Below is a list of topics covered. I'm showing you this, not to promote the site (I haven't paid for this section of his site) but simply to point out the many ways an image can be degraded.
- Banish Blur, or Blur for Beauty?
- Blur by Focus
- Blur by Autofocus Error
- Blur by Manual Focus Error
- Blur by Manual Focus Inconsistency
- Blur by Focus Shift
- Blur by Focus Lock and Recompose (FLR)
- Blur by Subject Movement
- Blur by Camera Movement
- Blur by Mirror Slap
- Blur Caused by System Alignment
- Blur Caused by Image Stabilization
- Blur from Haze and Refraction
- Blur Caused by Lens Optics
- Blur and Haze from Spherical Aberration
- Blur by Purple Fringing (Axial Chromatic Aberration)
- Blur by Red/Cyan Fringes (Lateral Chromatic Aberration)
- Blur Caused by the Laws of Optics (Diffraction)
- Blur by Depth of Field
- Blur from Field Curvature
- Resolving to Sensor Resolution
- Blur Caused by Anti-Aliasing Filter
- Blur Caused by Digital Capture
- Blur Caused by Demosaicing
On his site, Lloyd has several examples of commonly used top brand lenses hugely changing focus as one stops down, the difference between focussing on the eyelashes and the tip of the nose or the ears type of difference.
I couldn't get a sharp image with the Phase one camera and P65+ back I borrowed for a workshop - and finally got rid of my centre post, tall ball head and leveling base that stuck up another two inches, and now I get sharp pictures consistently - if there is no wind.
On the 5D2, I have been utterly amazed at how much image blur there is at full magnification live view when the wind is blowing.
Michael Reichmann found that tripods (the best tripods) don't stop shaking for 7 seconds - using mirror lock up and a two second delay doesn't cut it.
With medium format especially, focal plane shutters can add considerably to the instability and I wouldn't be surprised if that wasn't a sig. part of my diff. with the phase one camera.
Camera straps blowing in the wind contribute to movement as do cable releases. Let's not even talk about people who press the shutter button and hope the camera stops shaking by the time the self timer activates.
I have been paying attention to what I stand on. Ground isn't ground - ground can be springy, it can be soggy or even squishy, it can be a connection between your feet and a tripod leg and there goes your image.
I`m amazed at how many people are still stopping down their camera to an f stop that is severely diffraction limited. With a full frame sensor (my 5D2) I usually use f11 and focus blend if I have to. Sometimes I will use f16. it isn`t as sharp, though I think I can pretty much compensate with local contrast enhancement. At f22, I can`t compensate. With an APS-C sensor, I try to stick to f11 at worst, and with point and shoots, even f8 can be problematic.