In general, photographers agree on the common idea that the rule of thirds is an essential part of photocomposition.
Well, it is, however, almost. In fact, this rule is wrong.
So let me limit the scope of this article to landscape orientation, rather than portrait orientation.
The idea is initially based on the “Golden Rule Of Proportions”, and the original formula is
x : y = y : ( x + y )
In numeric values, that translates like
5 : 8 = 8 : ( 5 + 8 )
5 : 8 = 8 : 13
Now, 5 is NOT one-third of 13!
And 5 is NOT two-third of 8!
In other words, you should take a landscape grid like
13 divisions horizontal
8 divisions vertical
The following image illustrates the Golden Proportions grid:
The grid is exactly 8 : 13. The 4 Golden Spots that you see are the exact locations.
You may notice that there seems to be an offset of one division. It’s done on purpose as to allow counting the coordinates from any border direction to inside while preserving the overall perspective.
Aim your camera to this image to fill the entire viewfinder and in focus, and illuminate the autofocus dots (if you have this feature in your camera). Then see where the 4 Golden Spots are, relative to the autofocus dots. Remember the positions and then use your autofocus dots as a reference.
Those dots extend a bit with a black halo to show some slight slack but not too much. The white O center of them is the exact reference position.
Then the Golden Spots are at, from left to right and from bottom to top
horizontal 5 vertical 5 – i.e. near up-left
horizontal 8 vertical 5 – i.e. near up-right
horizontal 5 vertical 3 – i.e. near down-left
horizontal 8 vertical 3 – i.e. near down-right
As for the deviations, compare this with the commonly accepted one/third rule spots, marked with a black O
The horizontal deviation means that the one-third spots are too much outward relative to the original reference positions.
The vertical deviation is somewhat smaller, but still your target should be slightly more towards the equator in the viewfinder, which is a bit more than the one-third rule would suggest.
Camera manufacturers make the big mistake NOT to take into account the golden spot grid in their viewfinder or focus point matrix layouts.
And the biggest mistake is that the height width ratio is not 5 : 8 or 8 : 13 but 3 : 4 or 9 : 16 which is not even compliant with the rule of third.
Whoever masterminds camera design, screen design, well, any design, please go call Leonardo Da Vinci! If we love so much the golden rule or the golden proportions, then why do we not apply that rule in our technology?
The ideal viewfinder grid is 13 divisions wide and 8 same size divisons high, directly derived from the original proportions formula:
x : y = y : ( x + y )
If you have a removable viewfinder screen, you could put the Golden Spots on it with a marker or carefully engrave with a needle. In the viewfinder then you will see these 4 Golden Spots continuously.