Equipment Help with Canon 24-105L

My 24-105L simply won't take sharp pictures. I have tried everything to get tack-sharp landscape pictures at F/16 through F/22 and even F/8 with no success at all. Before finally giving up on it does anyone else have this lens and what are the sharp F/stop and focal length settings? Canon already serviced the lens and all my other 'L' lenses are very sharp eliminating the 40D as the source of the problem. It cannot be sold or used it in the field if the pictures it takes are unacceptable as prints. Any help would be helpful as I am at my wits end with this lens and it cannot be returned for a refund.

 

Vers has the lens so I'm sure he'll get back to you.

But honestly, if it's L series and doesn't take sharp pics then send it back to Canon. Again. Serviced once rarely means problems are fixed, as lenses are VERY complex and often one repair can cause another problem - let them fix it again and again at their expense until either they send you a good one or find out the issue. And if you get poor handling, start griping - L glass is meant to be top of the line and it has lifetime warranties worldwide. You may have just had a service tech that didn't know what he or she was doing.

As an aside, it may be a good idea to take the lens to a good local photo shop and see if they get or see the same problems as you do. If it matches up with other bodies but not yours, it may very well be your body that needs aligned even if your other lenses are more forgiving...though I highly doubt that's the case, it may also help to have that as an argument with Canon's people should they not fix it to your satisfaction.

 

First of all: Do you use a tripod? Are you using some sort of filters? Got any sample pictures that show the problem? Have you tried it on a different camera body?

I guess this one have IS. Do you notice any difference when using IS and when not using it?


It could still be a problem with the lens as DaDego says.

 

Can you post some 1:1 samples of problem areas? Landscapes are not only easily affected by shutter speeds (the lightest wind will send grass, leaves, and everything else moving), and if you're looking at distant trees for example, often times sensors will struggle to an extent to just capture the detail since you're often looking at a couple pixels per leaf or worse, and that ends up leaving a lot to guesswork frankly. That would be more of a problem at the wide end, but it depends on the subject.

Shooting around f/11 or so will probably provide optimal DOF/sharpness ratio. Each lens definitely has a sweet spot for sharpness, and stopping down all the way to maximize your DOF is definitely nowhere near the sweet spot.

 

I would manually focus the lense on a distant object that would provide sharp lines, (i.e a building) and then find the sweet spot by stopping down, taking a shot every stop.

Landscape photography is better done manually as auto-focus just guess's what you want, and most the time its correct.

 

Using a stable tripod, remote shutter, manual focus and IS disabled with Live View produced fuzzy pictures with very careful attention to the focus. In the 3" display at 10X the picture looked sharp but the final image was off-focus and soft. Testing various F/stops resulted in the same result. It almost if the lens reduces the focal length a little when the shutter is released. Focus points are often fuzzy with blurred lines. My lens has an odd square baffle on the back that is supposed to enhance image quality; all my other 'L' lenses don't have it and work fine.

Yesterday I took a picture of the sunset free-handed with the IS enabled and the image was soft F/8 @ 35mm. My monitor is a Planar PX2611W and all my work with images is done full screen at 100% viewing area.

 

take the lens and body to canon and have them calibrate it properly.

 

There really is no way to tell without samples. The first thing you need to do is shoot immobile/inanimate subjects or scenes making sure your shutter is at least +1/200 to eliminate any motion blur (think leaves on a tree). If you've got a large brick wall, buildings or something of that nature (The flatter the surface the better) go out with a tripod and shoot it using RAW, MLU, IS OFF, Av, AF to acquire proper focus and then switch to MF before pressing the shutter button using a remote shutter release (if you've got one). Shoot f/4, f/5.6, f/8, f/11, f/16 and f/18 (forget f/22) each at 24mm, 35mm, 70mm, 105mm. Using DPP adjust only the sharpness level to 4 or 5 then convert to JPEG, if you can try and make up some proper crops then post a link or directly to the forum for further "analysis". If all else fails JJ made the best suggestion. Your experience with this lens made me mount mine in order to go out to take some frames--its as sharp as I remember...actually seemingly sharper.

 

After a little testing the lens only seems sharp between 85 and 105mm. With the rain and low light today it would be better to do more through testing tomorrow when the sun is out and post the results on the forums. Thank you for the help.

 

I have the 24-105 F4 L and its very sharp on my 5D stopped down to F5.6 at all focal lengths, so should be even sharper on the 40D. Suffers a little at the edges at 24mm and F4 but sharp in the centre, Its good when stopped down to F5.6.

On the 40D you might start loosing sharpness if you stop the lens down below F8 due to diffraction. You can get an idea of how it should perform against your other lenses at specific apertures and focal lengths from the site below -
http://www.the-digital-picture.com/...355&FLIComp=3&APIComp=0&Camera=9&CameraComp=9

 

He shouldn't see any real noticeable diffraction at all until past f/18.

 

Well F18 would be quite remarkable for an APS C size sensor.

Most recent (and believable) explanation I have read on this is a feature article on Luminous landscape
http://www.luminous-landscape.com/tutorials/resolution.shtml

If you do not want to read the whole article, just page down near the end, goto
"Table 3 . Number of pixels of optimal size for different apertures of a diffraction limited lens,
wavelengths of the light and formats, considering 2 pixels per Airy disk diameter"

At F8 - the maximum resolution of an APS C sensor drops to 13 Megapixels
At F11 - the maximum resolution of an APS C sensor drops to 7 Megapixels

The article is a good explanation of diffraction and worth trying to understand that there are serious limits that will affect the resolution you can achieve with any given size sensor and aperture

 

Ah--was thinking of diffraction on FF. My fault.

 

All the lenses are tested and the 24-105L has some serious issues at 24mm that don't go away until 50mm. The lower straight wood beams curve in the picture looked like they went through a steamer before being nailed on. The 100-400L, 180L Macro and 105L are all included and carefully labeled with full 10.1 MP jpgs. Landscape pictures are included with each set of wall samples. Unfortunately the file is huge so please only download a single copy and back it up for safe keeping if needed later. I followed Vers directions to the letter but made the mistake of using 28mm instead of 35mm due to misreading writing on the lens.

It can be found here. It is a free account so I don't know how much bandwidth they will allow me to use before shutting down the link. Any comments and suggestions are welcome.

 

CG, why not just post them on a Flickr account?

 

I am a total novice with Flickr and don't know a lot about its hosting capacity and don't know reliable places to share files. They capped my account to 100MB/month and the file on megauploads is 661 MB in size. Each picture is about 9.6 to 12 MB each and theirs 69 pictures in five folders.

 

That's OK, you had me worried for a while so went away and checked

 

That lens is quite simply faulty or has been damaged.

If you cannot get it replaced/refunded as you say then its going to need repair - not sure what happened when it was serviced but sounds as if they failed to calibrate it. You need to go back to Canon and get them to calibrate it, it sounds as though its way out.

 

On Monday I will give Canon a call and get the lens repaired and calibrated. They will need my 40D to complete the repair and it works fine, if they 'fix' anything on the camera body to optimize performance with the 24-105L I will raze Hell with the tech support. This is the least used lens I have and by far the 100-400L is much more useful for wildlife photography.

 

I'm confused by this statement.