amfoto1 wrote in post #13036289
I have to agree with this... Your lens most likely isn't
the problem, unless there's something fundamentally wrong with it. In terms of image quality, the 17-55 is one of the most "L-like" EF-S lenses available.
Yes, I'd suggest using some MFA on the lens. This is easier to do with a prime than a zoom... but you likely can fine tune it quite a bit. You should test it at two or three focal length settings and arrive at how much MFA you need to dial in for each. Then you'll probably have to decide whether to average those for a single setting to use with the lens, or might bias it a bit toward whatever focal length you use the most with the zoom.
Canon recommends a different method of doing MFA, that doesn't involve actually taking any photos. They suggest using the more accurate but much slower Contrast Detect focus in Live Mode to calibrate the usual Phase Detection mode. The only caveat, it can only be used with a lens that has a visible focus distance scale.
Start by setting up a flat target with lots of detail, perfectly parallel to the sensor ("film") plane of the camera. A newspaper taped to the wall works pretty well. I've used a wooden fence with a lot of detail. It should be 50X the focal lenth of the lens from the camera to the target (so about 8 feet for a 50mm lens: 50 x 50 = 2500. 2500/25.4mm per inch = 98.425. 98.425/12 inches per foot = 8.2 feet).
Put the camera on a tripod, at the right distance for the focal length being tested and with the sensor plane kept parallel to the target. And, if possible, use a remote release to activate focus (half press of the shutter release... if using Back Button Focus normally, you might want to switch back temporarily to the standard method of focus activation). If don't have a remote release, be careful and gentle to not to bump the camera while pressing the button (of your choice) to activate AF.
Select the center AF point only, in One Shot mode, and use that to focus on the target. Then, while being careful not to bump the camera or change focus on the lens, switch to Live View and activate focus again. Keep an eye on the lens' distance scale. If it moves at all, you need to dial in some MFA to adjust it. Retest after doing that. Repeat as necesary, changing the amount of MFA a little at a time until there is no movement of the distance scale at all.
Again, with a zoom you will want to repeat this process at several different focal lengths (might want to temporarily tape the zoom ring of the lens, so it stays at that focal length during calibration). When the focus distance scale no longer moves at all (or as little as possible if you have to average some settings with a zoom), you will have set the lens as accurately as possible.
It might then be a good idea to take some test shots of a target like the batteries shown above or one of those angled calibration scales, examining the images on your computer monitor, just to confirm the setting. Use the lens at it's max aperture to get as shallow depth of field as possible. With some lenses, the max aperture isn't the lens' sharpest, so take that into consideration when viewing the images. Here we are simply using MFA to fine tune of focus accuracy. Later, taking images with the lens you may want to use a more optimum aperture. Here you are just using the largest aperture to get minimum DOF, to evaluate focus accuracy.
If you cannot adjust this pretty well using the range available within the MFA feature, the camera and/or lens might need to be sent to Canon Service for greater calibrations.
One last thing regarding MFA... it's camera body specific, but only lens model specific. So, for example, if you were using two or three different 17-55mm, any adjustment you dial into the camera with MFA will have the same amount of calibration applied on any copy of that lens that's attached to it. On the other hand, two different cameras might end up with quite different amounts of calibration with any particular lens used on both of them.
Beyond calibrating your focus with MFA, there are several things... But first understand that the 7D is designed with fairly experienced users in mind, people who normally would want to take a lot of control over their images.
Yes, it uses a strong Anti Alias filter and requires more sharpening than earlier and other models. This is not a "mistake" of Canon's, putting too strong a filter on the camera. It's deliberate, to reduce chance of moire occuring when shooting certain subjects with strong patterns with such a high pixel density sensor. Pretty much all DSLRs use an AA filter, but it varies how strong they are, and how effective. For example, 5D series cameras have considerably less densely crowded sensors, even the current Mark II model that captures more megapixels than the 7D. Cameras with weaker AA just need less sharpening of their images, straight from the camera.
One option, you might want to shoot JPEGs for a while. If you do, the initial sharpening will be done in-camera. Choose a Picture Style with fairly strong sharpening. You can go into any of the Picture Styles and set sharpening higher, too.
If you want to stick with RAWs instead, that's cool. You can use Canon Digital Photo Pro (DPP) and it will use whatever sharpening parameter you've set in the camera during RAW conversion, or you can change it at that time if you wish. Or, using a thrid party software such as Photoshop (etc.), just set the default sharpening higher in your RAW converter. That's possible with most RAW converters. Going from 50D to 7D crop sensor cameras two years ago, I also found the images a bit soft. I now tend to use 75 or 85% more sharpening now, on average, with 7D. The detail is there, you just have to do a bit more to find it in your 7D images. Also watch your apertures. Any lens softness wide open will be more apparent. At the other end of the aperture range, you can see more diffraction effects at the smaller apertures. All this varies from lens to lens, of course, but in general I try to stay in the f2.8 to f11 range, when I'm looking for top sharpness. Some f2.8 zooms I stop down to f3.5 or f4, and if I'm looking for the absolute minimum diffraction I might use no more than f8.
I also agree, try to use somewhat higher shutter speeds whenever possible. Don't be afraid to bump up ISO. Depending upon how the image will be used, I will go to 3200 with my 7Ds at times. Even higher on rare occasions. The optimum shutter speeds on the camera are a bit higher... It's not very forgiving of even a little camera shake. For typical daylight shooting I use 400 and 800 a lot of the time. Better to use a "too high" ISO with 7D, than too low! My "normal" ISO is probably 400 with these cameras, where I was regularly using 100 and 200 with earlier models. If anything, 7D has slightly more noise at lower ISOs, compared to earlier, lower resolution models. There is some noise at higher ISO, but somehow it's not as problematic... It might be more random or something.
Just watch out for accidental underexposure. If you need to add any exposure to your images during post processing, it will amplify noise with 7D, as much as and perhaps more than with other models.
Also, don't just rely on what you see on your computer monitor. Besides "pixel peeping" at silly magnifications (which you say you aren't doing), I think these images are stretching the limits and capabilities of the typical LCD monitor. I was using an "HD" consumer grade monitor and recently switched to a more graphics oriented IPS screen. That helped me a lot.
But also, make some prints. I think you'll be pleasantly surprised at the actual output. Prints are best evaluated on good, smooth, matte paper with a pretty good photo quality printer. When you resize and do final sharpening of the images for print, I think you will see a really good result. The same is true when images are sized down and final sharpening is applied for digital image pisplayed on the Internet, too.
Focus is more critical with such a high resolution camera, too. I've experimented with all the AF modes on 7D, and find some uses for all of them at different times. But I mostly use a simple Single Point, manually selected, usually shooting in AI Servo and using Back Button Focusing. Zone Focus, Expansion Points, and certainly All Points will leave it up to the camera to decide where to focus. That might not be where I want it to focus. I tend to use Single Point/Manually Selected most of the time for that reason. Spot Focus is even higher precision, quite useful at times, but slower focusing so not usable all the time. In modes other than Spot Focus, the actual AF sensor is somewhat larger than the box illustration in the viewfinder, and seems to be mostly biased slightly above the box.
Stick with it... There's a fairly steep learning curve to getting the best out of 7D... But it can be a great camera in the end.