Here’s a (non-exhaustive) list of things to consider when you want to make the very sharpest photo that you can possibly make in any given situation. While it’s not at all always important to have a super sharp image, if you want one – these steps will get you closer than anything else I can think of.
1. What’s Your Target?
Establish what you want to be sharp. In a portrait – it will be the eyes. In a landscape, it might be a prominent foreground object. Whatever it is, you can’t measure sharpness if you don’t know what your target is.
2. Use A Tripod
If you want the sharpest picture possible, use a tripod. If the camera moves when you make the photo, the photo will not be as sharp as possible. Even the slight pressure of your finger on the shutter can make a difference. So use a tripod and make sure it’s properly set up. Make sure that it’s stable and locked down. And use a sturdy tripod. The $30 tripod they sell at Ritz isn’t going to cut it.
3. Buy the Best Glass
Sharp photos start with good glass. Just like a stereo system requires good speakers, camera systems require good glass. The best glass on a cheap body is better than the other way around.
With very few exceptions, the sharpest lenses will be fast primes.
4. Shoot in the Sweet Spot
Most lenses have a spot where they are sharpest. Using special tools you can find this spot, but as a rule of thumb, the sweet spot is typically 2.25 your maximum aperture. For example on an f/2.8 lens, the sweet spot is often between f/5.6 and f/8.
Don’t make the mistake of thinking that stopping down to the smallest aperture will create the sharpest picture. It almost never will. What it will do is give you the greatest depth of field, but that doesn’t translate to the sharpest image. Most lenses perform poorly at their extreme apertures.
5. Lock up That Mirror
If you’re using an SLR, you have a mirror that causes the image to appear in your viewfinder. Most cameras have a mirror lock up feature that you can enable. This will keep the mirror from bouncing during the exposure since it will be locked up and out of the way. That mirror bounce can introduce vibration that causes the picture to be unsharp.
6. Use a Cable Release
Cable releases reduce the amount of human interaction with the camera and accordingly, reduce the chance of introducing vibration that can occur when pressing the shutter button.
7. Use Image Stabilization or Vibration Reduction
If your camera supports stabilization – use it. Even on a tripod this can be valuable if you’re using big and fast 500 or 600mm lenses. But be sure that your camera/lens combination supports tripod use. Not all stabilization systems work when the camera is mounted to a tripod.
8. Use Fast Shutter Speeds
While it’s not always possible to shoot a 1/2000th of a second, you do want to select the highest shutter speed you can while staying within the lens’ sweet spot while calculating your exposure. Fast shutter speeds reduce camera shake and therefore allow for greater sharpness.
9. Shoot in the Best Light
Here’s a tip you don’t often see in lists relating to sharpness, but it is important none-the-less. If you have good light, your autofocus will perform better, your scene will be rendered with better contrast, and the brightness necessary to achieve APPARENT sharpness will be increased. This is NOT to say you can’t make a sharp photo in low light because you certainly can. This item just reminds you that it’s easier in good light.
10. Consider Manual Focus
While I am old enough that I can no longer adequately rely on my eyes to make a sharp photo, I can read a tape measure. And in critical focus situations I do what the cinematographers do. I measure the physical distance from the film/sensor plane to the point of focus and manually focus using the lens distance guide. This is a fool proof method if you have a situation and circumstance that allows for it.
Are there other tips? Sure. But these are the ten that I rely on most.