Canon 70D Flash tips needed (built in and external OCF)

Ok, I have been using my 70D for several months now and am very comfortable with it and shoot mainly in M mode or Av/Tv when I dont have the time to deal with M.

Sometimes I will use the pop up flash for fill and sometimes I will put on my 270 Ex again mainly for fill or bounce.

But I am just not understanding how to use these for "fill or bounce". So I need tips for using Flash (built in and for external).

Disclaimer: I am looking for tips only for using built in flash or the External on camera flash...I am not looking for tips for off camera flash at this point. I am just a hobbyist this is not for professional use.

The main problem I am having is understanding High Speed Sync and when to use it for my 270 Ex. And when to use modes Av over M when using Flash.

Lately, I have been using the 270Ex for bounce (white ceilings at about 8ft tall taking pictures of people at dinner table) in Av mode or even Tv mode (250 3.5 ISO A) and the exposures are dark! But when not bouncing and having 270 flash pointed at subjects, its exposed properly but I do not like shadows it produces.

If you're bouncing with the 270, it is most likely dark because it's not that powerful of a flash. The idea of bounced light is that you point the flash head at a surface that you want to bounce the light from (usually a white ceiling or neutral colored wall), and light must travel to the surface, bounce off it (spreading the light MUCH more), and then make it to your subject. If there's a high ceiling, lots of area to light up, a dark bounce surface, or a very dark room, this can take quite a powerful flash to accomplish. The inverse square law is your enemy.

There are a couple ways to get more "power" from your flash- manually set your ISO higher (I think Canon defaults to either 200 or 400), or use a brighter lens. Both of these methods will increase the apparent brightness of all light sources (including flash), but at the end of the day, the 270 is just not that powerful of a bounced flash.

I'd recommend a 430exii (600ex would be better), but if money is an issue, I've heard really great things about the YN-568ii (should be comparable in power to the 600).

Lots of good tutorial type content available. Try http://www.canon-asia.com/snapshot/spee​dlite-139/ as a start.

Use HSS when your need to control the ambient exposure requires you to use shutter speeds above nativve max sync(1/250). So usually bright conditions, especially if you use larger apertures. Unfortunately neither of your flashes have enough power to be very effective in HSS mode.

As to which mode to use Av Mode works well when you want fill light when you have sufficient ambient. Manual is better when you have less light because ETTL tries to act as fill and the camera meters in Av mode asi if tbere is no flash contribution, meaning you get slower than desired shutter speeds.

Good tutorial over in the flash section as well...https://photography-on-the.net/forum/showthre​ad.php?t=138907

^^^ Thanks everyone...I have some reading to do and your feedback is exactly what I was looking for.