Hot shoe mounted flash assist for 5dIII/6D

Hey guys. I have a 16-35 f/4 and a 24-70 f/4. For wedding receptions and I'm on the dance floor, the F4 has a hard time focusing now and then. I think my 50mm f/1.2L has a much better hit rate when focusing. I may pick up a Mark I 35mm f/1.4L, but I'm also wondering about a cheap focus assist light. Last wedding it was so bad I busted out my cell phone and was using it to help focus. Something that would go on the hot shoe, but still allow my Yongnuo 560-tx to go on top of it.

Can't you use the focus assist light from your Yongnuo?

I think there's one on there but I've never seen it come on automatically and I don't remembver reading about it in the instructions. I assumed it is broken.

I use Canon Speedlite 90EX on my 6D, but for remotely firing other off-camera flashes. It does have intermittent AF assist up to about 3m (9.2 ft). While not the brightest bulb in my bag, for about $50 there are a lot of features in this little unit.

Silver-Halide wrote in post #17844303
I think there's one on there but I've never seen it come on automatically and I don't remembver reading about it in the instructions. I assumed it is broken.

the canon flash I have only emits the focus assist beam when the camera focus mode is set to one-shot, it's possible the Yongnuo does the same...

Yes you have to be in one shot for the focus assist to work. You would think that they could manage to kill the assist beam during the actual exposure in Servo, afterall during the mirror up period the AF isn't operating anyway, as the mirror is in the working position. At least on my Sigma flash it still works with BBF only set.

Alan

Thanks BigAl--that helps.

Because I use BBAF, 99% of the time I set my camera to AI Servo. Why do anything else? Push the back button to AF, let it go, recompose, and shoot for a One Shot type effect, or just hold the button down and track for AI Servo. Don't think I'm going to give this up. Perhaps I'll just carry a pen light and blast it in peoples faces

Silver-Halide wrote in post #17845099
Thanks BigAl--that helps.

Because I use BBAF, 99% of the time I set my camera to AI Servo. Why do anything else? Push the back button to AF, let it go, recompose, and shoot for a One Shot type effect, or just hold the button down and track for AI Servo. Don't think I'm going to give this up. Perhaps I'll just carry a pen light and blast it in peoples faces

This is exactly how I shoot, unless using the shoe mounted flash, AND needing the AF assist, at which point I will switch to One Shot. IMO it is better to compromise and allow the AF to actually be able to focus in those situations. Fortunately for me, that is not very often but I don't normally shoot event type situations.

You have to turn first press shutter button AF back on to use a remote switch too, which can be annoying. I shoot a lot of airshows and the like and am now using a Sigma 150-600 C, and I like to use a shoulder stock system, I used to use one back when I shot film with MF cameras, and you have to use a remote. I am in the process of making up a remote for the stock system that will have two buttons, so that I will effectively be able to maintain separation between AF and shutter. It should work OK for me, as I always shoot in manual metering mode, so I'm not worried about metering or bringing up the VF information. As long as I am in AI Servo it will fire the shutter without an AF confirmation.

Still it would be better to be able to keep them separate and just have the remote work independently.

Alan