A macro lens is able to produce beautiful images of close-up with bokehness. This is one application for owning an expensive prime lense.
First of all, what is bokehness, or simply bokeh in photography.
This term is used often in photography for producing visual effect blur in the background.
Generally, it aims to show imagery result that is out-of-focus on the far distant objects, such as landscape, while what is nearest to you is in sharp focus.
Beside creating bokeh by using macro lens, the magnification of subject-matter is also achievable. Usually to as close as life-sized object, such as an insects or flowers.
Others with better capability can produce with a magnification of one-is-to-two. Meaning to say, double the original size in real-life.
Technically, It is the super wide aperture that makes the bokeh and not because of the great magnification capability from prime lens.
Aperture value with f/2.0 or below is consider great lens. Most popular cameras come with wide-angle of aperture f/5.6.
For iPhone 8, it has wide-angle f/1.8 and telephoto of f/2.8 aperture, but there are emulated capabilities by software and not actual mechanical shutter from interchangeable lens.
Comparing to mobile camera, the feature of magnification and bokeh are much of the emulated capabilities than those from the expensive dSLR lens.
Yet, mobile camera still able to produce some similar results.
The zooming feature from the cellphone camera will only enlarge the subject-matter, however, not the blur effect on the background.
The golden rule to achieve this bokeh from mobile camera is to place the subject-matter very near, typically 6 ~ 8 cm away from your focus lens.
Do not zoom when you go near to the subject-matter, that might defeat the purpose for achieving the blurry background.
As for iPhone 7 or 8, the telephoto lens can help to magnify. And again, zoom is not recommended.
A steady hand can obtain good imagery that is sharp and in-focus.
“If the wind will not serve, take to the oars.” – Latin Proverb