I'm pleased to announce the launch of a website that I've been working on in my spare time over the last few months: GuessTheFormat is an experiment for photographers: can you guess the image sensor format of a photograph just by looking at it?

I've often pondered about my ability to identify camera image sensor size, also known as "format", just by looking at a photo. Am I able to distinguish images taken with a full-frame camera from those taken with an APS-C camera? Or compact from four-thirds? How much of an affect does image sensor format really have on photographs? Could an excellent photographer with a compact camera trick me into thinking an image was taken with a full-frame camera?

I decided to create a website to help me ponder some of these questions. is a result of my work and experimentation. Created using Scala and Play Framework, the website indexes images from Flickr Explore, and categorizes them by image sensor format. Images are then presented to the player along with two sensor formats: the correct one, and a random incorrect format. The player's challenge is to examine the photo and try to select the correct format. Results are recorded, aggregated regularly, and presented on the stats page.

Try it out for yourself, here: