BBF & IS

I just got my 55-250 IS from B+H yesterday, this is my first IS lens, and I have a question.

With back button focus, do I have to keep the button pressed to keep the IS functioning/active? From what I read in the manual, it seems I do, I just want to double check. Seems like the one downside to BBF.

What page of the manual (I assume the Rebel XT shown in your profile) are you reading? IS and AF are separate functions. The IS more or less operates all the time although it may be paused when you focus (by any method).

Back button focusing does just that, it focuses the image. IS will normally kick in when you press the shutter release and does not stay on. As the previous post says, they are seperate functions.

A half-press of the shutter will start the IS independently of the AF-On button for the IS lenses that I have

After playing around with it, the BBF will focus and start the IS, but just while it's focusing. The half-press of the shutter then re-activates the IS. I was referring to the lens manual, and it basically just says the IS will behave differently from what's stated in the manual if you have changed settings.

So, I take back what I said earlier, and now I still can't find any negative to using BBF.

KirkS518 wrote in post #14830441
After playing around with it, the BBF will focus and start the IS, but just while it's focusing. The half-press of the shutter then re-activates the IS. I was referring to the lens manual, and it basically just says the IS will behave differently from what's stated in the manual if you have changed settings.

So, I take back what I said earlier, and now I still can't find any negative to using BBF.

My problem is that I cannot retrain my brain. Its used to doing things in a certain way and refuses to consider BBF.

Lowner wrote in post #14830542
My problem is that I cannot retrain my brain. Its used to doing things in a certain way and refuses to consider BBF.

Initially, I had that problem too. It took me about 2 days of lots of shooting to get my brain retrained. I will say, I like BBF way better. It not only locks AF, but then it's easier to get an AE lock when you need it.

John from PA wrote in post #14830367
What page of the manual (I assume the Rebel XT shown in your profile) are you reading? IS and AF are separate functions. The IS more or less operates all the time although it may be paused when you focus (by any method).

I have several IS lenses, from two manufacturers and none of them have continuous IS. You have to press a meter or focus button to engage IS. I shoot the 60D and T1i, neither of them supports continuous IS. The only camera I own that will do that is the SX260HS.

KirkS518 wrote in post #14830720
Initially, I had that problem too. It took me about 2 days of lots of shooting to get my brain retrained. I will say, I like BBF way better. It not only locks AF, but then it's easier to get an AE lock when you need it.

I've just switched to BBF, same changeover issues as you (although compounded by trying to change from left eye to right eye at the same time - thumb and nose trying to occupy the same space!). I like having more control over when AF operates.