285 as compared to the 2800 is certainly going to be useful.

    And DBP, this is a good point. I didn't know the 285 was so great because I had only seen pictures of it on the internet. But some days ago I had one in my hands at a store and it's really quite big. I'll have a look at the Sunpak model you mentioned. Thanks.
     
  11. Steve Smith

    Steve Smith Subscriber

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    That's me then.

    I was not aware of any flashes which use the sync. contacts to directly switch the high voltage from the inverter to the tube (I'm not even sure if it would work).

    Most flashes have an inverter which charges the main capacitor up to a high voltage. This capacitor is permanently connected to the flash tube but the tube will not conduct until it is triggered.

    A second small capacitor is also charged up to a high voltage via a large value resistor. It is this small capacitor which is discharged via the sync. contacts into a transformer. The output of the transformer produces a high voltage pulse which triggers the flash tube into conduction.

    In simple flash circuits, the whole of the charge in the main capacitor is discharged into the flash tube. Early thyristor flashes used a thyristor to 'short out' the tube when enough light had been delivered. The thyristor bypassed the flash tube and took the remaining charge out of the capacitor.

    An improvement of this circuit was to use two thyristors. One was connected between the flash tube and the main capacitor and was effectively held on continuously. The second was used to temporarily switch off the first thyristor when enough light was received. This stopped the tube from conducting and had the advantage of preserving the remaining charge in the capacitor to improve charge time between flashes.



    Steve.
     
  12. tim_walls

    tim_walls Member

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    Now we really are into pedantry - yes, typically the actual connection is to the tube's trigger conductor. The tube itself is of course permanently connected to the high-voltage supply, the trigger pulse gives the gas a kick to ionise it so it will then conduct.

    The actual connection made by the flash hotshoe is from the high-voltage supply to a second step-up transformer which connects to the tube's trigger, such that when the flash hotshoe is closed a pulse in the 10,000volt+ range is applied to the trigger.


    The salient point - that in old-style flash circuits the full flash HV supply is present on the hotshoe - seemed to be made without needing a discussion on the ionisation of xenon, but I am frequently guilty of misjudging the fine line between necessary detail and necessary simplification.

    In other words, even I underestimate the depths to which pedants will stoop :D.
     
  13. DBP

    DBP Member

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    As long as we are on the subject, does anyone know what Nikon models will talk to a Sunpak 266D?
     
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  15. Ken N

    Ken N Member

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    Partly true. To the best of my knowledge, no 285HV marked other than "Made in Japan" are high voltage, but there are "Made in Japan" units which are not high voltage.

    Only the oldest units are high-voltage. These flashes, along with the 283 have been around forever and there were a few changes made through the years which can't be identified through external means.

    Always check an older flash with a volt-meter, and don't assume all of them are camera-killers.
     
  16. Steve Smith

    Steve Smith Subscriber

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    Guilty as charged!

    I did want to make a short simple point but found myself describing the whole circuit.

    I suppose the point I should have made was that whilst it is possible/likely that the voltage on the sync contacts is the same level as the main HT supply, it is however usually connected via a resistor of around 500K to 1M used to charge a small capacitor.

    Steve.
     
  17. Drew B.

    Drew B. Subscriber

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    An old 283 that I have (from 1981) measures 4.5 volts and so should work on a dslr. But the Wein people say that if you were to use one of their devices...in a "just in case" situation, that the flash won't even fire because the voltage isn't high enough. So, I guess if you have an older 283 or 285 that have high voltages, the Wein device will be good insurance. But, if like me, you have a low voltage flash, you're on your own!
     
  18. viridari

    viridari Member

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    The new 285HV has yet to fry my old Canon EOS Rebel G or my old Mamiya C330. That said, it really is a big heavy flash.
     
  19. Steve Smith

    Steve Smith Subscriber

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    One thing worth remembering is that all of these flashes were designed to work with all cameras. It is only recent paranoa with some digital cameras having low sync. voltage specifications which have brought up this worry.

    Pre-digital no one would have thought about sync. voltage and would have just used whatever flash they had with whatever camera they had.


    Steve.
     
  20. tim_walls

    tim_walls Member

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    Indeed - I reckon 2nd hand flash units are one of the great bargains still to be had and the voltage paranoia has to be part of that.

    If you have a halfway decent handheld meter then all the alphabet-TTL-metering and automatic this-that-and-the-other whatnot is completely unnecessary, and even if your camera does have a low-voltage hotshoe a Wein Safesync is all you need to open up the complete range of flash units on the market.

    Personally I use a Nikon SB28, Vivitar 283 and three of those cheapo fixed-output units I mentioned earlier; cheapo wireless triggers from eBay and/or optical trigger widgets bring it all together, and it all works perfectly with any of my cameras from the most modern to the most ancient. (Of course, the reality is I almost never use all those units, but it's nice to have the option.) The one flash unit I practically never use is the fully-automatix-for-Canon Metz unit I bought when I was still using a DSLR.

    Note to self - must get round to selling the Metz.


    Anyway, I actually intended to add something useful here - I just remembered there's quite a handy webpage listing various flash voltages as measured by volunteers on't Internet; it can be found here http://www.botzilla.com/photo/strobeVolts.html
     
  21. MattKing

    MattKing Subscriber

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    Steve:

    It is not just digital cameras that are susceptible. A lot of the more recent film cameras are as well. I've even be warned that my Mamiya 645 Pro could be damaged if I use it with something like my old Metz 202 or my old Bowens monolights..

    Matt
     
  22. Steve Smith

    Steve Smith Subscriber

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    Is this a warning from Mamiya or just passed on hearsay? The Mamiya probably has mechanical contacts (just my assumption, not fact).

    I just find it strange that a manufacturer of a camera (film or digital) would design a product which cannot use existing flashes and which could be damaged by them.

    There are a lot of threads on Photonet about this. Many of them are from people worried about high sync. voltages on their DSLRS who don't realise that their cameras are o.k. Most are specified up to 250v but they have heard somewhere that old flashes can damage new DSLRs so are worried about it.


    Steve.
     
  23. Steve Smith

    Steve Smith Subscriber

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    Putting aside my carefree attitude for a minute and putting my cautious head on, I would double those figures.

    The reason being that the voltage measured is via a high value resistor (as I described earlier). The meter's internal resistance will act with this resistor to produce a voltage divider.

    Simplistically, if the flash's resistor is 1M and the meter's internal resistance is also 1M then a 12v sync voltage will only read 6v.

    The amount by which the meter will affect the reading is probably related to the quality and cost of the meter. My ITT meter which cost a fortune ten years ago reads just under 11v when measuring a 12v power supply via a 1M resistor. This implies an internal resistance of around 11M which is quite good. The cheaper meters likely to be owned by hobbyists, etc. are likely to be a lot worse than this. Unfortunately I can't find a crappy meter here at work to prove my theory!

    Using a meter will determine if your voltage is a matter of tens or hundreds though.


    Steve.
     
  24. Steve Smith

    Steve Smith Subscriber

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    My father also has a Mamiya 645 so I thought I would look into it.

    You probably already have it but the Mamiya 645 Pro manual is here: http://www.mamiya.com/assets/pdfs/645/645_Pro_TL_v8.pdf

    On page 34 it gives this warning:

    When using the Hot-shoe,
    be sure to put an appropriate
    Safety Cover over the X-sync
    terminal so that you won’t
    receive a high voltage
    electric shock if the terminal
    is accidentally touched. (A
    Safety Cover is put on the Xsync
    terminal when the
    camera leaves the factory


    This implies that high voltages are fine but warn you not to get your fingers near them!

    This manual also shows examples of the camera set up with various Metz flashes.


    Steve.
     
  25. MattKing

    MattKing Subscriber

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    Hi Steve:

    The warning came from a local repair facility who at the time was authorized to perform Mamiya warranty work.

    The Bowens monolights and Metz 202s that I have are both 30+ years old, so they may be an extreme example.

    If I understand it correctly, the issue is whether the synch switching is either completely mechanical, or almost completely electronic, or takes some middle ground, and that the ability to handle high voltages turns on how much the switching is mechanical, and how heavy duty those mechanical switches are.

    Matt
     
  26. Edimilson

    Edimilson Member

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    Vivitar 285HV tried for the first time

    I finally had a chance to give my Vivitar 285HV a try. I was very satisfied. Here's one of the results (sorry about the quality of the scan. Dealing with photos on scanners and computers really isn't my cup of tea).

    http://www.apug.org/gallery/showphoto.php?photo=40916&ppuser=17129

    I ended up using the Vivitar 285HV with the Bessa R3A despite the flash's big size. It really looks excessive on the relatively small Bessa, but the flash seems to be a joy to use. I got good results without much previous experience after all. I bounced the flash off a white board held by the kid's mother. Following the instructions on the manual was all I did to set the flash.