Hasselblad was one of the first that used super resolution techniques. Today it can be found in many cameras, producing resolutions that are up to four times higher than the pixel count of the sensor. You can also do this with your camera. This is how it works.
The Olympus OM-D E-M5 II used the super resolution technique to make a 40 megapixel photo with a 16 megapixel sensor. For this it shot a series of images in a row, and shifted the sensor a little bit between each shot. By adding these images in a very smart way, the resolution is increased. Today the technique is found in a lot of cameras, making it possible to end up with amazing resolutions.
There is a way to achieve this with any camera, regardless if the technique is incorporated or not. It makes use in the same technique I previously explained in my article about making long exposures without the use of neutral density filters. You just have to take a series of images of a location. There are a few things to consider, but I will address those at the end of this article. For this technique, you need Photoshop or any other program that has the ability to use layers and smart objects.
Shooting the Images
For this technique you can use basically every camera available, but I want to advise a camera that can shoot series. There is one thing you have to keep in mind; don’t use a tripod. You need to shoot by hand because the technique is based on the shift between the series of images. But you can use image stabilization of course.
When shooting a scene, it is advised to keep the ISO level as low as possible, and use an aperture between f/5,6 and f/11. A raw file format gives the best result, but you could also use jpeg if you like. Make sure the shutter speed allows for images without motion blur, because you need to shoot without a tripod. Set your camera on continues shooting and make about 20 shots of a scenery. The more, the better. But don’t exaggerate. Twenty shots should do the trick.
Post Processing the Images
When you have imported these similar shots into your software program, you need to perform exactly the same post processing on these twenty images. Just do your thing on the first one, and copy the setting onto the other nineteen. I use Lightroom for this.
After you are done, open all images as layers in Photoshop. Using Lightroom for this is the most easy way; just select the images in Lightroom, right click with the mouse button and choose “edit – open as layers in Photoshop”.
After the images are imported as layers, you need to increase the resolution of your image. Choose “Image – Image size” and set the width and height to 200%. This way your image will become four times the original size. Make sure the method of increasing is “nearest neighbor (hard edges)”.
After that, you need to make sure all layers are perfectly aligned. This can be done by selecting all layers and choose the option “edit – align layers”. Don’t let Photoshop correct any vignetting or geometric distortion. You need to turn this off.
Check if all layers are perfectly aligned by turning off every layer for a second. Throw away any layer that is not aligned perfectly. If the layers are not aligned, you need to try aligning again. If it still doesn’t work, consider using another photo.
After you’re done, you can start merging the layers. The most easy way is to make a smart object from all the layers, and stack the smart object the the median method. The option can be found in the layers menu, under “smart object – stack mode”. It may take a while to finish, but when it is the image is ready.
To prevent a very large file size, I would suggest to rasterize the image, thus making it one normal layer, and use the crop tool to get rid of any unwanted borders. If necessary you can level the image also. The last step I can recommend is sharpening and you have an image that is roughly four times larger than the resolution of your camera. With the Canon EOS 5D mark III (20 megapixels) I ended up with an image that was about 87 megapixels.
There is a nice benefit from this method. The stacking of many images will reduce the amount of noise significantly, making the image really clean without the loss of detail you get from a normal noise reduction.
If your software doesn’t have the ability to use smart objects, but it has layers, you can also do the merging manually. You can reduce opacity of the layer stack in the following method: bottom layer, 100%; next layer, 50%; next layer, 33%, next layer, 25%; and so on. The percentage can be calculated by dividing 100% by the number of the layer. So 100/1; 100/2; 100/3; 100/4; 100/5, and so on. After you’re done, merge the layer stack and you have the same result.
A Real Panorama
Of course you can also make use of a panorama to end up with a higher pixel count. But often you need a nodal slide to get rid of any parallax, and it takes more time to shoot. But you can do that also by determine the composition you want, and shoot that scene with a focal length that is at least 4 times longer. Or more if you want. This way you can do crazy things like making a gigapixel photo, something that cannot be done with the super resolution method I showed.
When Your Camera Has Super Resolution
As I mentioned, some cameras have the ability to shoot super resolution. In that case the camera does all the post processing for you. I had the opportunity to test this function with the Panasonic Lumix G9, that offers a super resolution of 80,5 megapixels. And the beauty of it, Panasonic also produces a raw file. The image shows a lot of details, and the noise levels are also reduced due to the stacking. But the method has its down sides.
Downsides of Shooting Super Resolution
The main downside of this method are movements in the scene you are shooting. Any object that is moving will result in a blur. Even clouds, water, and branches or twigs will result in a blur. But for steady object you can get amazing results. The only question that remains is; do you really need that amount of resolution for your images?
Have you ever used super resolution and if so, what do you think of it. Would you try this method, or do you think it is useless? I would love to read your thoughts in the comments below.