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Canon EOS Crop Sensor for HD
APS-C sensor cameras including the 80D, 70D, 7D Mk. II, 7D, EOS M and Rebel models for HD video recording.


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Old June 23rd, 2010, 05:43 PM   #1
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Tokina 11-16, 7D focusing

I'm more of a videographer than a photographer so for the past six months I've been shooting short videos to try to learn how to overcome some of the cameras limitation and my shortcomings.

I just purchased a Tokina 11-16 and I'm getting some mixed results, some video and pictures look very sharp, some don't. So I thought I would ask for some pointers since I'm pretty sure its me doing something wrong.

I'm shooting in bright daylight, ISO 100, f/14-22 range, shutter around 100 for stills and 50 for video (24P). If I'm within about 10 feet of my subject I can get tack sharp focus. With the lens set to infinity, if I move back to twenty feet or more the subject goes a little soft. I can't seem to get it in focus at all.

What am I doing wrong?
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Old June 23rd, 2010, 05:54 PM   #2
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Can you try posting some pics?

It's possible that you may have a lens issue, or possibly just a bum lens. How are you checking the focus?
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Old June 23rd, 2010, 06:13 PM   #3
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Thank for the quick reply.

I'm going to shoot a bit more and I'll post the results. Is there a good procedure for testing focus?

PS: This seems to be similar to having the back focus out on a video camera. Is there an adjustment for that on the 7D?
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Old June 23rd, 2010, 06:52 PM   #4
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Nope, that's one of the great things about these cams - can't have the back focus be out.

I've got a Tokina 11-16 and have not had issues with it but I have heard of some quality control issues from forums. You should be able to get sharp focus. From what i understand the lens should be quote sharp in the f10 and lower range.

if you don't have a test chart maybe you could make or find something with sharp edges like a cross hatch pattern and try it at different distances. Maybe try stopping down to f2.8 to accentuate focus issues. I'm also a little curious as to how you are focusing the camera. LCD? HD monitor?
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Old June 23rd, 2010, 07:50 PM   #5
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Isn't there a rule of thumb for these lenses where the sharpest focus is 2-3fstops of either end? For an F2.8 its sharpest between 5.6 and 11? I've never gone as high as F14-22 on this lens. Outdoors I typically shoot F8 with filters tacked on. In broad daylight have you tried using ND filters so you can keep within the 'sweetspot'?

Look for word sweetspot:
Tokina AF 11-16mm f/2.8 AT-X Pro DX (Canon) - Review / Lens Test Report - Analysis
http://photography-on-the.net/forum/.../t-701872.html
First Look: Tokina 11-16/f2.8 AT-X Pro DX
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Old June 23rd, 2010, 08:36 PM   #6
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Hi Burk and Mark.

Unfortunately my Fader ND is a 72 mm and the Tokina is a 77 mm - Doh!

I'm focusing using the magnification on the LCD. Its difficult focusing through the prism for stills so I use live view, magnify 10x, focus and switch back to normal for stills and focus seems to be right on. But with stills I change the shutter so I can get it around f/8, for video with a 1/50 shutter the f-stop is much higher so I think you guys are right.

I was just under the impression that after say f/8 and the focus set to infinity, everything beyond 7-10 feet should be in focus.

You know I just expected everything to be tack sharp right out of the box with full auto point and shoot. Go figure. Thanks for the link Mike, I'll check that out. It does seem as it gets later in the day and I can bring the f-stop into more reasonable setting things are starting to look good. I did get this lens for mostly interior dolly shots.

Its just so hard to get this lens I had a little panic attack : )
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Old June 23rd, 2010, 09:21 PM   #7
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Chuck,
You can buy the fader nd in 77m. There's a place down here and if you need the info, pm me and I'll send it to you.
I think maybe your problem is stopping down too much. If you use the fader nd, you can keep the lens in more of the sweet spot range. Another thing I've found is that there isn't a huge anount of paly in the focus ring, and since the lens is so wide, I have to use tha magnification functions to see what's in.
All things considered it's agreat lens. I've also been practicing with it on my indicam, and have been getting better and better results. I used it for a couple of shots handheld on a music video last Sunday, and it cut real well with footage from ny 17-55 and 70-200.
Let us know what resukts you have.
Bruce Yarock
Yarock Video and Photo
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Old June 24th, 2010, 01:42 AM   #8
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"You know I just expected everything to be tack sharp right out of the box with full auto point and shoot. "

Yea, that's just not going to happen with the giant imagers in these DSLRs. I have to rack focus constantly with my Tokina for shots, but then I seem to always be shooting at around 2.8. Focus on these little cameras is a whole other world.

Oh, and just to add. Another thing you may be experiencing is a combination of shooting with the lens at it's "softest" range at around f22 and just the inherent lack of resolution of these cameras. Of course this would only be the case with video for the resolution thing.
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Old June 24th, 2010, 02:17 AM   #9
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Chuck, this is probably a classic case of diffraction softening if you're shooting in the F14-F22 range.

I don't have the Tokina 11-16 (I have the Canon 10-22) and with that wide angle lens I sometimes (rarely) DELIBERATELY shoot at a high F stop like this (out of doors in bright sun) simply to soften the image a little if there is a lot of moire/aliasing "potential" in the video clip about to be shot.

Normally, however, I'll put on a circular polariser which cuts a little light, or more often now my new Tiffen 0.9 neutral density filter, and shoot in the F5.6-F8 sort of area. At least with the Canon ultra wide angle (and it should be the same with the Tokina) everything is as sharp as it can be (within the current DSLR HD video resolution limitations), i.e. with the lens aperture more open/using more of the glass. To stay in a lenses sweet spot, just don't go completely wide open on aperture (in your case F2.8) as that's where it'll soften again with most lenses, although not much will be in focus anyway at F2.8 (and of course this is the more common way of controlling a subject with the potential to induce moire artifacts, blurring those and focussing attention on the subject). Not all lenses get soft wide open though - my Canon 70-200 F4 IS lens is razor sharp even at it's widest aperture. Get to know you're lenses is the main rule!

Hope this helps and apologies if it's obvious.
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Old June 24th, 2010, 08:21 PM   #10
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For still photography shutter speed is more important than aperture with such a wide angle lens, so go for a minimum of 1/125 or better still 1/200th. I think you might be seeing camera shake, f8 to f16 is the ideal range for optimal sharpness. If you are using a longer lens then the shutter speed should be a minimum of twice the focal length, so if your zoomed to 100mm, then the shutter should be a minimum of 1/200th.

For focus on still photography, make sure you have the focus points selectable, and move the focus point to the point of interest, if it's a person, choose the eye and select the focusing point to cover the eye, or move the camera until the focus point is where you need it, half depress the shutter and then move the camera to frame the scene. The autofocus works great on the 7D and is very quick for still photos.
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Old June 25th, 2010, 03:51 AM   #11
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This may be a stupid question but my Tokina only focuses in video mode if you squeeze the shutter button (in the same way as when you take a photo). The lens is set to manual mode and no other lens I have works like this. Is this perculiar to the lens itself or just me lens?
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Old June 25th, 2010, 03:57 AM   #12
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"my Tokina only focuses in video mode if you squeeze the shutter button"

Boy that doesn't sound right. I'm assuming you have the auto/manual focus "ring" pushed to manual. Mine works just like you would expect, spin the focus ring and it changes the focus. I also really like the hard stops too.

So what happens when you turn the focus ring? Nothing?
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Old June 25th, 2010, 10:12 AM   #13
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Yup, afraid so. I didn't even think autofocus was possible in video mode?
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Old June 25th, 2010, 11:30 AM   #14
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Sounds like the lens has issues. I got a rental Canon lens that had the some problem a couple months ago. Auto focus worked fine but the focus ring did absolutely nothing.
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Old June 26th, 2010, 02:50 AM   #15
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Burk, the focus ring probably "did nothing" because in order to manually adjust focus with the Tokina 11-16, you first need to slide the focus ring backward (toward the camera). This switches the lens into manual mode. If you don't set the focus ring to the manual position, it won't do a damn thing. By the way Burk, I think I met you at Pro Photo in PDX. Hope you're doing well.
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