The F16 ruler can also save your photos with your mobile: that’s how it works

Throughout the history of photography, we have worked with a ruler to obtain the best shot from a technical point of view: that of the F 16. In mobile photography, we tried to adapt it with the help of reciprocity law. The only thing is that we will be very limited.

In current photography, the author has less and less to say in the technical part. Today, Kodak’s motto “You shoot, we do the rest” holds true. The photographer must choose two fundamental aspects: the subject and the framing. But we can almost forget the technique with mobile phones.

The computational photography and the various advances make it possible to forget the most technical part of photography. But those of us who enjoy doing things for ourselves still have a chance to fully feel like authors.

What matters is the end result, without a doubt, and we will never underestimate a photograph for the steps that have been taken to achieve it. It only matters that the image is good and communicates what the author intended. We are going to look for a technique that allows us to get the most out of our mobile camera.

The famous f16 rule

This rule has been essential for many photographers over time. If we didn’t want to depend on automation, there was no choice but to learn it in order to have complete technical mastery of it. It’s very simple and perfect for our mirrorless cameras.

The f16 rule comes from the time of the reel. And it is the perfect technique to know what shutter time to set depending on the ISO sensitivity and the light we have at the time of shooting. When you get the hang of it, you can stare at the sun and be a veteran when it comes to setting exposure.

It is very simple. It’s all based on how much light there is at that time. And according to your needs, you choose certain values ​​or others. The base is as follows:

On a totally sunny day, you get the perfect exposure if you shoot at f16 with the inverse of the sensitivity as the shutter time. That is to say that you put an f16 diaphragm, and if you have 100 ISO the shutter time will be 1/100. It’s not a mathematical rulebut it works quite accurately.

Even better, you can, thanks to the exposure triangle, adjust for each type of light. If a cloud is covering the sun, you can open the aperture a notch (from f16 to f11) or slow down to 1/50… We have all sorts of combinations depending on what we need. The only important thing is to memorize the rule to know how to act.

In the table you can see how if we modify a parameter of the exposure triangle, we can leave it fixed depending on what we want to achieve, more speed or more depth of field. It’s so simple. You just need to memorize the ruler to get the photo you want.

The f16 rule in mobile photography

Some nostalgic people may want to do the same with their mobile phone. And when you try to put it into practice, you’ll find that phones don’t have a diaphragm. Its lenses have a single diaphragm, the brightest possible, to compensate for the small size of the sensors.

It all depends on shutter time and sensitivity. Computational photography does not let us act and always decides for us. But if we work with Manual mode that some applications allow us, we have the possibility to test the rule f16 with it.

The f16 rule with the iPhone 13

To put it into practice, we just have to see the diaphragm of our mobile and make the relevant calculations to see what is the perfect exposure with the nominal ISO. For the example, I’m going to use the angled lens of my iPhone 13the 26mm f1.6.

This phone has a Rated ISO of ISO 40. We don’t have whole steps, so the f16 rule calculation will be approximate. And it will have to be adjusted by the classic trial and error. Let’s start.

A photo on a summer day, with this mobile, this would be done with an exposure of f16, ISO 40 and 1/40. The problem is that it can’t close that much, so you have to open and adjust the time according to the reciprocity law. The ISO is not modified:

f16 1/40>f11 1/80>f8 1/160>f5.6 1/320>f4 1/640>f2.8 1/1280>f2 1/2560>f1.4 1/5120

To complete the calculation, to obtain a perfect exposure with our mobile, we must photograph, in broad daylight, with an ISO 40 and a diaphragm f1.6, with a time of 1/5000. We need to memorize this information.

Thus, if we have less light, we only have to raise the ISO a notch, to 80 ISO for example. But to make it clearer, I’m going to put a table.

Computational photography does this job for us. And you will surely do much better and get superior results. But staying in control from start to finish and knowing we’re on the right track is priceless. We know photography is important, but everything changes depending on the path we take.