Auto thyristor questions

[mmahoney]

A lot of time I'm shooting manual flash (static subjects) but do like having ETT-L for some quick changing light conditions. Lately I can't help but look at my 580 and think that maybe for me an old-school flash like the Vivitar 285 would do just fine.

My question is how accurate is the auto-thyristor with these units? .. is it accurate even with bouncing? .. how are they off camera with triggers? .. can you still get the same control with the background exposure using manual camera settings (like inside dragging the shutter or outside underexposing the BG but still having the subject properly exposed)?
Many questions .. many thanks :D ,
Mike

[scottbergerphoto]

Auto-thyristor flashes are very consistent if you stay within the distance ranges specified for each ISO/f stop combination. Bouncing gets tricky because it's hard to judge distance.

[E-K]

WRT off camera use, the 285 has a removable sensor which you place on the camera hot shoe (with the appropriate cable) so it should be just as accurate as on camera.

As far as dragging the shutter, etc..., you can still do it but I image in some cases it will be harder to setup than with E-TTL (and in other cases maybe it's easier ;).

For example, underexposing the background: just set the camera to the aperture indicated on your flash and set the shutter speed to a high enough value (but not faster than your camera sync speed) to underexpose the background.

Nice thing about my 285HV on the 350D is that I've been able to use a shutter speed faster than the indicated camera sync speed (1/300s).

e-k

[Curtis N]

The thing to remember about auto-thyristor flashes is that their sensors measure light from a circular area with a predetermined angle of view. This is the same regardless what lens you're using, so the field of view of the sensor could be significantly larger or smaller than your lens field of view. Because of this, they are at a disadvantage vs. TTL systems when used with long telephoto or wide angle lenses, depending on whether the area seen by the sensor is representative of your subject. When used off-camera, getting them properly aimed is more difficult than it might seem.

Each auto setting has a specified distance range shown on the back of the unit, but as Scott mentioned the range is entirely different when you bounce the flash and it will require some trial and error at first. These units have confirmation lights that illuminate after each successful shot, and when combined with a bit of histogram chimping it usually doesn't take long to find a useable setting.

Within their limitations, they are very consistent. I find the biggest disadvantages of these older style units are lack of an AF assist light and slower recycle times. But without an E-TTL pre-flash, they work great as a master with optical slaves.

[Wilt]

The thing to remember about auto-thyristor flashes is that their sensors measure light from a circular area with a predetermined angle of view....Within their limitations, they are very consistent. I find the biggest disadvantages of these older style units are lack of an AF assist light and slower recycle times. But without an E-TTL pre-flash, they work great as a master with optical slaves.

More consistent than ETTL!

Yes, fill flash is not as mindlessly simple, though, since their exposure is entirely independent of the camera exposure setting.

[mmahoney]

Thanks for the replies,
Mike