I find this way of describing the iPhone cameras frustratingly misleading. It's not the author's fault; Apple does it in their official specs.
The "26mm" rating is "equivalent", meaning "this looks like a 26mm lens on a 35mm film camera". It basically tells you the FOV angle.
The "f/1.5" rating is not equivalent. It's very dishonest to mix and match equivalent and non-equivalent specs, because it makes the lens sound a lot better than it is to non-expert readers. If they were being honest, the equivalent aperture would be a lot smaller, like f/16 or something.
Every other camera mfg I am aware of will consistently use equivalent or non-equivalent for all specs, and make it clear which they are using.
For example, most mirrorless camera lenses are spec'd non-equivalently, meaning that a "26mm f/1.5" means "if you put this lens on a 35mm camera and extrapolated the output to cover the whole sensor, that's what you would get". To understand what it will look like on a different sensor, you multiply 26 and 1.5 by the crop factor.
In Apple's case, it's actually impossible to tell what the image will look like from the specs without looking up the crop factor, which of course they don't advertise front and center like they do this misleading tuple of specs.
In general, lenses with smaller f/N aperture values tend to be better and more expensive (because they have a larger aperture, let in more light, narrower depth of field), so if you don't mind misleading customers, you just pick the smallest denominator you can get away with.