How important is sharpness? Well, this depends on the end-use of your image. If you are only ever going to display your image at a maximum size of 1200 pixel on Instagram, Facebook or a website, I would say not very. If however, you intend to make large scale prints of an image, it can be the one thing to make or break the end quality of that print. As a landscape photographer that often produces prints as large as 1.2 meters wide of my work, sharpness in my original capture files is paramount for me.
I would not consider myself a “pixel peeper”, and I am not interested in spending all my time testing the latest sharpness lens at a different setting (there are websites to use for that!). Where having the right equipment for the job and some knowledge of its limitations are important, I feel that equipment is not the main reason that people don’t get sharp shots. The one thing I consistently see when teaching on workshops is bad shooting techniques, and I would say this is the biggest reason for ending up with soft images.
First of all, let’s consider some of the things that can lead to a soft image and then we can look at how to minimise these.
- Quality & knowledge of your equipment
- Correct focusing techniques
- Minimising camera shake
Quality & Knowledge of Your Equipment.
All the time, I see people blaming the quality of their shots on the quality of their equipment. Where gear can make a difference, I feel that this is not the main reasons people don’t get sharp images. If used correctly any camera setup can capture a reasonably sharp image.
Camera:Today I think we have all been sold on the "megapixel dream" by camera (& phone) manufacturers. My current phone even has a 40MP sensor in it! In reality, this whole megapixel race has become a joke, as the files from my 40MP phone would never withstand the enlargement needed to print to the size that I do from my "real" camera due to other factors like the quality of these pixels and the optics in front of them. For my landscape photography, I shoot with a Nikon D850. One of the reasons I use this camera is its resolution of 45MP, which helps me to make large scale prints of my images. However, most photographers do not print to this scale, if they even print their work at all, so do not require this sort of file size. Anything over 14MP produces an image of about the quality of traditional 35mm film. So for most photographers, if left uncropped this would be more than enough for everything they would ever use it for, including for A3+ prints. The number of megapixels your camera has, only impacts sharpness if you intend to make huge prints of your photographs.
Lens:I think lens quality is a more important factor to consider when it comes to image sharpness. A camera body only records light; it is the lens that controls the quality (sharpness) of this light and focuses it onto the sensor. There is no point owning a camera with a 45MP sensor and using a cheap lens that is only capable of sharpness of 12MP, and some low-quality lenses would not even be capable of rendering this sharpness. Even the very best full-frame lenses available today are still not capable of resolving 45MP in terms of sharpness, but some do a much better job than others. The DXOMARK website is an excellent resource for lens tests and saves the work of testing them yourself. Coming back to my earlier point about the 40MP phone and why this is a bit of a joke, I doubt the tiny optics on its lens would be able to resolve much of this resolution sharply.
Sharpest Aperture / Diffraction:All lenses have a sweet spot, and you need to test your lens or use a website like DXOMARK to find out this information. This will differ from lens to lens. As a go-to for most full-frame camera lenses, your sharpest aperture will be around f8, with f11 only having very minimal diffraction. With each aperture narrower than this (e.g. f16, f22) you will lose noticeable sharpness in your image due to diffraction.
Correct Focussing Techniques.
Focusing in the right place and obtaining enough depth of field to get both your foreground and background in sharp focus is critical for most landscape images. A slightly out of focus image on your camera will be extremely noticeable when viewed at 1:1 zoom later on your computer and even more in a large scale print.
Take Control of Your AF Point:People tend to rely on their camera's Auto AF point selection mode. While using AF is not a problem we need to take control of the AF system and where it focuses; by using the Auto AF point selection, the camera would focus on the closest subject it can find, and this would likely leave the background out of focus. By manually selecting our AF point, we can still utilise the AF system but decide where we wish the camera to focus within the image to obtain the best depth of field.
Hyperfocal Distance:If we are to focus on the closet subject in the landscape (e.g. the rock at our feet), then the background (e.g. the distant mountain peaks) would be out of focus. Likewise, if we were to focus on the distant mountain peaks, the rocks in the foreground would be out of focus. Therefore we need to focus on a midpoint within the landscape to obtain focus throughout; this point is called the hyperfocal distance. Hyperfocal distance is a complicated subject, as it depends on many factors. A good rule of thumb is to focus at a third of the way through the landscape.
Enough Depth of Field:Depth of field extends in both directions from our focus point, but not in equal amounts. It is also dependent on lots of factors such as our choice of lens focal length and distance to our closest subject, but we also need to select the correct aperture to obtain enough depth of field. So for shooting landscape photographs, this will generally lead us to use a narrow aperture (e.g. from f11 to f22) to get everything in sharp focus, but we also need to be mindful of diffraction when using these narrow apertures.
Minimising Camera Movement.
When shooting landscapes, you often end up using longer shutter speeds, which require the use of a tripod. Tripods also have the added benefit of allowing us to slow down to master your composition, along with your focus and depth of field. A sturdy tripod is a must for landscape photography, all too often I see people with a lightweight flimsy tripod which can not hold the weight of their camera sturdily, let alone when shooting outside in the elements like a strong wind.