I am using a high pixel count camera from Nikon called the D800. At the time ( a few years back) it was unique in this category of digital SLRs in that it contained a 36 megapixel Sony manufactured sensor. When it was released, only digital back mounted medium size cameras provided such high resolution options. Even today it is rare to find dSLRs with this kind of sensor resolution. Sony introduced the 36mp Alpha a7R and Canon just released its 5Ds with almost 50 megapixels.
Putting aside pixel wars and "pixel peeping" and all their geeky permutations, there are a couple of substantive advantages for such high pixel count. It allows for more agressive cropping in post, which means more creative freedom to reframe the picture after it was taken while still ending up with a file that contains decent amount of details (depending on how much is cropped). But it's most useful for printing larger prints, which is my main reason for using all the megapixels I can get my hands on. I should add that the Nikon D800/D810 can be configured to take photos using less resolution for situations when such high resolution is not needed.
For landscape and even portrait photographers the Nikon D800/810, Sony Alpha a7r and and now the Canon 5Ds are a boon, especially in light of the prohibitive costs of medium size camera systems, their bulk and very expensive lenses. But there's a price to pay for all those megapixels: you quickly lose the advantage of crisp, sharp, detail saturated images, if you end up with blurry images due to lax camera and exposure handling practices. All you end up with are very large files (especially if you shoot RAW format). It therefore requires that you adopt classic medium and even large format techniques that have been around for a long time.
If you want to extract every bit of sharp, pleasing details from your high res camera, you should adopt some of these practices:
- Fast shutter speeds: If you hand hold your camera, make sure you can use shutter speeds of at least 250th of a second or more. That means 1) lots of light 2) fast lenses 3) and even higher ISO settings
- Tripod: Whenever you can, attach the camera to a solid tripod, and if you're using large telephoto lenses, make sure they're attached directly to the tripod head
- Reduce impact of mirror vibration: Even when using a tripod, it is important to control mirror vibrations. SLR cameras use a mechanism that raises a mirror just before the shutter opens to redirect the light coming through the lens, from the viewfinder to the sensor. This movement results in vibration. Most advanced cameras will allow you to specify how much time after the mirror is raised, the shutter will open and allow the image to register on the sensor. Delay will ensure vibration is minimized. But if you thing this sounds obsessive, I go one step further by using a remote trigger instead of the camera's shutter release button. You can see mirror motion and shutter release sequence in this video (you can go directly to minute 2:50 in the video)
- Ensure image is in focus: this may seem obvious, but here again your ability to ensure perfect focus makes a big difference. Whenever I can, I'll use a live preview option (seeing the image on the camera's LCD monitor), electronically zooming in as far as possible to see the subject's details and then using the lens manual focus ring
So to summarize: for those of you who can see the value of very high resolution sensors either because of print size advantage or greater post production creative freedom, following more rigorous techniques to minimize blur is a must.