One of the classic questions a photographer faces every day. Vertical or horizontal. A long time ago, in the analogue ages, most pictures would have been shot horizontally. This is how camera were held and it was a most convenient way of taking pictures.
One expeption I can think about, was the Olympus Pen camera, which split the standard 24x36mm format into 18x24mm, reating 72 pictures on a standard roll of film. This resulted in an almost automatic vertical picture taking.
But otherwise, you had to rotate the camera and this sometimes resulted in very ackward positioning, with one arm raised to snap a picture.
All this changed with the mobile phone, in particular smart phone. Due to the way, we tend to hold the phone, many more pictures are taken in a vertical or portrait format.
Now, that is not neccessarily a bad thing, except videos. I personally hate it, if the video takes up only 1/3rd of your computer ot TV screen, because the phone was not rotated.
But the essential question is, what is better, vertical or horizontal?
I think that vertical images give you a better dynamic and subject positioning. The ability to get to the essenence of the subject and to provide a different, or even provocative view of the subject, since vertical differs from the way we see the world.
Horizontal images give us the ability to show the surrounding, the landscape, the panorama. Often one can see horizontal images with the key subject just very small and unfortunately, placed right in the centre of the picture.
What about Portrait photography.
So can I take portraits in a horizontal format? Yes, but position your subject to the side. Let him or her face the centre of the picture, looking into the picture, facing slightly away from the camera. This not only adds a dynamic, but also leads the eye.
But ultimately, for all subjects, it is a matter of taste and creative vision. When I take pictures for audio visual programs, I tend to use horizontal. But if I want an extra dynamic or focus the view, I like to use Portrait.
With the emergence of high and very high resolution cameras, we often can make the final decision on the computer screen. Just take a horizontal picture, mask it to vertical, position the frame and you may find that a picture you would have deleted, suddently has a great appeal. Try it.