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Old Jun 23, 2010, 5:53 PM   #1
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Default New Vivitar 383 stuck at 55mm?

I just bought a new Vivitar 383 external bounce flash for my Sony Alpha camera. I love the flash so far, I'm still learning it, and I have a question. When it's on auto, it seems to always think that I'm 50mm away? It always says 55mm on the screen unless I go to manual. It has auto-focus, right?

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Old Jun 23, 2010, 9:28 PM   #2
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That number is not the focus distance, it is the lens focal length. If you are using a zoom lens, it should change when you zoom in or out. If you are using a fixed focal length lens, it won't change automatically. There is, I believe, a table showing distance in feet and meters, which should indicat the maximum distance at which the flash will be effective for the camera setting chosen. The flash doesn't actually focus, but it does change the width of the beam to correspond to the lens focal length. (sort of changes focus)

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Old Jun 24, 2010, 3:34 PM   #3
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Ok. Thanks for your help. I do have a zoom lens, but when I zoom in or out it doesn't change. Most pictures it's fine, but if I'm taking a photo of something that is close up, with the flash pointed at the ceiling, the lighting is really over-exposed.

I'm still learning...
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Old Jun 24, 2010, 10:32 PM   #4
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When you tilt the flash out of the straight ahead position, the automatic zoom function is disabled, since the program for it is not able to know how far what you are bouncing the flash off, is from the flash or the subject.
If it doesn't work with the flash in the straight ahead position, with the camera in an automatic exposure mode, then I would say you have a bad flash, or the pins on the flash are not making contact correctly with the hotshoe.
The flash and camera are supposed to work together (in auto or Av mode) to determine proper exposure by triggering a pre-flash, which the camera then measures, then tells the flash what settting to use. If you are in manual exposure, or the pins on the flash are not making proper connection with the shoe, then the communication doesn't happen, and the flash will simply fire at full power.

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Old Jun 25, 2010, 1:26 PM   #5
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The 383 really doesn't really "auto-focus" but "zooms" to provide the proper area coverage based on the focal length of the lens including, at least in the case of my Oly E620, the sensor crop factor. When I am using direct flash and I zoom my 14-42 kit lens to 42mm the flash's LCD shows 85mm (2x crop factor). If I put the 50mm f/2 macro lens on the flash goes to 85mm, as close as it can get to 100mm. When I move the flash head to bounce mode the flash goes to 50mm as area coverage is irrelevant in bounce mode.

So far I've only used my 383 for close-ups with the f/2 50mm lens. In that use direct flash will over expose (the flash is more intense when set to 85mm) without the deploying the built in diffuser. For the record, with the default ISO 200, the Oly set the aperture to f/8 with bounce and f/16 with direct flash when doing those close-up tests: http://forums.steves-digicams.com/ol...diffusers.html .

Really we need some more info to fully get a handle on the problem. What lens? What model Sony or at least what crop factor? EXIF data for the overexposed close-ups. For example if you where using an 18-55 lens on an a950 (1x crop) then 55mm is the correct readout on the 383s LCD and you simply need to drop the diffuser into place for the close-up. On the other hand if you're using an a330 w/ an 18-85 lens and all the LCD shows is 55mm in direct made then Brian is right in the pins not making contact (corrosion, misalignment or wrong sub-model flash) or the flash is malfunctioning.

A. C.

Last edited by ac.smith; Jun 29, 2010 at 1:03 PM.
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