photo nuts
Senior Member
Yup. It's confirmed.
Using auto AF point selection and AI servo is impeccable. Simply works.
On the other hand, auto AF point selection + single shot AF = recipe for disaster.
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7D consistenly OOF when using zone AF or 19-point auto selection
- Thread starter Grumpy42
- Start date
Using auto AF point selection and AI servo is impeccable. Simply works.
On the other hand, auto AF point selection + single shot AF = recipe for disaster.
I am sure you already realize that there are 4 custom functions on the 7D that heavily impact the AI servo algorithm on the 7D. You need to set those appropriate to what you are shooting, to achieve ideal tracking. What did you set them to, and did you try other combinations?
Yes, if viewed at the same size - DUH!!!
The whole point of a high resolution camera (at least for me) is to effectively increase the "reach" of the camera. High pixel density has the effect of essentially providing a magnification factor. When comparing 100% crops a higher resolution camera may show deficiencies in either focus or lens quality that were not noticeable on a lower res camera.
I realize this.
I am not talking about motion blur. Theoretically, if "perfect" focus is achieved a 100% crop should look sharp regardless of resolution.
A larger res camera provides an effective zoom. If I take a picture of a bird, that bird occupies more pixels on higher res camera. If I crop the image to the area occupied by the bird, the image may be large enough for a reasonable size print. If I take the same picture with a 3MP camera, the resulting cropped image will not produce a good print.
I compare 100% crops to 100% crops. By your logic, if I were upgrading from a 3mp camera I should limit myself to looking at the 7D images zoomed out to the same size as the 3mp images. A bad lens may look good when used on the 3mp camera, but may have noticeable problems when used on the 7D (when viewed at 100%)
I don't know about you but I generally crop my photos and a higher res camera gives more cropping ability. So, yes it is a problem in real life, since in real life people crop their images.
JulesJ
Forum Pro
Which particular point that i made are you referring to?Jules that's only true in"one shot" focus.
http://forums.dpreview.com/forums/read.asp?forum=1019&message=35891748
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Brian Schneider
In your ref, Brain said..If you disabled it you may be missing something in sports of bird photos.
Fine, I'm photographing birds.
jules
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Julesarnia on twitter
There is a very visible camera shake blur here, in NE-SW direction. Did you wait for the IS to stabilize?
Center Zone AF
Yes, but the bad lens will look EXACTLY THE SAME when used on the 7D if you view at the same size as the 3MP camera. On the other hand, yes, of course it will look worse when viewed at 100%, because you are looking at an image that is physically 2.5x larger in each dimension! This is totally obvious. This is not a technology issue - the lens looks worse because you are viewing the same thing at a larger size.
My point is: "who cares"? Why compare 100% crops to 100% crops? We are not talking about rocket science here.. the 7D images at 100% are physically larger than lower resolution images at 100%, so of course the blur and lens flaws are larger, as well. I think we are on the same page, but if you frame the picture of a bird on a 10MP APS-C sensor exactly the same way as you frame the picture on an 18MP APS-C sensor, and you print both photos out at the same size, then the sharpness, the blur, the DOF, etc., are all exactly the same.
Now, if you personally have decided that because of the extra resolution, you are going to crop more aggressively and therefore enlarge the photo more than the 10MP sensor, that's great. Congratulations. But that is your personal decision, not a limitation of the camera or the technology! Of course the decision to crop and enlarge will lead to enlargement of flaws in the picture. The exact same thing would happen if you cropped the same physical area of the frame on the 10MP camera also.
If you think that just because you have 80% more pixels, you can crop 80%, then enlarge 80% more, and get the same quality image as uncropped on a lower resolution camera, you are deluding yourself. The resolution does not change the optical and physical properties of your image. When cropping and enlarging, You are enlarging artifacts stemming from imperfections in your lens. You are enlarging camera shake. You are enlarging subject motion blur. Etc. The extra pixels don't shrink those optical effects to make up for it! Cropping and enlarging will make all those flaws bigger. This has nothing to do with resolution, except for the fact that you personally feel compelled to crop because you have more resolution. It's a psychological issue, not a technical issue.
Well... I care... Since to me high pixel density means more cropping ability. If looking at an 18MP image at 100% essentially looks like the 10mp image zoomed in then what is the point of a higher pixel camera? I realize that there are limitations to the optics but quality glass should still yield 100% crops that are sharp on a 18mp camera.
Not exactly. The cropped 10mp image will need to be enlarged more to achieve the same size print, thus making it look less sharp.
Granted, it may not be a 1:1 relationship but more pixels should yield greater cropping ability (assuming quality glass).
I believe that this was exactly my original point (the one that made you want to cry). Some people may blame (incorrectly) the 7D for soft images (100% crops) when the fault may be the lens. A cheap lens may look fine on a 3mp camera but as you said artifacts and deficiencies in the optics may lead to less than adequate results when viewed on an 18mp camera (again at a 100%).
No, it is a technical issue if the camera can out resolve the the lens. Maybe not be a problem with the camera, but it is a problem with the lens. I would also consider it a technical issue if an 18MP camera provides no advantage over a 10MP camera.
I don't think that it is an issue with the IS. Just for the hell of it I took several more pictures of that same tree with IS turned off. Some images were not as bad as the one posted while others were just as bad, but as long as I was using Zone AF NOT ONE image was in focus.
I am starting to think that it is the lens since my 100-400L seems to work fine with Zone/19-point AF. I just don't understand why it will focus fine with Spot AF (or center point AF), but not Zone AF.
Keith Reeder
Senior Member
n/t
Keith Reeder
Senior Member
And again - on at the camera, but almost certainly off at the lens. Either that, or the lens and camera weren't communicating - but either way there was no AF going on in the "problem" shot.
Read this: http://forums.dpreview.com/forums/read.asp?forum=1019&message=35898966
And again - AF was enabled ON THE LENS!
I have a dozen photos just like it (samples I took for Canon support), all with AF enabled. The photo I posted was quite dramatic. Not all are quite as bad as that one, but it seems that none of the images I take with Zone AF, under the circumstance I specified, are in-focus.
Here are some full size images that I intend to send to Canon (if their "Contact US" form ever works). The images are unaltered directly from the camera. I also have the corresponding photos taken with Spot AF that are in focus (These were taken with Center Zone AF)
http://www.oxford-observatory.org/test_images/7D/IMG_6688.JPG
http://www.oxford-observatory.org/test_images/7D/IMG_6663.JPG
http://www.oxford-observatory.org/test_images/7D/IMG_6730.JPG
It seems that there is some confusion with the EXIF data going on. I don't know if this is due to the fact that I used an old version of ACDSee to crop the photos or something else. But I can assure everyone that IS was enabled (on the camera and lens) and the First photo was using one-shot Zone AF while the second was taken with one-shot SPOT AF.
I have taken a couple more quick examples shots for Canon support. Unfortunately I currently can't send them to Canon since I keep getting a "Ajax request failure" error when I use the "Contact US" form on the Canon Canada site. So until I can contact Canon here are some of the images I am going to send them. These are large unaltered jpgs directly from the camera.
24-105L (approx. 70mm)
Zone AF images
http://www.oxford-observatory.org/test_images/7D/IMG_6688.JPG
http://www.oxford-observatory.org/test_images/7D/IMG_6663.JPG
http://www.oxford-observatory.org/test_images/7D/IMG_6730.JPG
The following image is about the BEST that I can I can get from the ZONE AF (under the circumstance in my original post). It is not horrible but not as good as SPOT AF. And images this "good" are the exception, not the rule.
http://www.oxford-observatory.org/test_images/7D/IMG_6267.JPG
Corresponding images taken with SPOT AF
http://www.oxford-observatory.org/test_images/7D/IMG_6689.JPG
http://www.oxford-observatory.org/test_images/7D/IMG_6664.JPG
http://www.oxford-observatory.org/test_images/7D/IMG_6731.JPG
http://www.oxford-observatory.org/test_images/7D/IMG_6268.JPG
I tend to believe that the culprit is the lens since Zone/19-point AF (one-shot) images are generally as good as SPOT AF on my 100-400L lens. Either way, I think that it is undeniable that something is not right and the camera and lens will need to go to Canon.
I have taken a couple more quick examples shots for Canon support. Unfortunately I currently can't send them to Canon since I keep getting a "Ajax request failure" error when I use the "Contact US" form on the Canon Canada site. So until I can contact Canon here are some of the images I am going to send them. These are large unaltered jpgs directly from the camera.
24-105L (approx. 70mm)
Zone AF images
http://www.oxford-observatory.org/test_images/7D/IMG_6688.JPG
http://www.oxford-observatory.org/test_images/7D/IMG_6663.JPG
http://www.oxford-observatory.org/test_images/7D/IMG_6730.JPG
The following image is about the BEST that I can I can get from the ZONE AF (under the circumstance in my original post). It is not horrible but not as good as SPOT AF. And images this "good" are the exception, not the rule.
http://www.oxford-observatory.org/test_images/7D/IMG_6267.JPG
Corresponding images taken with SPOT AF
http://www.oxford-observatory.org/test_images/7D/IMG_6689.JPG
http://www.oxford-observatory.org/test_images/7D/IMG_6664.JPG
http://www.oxford-observatory.org/test_images/7D/IMG_6731.JPG
http://www.oxford-observatory.org/test_images/7D/IMG_6268.JPG
I tend to believe that the culprit is the lens since Zone/19-point AF (one-shot) images are generally as good as SPOT AF on my 100-400L lens. Either way, I think that it is undeniable that something is not right and the camera and lens will need to go to Canon.
chetcarson
Leading Member
Maybe you have dust or something on the sensor array. Use a bulb blower on the bottom of the mirrorbox where the sensor is.
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http://imageevent.com/chetcarson
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http://imageevent.com/chetcarson
Brian D. Schneider
Forum Pro
Grumpy have a real close look at IMG 6688. Many branches & leaves have a double image that can only be caused by camera motion. You should repeat the tests on a tripod. Zone focus is not very reliable for the kind of pictures you're taking but it's impossible to get to the bottom of your problem when you have motion blur.
You might be having better luck with the 1-400 because the zone covers a much smaller area of a scene.
I gave up on zone abt 2 days after I got the camera (October) Doesnt mean something is wrong with the camera, zone is just not suitable for very many situations.
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Brian Schneider
It is not camera shake or motion blur. It is the bokeh of the lens. Take a look at this image:
http://www.oxford-observatory.org/test_images/7D/trailer.jpg
The grass in front of the trailer is definitely in focus but the trees in background exhibit the same effect that you mistake as camera shake.
IMG_6688 was take at 1/200s (approx. 70mm) . I would have had to have shaken the camera quite a bit to achieve that result.
That is why I am still not quite sure whether it is the camera or lens.
I don't know if this has already been asked, but are you using any kind of filter?
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http://www.flickr.com/photos/39169343@N04/
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http://www.flickr.com/photos/39169343@N04/
The only thing that I am using is a B+W clear lens protector. I have taken some shots with out the lens protector with similar results.
RobMcK
New member
Grumpy,
I downloaded your photos and looked at them in Zoombrowser. You definately have a focusing problem. I had a simiilar problem on my 40D when I first got it. Sent it into Canon in California and they fixed it. My center point would focus perfect but in auto point selection mode the focus was almost always off. I would suggest calling their technical support line vs using their website. I used the phone method and had great service. 1-800-OK-CANON
Bob
I downloaded your photos and looked at them in Zoombrowser. You definately have a focusing problem. I had a simiilar problem on my 40D when I first got it. Sent it into Canon in California and they fixed it. My center point would focus perfect but in auto point selection mode the focus was almost always off. I would suggest calling their technical support line vs using their website. I used the phone method and had great service. 1-800-OK-CANON
Bob
Brian D. Schneider
Forum Pro
1/200 is not that high a speed. The picture is OOF but if you look very closely there is evidence of movement in the branches. A tripod will eliminate that possibility. Or, like most of us who have the camera a while-stop using zone.
The kind of picture you're doing there will be much better with single point.
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Brian Schneider
Sorry Grumpy42, I originally thought you were making the reverse, long disproven, kookoo claim that 18MP produced less sharp images than 10MP. I apologize I interpreted your point backwards. So you are much less mistaken than I thought. But...
I am losing you here. Who is talking about cropping in the example I gave? The bird is being framed the same way in 2 identical sized sensors. The only difference is one has larger (and thus fewer) pixels. There is no cropping involved in either image. The enlargement is exactly the same, the sharpness is exactly the same.
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