BIF and 400mm 5.6 lens

SilverTip · 18th of April 2012 (Wed)

I have my first prime lens and have a couple of questions about it.
a) If I focus on a stationary bird and then allow the lens to drop (arms get tired) it will lose its focus. At first I thought this occurred because I manually changed the focus when I lifted the lens back up. Is this what is supposed to happen or should I expect it to stay on focus?
b) While shooting birds in flight, and using back button focus on my 60D, should I hold the focus button until I shoot or just until the image appears sharp?
c) After the bird has travelled several yards I have been focusing again. Is this the correct method to use for bif.
Thanks for the help.

jhayesvw · 19th of April 2012 (Thu)

1. when you drop the lens and bring it back up you may change the focus ever so slightly.
your head can move and therefore throw the focus off a bit.

2. when shooting BIF I hold the back button focus and then try to release and tap it just before I snap the shot. This is called bumping the focus.

3. yes. you will need to continually refocus to get the sharpest picture.
I have a 60d. it shares the AF with the 50d. its good but not 7d good.

enjoy your combo, it should produce images as good an any you see on here if you do your job.

Duane N · 19th of April 2012 (Thu)

A. Unless you're using a tripod expect to have to re-focus when you move off the subject depending on the distance you are from it.

B. There are several ways to shoot bif's. Some bump focus and some just hold the focus button down. I think it really depends on the photographer and what gives you more keepers. I hold the focus button down and only bump focus when I stray off the subject. There's no right or wrong...it's whatever works best for you and in your situation.

C. See above.

jhayesvw · 19th of April 2012 (Thu)

I also think that different cameras do a better job on focusing by just holding the AF button.
the 60d and the 50 before it benefit from a bumping method where the more expensive cameras with better AF probably track with just holding the button (7d, 1d,)

Larry Weinman · 21st of April 2012 (Sat)

Quote:

Originally Posted by jhayesvw

I also think that different cameras do a better job on focusing by just holding the AF button.
the 60d and the 50 before it benefit from a bumping method where the more expensive cameras with better AF probably track with just holding the button (7d, 1d,)

I find it necessary to bump the focus on my 7D.

SilverTip · 21st of April 2012 (Sat)

Thanks for clearing this up for me!!

18th of April 2012 (Wed)	#1
SilverTip Member Join Date: Aug 2007 Location: Ontario, Canada Posts: 50 IMAGE EDITING OK	BIF and 400mm 5.6 lens I have my first prime lens and have a couple of questions about it. a) If I focus on a stationary bird and then allow the lens to drop (arms get tired) it will lose its focus. At first I thought this occurred because I manually changed the focus when I lifted the lens back up. Is this what is supposed to happen or should I expect it to stay on focus? b) While shooting birds in flight, and using back button focus on my 60D, should I hold the focus button until I shoot or just until the image appears sharp? c) After the bird has travelled several yards I have been focusing again. Is this the correct method to use for bif. Thanks for the help.

19th of April 2012 (Thu)	#2
jhayesvw Goldmember Join Date: Jan 2011 Location: Tucson AZ Posts: 4,479 IMAGE EDITING OK	Re: BIF and 400mm 5.6 lens 1. when you drop the lens and bring it back up you may change the focus ever so slightly. your head can move and therefore throw the focus off a bit. 2. when shooting BIF I hold the back button focus and then try to release and tap it just before I snap the shot. This is called bumping the focus. 3. yes. you will need to continually refocus to get the sharpest picture. I have a 60d. it shares the AF with the 50d. its good but not 7d good. enjoy your combo, it should produce images as good an any you see on here if you do your job. __________________ Jeremy 7d, 50mm 1.8, 18-55 IS, 100-400L,430 exII My Flickr

19th of April 2012 (Thu)	#3
Duane N Cream of the Crop Join Date: Nov 2007 Location: Chesapeake, VA USA Posts: 7,825	Re: BIF and 400mm 5.6 lens A. Unless you're using a tripod expect to have to re-focus when you move off the subject depending on the distance you are from it. B. There are several ways to shoot bif's. Some bump focus and some just hold the focus button down. I think it really depends on the photographer and what gives you more keepers. I hold the focus button down and only bump focus when I stray off the subject. There's no right or wrong...it's whatever works best for you and in your situation. C. See above. __________________ www.3rdicreations.com

19th of April 2012 (Thu)	#4
jhayesvw Goldmember Join Date: Jan 2011 Location: Tucson AZ Posts: 4,479 IMAGE EDITING OK	Re: BIF and 400mm 5.6 lens I also think that different cameras do a better job on focusing by just holding the AF button. the 60d and the 50 before it benefit from a bumping method where the more expensive cameras with better AF probably track with just holding the button (7d, 1d,) __________________ Jeremy 7d, 50mm 1.8, 18-55 IS, 100-400L,430 exII My Flickr

21st of April 2012 (Sat)	#6
SilverTip Member Join Date: Aug 2007 Location: Ontario, Canada Posts: 50 IMAGE EDITING OK	Re: BIF and 400mm 5.6 lens Thanks for clearing this up for me!!

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