Since no one has helped you, let me try.
There are many reasons for an unsharp photo
1) lens quality (Kit lens vs High end lens)
2) camera quality/ pixel size (ie 12 MP, 24 MP, 36 MP)
3) Diffraction (sometimes the smaller the aperture, it gets you unsharp pictures rather than sharp ones)
4) chromatic aberration
I haven't been following camera models for Canon but I think it may be just a prosumer kind.
Welcome to the club of pixel-peeper. I am one of them and I enjoy my pictures tack sharp too.
Your answers hit the most bull's eye...:thumbsup:
1) lens quality (Kit lens vs High end lens)
EF28-105 F3.5-4.5 usm II - Some say it sucks on APSC sensors while others say it's good from F7.1 but better from F8 - F11. Does a PRO lens like L series really do better? Also do remember this is EF lens for full frame film cameras.
Edit: Some say kit lens perform better than this old lens.
2) camera quality/ pixel size (ie 12 MP, 24 MP, 36 MP)
Sensor size do have a co-relationship to sharpness/resolution but don't really determine final output of image.Nikon's pro cameras of old is only 12Mp compared to canon 500D's 15Mp.So what gives?
3) Diffraction (sometimes the smaller the aperture, it gets you unsharp pictures rather than sharp ones)---see 1.
4) chromatic aberration ---See 2nd. photo at 100X. Colour fringes at the edges of the ladder mast. Now look at the photo in Ken Rockwell's review of 28 -105 usm II. Shot on Canon 5D MK3 full frame.This advance camera has built-in lens correction for CA ( chromatic aberation)plus other goodies. Notice the photo is post card size rather than big enlargement ,it's razor sharp to the eye. What's the secret apart from lens correction?
Edit: Note that you can correct for CA (chromatic aberation) in photoshop and may be in Lightroom (newer version) I think.
Here's the secrets...
1. Camera settings - set noise reduction to off.It affects jpeg image quality.RAW is left untouched.
2. Use lowest ISO. Know what is the "native ISO" of the camera's sensor.This is the ISO that gives
the best resolution. Truth is there is only ONE ISO - native iso.:bigeyes: It's also the real analog output (voltage signal) of the sensor vs amplified ISO rating eg. If native is 100 then 200,400,800,1600 are pushed or amplified signal. As common knowledge the more signal is amplified ( bigger amplitude) the more electrical noise it generates. Hence to turn off all noise reduction settings. Read the native ISO links below, it's an eye opener! Rather than pushing digitally ISO ,pulling ISO eg. 125,250, etc. has benefits -- better dynamic range in terms of exposure. Note some sensors native is at ISO 200 but can set to 100 which is digital pulling ( reduced amplification of actual analog signal).
3.Image sharpness, the science of optics or lens engineering. It's relative meaning the
term known as accuity. It can be defined as how a lens resolve fine details (hardware/lens quality) or how humans see how sharp an image is. This is primarily about image contrast vis-a-vie sensor resolution. See Cambridgeincolour article below.
So in essence if the lens cannot resolve fine details it can be enhanced by image processing -boost/increase image contrast.You only sharpen image LAST after all other adjustments are done like white balance,colour,etc.Note if you got the exposure spot on/correct this contrast adjustment will not be necessory.Sharpen adjustment actually
increase contrast of light and dark areas especially along lines or edges to simulate optical/lens accuity or sharpness.
4. Understand how camera meter works and how to compensate the exposure.Read Ansel Adam's Zone system of exposure, the famous zone 5 relative to the other zones.Know and recognise what these zones are in a scene you compose. Edit: Strange that TS use spot metering when the overall scene's brightness/contrast does not require it when matrix mode or whatever canon calls it is sufficient.
5. Shoot in RAW or RAW + Jpeg. Gives you a better chance of retrieving fine details/dynamic range when post processing.
6. Use a better image processing software other than the one included in the camera's CD like Lightroom or photoshop. If after all this you cannot take sharp photos please kick yourself..just joking.:bsmilie:
http://kenrockwell.com/canon/lenses/28-105mm.htm
http://www.cambridgeincolour.com/tutorials/sharpness.htm
http://www.imatest.com/docs/sharpness/
http://improvephotography.com/686/tips-sharper-photography-sharpness/
Native iso:
http://www.bobatkins.com/photography/digital/canon_digital_rebel_T1i_review_3.html
http://shootintheshot.joshsilfen.com/2010/05/13/canon-hd-dslr-native-iso/