Vivitar 285HV flash and Canon 430ex

Hi I am still fairly new to flash and I am looking to purchase my 2nd flash, Vivitar 285HV (unless someone recommends a better flash at a cheap price).

On the Canon 430ex I can control the flash power by decreasing and increasing the "stops" -1, 0, +1 on the flash unit. I noticed that the Vivitar 285HV just has a knob. Does turning the knob all the way to the right(clockwise) means the flash power on the Vivitar is similar to the flash power on the Canon 430ex when set to "0"?

The Vivitar's manual setting are from 1/16 (iirc) to M for full power. The other settings are the auto settings.

So If I set the flash to "M" on the Vivitar is it like setting the 430ex to ETTL?

No, M on the Vivitar is full power (as long as it's fully charged before the fire of course!).

The Vivitar does not have ettl capabilities.

ETTL works with the current focal length of the lens? For example of I zoom in to 100mm the ETTL flash will fire stronger to provide more light?

Sounds to me like you need to do quite a bit of reading on flash technologies, or stick with the Canon system. If you want to use multiple flashes within the Canon system you'll need a 580 v1 or v2. If you go with a manual flash you'll need triggers and the 430 will have to be in manual, so you use ETTL.

To your focal length questions the answer is yes. Whatever settings you have the camera on the flash will go about the right brightness to match. TTL stands for through the lens, the preflash is basically the flash putting out some light, seeing how much comes back, and then putting out the main flash at the correct brightness to light the scene.