Today’s Question: If you lower your screen resolution below its native resolution, does that not affect accuracy when assessing image sharpness at 100% view?
Tim’s Quick Answer: Yes, in terms of the image generally not appearing as sharp as it otherwise would. It is best to evaluate sharpness and apply sharpening at a 100% scale with the display set to native resolution, but with experience you can use different settings without difficulty.
More Detail: LCD displays have a fixed number of pixels, which limits their ability to adjust overall display resolution without impacting quality. Therefore, it is generally best to use the native display resolution for an LCD monitor.
As noted in a previous Ask Tim Grey eNewsletter, using a lower resolution on a display can provide a benefit in terms of making text larger and easier to read. However, this can also lead to lower display quality.
For very high-resolution displays this often isn’t a problem, because the smaller pixel size enables better quality when scaling the display. For example, a 13-inch Apple Retina laptop display has a resolution of 2560×1600 pixels. However, the standard display setting actually mimics a resolution of 1440×900 pixels.
So, if you’re using a display with a very high resolution, it is generally less of an issue to use a lower resolution than the native value. However, anytime an LCD display is set to something other than the non-native resolution there is some risk that the display will not appear as sharp, which can make it a little more difficult to properly evaluate sharpening settings for a photo.
That said, when evaluating sharpening settings, the focus is really more about the size of the effect relative to the size of texture transitions in the image, so I wouldn’t consider this a major issue. If you are more comfortable with your display set to a lower than native resolution, you can still apply sharpening very effectively.