> 3 minute read

Why Maximum Apertures Matter

Along with focal length, maximum aperture is one of the most important characteristics of any optic and can help you select the right X Series lens to purchase. Here’s why.

When you look at the name of a lens in the X Series, there are a few numbers to note. You probably already recognise the focal length, measured in mm, which gives an indication of the angle of view the lens makes images in, but there is a second number in there, too, prefixed by an ‘F’. Like this: XF35mmF2 R WR

This F number is the largest (or ‘maximum’) aperture that the lens can open up to – the smaller the number, the larger the size. Obviously, you can select other apertures using the lens’s aperture control ring, but this largest aperture is beneficial for a number of reasons.

The first is that it lets in lots more light, which means your camera will be able to use a faster shutter speed in low light. This is why lenses with a large maximum aperture are sometimes referred to as ‘fast aperture’ lenses – because of the fast shutter speeds they let photographers use. When your largest aperture is F2 or F1.4, then you can use shutter speeds that are about three stops faster than you’d get with an XC15-45mmF3.5-5.6 OIS PZ standard zoom. In other words, a blurry 1/15 sec becomes a very useable 1/125 sec.

It’s All a Blur…

The other advantage of a wide aperture lens is the shallow depth-of-field it lets you create. If you’re into landscape or architecture photography, this probably doesn’t matter too much, but if you make portraits or documentary images, then the ability to emphasise a subject by placing it against a blurry background is a massive bonus.

Some lenses in the X Series were created with portrait photographers in mind, such as our XF50mmF1.0 R WR, which uses a massive F1.0 aperture to create silky smooth out-of-focus areas behind a pin-sharp subject in the foreground. You can get similar but less pronounced effects in a more portable package from the XF50mmF2 R WR.

For many zoom lenses, the maximum aperture is not a single figure, but a range of values that matches the lens’s range of focal lengths. For example: XF55-200mmF3.5-4.8 R LM OIS

Here, the maximum aperture is F3.5 when the lens is at its 55mm setting, but F4.8 when zoomed to 200mm. Not all zoom lenses are like this; some have a constant maximum aperture right the way through their zoom range, such as the XF16-55mmF2.8 R LM WR.

Your Next Steps

• CHALLENGE Explore the fastest aperture of the lenses you already own, then visit your local FUJIFILM dealer to try out something else in the X Series range. What are the differences you notice in the pictures you can shoot? Post your findings to social media with the hashtags #learnwithfujifilm and #fastaperture. You can also submit your work here for a chance to be featured on our social media channels.
• WATCH Check out our video below to learn more about Aperture.