Considering macro lenses for smartphones / If you don't have the skill, rely on the equipment! Gadget Lab for watch enthusiasts

"I want to take cool photos of watches, but photographing wristwatches is difficult!" This is a series aimed at watch enthusiasts who are troubled by this problem, introducing useful equipment to help them take photos that look like they're made with as little effort as possible. In the first installment, we'll explore whether it's possible to take impressive close-up photos using a clip-on macro (close-up) lens for smartphones.

A media society of 1 million people?

　Thanks to the development of social media, we have long since entered a society where anyone can easily transmit and share information. In particular, since the 2010s, when smartphones became commonplace, the barrier to posting photos or videos on social media has suddenly dropped. Today, we live in a media-rich society, where it's easy to instantly share what you see and hear with the world using text and photos.

　Living in such a world, there must be many watch enthusiasts who want to take cool photos of their own collections and share their wonders with watch lovers around the world, or who want to be the first to share information about new watches they find at specialty stores or events with photos. However, as webChronos readers know, photographing watches is extremely difficult.

It's difficult because there are many curved surfaces.

　There are many reasons why photographing a watch can be difficult, but the simplest and most important one is that watches are made up of curved surfaces.

　The crystal is particularly bad. Whether it's sapphire crystal, plastic, or mineral glass, if you point the camera straight on, the photographer and the lens will be reflected, and if you're indoors, a lot of fluorescent light will enter.

　The best solution to these problems would be to cover the clock with tracing paper or a simple studio to reduce reflections, turn off the fluorescent lights, and set up lighting specifically for the clock.

　But how many people can afford to do that? It's not realistic to spread the word about makeshift studios at retail stores, event venues, or offline meetups for enthusiasts.

　Even if you had the space and courage to set up a makeshift studio, the lighting is extremely difficult to achieve. You have to move the lights and strobes back and forth, left and right, and make fine adjustments to avoid the dial being too bright or the case being completely black.

　So what should we do at an event venue when we don't have the space to expand our studio, the time to set it up in a relaxed manner, and the right lighting knowledge?To solve this problem, we tried taking detailed photos using a smartphone camera and macro lens.

Smartphones have the advantage in macro photography

　In other words, if various objects are reflected in the crystal or case, give up on taking a cool photo of them and just cut out a part of the dial or movement.The idea is that because the actual area being photographed is small, you can take a "real" photo without having to struggle too much with lighting.

　If you prioritize ease of use, you'll probably want to use a smartphone camera. Of course, some people prefer to take high-quality photos with a single-lens reflex camera or mirrorless camera. However, smartphone cameras are ideal for taking macro shots of watches at events for the following reasons:

- Convenient size for carrying around

First, one of the overwhelming advantages of iPhones over interchangeable-lens cameras like SLRs and mirrorless cameras is their portability. The iPhone series* currently boasts the largest market share in Japan, with the iPhone 8 measuring 138.4mm high x 67.3mm wide x 7.3mm thick and weighing 148g. The largest current model, the iPhone XR, is 150.9mm high x 75.7mm wide x 8.3mm thick and weighs 194g. In comparison (and not even worth comparing), the standard full-frame mirrorless camera, the Sony α7 III, is 95.6mm high x 126.9mm wide x 73.7mm thick. It also weighs an impressive 565g.
(Source: ITmedia Mobile "Domestic mobile phone shipments from October to December 2018: iPhones fall 18.8% to 504.7 million units"https://www.itmedia.co.jp/mobile/articles/1902/19/news125.html）

　To begin with, full-frame cameras, equipped with 36mm-wide image sensors, cannot compete in terms of compactness with mobile phones, which are designed to fit in your pocket. Even the Olympus OM-D E-M10 Mark III, a Micro Four Thirds camera that is considered compact for this type of interchangeable lens camera, measures 83.6mm high and 121.5mm wide, but is only 49.5mm thick, about six times the thickness of an iPhone. Furthermore, the size of the lenses added to the cost of these interchangeable lens cameras is an additional factor.

・Sufficient number of pixels
The pixel count of a smartphone camera is also not to be underestimated. The iPhone 6S, which I use as my main camera, was released in September 2015, making it a model that's four years old. However, its effective pixel count is 3024 x 4032 pixels, or approximately 12 million. At this size, as long as you don't crop it, you can print a photo to fill an A4-sized piece of paper and still get a resolution of 350 dpi. In other words, in terms of image size alone, a photo taken with an iPhone four generations ago can fill an entire page in Chronos magazine.

- Small sensor size
At first glance, it may seem like a weak point, but a small sensor size can also be an advantage when it comes to macro photography. Let's take a look at this with three common image sensor sizes.

Macro lenses, which are essential for close-up photography, are lenses with a maximum magnification of 1x (= 1x). Maximum magnification refers to the magnification at which you can capture a subject when you get as close as possible to the lens's shortest focusing distance. The key here is the size of the image sensor. When you attach a macro lens and take a photo at 1x, you can only capture up to the size of the image sensor. In other words, when you place an object 20mm wide x 10mm high in the center and take a photo at 1x,

- Shooting with a full-size (36 x 24 mm) sensor
The entire image is captured (with 0.8mm margins on the left and right and 0.7mm margins vertically)

- Shooting with Micro Four Thirds (17.3 x 13mm) sensor
The entire vertical portion is captured, but the horizontal portion is cut off (1.35 mm is cut off on the left and right, and there is a 0.15 mm vertical margin).

- Shooting with a 1-inch (13.2 x 8.8 mm) sensor
Can cut both vertically and horizontally (3.4mm each on the left and right, 0.6mm each vertically)

It appears as shown above.

This alone is difficult to understand, so let's take a look at the angle of view when photographing the cover of Chronos Japan issue 83 with each sensor size.

- Full-size sensor

・Micro Four Thirds sensor

・1-inch sensor

The resulting photo looks like this.

In other words, the smaller the sensor size of a camera, the larger the subject will appear when shooting at life size. And even the smallest of the three sensors we've looked at here, the 1-inch sensor, is a relatively large image sensor used in high-end compact digital cameras. Most image sensors used in smartphones are even smaller than these. In fact, clip-on macro lenses for smartphones are not life size lenses, so the image will not be extremely large compared to these sensors, but it shows how well-suited cameras with small sensors are for macro photography.

-A wide range of affordable clip-on lenses for macro photography

And above all, we must not forget this: Macro lenses for interchangeable lens cameras are all expensive. The Nikon AF-S Micro NIKKOR 60mm f/2.8G ED, which I own and consider to be inexpensive among 1:1 macro lenses, has a manufacturer's suggested retail price of ¥8 (excluding tax) and a street price of ¥7500 to ¥7. Even Tamron's SP AF90mm F/2.8 Di MACRO8:6, known as "Tamkyu" for its excellent cost performance, has a manufacturer's suggested retail price of ¥8000 and a street price of around ¥4. While photography may be a hobbyist, acquiring all this equipment just for posting on social media seems like a significant hurdle. However, inexpensive clip-on lenses for smartphones, even those designed for macro photography, can be purchased at 100-yen shops. And that's no surprise. Clip-on lenses are essentially like attaching a magnifying glass to the front of a camera, and are completely different from camera lenses, which are designed with aberrations and resolution in mind. Furthermore, as mentioned above, smartphones have small image sensors, so the lenses you use can be compact, making it perfect for those who want to enjoy macro photography at an exceptionally low price.

So, can we really take photos that look like this under these conditions? Next time, I'd like to try taking some test shots using some smartphone macro lenses.