A700 and Alien Bee

[mcddeb]

I need an assist. With the intent to get into portrait photography, I have purchase an off camera strobe flash called an Alien Bee. I have been reading the manual and have left it somewhere and can't find it!!! Plus, most camera equipment here is not very Sony friendly, they usually tell you how to use stuff with Nikon and Canon, but not Sony. So, I finally got the nerve to hook everything up, don't have a radio trigger yet, so I am attaching the A700 to the Light with the cord (PC Sync?). When I first fired the camera I only ended up with the lower half of the frame exposed. After several tries, I thought I would see what happened if I flipped up the on camera flash and the whole frame is exposed-somewhat under exposed but I did have a decent photo. I have the flash setting in the camera set to manual. And I had the camera set on manual as well. I had to set the ISO to 3200, I don't remember now what the f/stop was or the shutter speed. Am I doing this right?

Debra

[Javelin]

sounds like they are going off at the wrong time or the flash is done before the front curtain is all the way open. is there a slave trigger on the unit that the camera built in flash might be setting off? seems to me these should work at pretty low iso settings. have you tried a shuter speed of around 1/60?

I found this link to their online manuals. hope that helps.

http://www.paulcbuff.com/manuals/

[harveyzone]

When I first fired the camera I only ended up with the lower half of the frame exposed. After several tries, I thought I would see what happened if I flipped up the on camera flash and the whole frame is exposed-somewhat under exposed but I did have a decent photo. I have the flash setting in the camera set to manual. And I had the camera set on manual as well. I had to set the ISO to 3200, I don't remember now what the f/stop was or the shutter speed. Am I doing this right?

Your shutter speed is too high. Use a speed lower than x-sync which I believe is 1/200 (1/250 when SSS is switched off) on tha A700. The second shutter curtain is starting to shut before the first is fully open, and casting the shadow on the sensor. The internal flash works because it can do HSS at speeds greater than x-sync speed (it strobes the light so that it is essentially 'on' for the whole duration of the shutter being open). The external 'conventional' flash can not do this.

[David Kilpatrick]

The A700 should sync with the AlienBee, as suggested, up to 1/200th regardless of settings (officially 1/160th but I have tested cable-sync flash at 1/200th with consistently perfect results); and 1/250th with SSS off, and a good response from the flash units in terms of duration and slave sync timing. I think AlienBee strobes are a fairly short flash duration and will be unaffected. If you use longer duration studio flash, such as 1980s Bogen (Bowens) Monolites or Multiblitz Vario, ProFoto and similar high-end brands pre-1990, the actual flash have have a T=0.5 duration of 1/250th which means that if you use 1/250th you get exactly half the stated flash power. The 'tail' of the flash duration can take the overall meaningful duration (T=0.9) up to 1/60th, so to get the full output of these earlier large systems, you need to use 1/60th.

These flash units (typically 250-1000 Ws or Joules in rating) often have exceptionally high power modelling lamps. We used to work with two Multiblitz Vario 500s and one Vario 1000. They had 350W halogen bulbs in the 500s, and a 650W in the 1000, along with frosted covers for the modelling and tube together, and very noisy cooling fans. The long duration of the flash with these heads meant working at 1/30th or 1/60th was advisable to get maximum output, but you could also trim the exposure by using leaf shutter speeds to 1/500th. For a long time, we thought these heads had amazingly good colour, warm and vibrant. Then one day I ran a test to see how much of the exposure was being added by the modelling lamps at full power, and it turned out that at 1/30th sync speed, 1/3rd of the exposure was tungsten and 2/3rds flash! No wonder the colour was warm.

Since then I have always been careful with modelling light power. I like really bright modelling - it helps focusing and viewing - but if you combine it with a low flash output (my current Elinchrom flash heads allow separate control) you may end up with a significant part of the exposure being from the modelling light.

Good luck with the studio set-up. Here's an example of two strobe heads used with natural light and modelling light:

Alpha 700 food shoot on location

Some of the light is from a window, creating the reflection in the gravy. The light striking the top of the potato tower from the right is a honeycomb gridded 44cm rigid square dish, flash. The beam of tungsten aimed at the meat (wild woodpigeon breast) from the left is the modelling lamp of a second head, with the flash turned off, through a conical snoot tube.

For comparison, here is a shot using just the two flash units, without natural light added, and without the tungsten modelling to change the colour of the meat:

Alpha 700 flash only

For this job I used the 100mm f2.8 Minolta Soft Focus lens (without the soft focus turned up) which, for me, has the best colour and bokeh/feel of any similar lens for this type of work.

David