Today’s Question: When exporting a sharpened NEF or TIFF as a JPEG from Lightroom, should sharpening be applied to an already-sharpened master image, or should sharpening be turned off?
Tim’s Quick Answer: Under most circumstances you should apply “capture” sharpening to the original image (the RAW capture, for example) as well as “output” sharpening for the final image.
More Detail: In the context of Lightroom that means applying sharpening to the original capture in the Develop module to compensate for the loss of sharpness caused in the capture process, and sharpening when exporting to optimize the image that has likely been resized.
A variety of factors cause your original capture to be less than perfectly sharp. That includes the analog-to-digital conversion process, various filters on the front of the image sensor, a lens that is not optimally sharp, and other factors. This is the reason for “capture” sharpening, which is the reason for the sharpening controls in the Develop module in Lightroom.
In addition, you want to ensure the final image that will be shared is sharpened for the final output. For images that will be displayed on a monitor or digital projector (such as in a digital slideshow) the need for output sharpening will be relatively modest. For printing that output sharpening will need to be stronger.
In theory you could perform all of your sharpening in one step, but there are some advantages to taking a multi-step approach. In the context of Lightroom a key reason to perform sharpening in two steps is that the initial capture sharpening is being applied to the full-resolution image, while the output sharpening is being applied based on the final image that has been resized for the specific output you’re preparing for.