Stock Photography is as a popular way of taking photographs of anything from nature to portraits and can be either sold over the Internet or displayed in photo albums. The reality is that there are more stock photographers around the world than in any other photography discipline. Stock Photography follows the same basic principles required for any other photography dealing with backgrounds, lighting, camera, lens, films, subjects etc. The remarkable thing is that there are many amateurs involved. For example, you can go for a mountaineering expedition and use your SLR or digital camera to take pictures of the base camp. If the picture comes out as an excellent composition then you can always display it on your website.
The standard format for stock photographs is 6x7cm and the smallest format is 6x4.5cm. Initially, the 6x4.5cm appealed more to most photographers because the image proportions of this format matched those from the 35mm. The camera and lens used for the 6x4.5cm is compact and small and can be carried around with ease. You will get around 15 shots with a roll of 120 speed film. It was not long back when the 6x4.5cm was rejected as the image size was no different from 35mm. This led to the introduction of the 6x6cm, which is a traditional size for medium-format photographs. The 6x6cm is ideal for fashion and portrait photography and even for social photography. But if you are specializing in nature or landscape photography then the square format of the 6x6cm will limit certain elements used in the composition of the photo. There will be more cropping, which will defeat the entire purpose of taking a stock photograph.
This leaves you with three options, which are 6x7cm, 6x8cm and 6x9cm. If you are in love with the 3:2 proportions of a 35mm, then the 6x9cm will seem like the ideal solution because it will offer the same ratio. The only camera available in this format is the Fuji GSW690III. The limitation of this format is that it will be difficult to use it with a polarizer and neutral density graduates. The next option is the 6x8cm but it is not good enough for stock photography. The only model available for this is the Fuji GX680. So this will leave you with only one option, which is the 6x7cm.
So now you know why the 6x7cm is considered as the ideal format for stock photography. Due to the rectangular image of the 6x7cm, it is easier and possible to create a dynamic composition, which can be horizontal as well as upright. The image size is also bigger and is five times that of the 35mm. One small limitation if you perceive it as a limitation is that you will get 10 frames only in a 120 film roll. But the good part is that due to the increased image size, you will be able to enlarge without any considerable loss of quality. The other key thing is that the 6x7cm color transparency is very impressive on a light box as compared to the 35mm and 6x4.5cm.
If you are aspiring to be a stock photographer then you need to start with the 6x7cm.