Canon 7D - Video focus - Is it me?

[FireyPed]

Hello folks

My first post and sorry if it's a dumb one.

I have just bought a 7D body and I am trading in my 30D.

From what I have seen the 7D is superb, but despite having read the manual (several times), I cannot really see how the video focus works.

If I start to take a video, it is in focus, but then if I zoom, the image is out of focus unless I focus manually or press AF-On for what seems like ages, all of which means that the video looks amateurish etc.

What am I doing wrong?

I hope you will forgive for this possibly stupid question!

Thanks

Peter

 

[Mark B.]

Hello folks

My first post and sorry if it's a dumb one.

I have just bought a 7D body and I am trading in my 30D.

From what I have seen the 7D is superb, but despite having read the manual (several times), I cannot really see how the video focus works.

If I start to take a video, it is in focus, but then if I zoom, the image is out of focus unless I focus manually or press AF-On for what seems like ages, all of which means that the video looks amateurish etc.

What am I doing wrong?

I hope you will forgive for this possibly stupid question!

Thanks

Peter

You're doing nothing wrong. AF does not work continuously during video mode.

Mark

 

[Xico]

In other words, when filming you have to focus manually all the time. You can use autofocus when in pause, but it is a little bit slow.

 

[bhollis]

First, for all practical purposes, you should forget about using auto focus while filming. You can only use auto focus to pre-focus the shot. If focus needs to change during filming, your only real option is to manually adjust the focus. Lots of folks complain about this, but this is something motion picture photographers have been doing for years.

Also, if you're going to zoom in during a shot, zoom in and focus before you begin filming. Once you've focused while zoomed in, back off to your original focal length. Don't reset the focus, as you should still be in focus at the shorter focal length. Now begin shooting, and the image should remain in focus as you zoom in.

If the above doesn't work, then chances are your lens is not a parafocal lens (maintains focus throughout the zoom range), and you won't be able to zoom and maintain focus.

 

[ShawnCo]

If the above doesn't work, then chances are your lens is not a parafocal lens (maintains focus throughout the zoom range), and you won't be able to zoom and maintain focus.

The point above is key - many zoom lenses are not parfocal and as a result the focus will change when zooming. Even with parfocal zoom lenses there can still be a very slight change in the focus but it should be insignifcant.

Parfocal canon zooms are said to include the following:

• 16-35L (mkI and mkII I believe)
• 17-35L
• 24-70L
• 28-70L
• 24-105L
• 70-200 f4L (i believe both IS and non-IS models)
• 70-200 f2.8L (both IS and non-IS models)

Unfortunately Canon does not provide a listing of parfocal lenses but you can see that they are all "L" lenses. It should be noted that the 100-400 L is not parfocal. I don't think many of the non-L models are parfocal.

When using the video feature the focus system you must use is the one where your left hand rotates the focus adjustment on the lense - this ain't a handycam...which in many ways is good and in other ways is not so good.

 

[FireyPed]

Brilliant - thank you all so much for this in depth advice.

Fortunately, one of the lenses I have is the 24-105 F4L IS USM!! It will be put to the test tomorrow.

Thanks again

Peter

 

[the vid guy]

Congrats on the 7D!

Do not autofocus in video continuously. Maybe to spot it first then you want to turn it into manual. Nothing wrong with you or your camera.

 

[Bungalow Bill]

I feel I understand that manually focusing the 7D during video is essential, however, while using a 70-200mm F2.8, I can focus via the magnifier at 70mm, but when I zoom in on the subject while recording, the lens goes drastically out of focus. Doing it the other way around with a 24-70mm doesn't seem to bother the focus - focussing at 70mm and pulling back. I've found that holding my finger down halfway on the shutter release button, the camera will try to focus while shooting video. Is the camera overriding the manual focus in some way?

 

[AndreasOberg]

Fantastic information! I didn't know that "parafocual lenses" existed.

I'm using the 17-85 lens and I thought I would have to accept that it's near impossible to zoom and focus at the same time.
Andreas

If the above doesn't work, then chances are your lens is not a parafocal lens (maintains focus throughout the zoom range), and you won't be able to zoom and maintain focus.

The point above is key - many zoom lenses are not parfocal and as a result the focus will change when zooming. Even with parfocal zoom lenses there can still be a very slight change in the focus but it should be insignifcant.

Parfocal canon zooms are said to include the following:

• 16-35L (mkI and mkII I believe)
• 17-35L
• 24-70L
• 28-70L
• 24-105L
• 70-200 f4L (i believe both IS and non-IS models)
• 70-200 f2.8L (both IS and non-IS models)

Unfortunately Canon does not provide a listing of parfocal lenses but you can see that they are all "L" lenses. It should be noted that the 100-400 L is not parfocal. I don't think many of the non-L models are parfocal.

When using the video feature the focus system you must use is the one where your left hand rotates the focus adjustment on the lense - this ain't a handycam...which in many ways is good and in other ways is not so good.

 

[Mark B.]

I feel I understand that manually focusing the 7D during video is essential, however, while using a 70-200mm F2.8, I can focus via the magnifier at 70mm, but when I zoom in on the subject while recording, the lens goes drastically out of focus. Doing it the other way around with a 24-70mm doesn't seem to bother the focus - focussing at 70mm and pulling back. I've found that holding my finger down halfway on the shutter release button, the camera will try to focus while shooting video. Is the camera overriding the manual focus in some way?

No, as far as I know that's as it should be - anytime you half-press the shutter the lens will AF; the point is that during video the focus will not be continuous unless you do this - it's not automatic.

You say the lens goes out of focus when zooming with the 70-200 - is this without half-pressing the shutter button?

 

[PicPocket]

I feel I understand that manually focusing the 7D during video is essential, however, while using a 70-200mm F2.8, I can focus via the magnifier at 70mm, but when I zoom in on the subject while recording, the lens goes drastically out of focus. Doing it the other way around with a 24-70mm doesn't seem to bother the focus

one of your lens is parfocal while the other is not - http://en.wikipedia.org/wiki/Parfocal_lens

--
PicPocket
http://photography.ashish-pragya.com

 

[riknash]

I feel I understand that manually focusing the 7D during video is essential, however, while using a 70-200mm F2.8, I can focus via the magnifier at 70mm, but when I zoom in on the subject while recording, the lens goes drastically out of focus. Doing it the other way around with a 24-70mm doesn't seem to bother the focus - focussing at 70mm and pulling back. I've found that holding my finger down halfway on the shutter release button, the camera will try to focus while shooting video. Is the camera overriding the manual focus in some way?

No, as far as I know that's as it should be - anytime you half-press the shutter the lens will AF; the point is that during video the focus will not be continuous unless you do this - it's not automatic.

You say the lens goes out of focus when zooming with the 70-200 - is this without half-pressing the shutter button?

From his description, it doesn't sound like he prefocused the 70-200mm at the short distance, since he then says ... "but when I zoom in it goes drastically out of focus..". He needs to prefocus at the short focal length first.

 

[jm67]

I feel I understand that manually focusing the 7D during video is essential, however, while using a 70-200mm F2.8, I can focus via the magnifier at 70mm, but when I zoom in on the subject while recording, the lens goes drastically out of focus. Doing it the other way around with a 24-70mm doesn't seem to bother the focus

one of your lens is parfocal while the other is not - http://en.wikipedia.org/wiki/Parfocal_lens

Good link. Have you got one that actually lists the Canon lenses as to which are par. and which are var. ?

--
I am as ignorant as ever, and wiser than I've ever been.

 

[the vid guy]

EDITED OUT. I already replied to it earlier. LOL.

Hello folks

My first post and sorry if it's a dumb one.

I have just bought a 7D body and I am trading in my 30D.

From what I have seen the 7D is superb, but despite having read the manual (several times), I cannot really see how the video focus works.

If I start to take a video, it is in focus, but then if I zoom, the image is out of focus unless I focus manually or press AF-On for what seems like ages, all of which means that the video looks amateurish etc.

What am I doing wrong?

I hope you will forgive for this possibly stupid question!

Thanks

Peter

 

[PicPocket]

one of your lens is parfocal while the other is not - http://en.wikipedia.org/wiki/Parfocal_lens

Good link. Have you got one that actually lists the Canon lenses as to which are par. and which are var. ?

There is one here - http://135mm.multiply.com/journal/item/9 - this is more or less the same as what ShawnCo posted below. I think all of these originated from Roger Cavanagh's site; but he took down the page when he re-did his website last year

As mentioned, Canon does not publish this list officially. I am a bit surprised about 70-200 though... as it has been reported to be parfocal (all 4 versions of it)

--
PicPocket
http://photography.ashish-pragya.com

 

[Tom C11968]

Nice to know I have two, the 16-35 and 24-70.

one of your lens is parfocal while the other is not - http://en.wikipedia.org/wiki/Parfocal_lens

Good link. Have you got one that actually lists the Canon lenses as to which are par. and which are var. ?

There is one here - http://135mm.multiply.com/journal/item/9 - this is more or less the same as what ShawnCo posted below. I think all of these originated from Roger Cavanagh's site; but he took down the page when he re-did his website last year

As mentioned, Canon does not publish this list officially. I am a bit surprised about 70-200 though... as it has been reported to be parfocal (all 4 versions of it)

--
PicPocket
http://photography.ashish-pragya.com

--
Tom

 

[jm67]

Thank you.
--
I am as ignorant as ever, and wiser than I've ever been.

 

[vizwiz]

Just tried a zoom test with my 24-105L and the focus does NOT hold when zooming in.

--

 

[hjulenissen]

Why can't I use the (+) magnifyer button while filming? It would be a great aid to be able to manually focus while using the screen estate to show what is most important to me...

-h

 

[huan37]

You're doing nothing wrong. Maybe to spot it first then you want to turn it into manual.