Why are these photos blurry?

[dtrachtman]

I have a Canon Rebel T3i. I have taken a number of group photos w/tripod, w/o tripod, w/flash, w/o flash, various apertures, many on automatic mode. All on autofocus. All of them come out fuzzy, especially the people on the ends. The attached might look ok small on this web page, but if you download it and look at it 100% you will see what I mean. I have two T3i cameras and they both yield the same results. I would probably get a better photo with a phone. Any ideas?

[RobertTheFat]

A better lens might help. (That's suggested by the fact that the ends of the group are blurrier.) Given the paucity of information you've supplied (aperture, shutter speed, etc.), it's hard to come up with a more relevant suggestion.

[dtrachtman]

The lens is a Canon EF 18-135. Photos taken at shutter speeds from 1/8 to 1/250 and f3.5 - f9.0. Why does the fact that the ends are blurrier imply this is a poor quality lense? What type of lens should I buy? thanks

[RobertTheFat · Accepted solution]

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@dtrachtman wrote:

The lens is a Canon EF 18-135. Photos taken at shutter speeds from 1/8 to 1/250 and f3.5 - f9.0. Why does the fact that the ends are blurrier imply this is a poor quality lense? What type of lens should I buy? thanks

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The 18-135 has a pretty good reputation, but for this purpose you'd be using it at the wide end. Lenses with a long zoom range (and yours is fairly long) tend to be sharper in the middle of their range than at the ends. The ends of your group are blurry because sharpness falls off as the subject gets farther from the center of the lens. More expensive lenses tend to do a better job of minimizing that effect. 1/8 of a second will usually work if you're using a tripod, but it's too slow for this kind of picture, because the subjects will move around. I wouldn't use anything slower than 1/160 for group pictures, the only exception being when a flash is providing most of the light. For group pictures I normally use the Canon 17-55mm f/2.8 IS on a 7D body. That lens is very good and cheaper than it used to be. Whether that lens would solve your problem, I don't know. Maybe you could rent or borrow one and try it. Note that although you'd still be using it at the wide end, it doesn't have to worry about being sharp at 135 mm.

[dtrachtman]

I'll try it. thanks!

[TCampbell]

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@RobertTheFat wrote:

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@dtrachtman wrote:

The lens is a Canon EF 18-135. Photos taken at shutter speeds from 1/8 to 1/250 and f3.5 - f9.0. Why does the fact that the ends are blurrier imply this is a poor quality lense? What type of lens should I buy? thanks

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The 18-135 has a pretty good reputation, but for this purpose you'd be using it at the wide end. Lenses with a long zoom range (and yours is fairly long) tend to be sharper in the middle of their range than at the ends. The ends of your group are blurry because sharpness falls off as the subject gets farther from the center of the lens. More expensive lenses tend to do a better job of minimizing that effect. 1/8 of a second will usually work if you're using a tripod, but it's too slow for this kind of picture, because the subjects will move around. I wouldn't use anything slower than 1/160 for group pictures, the only exception being when a flash is providing most of the light. For group pictures I normally use the Canon 17-55mm f/2.8 IS on a 7D body. That lens is very good and cheaper than it used to be. Whether that lens would solve your problem, I don't know. Maybe you could rent or borrow one and try it. Note that although you'd still be using it at the wide end, it doesn't have to worry about being sharp at 135 mm.

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I'm studying the image carefully at 100% size and while your points are true, I don't think they apply to this particular image.

The image posted has a shutter speed of 1/60th sec at f/4.  As I study it carefully, there are no signs of blur caused by motion (which will generally show a directional blur) so I do not think the shutter speed is too slow.  This was taken at 18mm.  It would typically be possible for a person to hand-hold that shot at 1/30th sec even without an image stabilizing lens.  

Also, the subject at the very center of the lens axis is out of focus.  This image simply looks like the camera did not focus correctly.  If the camera was in AI Servo focus mode then another possibility is that the photographer pressed the shutter button to take the shot before the camera had finished focusing ("AI Servo" mode will take the shot when the shutter button is fully pressed regardless of whether or not it had time to focus -- it will not wait to confirm focus in that mode.  It will only wait for a focus lock in "One Shot" mode.  These behaviors are known as "Release Priority" (in "AI Servo" mode) vs. "Focus Priority" (in "One Shot" mode.))

What I notice more than anything is that the carpet texture on the floor... it's blurred under the subject's feet.  But inspect this carpet texture as you get nearer to the camera and you see it coming into focus.  This tells me that the camera was focused for a much closer distance.  The lens was not focused at the subject distance.  The next question is why wasn't the lens focused at the subject distance, and to answer that, we'd need more information.

[RobertTheFat]

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@TCampbell wrote:

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@RobertTheFat wrote:

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The 18-135 has a pretty good reputation, but for this purpose you'd be using it at the wide end. Lenses with a long zoom range (and yours is fairly long) tend to be sharper in the middle of their range than at the ends. The ends of your group are blurry because sharpness falls off as the subject gets farther from the center of the lens. More expensive lenses tend to do a better job of minimizing that effect. 1/8 of a second will usually work if you're using a tripod, but it's too slow for this kind of picture, because the subjects will move around. I wouldn't use anything slower than 1/160 for group pictures, the only exception being when a flash is providing most of the light. For group pictures I normally use the Canon 17-55mm f/2.8 IS on a 7D body. That lens is very good and cheaper than it used to be. Whether that lens would solve your problem, I don't know. Maybe you could rent or borrow one and try it. Note that although you'd still be using it at the wide end, it doesn't have to worry about being sharp at 135 mm.

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I'm studying the image carefully at 100% size and while your points are true, I don't think they apply to this particular image. ,,,

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Yes, I was just answering the OP's questions, not trying to analyze the picture.

[TCampbell]

The lens appears to be front-focused... as I inspect the carpeting the focus appears to improve as we get closer to the camera.

How did you focus?

Was this via the viewfinder?  Liveview?  If viewfinder, how did you select the AF point (or did you let the camera select the point)?

[dtrachtman]

I use auto-focus, no liveview. I let the camera select but make sure it is focused in the middle.

[TCampbell]

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@dtrachtman wrote:

I use auto-focus, no liveview. I let the camera select but make sure it is focused in the middle.

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If you press the focus point selection button (upper right corner on the back of your camera) you can then use the main dial (wheel in front of camera - next to the shutter button) to select a specific AF point that you'd like to use.   The choices cycle through each point (it will illuminate as you scroll) and then all points illuiminate (meaning the camera can auto-select the point).  

If you allow the camera to auto-select, it will select the AF point which is able to achieve focus at the closest possible distance to the lens.

What this means to an image like this is that the lower middle point will lock on the carpet INSTEAD of using a point over a subject in the group.  This would cause the camera to miss focus (technically it nailed focus on what it was programmed to select.)

If you can can upload an image which was taken directly from your camera and not touched by any other program (don't open it in Photoshop, etc.) then we can see more image meta-data including the select AF point (Canon records that in the meta-data file but I see that your image posted above has that data stripped out because the image was processed by Photoshop and Photoshop doesn't support focus point meta-data.)