Why super wide aperture lenses are important  even if your camera is exceptional at handling ISO.

In this day and age with modern cameras, it is so easy to just forget about your ISO and go out and shoot with slower lenses, but when you are shooting weddings, events, portraits, or even just capturing everyday people and places around you, a super wide aperture lens between F/1.2 and F/2 is extremely important in your photography for a number of reasons. Let us take a deep dive…

Even with excellent ISO performance, a super-wide aperture remains crucial for several reasons in making your photography and photographs look well presented and professional.

Firstly, Shallow Depth of Field (DoF) and Subject Isolation: This is perhaps the most significant advantage. A wider aperture (smaller f-number like f/1.4 or f/1.8) creates a much shallower depth of field, blurring the background and foreground significantly. This beautifully isolates your subject, making them pop out from the scene. While good ISO allows for cleaner images in low light, it doesn’t give you this artistic control over focus and blur. You can’t replicate a creamy, out-of-focus background (bokeh) with a narrower aperture, no matter how clean your high-ISO images are.

Secondly we have Low Light Performance (Beyond ISO): While high ISO helps capture more light by amplifying the sensor’s signal, a wide aperture physically lets in more light. This means your sensor receives a stronger signal to begin with. This leads to:

• Lower Noise at Lower ISOs: You might be able to shoot at ISO 400 with a wide aperture where you’d need ISO 3200 with a narrower one. Even if your camera’s ISO 3200 is good, ISO 400 (or your second base ISO which is often ISO800) will almost always be cleaner.

• Faster Shutter Speeds: In low light, a wider aperture allows you to use faster shutter speeds to prevent motion blur (from your subject moving or camera shake). This is especially critical for handheld shooting or capturing fast-moving subjects. While high ISO can also enable faster shutter speeds, it comes with the noise trade-off.

Thirdly, you will have More Accurate Autofocus in Low Light: Autofocus systems often rely on light information. A wider aperture provides more light to the autofocus sensor, leading to faster and more accurate focusing in challenging low-light conditions.

 Forth in the list we have Creative Control and Artistic Expression:

• Dreamy Aesthetics: The unique bokeh produced by wide apertures can create a dreamy, ethereal, or cinematic look that is highly sought after in portraiture, event photography, and even some landscape work (to isolate a specific element).

• Separation and Storytelling: By selectively blurring elements, you can guide the viewer’s eye to exactly what you want them to focus on, enhancing the narrative of your image.

Fifth, and by no means last, Optical Quality: While not universally true, many prime lenses with very wide apertures are designed with superior optics, leading to better sharpness, contrast, and reduced aberrations compared to slower (narrower aperture) lenses, even at comparable focal lengths. This isn’t directly related to light gathering, but it’s often a side benefit of investing in wide-aperture lenses.

In essence, while great ISO performance helps you see in the dark, a super-wide aperture helps you sculpt the light and focus, offering creative possibilities and technical advantages that ISO alone cannot provide. It’s about more than just brightness; it’s about control, aesthetics, and achieving a distinct visual style.

And talking of “visual style”, it is this that separates the amateur looking images (often these photos are taken with kit-lenses at F/3.5 or so and lack that F/1.8 “look”, or taken on mobile phones that you can clearly see are processed to look like they have bokeh) compared to the professional looking images.

So, if you have to make just one investment in improving your photography “look” if you photograph any of the things mentioned, treat yourself to a wide aperture prime lens and you will instantly see a difference. Even on smaller sensors such as APS-C and Micro Four Thirds, it can make a difference (and remember, your light gathering capabilities do not change, no matter what sensor you use. An F/1.8 lens gathers the same light on a small sensor that it does on a larger sensor).

Most importantly, have fun with your photography.