Canon 24-70mm L Series / Blurry Images

[wcjacobs]

Ok, so I bought a Canon 24-70mm 2.8 USM. I had high expectation for this lens but have developed mixed emotions. Before I continue let me say I am still semi new to photography so I'm aware it may be, or should I say probably is me causing the following concerns.

I have noticed that the images have been blurry alot of the time. Sometimes they are very sharp but other times they a quite blurry. Being it's not a IS lens I have increased the shutter speed usually about 160-200 depending on the subject matter) to compensate for camera shake. I have tended to want to shoot at lower apeture settings since I got this lens and I'm thinking that may be the problem. I was getting clearer images with my kit lens (18-135 3.5-5.6 IS) which forced me to stay above f/3.5. Am I on the right track?

I have read mixed reviews on this lens from people complaining about blurred images and wonder if they too were shooting at too low a apeture. I've read that some think the 24-105mm is a clearer lens. I also wonder if that is because it bottoms out at f/4. I have also heard about people getting "bad copies" and wonder if I should send it to Canon to check if it's within specs...

I REALLY want this lens to work for me. I love the build quality and the weight has never bothered me as it seems to be an issue with others. Any input or advise is greatly appreciated...

[shreds]

You mention weight as not being a problem, but I wonder if using a heavier lens does have an effect upon your handling of the camera and lens?

I would try and eliminate all possibilities before you resort to hauling the lens back to Canon, especially as it seems to be intermittent?

Do you have any lens calibration/aberration etc charts that you could set up and shoot from a tripod to test the camera and lens?

Are you using it around 2 stops down from max aperture eg f5.6-f8 as few lenses work at their best at the extremes?

Have you tried using it on a tripod, possibly with the camera timer so that you can eliminate any movement that you may be introducing.

The 'blurriness' may also be due to the subject, depending on what you are photographing!

Just a few quick thoughts....

[FrankMi]

Hi wcjacobs, One other thought. Are you using autofocus or manual focus?

[Dave Humphries]

Hi "wcjacobs",

I think a good and a bad example image are called for, with EXIF data intact, or supplied.

Also, please tell us a first name and add it to your profile in the Real Name field - thanks.

I can see your point of view; you bought an f/2.8 lens to shoot at f/2.8 for the narrow DoF, it would be a nasty surprise to find it softer than your kit lens

Cheers,

[rpcrowe]

Hi wcjacobs...

The 24-70L can be capable of exceptionally sharp images. I used one for years and ws quite happy with it. However, there can be problems with the lens or with the camera/lens interface.

There are two basic reasons for a photo being fuzzy and they are not self eliminating. What I mean is that both can occur in the same image but, that is the exception rather than the rule...

BAD FOCUS...

Usually problems with focus will end up with portions of the image fuzzy from being out of focus while other portions of the image turn out sharp. The problem is when the wrong portions of the image are sharp and the parts you waant sharp are fuzzy. This can result from a problem with the camera or lens' focusing or it can simply resut from allowing the camera to select the focus point resulting in the camera making a bad decision as to what point to focus on. Use the single center point and choose which portion of the image you want sharp.

Shooting at a fairly large aperture such as f/2.8 and at a fairly close distance will provide a very narrow depth of field which might result in subjects being out of focus. If you shot with a 1.6x crop camera at 70mm using f/2.8 focused on 5 feet; you would have a DOF of .16 feet or slightly less than two inches; at 10 feet, the DOF would be .65 feet or slightly less than 8 inches. It is hard to focus correctly with a DOF like this. Using a f/f camera at 5 feet, your DOF would be .25 feet (3 inches) and at 10 feet it would be a little over a foot.


CAMERA SHAKE...
This will normally cause the entire image to be fuzzy or unsharp. You can usually learn if camera shake is the culprit by placing your camera on a solid rest (tripod is best but a table will do) and fire your camera with mirror lock-up and with the self timer. The old formula of 1/focal length x crop factor is just a starting point. Some photographers, especially when working with heavy lenses or unbalanced equipment (I had a hard time with my 24-70L on my Rebel XT) need a faster shutter speed.

[Colin Southern]

Hi Bill,

As others have mentioned, it is possible to get a bad copy, although in my experience, that's not usually the case. Personally - again, as others have mentioned - I think the key thing to do is some testing - definitely using a tripod, and definitely using mirror lockup, and preferably using either a remote release or the self timer. Also, I'd strongly suggest shooting RAW, and not forgetting to apply capture sharpening.

Happy to help you evaluate the images if this helps.

[Hansm]

Hi Bill,
What camera are you using?
Does it have microadjust to adjust the lens to the body?

As Colin stated also I doubt if it's a bad copy. I read lots of stuff on the net about it but lots of times the real problem is not the lens but something else.
Also check with CPP where the focus point was during the expose.
Some examples might also help to understand the problem.

[rpcrowe]

Both the various cameras and the various lenses have certain focus error tolerances allowed by the factory. Occasionally (very occasionally) a cameras tolerance and a lens tolerances are cumulative and add up to bad focus. As mentioned by Colin and others, the chance of the camera/lens being at fault is rather slim. However, if you have exhausted all other testing (and only then) and you decide to send the lens in for service, I suggest that you send the body also.

User or camera error in focus, camera shake and shooting with a very thin depth of field could most likely be your problem.

It was mentioned that shooting at the maximum aperture might be your problem. I have shot my 24-70L at f/2.8 on many occasions and other than problems arising from a thin DOF (which is not the fault of the lens) the results were more than satisfactory. Sure, stopped down a couple of stops will provide a bit better IQ. However, the ability to produce acceptable image quality wide open is one of the reasons we pay the extra bucks for the "L" grade lenses.

BTW: the reason I sold me 24-70L was not because of any problems with this lens but simply because I was not using it as often as I might have because I have been shooting with a combination of 17-55mm f/2.8 IS and 70-200mm f/4L IS lenses. I sold the 24-70L in order to fund my 7D camera. I also sold it because I was anticipating the release of a 24-70L Mk-ii which would heve lowered the used value of my lens. I figured that this was the prime time to sell the zoom (sorry for the awful pun). I actually received more money for the 24-70L than I originally paid for it several years ago when I purchased it used.

There is one more possibility which I did not see mentioned in any of the postings. An inexpensive protective filter can be a factor in image deterioration. If, by any chance, you have been using ANY filter (even a good brand) I suggest you remove it for your lests...

[wcjacobs]

Thank you all for the advise and remarks. I will be applying all the input this weekend. I'll let you know the results and post some samples...

[wcjacobs]

To fill in a few blanks that some of you had questions about...I have a Canon 7D, I shoot mainly auto focus and do use the point focus feature on some occassions. I always shoot freehand and don't even own a tripod. I'm not sure about the micro adjust on the Body Hansm but I'll dive back into the manual and see. Colin, I always shoot in RAW and I'm not sure if my 7D has the capture sharpening feature but I will also investigate the manual for that. I am still learning the camera as well as the lens. Part time thing for me so it's a slow process...

[Colin Southern]

To fill in a few blanks that some of you had questions about...I have a Canon 7D, I shoot mainly auto focus and do use the point focus feature on some occassions. I always shoot freehand and don't even own a tripod. I'm not sure about the micro adjust on the Body Hansm but I'll dive back into the manual and see. Colin, I always shoot in RAW and I'm not sure if my 7D has the capture sharpening feature but I will also investigate the manual for that. I am still learning the camera as well as the lens. Part time thing for me so it's a slow process...

Hi Bill,

If you're letting the camera choose the AF point then generally it'll focus on whatever is closest to the camera, which may or may not be what you want. I'd suggest just using the centre AF point and see if what you're pointing at is sharp.

Capture sharpening is something you do in post-processing - generally, all you need to do is apply an Unsharp Mask of 0.3 pixels @ 300%.

MicroAdjust on a zoom lens probably won't help as you'll probably need different settings for different focal lengths.

[wcjacobs]

Thanks Colin, I use both Lightroom 3 and CS3, so I'll make sure I use that process....

[Hansm]

Micro adjust is worth a try also with zoom-lenses.
Your body has this feature.
In fact if you send lens and body to Canon they will do the same.
You have to do the adjustment with the zoom-lens set to the max. focal length in this case 70 mm.

If you google on this issue there are some good explanations how to do so.
However to do it properly you need a tripod, maybe someone in your neighborhood can borrow it to you?

[Hansm]

Hi Bill,

Just wondering if you found already the reason of the blurry images.