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Wireless flash

Discussion in 'Accessories' started by mrwinter, May 20, 2013.

  1. mrwinter

    mrwinter TalkEmount Rookie

    11
    May 7, 2013
    For my Alpha, I bough the HVL-F42AM which has a wireless mode.

    On the alpha cameras, the flash can be triggered externally using the in-built flash.

    The nex-6 has a 'wireless' flash mode, which only works ... wait for it ... if you have an external flash installed.

    So I need an external flash to trigger my external flash. Thanks Sony.

    Does anyone know if there is some physical reason the nex-6 in-built flash cannot be used as a wireless trigger, or if they were just to lazy (or greedy) to program it into firmware?

    Perhaps it will be available in later firmware version, or perhaps you can BUY this function soon in Sony's app store.
     
  2. xXx1

    xXx1 TalkEmount All-Pro

    Jan 15, 2013
    The flash business with Nex isn't well thought at all. I have thinked about it for some time and I think that they should have implemented radio ttl instead of hot shoe. Some kind of possibility to fix that external flash to camera of course.

    Yes, you need external flash to control external flash with Nex. Of course you can use internal flash to trigger a manual flash but no TTL. I don't know how Sony flashes communicate (infrared/radio?) but I suppose that internal flash doesn't have it.
     
  3. Poki

    Poki TalkEmount Hall of Famer

    Aug 30, 2011
    Austria
    The NEX-7 was supposed to be able to trigger external Sony flashes using the built-in flash, but Sony decided in the last moment to pull this function out. I'd say they wanted to sell some of their HVL-F20AMs as wireless triggers ... And they may built it into the successor of the NEX-7 to give one more reason to buy a 7 instead of a 6.

    Whatever, if you want to use Sony's infrared wireless flash system, you need a HVL-F20AM (or any other Sony flash) as a trigger.
     
  4. mrwinter

    mrwinter TalkEmount Rookie

    11
    May 7, 2013
    Not quite sure what you mean. When you try to select wireless flash mode on nex-6 you get "Invalid with this (internal) flash."

    So you can't use this internal flash to trigger an external flash, TTL or no TTL. No sure either how the alphas did it either, but I assuming it was an optical signal because it involved the internal flash firing. There is some signal emitted by the internal flash itself, but if the nex flash can do red-eye, and all the other tricks, why can't it emit a signal for the external flash?

    And if, for some secret reason, the nex hardware is incapable of emitting the necessary light pulse, why doesn't sony admit this shortcoming and offer something like a cheap, miniature flash cube accessory, specifically for this purpose?

    Writing "flash controller" in the copatibility notes, when what is meant is "another external flash" is just marketing trickery.
     
  5. mrwinter

    mrwinter TalkEmount Rookie

    11
    May 7, 2013
    Thanks Poki, its starting to make sense.
     
  6. xXx1

    xXx1 TalkEmount All-Pro

    Jan 15, 2013
    You use a slave flash that reacts to the internal flash. It is probably possible to use infrared filter to filter out visible light if you don't want to use it. Technology from 1980's ... .

    The flash units work by using xenon flash tube. It is quite hard to use that for communication and flash units have usually some other means to communicate with each other (infrared or radio transmitter/receiver).

    Yes, I think that Nex should have that circuitry or a cheap add on. That way the camera would be much more practical.
     
  7. mrwinter

    mrwinter TalkEmount Rookie

    11
    May 7, 2013
    Thanks xXx1,

    to satisfy my technical curiousiy, do you mean that the nex flash is missing circuitry or using a flash bulb that does not emmit enough IR for the external flash (i.e. nex uses different flash bulb type to alpha SLR)?
     
  8. xXx1

    xXx1 TalkEmount All-Pro

    Jan 15, 2013
    Missing a circuit. The xenon tube is basically a bulb that discharges a capacitor at once (there are ways to stop it mid way) and as it needs to provide light for photograph it is impractical to use it for communication between flash units. The ir communication works much like a tv and a remote. There is a IR LED that is very easy to drive with a microcontroller and it is used to generate short pulses of light that can be detected with photodiode or phototransistor. Some cameras use a radio link (both are very cheap these days).

    Almost all flashes use xenon tubes these days. It works much like a fluorescent lighting tubes except that it is triggered by high voltage discharge (spark, that is) and not by mercury vapor. Xenon tube will be on until it's power source is turned down (that is how modern flashes regulate the flash energy, there is a semiconductor switch that turns power off).

    There are radio operated flash triggers for Nex-6 (but not for Nex-3 and Nex-5 [there is Allacax unit but it is really bad and there are flash adapters that take normal ISO flash]) but they have no TTL.

    Some manual flashes have a slave function. Some of these even work with Nex (there is a pre flash that must be ignored) but again no TTL.
     
  9. suntoryjim

    suntoryjim TalkEmount Regular

    102
    May 17, 2013
    For the F3 users out there looking to trigger an external flash, here is how I sorted this. I set my YN-560 speedlight to Mode 2, which ignores the TTL pre-flash, set the flash to -2 exp comp and bend the flash head upwards and shoot. Works really well.
     
  10. xXx1

    xXx1 TalkEmount All-Pro

    Jan 15, 2013
    I suppose that you could use infrared filter with internal flash too. Old trick is use unexposed but developed slide film for that but I think that gel filters work too (red+green makes a black filter so no visible light but IR passes thru).