Working with aspect ratio
Having used a variety of cameras with different sensor sizes I have come to realise how much aspect ratio plays a vital role in both composition and post-processing. Like most people I started out with a digital camera based on a 35mm sensor with a ratio of 2:3. As I dabbled in black and white film I also bought a Bronica SQ-A medium format film camera, which produced a rather pleasing square image (1:1). This thought of aspect ratio stayed in my mind when I upgraded my digital gear to the medium format Pentax 645Z, which had a ratio of 3:4.
There is no right or wrong aspect ratio to use, but it is important to understand how to apply aspect ratio when composing and cropping our work. The following unedited image was originally shot on my Pentax 645Z in portrait. I chose portrait because I was interested in the river leading from the bottom of the screen up to the mountain in the distance. If I shot it in landscape, I would have had too much of the black landscape on either side, which was just dead space.
It is a nice enough image with a ratio of 3:4, but I feel the foreground plays too much of a role, dragging the eye away from the central part of the image. This becomes even worse if the original image was 2:3.
If I draw a line across the middle you can see that the foreground actually takes up almost half of the image, dwarfing the detail in the bend in the river and the mountain in the distance, which I feel should play a much bigger role in the final image. With the longer shape of 2:3 and 3:4 I also feel that the eye isn't able to take the whole image in, and has to look up and down between the different areas of the image.
Raising or lowering the camera at the time of composition wouldn't really have fixed this problem, it either would have exacerbated the problem of the foreground, or added in far too much sky.
So choosing to crop the image with a different aspect ratio would be the best approach. Moving away from the letterbox shape of 2:3 and 3:4 we begin to see bit of a difference. At 4:5 the bend in the river is becoming more pronounced.
I thought I would try cropping this to 6:7 as well, this is the ratio of some medium format cameras such as the Mamiya RB67.
I quite like the 6x7 crop, By this stage the whole image can be taken in by the eye, rather than the eye having to look around the image. The foreground, bend in the river and mountain in the distance all start to balance nicely.
And finally, square.
Overall, both 6x7 and 1:1 seem to work. Although for my final edit I went with 1:1, and cropped it slightly tighter to remove the rock in the bottom left hand corner. This brought the bend in the river into the centre of the image, it was an area of the photo that I thought needed to be given full attention. In my final edit you'll see that I darkened down the river in the foreground to help with this.
But I'm glad I tried 6x7, it's a ratio I've never used before as it's not that common and it seems very pleasing. Maybe sometime in the future I'll get a 6x7 camera!
So by looking at the different crops hopefully you can see how the ratio of an image affects the overall composition, and don't always assume that using the full image captured by your camera is necessary.