Bill, The only drawback I experience on my SU-4 is that the slave flash unit must be in direct line of sight of the main flash (for TTL operation). That sounds pretty easy, but it does take some effort and puts some constraints on your style, especially if you dynamically change the setup on location. To keep clear of the lens coverage area, you end up putting your flash out of direct line of sight from the camera mounted flash. Maybe where a flash setup is fixed, it may be less of a trouble. The symptoms are the "beep beep beep" sounding from the SU-4 telling you it has fired all available power into your subject, flooding it, while you know it should have approx. half charge left in the flash. This happens because the SU-4 saw the main flash start, but due to the abundance of flash light (including it's own light), it fails to see the main strobe (when not in the line of sight) turn off, blasting it's entire charge into your subject. I would imagine with your weaker built-in on-camera flash it could be worse. Fact remains: multiple flashes are a must. Light trigger slave flash units have no cables, you can put them down easily, but is more difficult to set up and constantly change (TTL), and if you hear the beep, you have possibly spoilt an otherwise good shot. I now prefer using the flash and SU-4 in M mode again, balancing with my Minolta V meter. I just bought the SB-22s (with no 3-pin socket) (with no graded M settings) hoping that the TTL on the SU-4 works well. Snookered. Jaco http://www.cocoon-creations.com for HarTALK and SoftTALK
