ir assist with flash off ?

Try insulating one of the Canon E-TTL flash foot's contacts (I think the lower left one.) That should make the flash act as if it's just a TTL flash; the flash shouldn't fire anymore. Unfortunately, I think only one of the AF assist lights will come on in TTL mode, instead of all of them. You should be able to use the central AF point though. http://eosdoc.com/manu​als/?q=EX-M-TTL

" I was shooting in manual mode,"

PacAce wrote in post #5740152
The purpose of the AF assist beam is to help the camera in auto focusing in dim lighting. When you switch the lens to manual focus mode, the camera no longer has to auto focus the lens so it doesn't need to have the AF assist beam emitted from the flash. That's how it was designed.

I think the manual mode he is talking about is exposure, not focus.

Bob D. wrote in post #5741691
" I was shooting in manual mode,"



I think the manual mode he is talking about is exposure, not focus.

Thank you for clearing that up. Yes, the camera was in 'manual' mode, not the lens. It was quite vexing...I didn't know the 70-200 2.8L would 'focus-hunt' as much as it was. I was beginning to wonder if I rented a faulty lens...

Bob D. wrote in post #5741691
" I was shooting in manual mode,"



I think the manual mode he is talking about is exposure, not focus.

Sorry, did I misread the previous post? Rereading it again, it looks like maybe I did. But the thing is, shooting the camera in manual mode shouldn't make any difference as far as AF assist is concerned.

S-Man wrote in post #5742187
Thank you for clearing that up. Yes, the camera was in 'manual' mode, not the lens. It was quite vexing...I didn't know the 70-200 2.8L would 'focus-hunt' as much as it was. I was beginning to wonder if I rented a faulty lens...

Sorry for misreading your post. As stated in the previous post, setting the camera to manual mode should affect how your AF assist beam works. Did the you try working the camera in one of the other modes to see if it really was the manual mode that was making the AF assist beam not work?

Actually I did. I put it on the green box- "full auto" and the red beams started shinin'... Tv, Av, and M however produced no AF-Assist...

S-Man wrote in post #5744736
Actually I did. I put it on the green box- "full auto" and the red beams started shinin'... Tv, Av, and M however produced no AF-Assist...

In that case, I'll wager a nickel that you had your camera in AIServo mode (assuming AF assist was not turned off on your camera via a custom function).

Awwwwww....I'll have to fill out an I.O. You Slip on this one...Your a genius...I, on the other hand, possess an intelligence level that hovers below mediocrity...
Thank you so much!

P.S. I like A.I. Servo because of the constant movement during weddings. On "One-Shot" I get alot of OOF shots due to the slightly changing DOF, especially when I'm shooting wide open.

S-Man wrote in post #5746437
Awwwwww....I'll have to fill out an I.O. You Slip on this one...Your a genius...I, on the other hand, possess an intelligence level that hovers below mediocrity...
Thank you so much!

P.S. I like A.I. Servo because of the constant movement during weddings. On "One-Shot" I get alot of OOF shots due to the slightly changing DOF, especially when I'm shooting wide open.

No, I'm no genius although it was kind of you to say so. The geniuses in my family are my sister and brother. I, on the other hand, am just an average Joe who learns things from experience, meaning I was in your shoe once myself trying to figure out why my darn AF assist light wasn't turning on and pulling my hair out in the process. Thanks for the nickel. I'll go out and buy me some hair growth formula.