16x lens backfocus? at DVinfo.net

Daniel Hollister · June 7th, 2006, 02:08 PM

Hey guys -

I have the 16x manual lens but I'm kind of confused. There's that backfocus/macro adjustment on the back, and it has 2 things. It has the button you push in to move it around, but it generally locks in place. And then there's the lever that tightens and loosens the whole thing to determine where the locking is.

So a friend of mine (who has had an XL2 much longer than I have, I just got it) borrowed it for a broject and changed the adjustment on this. Now the backfocus ring thing does not lock in any particular place, and the place it is set at right now does not seem to be where it SHOULD be. Everything is out of focus right now, no matter what. I tried to adjust it, but then it ended up in a place where EVERYTHING was in focus no matter what.

Is there any easy way to get this lens situated the way it came before, where this ring locked in place and the lens could go fully in and out of focus on distand objects normally, with the backfocus working properly?

Mike Cassidy · June 7th, 2006, 03:12 PM

Hi,
I'm no expert, but are you keep switching the Macro Focus on, by mistake? If that,little button is activated, it'll make everthing out of Focus.
Mike.

Josh Bass · June 7th, 2006, 03:43 PM

Macro is the little black press button. the silver, long, piece you twist is the back focus adjustment knob; you loosen to allow the back element of the lens to turn, then re-tighten it to set the back focus position.

Macro is for focusing on objects very close to the lens (I think closer than 1.5 feet or so, not sure, won't focus correctly without using macro, even when fully zoomed out).

The back focus is an adjustment only meant to be used very occasionally, and is meant to be rather permanent.

When you first receive the lens, you should adjust it, and when remove the lens and put it back, I've heard it recommended to adjust it. Or if you notice, when zoomed out all the way, your shots look a little soft.

The idea of the back focus is to guarantee that your lens focuses correctly from being fully zoomed in to all the way zoomed out.

To adjust back focus, the best way is to get a focus chart (you can find 'em online and print 'em out), put it six feet away, or so, open your iris all the way, zoom in on it, focus, then zoom out. If you're still in focus when all the way zoomed out, great! Your back focus is correctly set. If not, then loosen the back focus knob, and adjust the back focus 'til it's sharp when the camera is fully zoomed out. Now zoom in again, focus, and zoom out. Is your widest focal length also in focus? If not, repeat the process 'til it is.

You shouldn't have to adjust the back focus often. It's not a daily or weekly thing.

Henry Cho · June 7th, 2006, 03:56 PM

if i'm reading your post correctly, you're saying the macro adjustment ring rotates without stopping. is that correct? if so, your lens in broken and needs to be sent in to canon service. otherwise...

the backfocus and macro settings are two different adjustments. first, make sure you're lens is not in macro mode. with the camera pointing away from you, press the little button with the orange "m" on it and rotate it to the right until it clicks into place.

for backfocus, put the camera in manual, open the iris to it's widest setting, and zoom as far as you can into an object (pick something with high contrast) 10-15 feet away from you. a focus chart would be ideal. adjust the focus ring until the object is sharp. now pull the zoom to full wide. loosen the backfocus adjustment knob (the screw like handle near the lens mount) and gently rotate the backfocus ring in small increments until the same object is in sharp focus on the wide end. tighten the screw, and fully zoom in again on the object. adjust the backfosuc again. you want to get to a point where the object is in sharp focus on both the long and wide ends of the lens. once your backfocus is set, you should never have to touch it again (until you remove the lens from the body).

once your backfocus is set, you should have no problem using the macro option on the lens.

<-- added after i saw josh's post -->

just saw josh's post... sorry for any duplicate info.

Josh Bass · June 7th, 2006, 04:06 PM

If the rear element won't stop turning, make sure the silver knob is tight. Sounds like it's loose. Hopefully that's all that's wrong.

June 7th, 2006, 02:08 PM	#1
Daniel Hollister Regular Crew Join Date: Oct 2003 Location: Hollywood, CA Posts: 128	16x lens backfocus? Hey guys - I have the 16x manual lens but I'm kind of confused. There's that backfocus/macro adjustment on the back, and it has 2 things. It has the button you push in to move it around, but it generally locks in place. And then there's the lever that tightens and loosens the whole thing to determine where the locking is. So a friend of mine (who has had an XL2 much longer than I have, I just got it) borrowed it for a broject and changed the adjustment on this. Now the backfocus ring thing does not lock in any particular place, and the place it is set at right now does not seem to be where it SHOULD be. Everything is out of focus right now, no matter what. I tried to adjust it, but then it ended up in a place where EVERYTHING was in focus no matter what. Is there any easy way to get this lens situated the way it came before, where this ring locked in place and the lens could go fully in and out of focus on distand objects normally, with the backfocus working properly?

June 7th, 2006, 03:43 PM	#3
Josh Bass Slash Rules! Join Date: Apr 2002 Location: Houston, Texas Posts: 5,472	Macro is the little black press button. the silver, long, piece you twist is the back focus adjustment knob; you loosen to allow the back element of the lens to turn, then re-tighten it to set the back focus position. Macro is for focusing on objects very close to the lens (I think closer than 1.5 feet or so, not sure, won't focus correctly without using macro, even when fully zoomed out). The back focus is an adjustment only meant to be used very occasionally, and is meant to be rather permanent. When you first receive the lens, you should adjust it, and when remove the lens and put it back, I've heard it recommended to adjust it. Or if you notice, when zoomed out all the way, your shots look a little soft. The idea of the back focus is to guarantee that your lens focuses correctly from being fully zoomed in to all the way zoomed out. To adjust back focus, the best way is to get a focus chart (you can find 'em online and print 'em out), put it six feet away, or so, open your iris all the way, zoom in on it, focus, then zoom out. If you're still in focus when all the way zoomed out, great! Your back focus is correctly set. If not, then loosen the back focus knob, and adjust the back focus 'til it's sharp when the camera is fully zoomed out. Now zoom in again, focus, and zoom out. Is your widest focal length also in focus? If not, repeat the process 'til it is. You shouldn't have to adjust the back focus often. It's not a daily or weekly thing. __________________ The Bass' camerawork The Bass on IMDB

June 7th, 2006, 04:06 PM	#5
Josh Bass Slash Rules! Join Date: Apr 2002 Location: Houston, Texas Posts: 5,472	If the rear element won't stop turning, make sure the silver knob is tight. Sounds like it's loose. Hopefully that's all that's wrong. __________________ The Bass' camerawork The Bass on IMDB

June 7th, 2006, 03:12 PM	#2
Mike Cassidy Regular Crew Join Date: Mar 2002 Location: Tyneside/ United Kingdom Posts: 47	Hi, I'm no expert, but are you keep switching the Macro Focus on, by mistake? If that,little button is activated, it'll make everthing out of Focus. Mike.

June 7th, 2006, 03:56 PM	#4
Henry Cho Major Player Join Date: May 2005 Location: NYC Posts: 516	if i'm reading your post correctly, you're saying the macro adjustment ring rotates without stopping. is that correct? if so, your lens in broken and needs to be sent in to canon service. otherwise... the backfocus and macro settings are two different adjustments. first, make sure you're lens is not in macro mode. with the camera pointing away from you, press the little button with the orange "m" on it and rotate it to the right until it clicks into place. for backfocus, put the camera in manual, open the iris to it's widest setting, and zoom as far as you can into an object (pick something with high contrast) 10-15 feet away from you. a focus chart would be ideal. adjust the focus ring until the object is sharp. now pull the zoom to full wide. loosen the backfocus adjustment knob (the screw like handle near the lens mount) and gently rotate the backfocus ring in small increments until the same object is in sharp focus on the wide end. tighten the screw, and fully zoom in again on the object. adjust the backfosuc again. you want to get to a point where the object is in sharp focus on both the long and wide ends of the lens. once your backfocus is set, you should never have to touch it again (until you remove the lens from the body). once your backfocus is set, you should have no problem using the macro option on the lens. <-- added after i saw josh's post --> just saw josh's post... sorry for any duplicate info.