Parfocal zooms for 5D Mark III

L

Legion6789

Active member
I've been trying to find some parfocal zoom lenses for the 5D Mark III. So far I haven't had much luck. I've searched around and found some lists of parfocal lenses. Unfortunately, my experience with the lenses on these lists is that they are in fact, not parfocal. This weekend, for example, I rented a Canon EF 70-200mm f/2.8 L IS. However, once focused, any adjustment to the focal length causes the image to soften. I will say it's kinda close, but going from 70 to 200mm is unusable. 70 to 135 might be ok because of the lower resolution of video vs stills. I also tried the Canon EF 24-70mm f/2.8 L and it too was not parfocal.

So, does anyone know of any parfocal zooms? Old glass is ok too, as long as the picture is good. I'd be willing to spend as much as $2000 for the right lens.
 
Ken Rockwell does great lens writeups. These are from a stills perspective though. Still a great place to start your quest.

Was wondering though... do you really shoot while zooming? This is such an outdated 1970s shooting style that has a very period look to me.
 
I haven't tested these myself, but here's what I found spending an afternoon digging around on the web...


Canon Parfocal (EF)

EF 17-35mm f/2.8L USM ( discontinued )
EF 16-35mm f/2.8L USM
EF 17-40mm f/4L USM
EF 20-35mm f/2.8L ( discontinued )
EF 24-70mm f/2.8L USM ( Mark II is not parfocal )
EF 24-105mm f/4L IS ( discontinued )
EF 28-70mm f/2.8L USM ( discontinued )
EF 28-80mm f/2.8-4L USM ( discontinued )
EF 50-200mm f/3.5-4.5 USM ( discontinued )
EF 50-200mm f/3.5-4.5 ( discontinued )
EF 70-200mm f/2.8L USM
EF 70-200mm f/2.8L IS USM
EF 70-200mm f/4L USM
EF 70-200mm f/4L IS USM
EF 70-210mm f/4 ( discontinued )
EF 75-300mm f/4-5.6 IS USM
EF 75-300mm f/4-5.6 III USM
EF 75-300mm f/4-5.6 III
EF 75-300mm f/4-5.6 II USM ( discontinued )
EF 75-300mm f/4-5.6 II ( discontinued )
EF 75-300mm f/4-5.6 USM ( discontinued )
EF 75-300mm f/4-5.6 ( discontinued )
EF 80-200mm f/2.8L ( discontinued )
EF 90-300mm f/4.5-5.6 USM
EF 90-300mm f/4.5-5.6
EF 75-300mm f/4-5.6 IS USM
EF 75-300mm f/4-5.6 III USM
EF 75-300mm f/4-5.6 III
EF 90-300mm f/4.5-5.6 USM
EF 90-300mm f/4.5-5.6
EF 100-300mm f/5.6L ( discontinued )
EF 100-300mm f/5.6 ( discontinued )


Nikon Parfocal

17-35mm f/2.8
24-70mm f/2.8 AF-S
70-200mm f/2.8 VR Mark I ( Mark II is not parfocal )


Olympus Parfocal

11-22mm f/2.8-3.5 ( 4/3 mount )
35-70mm f/4.0 ( OM mount )
75-150mm f/4.0 ( OM mount )
85-250mm f/5.0 ( OM mount )


Panasonic Parfocal

7-14mm f/4.0
14-140mm f/4-5.6
45-175mm f/4.0-5.6


Pentax Parfocal

Pentax M 28-50mm f/3.5-4.5
Pentax M 80-200mm f/4.5 ( push-pull )
Pentax F 100-300mm f/4.5-5.6
Pentax DA 16-45mm f/4.0
Pentax A 35-105mm f/3.5
Pentax FA 24-90mm f/3.5-4.5
Pentax F 28-80mm f/3.5-4.5
Pentax DA 50-200mm f/4-5.6 WR
Pentax F 80-200mm f/4.7-5.6
Pentax FA 100-300mm f/4.5-5.6


Tamron Parfocal

17-50mm f/2.8
28-75mm f/2.8


Tokina Parfocal

11-16mm f/2.8
16-50mm f/2.8


LensRentals.com : Photo Lenses for Video
http://www.lensrentals.com/blog/2011/02/photo-lenses-for-video/

Doug Chinnery Photography
http://dougchinnery.blogspot.ca/2010/01/canon-parfocal-lenses.html

Ben Edwards
http://www.funkytwig.com/blog/canon-dslr-lense-parfocal-constant-aperture
 
Steve Kahn said:
Was wondering though... do you really shoot while zooming? This is such an outdated 1970s shooting style that has a very period look to me.
Click to expand...

The OP didn't say what he was shooting, just wants the lens to hold focus. Parfocal lenses are very useful. With motion picture film parfocal lenses you can always zoom in to focus on the subject and then where you changed focal length it remains in focus. This was normal before autofocus came along.
Perhaps changing the focal length of the same subject while the camera is rolling and not using the zoom move in your edit. Getting wide and tight shots would be more useful if the were both in focus.
 
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@TheDingo: Those are the same lists/sites I've been looking at. The problem is I'm doubtful of their veracity. For example, the EF 70-200mm f/2.8L IS USM is on the list, but I just shot with it and it's clearly not parfocal. On the Lens Rentals site I saw a comment from the owner stating that a lot of the lenses he had listed as parfocal only behaved that way because they were being used with crop sensor cameras. He said his list is no longer accurate.
 
ROCKMORE said:
The OP didn't say what he was shooting, just wants the lens to hold focus. Parfocal lenses are very useful. With motion picture film parfocal lenses you can always zoom in to focus on the subject and then where you changed focal length it remained in focus. This was normal before autofocus came along.
Perhaps changing the focal length of the same subject while the camera is rolling and not using the zoom move in your edit. Getting wide and tight shots would be more useful if the were both in focus.
Click to expand...

Ah, yes. That makes complete sense. Here, I'm dealing with my own 5D3 focusing issues...
 
One thing I've seen stated on forums is that if you focus on your subject and then zoom in, it will go out of focus, even with a parfocal lens because the DoF shrinks. I can see the logic in that, however, I'm curious... If I focus on a subject 10ft away at 70mm, and then I zoom in to 200mm my DoF will shrink. But with a parfocal, will be DoF be centered at the same point? So at 70mm, f/5.6, DoF is about 2.08ft, at 200mm, f/5.6 it's 0.24ft, will the 0.24ft be centered on the same point as the 2.08ft? Or will the entire area have shifted closer/further from the camera?
 
Legion6789 said:
The problem is I'm doubtful of their veracity. For example, the EF 70-200mm f/2.8L IS USM is on the list, but I just shot with it and it's clearly not parfocal.
Click to expand...

...Also the lens version makes a big difference. The EF 70-200mm f/2.8L IS USM has gone through at least three internal versions, but it might be that only the first version is parfocal.
 
Legion6789 said:
if you focus on your subject and then zoom in, it will go out of focus, even with a parfocal lens because the DoF shrinks.
Click to expand...

...This is complete BS. Yes the DOF might shrink, but whatever point that you focused on will still be in focus with a parfocal lens when you zoom in. ( you may notice focus mistakes when you zoom in, where you realize that you are actually focused behind or in front of your subject, but you did not realize it until the DOF shrinks and the details are more noticeable when zoomed in )
 
TheDingo said:
...Also the lens version makes a big difference. The EF 70-200mm f/2.8L IS USM has gone through at least three internal versions, but it might be that only the first version is parfocal.
Click to expand...

True, I thought about that. The version I rented was the first release. It was about 8 years old, according to the store owner.

I gotta say, finding a parfocal lens has been a lot more difficult than I anticipated. I'm amazed at how often I get a blank stare when I go to a camera store and ask if they have any parfocal zooms.

I've also read (and Rockmore alluded to this) that older model zooms are more likely to be parfocal since it was a useful feature before fast AF systems were available. I guess now with fast AF, manufacturers will sacrifice parfocal to save costs or improve other features.
 
I wouldn't trust that list, I have the Pentax A 35-105mm f/3.5 and it's not parfocal. I've got a Tokina 28-70mm which is supposed to be parfocal but it doesn't hold focus through the zoom either. I had an old Nikon 35-70mm ai-s lens which was parfocal. There's a few discussions @ reduser about parfocal lenses, one of the Nikon 70-200mm zooms is really popular and gets rehoused with a PL mount, that's the one to get.
 
I don't trust that list either. This one, which comes from a reliable source, is A LOT shorter:
http://www.lensrentals.com/blog/2011/02/photo-lenses-for-video/4

And then, about the "if it is parfocal, what happens when I zoom in" debate: in theory, the focus point will be exactly the same, but DoF is reduced and this can create issues.
An example: if you have a parfocal 70-200 lens on a FF camera, set at f/4 and focusing at 5m, with the lens at 70mm DoF goes from 4.54m to 5.57m, but with the lens set at 200mm DoF goes from 4.94m to 5.06m
http://www.similaar.com/foto/dof/dof.php?f_x=1&f_r=1.77&f_mm=70&f_f=4&f_d=5
http://www.similaar.com/foto/dof/dof.php?f_x=1&f_r=1.77&f_mm=200&f_f=4&f_d=5
So yes, even with a parfocal lens, zooming in after setting your focus point can result in an out-of-focus picture: in the above example, something that is 4.80m from the camera would be perfectly in focus at 70mm and out of focus at 200mm.
If you use a lens with accurate markings and set your focus point using measure tape, this won't be an issue. If you use your viewfinder and eyeball focus (as I do), best practice with a parfocal lens would be to zoom in to focus, then set your desired focal length. But you better make sure it is really parfocal!!
 
squig said:
I wouldn't trust that list, I have the Pentax A 35-105mm f/3.5 and it's not parfocal. I've got a Tokina 28-70mm which is supposed to be parfocal but it doesn't hold focus through the zoom either. I had an old Nikon 35-70mm ai-s lens which was parfocal. There's a few discussions @ reduser about parfocal lenses, one of the Nikon 70-200mm zooms is really popular and gets rehoused with a PL mount, that's the one to get.
Click to expand...

Did you have to modify the Pentax for it to work with your 5D?
 
As I mentioned in another thread, I ended up buying the Canon 70-200mm f/2.8L IS II and the Canon 24-70mm f/2.8L II. Both are officially not parfocal. However, the two I have seem to be, at least in some cases. I just did some video tests where I zoom from 70 to 200mm and 24 to 70mm and in both cases the focus held. However, in this case my subjects were at infinity with aperture at f/8 and f/11. I then tried with a closer subject about 5 ft away for the 70-200mm and about 3ft away for the 24-70mm. Here I could see both lenses weren't perfectly sharp all the way across. However in 1080p it's really difficult to notice. For a photo at 22MP you could see it's a bit soft, but I guess at such a low resolution as 1080p it's not noticeable. At least not to my eyes, I'm just an amateur though. At 2k-4k RAW it could be an issue.

Overall I'm really happy with the lenses. It seems like whatever camera/lens you use there's always some kind of shortcoming but you learn to work around it. I remember going to an event where Shane Hurlbut was talking about making Act of Valor with the 5D2. I asked him how he dealt with the moire issue and he said he just found creative ways to hide it. In one case they had a brick wall in the background so they used a shallower DoF to soften the wall which eliminated the moire.

Anyway, I can't wait to go out and shoot with these lenses.
 
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