Back Button Focus Question

Thats right. If you're manually focusing and letting the camera tell you when its in focus you might just as well put it in AF and let the camera do it. The reason behind Manual Focus is to do it better than the camera can.

Michelle Brooks Photography wrote in post #9686507
Question-- if you aren't looking for the confirmation light/beep to tell you when you've achieved focus, are you just going by when it looks to be in focus?

Question: Why are you manually focusing an AF lens under conditions that allow the AF system to detect that the lens has something in focus? What are you gaining by manually focusing the lens instead of just letting the AF system handle it?

The only situation I can think of where this would be a benefit would be macro photography where you are moving the camera back and forth to get focus, and there are better ways of doing that.

krb wrote in post #9687659
Question: Why are you manually focusing an AF lens under conditions that allow the AF system to detect that the lens has something in focus? What are you gaining by manually focusing the lens instead of just letting the AF system handle it?

The only situation I can think of where this would be a benefit would be macro photography where you are moving the camera back and forth to get focus, and there are better ways of doing that.

Logical question. I have only been seriously pursuing photography for about 6 months, and I primarily shoot people (so to speak) and I was having a hard time getting the eyes really sharply in focus (still do a little). I read a lot of posts (and posted questions myself) and it seemed many people got better results when they switched to manual focus. I tried it, and my focus improved. I couldn't tell you why, but it did, so I've stuck with it and just am trying to continue to improve, hence the attempting back button focusing. I sincerely appreciate any suggestions, advice, pointers, etc.

Michelle Brooks Photography wrote in post #9686507
Question-- if you aren't looking for the confirmation light/beep to tell you when you've achieved focus, are you just going by when it looks to be in focus?

Yes. That's where the term manual comes into play

Michelle Brooks Photography wrote in post #9688041
Logical question. I have only been seriously pursuing photography for about 6 months, and I primarily shoot people (so to speak) and I was having a hard time getting the eyes really sharply in focus (still do a little). I read a lot of posts (and posted questions myself) and it seemed many people got better results when they switched to manual focus. I tried it, and my focus improved. I couldn't tell you why, but it did, so I've stuck with it and just am trying to continue to improve, hence the attempting back button focusing. I sincerely appreciate any suggestions, advice, pointers, etc.

Sounds good, that's exactly the kind of situation where MF is better than AF. But in order to really get the most use out of it you need to focus by sight and not use the AF system, since it is the AF system's lack of ability to get the eyes really sharp that you are trying to work around.

Using the back button for AF and a lens that supports full-time manual is perfect for this type of shooting.

krb wrote in post #9688296
Sounds good, that's exactly the kind of situation where MF is better than AF. But in order to really get the most use out of it you need to focus by sight and not use the AF system, since it is the AF system's lack of ability to get the eyes really sharp that you are trying to work around.

Using the back button for AF and a lens that supports full-time manual is perfect for this type of shooting.

So you do encourage me to use the back button to get initial focus then tweak manually?

Michelle Brooks Photography wrote in post #9688319
So you do encourage me to use the back button to get initial focus then tweak manually?

Absolutely, I do it all the time so long as I'm shooting a subject that sits still long enough to let me. The AF will at least get you very close and then a little manual adjustment if needed will make it that much better.

Michelle Brooks Photography wrote in post #9688319
So you do encourage me to use the back button to get initial focus then tweak manually?

Sure, that's a good way especially if you have a full-time MF lens (not every lens is). If you don't, you might save yourself the hassle by just leaving the lens in AF and focusing manually from the start rather than switching the lens back and forth.

But, with a full-time MF lens it's a snap using the BB method -- press the back button to acitvate the AF, un-press when the AF snaps in, then just tweak the focus ring, although it would help to turn on and zoom Live View before teaking the focus.

tonylong wrote in post #9688502
Sure, that's a good way especially if you have a full-time MF lens (not every lens is). If you don't, you might save yourself the hassle by just leaving the lens in AF and focusing manually from the start rather than switching the lens back and forth.

But, with a full-time MF lens it's a snap using the BB method -- press the back button to acitvate the AF, un-press when the AF snaps in, then just tweak the focus ring, although it would help to turn on and zoom Live View before teaking the focus.

I guess my lens manuals tell if it is full time manual?

Any Canon USM lens is FTM. Same with any SIGMA HSM lens.

CyberDyneSystems wrote in post #9689123
Any Canon USM lens is FTM. Same with any SIGMA HSM lens.

Any Canon "Ultrasonic" lens that uses ring USM allows FTM, as does the 50 1.4. There are several Canon lenses marked Ultrasonic that use a micro motor USM and these do not allow FTM. I think the only current production USM lenses that don't support FTM are the 75-300 and 70-300 but there might be some others.

The easiest way to tell is to leave the AF/MF switch set to AF and -gently- try to turn the focus ring. If the ring either doesn't move or moves but you can feel that it seems to be turning gears inside the lens, then it does not support FTM.

BTW Michelle, this is a perfect example of why having a "gear list" in your signature is a good idea. People would be able to just look at the list and tell you whether your current collection has any lenses that don't support FTM.

CyberDyneSystems wrote in post #9689123
Any Canon USM lens is FTM. Same with any SIGMA HSM lens.

krb wrote in post #9689543
Any Canon "Ultrasonic" lens that uses ring USM allows FTM, as does the 50 1.4. There are several Canon lenses marked Ultrasonic that use a micro motor USM and these do not allow FTM. I think the only current production USM lenses that don't support FTM are the 75-300 and 70-300 but there might be some others.

The easiest way to tell is to leave the AF/MF switch set to AF and -gently- try to turn the focus ring. If the ring either doesn't move or moves but you can feel that it seems to be turning gears inside the lens, then it does not support FTM.

BTW Michelle, this is a perfect example of why having a "gear list" in your signature is a good idea. People would be able to just look at the list and tell you whether your current collection has any lenses that don't support FTM.

Thanks, both of you!

Funny you would mention the Gear List--I was in the middle of trying to get it done but was having trouble getting the link right..check it out, it's done!

Michelle Brooks Photography wrote in post #9689904
Thanks, both of you!

Funny you would mention the Gear List--I was in the middle of trying to get it done but was having trouble getting the link right..check it out, it's done!

Cool. How's that 24-70mm 2.8L working for you?

The 50 1.8 is the only lens in your list that needs to be set to MF when manually focusing.

krb wrote in post #9690147
Cool. How's that 24-70mm 2.8L working for you?

The 50 1.8 is the only lens in your list that needs to be set to MF when manually focusing.

Hey, thanks, Ken! And OMG, I am lovin' that 70-200! I haven't really gotten to use it for a shoot yet, but just messin' around, it's stellar.

Michelle Brooks Photography wrote in post #9690436
Hey, thanks, Ken! And OMG, I am lovin' that 70-200! I haven't really gotten to use it for a shoot yet, but just messin' around, it's stellar.

Not the 70-200, the 24-700. Just givin' you a hard time about the typo.