It seems each recent camera announcement has brought a higher megapixel count — including Sony's latest 60mp+ release. But whether you're shooting on 24mp APS-C, 50mp full frame, or 100mp medium format, you might not be getting all the resolution you paid for. Check out this list for 3 clarity-robbing problems and their fixes.
Your sensor doesn't actually see the full range of color at every photosite. Instead, an array of colored filters combined with some clever interprolation transforms luminance and partial color information into a usable picture. This process is called debayering (coming from the Bayer filter typically used) or demosaicing. The process of debayering, particularly when applied to raw images with atypical sensor layouts, like Fuji's X-Trans, can produce different results from raw processor to raw processor.
Adobe Camera Raw, which powers Lightroom and Adobe Photoshop, has had a particularly bad history with Fuji's files, occasionally producing weird shapes in green areas. In response, Adobe has introduced a tool called Enhance Details, a new twist on their debayering process that happens to provide better results for all sensors. Now, this process isn't meant for every photo. It is significantly more computationally expensive, taking upwards of 15 seconds per image from my Z7, for example. For certain images, however, it is worth the wait.
If you have false colors appearing on fine patterns, called moire, or have seen the sometimes-weird results from your X-Trans sensor's files, give it a try. In Lightroom, while in the Library Module, right click the image, and select enhance details. A pop-up will show you the previewed results, as well as the expected render time. This tool can have any degree of effect, from basically unnoticeable to image saving, so check it out with a couple of images before dismissing it outright.
A technique already known to astrophotographers and users of Sony's pixel shift, stacking images can greatly improve resolution and noise performance. Fortunately, you don't need to switch brands or buy a telescope to get the same results.
To successfully stack, all you need to do is shoot multiple images without moving the camera. These additional samples can then be combined in Photoshop to improve the base image. For best results, try this on an image where you're using a high ISO, without much movement in the frame. If you have a steady hand and a high framerate camera, you can shoot your images without a tripod, but locking your camera down will guarantee easy alignment.
Once you've got your set of images opened in a stack in Photoshop, align them by selecting all the layers, then using edit> auto-align layers. From here, I like to duplicate those layers with Control+J, then merge to smart object by right clicking on the selected layers. In the Layer menu, select smart objects>stack mode>median.
This will take a few seconds to process, but will result in Photoshop selecting the middle value for each pixel, from the set of layers. What this means in practical terms is a significant reduction in noise. While it won't get rid of truly hot pixels, which are stuck on, or dead pixels, which are completely black, it improves the appearance of the image.
You can think of noise as a range of values, distributed around the actual value. With more samples, or images, you can better determine the actual value that pixel should be. In any individual frame, especially at high ISO, that photosite may have received slightly more or less light, leading to the random patterns of noise. With that in mind, you can see how stacking can be effective with just a few frames, but improves with more frames. For typical subjects at high ISO, I've seen diminishing returns at about 8 frames, but I know for deep sky images, hundreds of frames can be used.
While this technique is especially well suited to use at high ISO, the same process can be used to improve very fine detail in normal ISO images. Since even locked down on a tripod, your camera may shift a tiny amount between shots, you can imitate the effects of Sony's Pixel Shift. This doesn't have the exact same performance gain, however.
Shake and Bake
At higher resolutions, the impact of shake becomes more apparent when viewing images at 100%. While new cameras are deploying ever more advanced image stabilization systems, there is still something to be said for proper technique.
Shooting handheld can introduce a number of issues. They are all related to having too low of a shutter speed: unsteady hands, being overly reliant on VR (I'm guilty of this one), or raising the ISO too high to get a workable shutter speed. The solutions for this will depend on the situation, and it may not even be possible to solve, like when shooting a concert from the pit. Potential solutions include adding light via flash, raising the ISO, being able to brace yourself against something, or deploying a tripod/monopod.
Even when you're on a tripod, however, all the problems aren't solved. You can observe the effects of an unsteady tripod or head, mirror slap, or residual shake from activating the shutter. To address the camera based causes, try using mirror lockup, a shutter delay, a remote trigger, or an electronic front curtain. For tripod issues, besides getting sturdier gear, you can try hanging your bag from the center column to provide some damping.
All these factors together mean that to get the most performance out of a high megapixel camera, you have to really emphasize technique and discipline in taking the shot. That can mean dozens of things to check for each frame, and can really slow down your process. If you have the time and dedication to put each of these best practices into use, you can be virtually guaranteed the best performance out of your camera. But we aren't perfect, and I can't imagine many situations that will call for each of these techniques to be used.
Instead, try to be aware of these things, and double check them the next time you notice a shot isn't coming out as sharp as it should be. Some techniques, like stacking, can produce dramatic improvements when used appropriately. Others, like the Enhance Details option and mirror lockup, are more niche, but together, they can all help build your technical skill as a photographer, and squeeze every last bit of performance from your camera.