David,
The other posters have all given good advice. To build on what Kevin said in his post above. When it comes to sharpness with moving objects,
the most important single setting is to have your shutter speed high enough. I own a lot of older Kodachromes that would have been much sharper if I had known that lesson when I started over 40 years ago.
At just 10 MPH, a moving object will move .117ft, or a bit under an inch during a 1/125 second exposure. Going to 1/250 halves that, etc. I shoot at 1/500 second minimum for anything moving. With the high ISO capability of most digital cameras now, there is no reason not to use a high shutter speed. Using the sunny F/16 rule, at ISO 200 you could shoot at 1/200 @ F/16. (I/250 is only a fifth of a stop off and close enough) Converting that to a higher speed 1/500 @ F/11, 1/1000 @ F/8, 1/2000 @ F/5.6. If you up your ISO to 400, you can double the preceeding shutter speeds.
Rehunn mentioned use of a monopod. I completely agree with him, get one and use it. I have used one for decades and it has been the one thing that contributed to sharp photos more than any lens I ever used. Camera support is extremely important especially with any lens much over 100mm in 35mm terms.
That brings us to lens choice. The reason everyone says buy the best you can get has a number of factors, but mostly revolves around lens speed and sharpness. The inexpensive zooms with long zoom ranges like 18-300mm will always have small maximum apertures. I assume yours has a maximum aperture range of around F/3.5-F/6.3. Where overall sharpness is concerned, when the aperture on a lens closes down, there is a point where diffraction will start to limit the sharpness possible with the lens. With some cameras this can start as low as F/8 and I have seen claims for even lower with some lens-camera combos. It doesn't mean you can't get an acceptable photo shooting at say F/11 or F16, just that you are giving up some sharpness. The more expensive lenses generally have wider apertures such as F/2.8 or F/4 throughout their zoom range, thus even stopped down a bit can stay out of the diffraction area. Photographers talk about lens "sweet" spots. That is largely true. All factors considered, shooting your 18-300 one stop down from it's maximum aperture would probably render the best sharpness possible.
Nearly all lenses are acceptably sharp in the center. It's the corners where the cheaper ones fall down. With digital cameras there is even a way to help this. You don't mention what Canon you have, but if it's a crop sensor camera, (not full 35mm size sensor) your camera doesn't really use the corners of the lens. So even if the lenses you have aren't very sharp in the corners, your sensor doesn't see the image area produced by the corners. However, if it's a full 35mm size sensor, the corners are in play.
Kevin mentioned that post-processing is more than half of getting good photos. He is totally correct. In film days unless you processed your own, a lab made a lot of decisions as to how your photos looked. (except for Kodachrome) Now, it's generally up to the shooter. I have met very few people that have mastered digital post-processing. The vast majority just shoot jpegs and are happy. Nothing wrong with that, but shooting raw files will give you way more control over the process. The one area that is sorely neglected in digital processing is sharpening. The digital process breaks up the image into pixels and that effectively results in a "de-sharpening" of the image. That process can be compensated for by proper sharpening. If you are leaving it up to the jpeg process in your camera or not doing it at all in post-process you are leaving a lot of "sharpness" on the table.
Edited 3 time(s). Last edit at 09/19/2014 10:04AM by jgunning.
