When my article on field curvature was published a while ago, where I talked about how one could do a quick analysis of lens MTF data and determine if it exhibits any field curvature, some of our readers expressed interest in understanding how to read MTF charts. Since we talk quite a bit about lens performance and MTF data here at Photography Life, I decided to write a detailed article on the subject and do my best to thoroughly explain everything related to MTF curves, charts and all the verbiage that comes with them.
Adobe Photoshop Lightroom comes with powerful tools to sharpen images during post-processing. Located in the Develop module of Lightroom, the “Detail” box contains both Sharpening and Noise Reduction tools that allow Photographers to enhance their digital workflows by fine-tuning images and getting them ready to be published and printed in a quick and efficient way. Since I have already covered the noise reduction part in my Noise Reduction Tutorial, in this article, I will show you how to properly use the Sharpening tool instead.
1) Problems with Sharpening Images
Sharp images look aesthetically more pleasing than soft or blurry images. Because of this, most photographers try to sharpen their images in post-processing applications, which can result in all kinds of problems such as:
- Over-sharpening – when too much sharpening is used, it results in harsh, visible lines on edges and around objects. Over-sharpened images often look too “textured”.
- Too much noise – using excessive amounts of sharpening can add a lot more noise to an image. The worst result is when an image is already shot at high ISO levels and sharpening is applied on top of the digital grain, resulting in even more noise.
- Zigzag lines – straight thin lines can get converted over to zigzags and circular shapes can get cubic transitions when excessive sharpening with a large radius is applied.
Here is an example of an over-sharpened image:
One of the things that makes photography frustrating, is softness and blur in pictures. Sharp photos are much more appealing than soft images. It is very disappointing when you take a picture at a special moment and images come out soft/blurry or out of focus. In this article, I will go through the techniques that I use to make sure that my images always come out tack sharp.
Let’s start with the reasons why an image might come out blurry:
- Slow shutter speed could cause camera shake, which would produce a blurry image
- Poor focus acquisition would result in a soft image
- Your subject could be moving and causing a motion blur
- You might have a bad lens or a lens that is not capable of producing sharp photos
- Your ISO could be set to a very high number, resulting in lots of noise and loss of detail