It’s a situation many photographers can relate to. For a perfect wide-angle shot, there are two lenses on the shelf, both labeled “14mm.” You might think they operate the same, but Fisheye and Rectilinear Lenses behave differently. As you check the prices and lens shapes, you realize there’s a complex world of optics.

In a recent video on Adorama, David Bergman addresses this exact confusion. He compares two popular Canon lenses: the RF 7-14mm f/2.8-3.5 L Fisheye Zoom and the RF 14mm f/1.4 L VCM Rectilinear Prime. It seems Canon is giving photographers plenty of options for wide shots, but as David explains, these two lenses are quite different.

I believe much of the confusion comes from the focal length. When you see 14mm, you might expect a certain type of image, but it’s how light interacts with the sensor that truly shapes the final photo. David explains why these two lenses offer distinct experiences. Additionally, understanding the fundamental differences between Fisheye and Rectilinear Lenses helps clarify this confusion.

The Secret Sauce of Optical Distortion

Before you spend a lot of money on lenses, it’s important to grasp what David refers to as the “basic difference” in how these lenses represent the 3D world. It’s not just about fitting everything in. It’s about how the lens projects that scene onto your flat sensor.

David notes that the Rectilinear 14mm lens keeps straight lines straight. When photographing a building, the walls should appear as walls, without bending. To achieve this, the lens literally stretches the image at the edges.

On the contrary, David points out that the Fisheye lens focuses more on capturing a wide angle than on keeping lines straight. It allows lines to curve, fitting a lot of visual detail into one shot. This creates a particular style that some people love, while others might not enjoy as much.

Why Perspective Distortion is Actually Your Fault

David offers a useful reminder about photography. There’s a difference between optical distortion (which comes from the lens) and perspective distortion (which is about how you position yourself).

Perspective distortion occurs based on your distance from the subject. It doesn’t matter what lens you’re using. Getting too close will make things look odd. If you want to keep images looking natural when using an ultra-wide lens, he recommends keeping your camera perfectly straight with the subject. It’s an easy tip that can really help you avoid that awkward falling over appearance in your architectural photos. Clearly, Fisheye and Rectilinear Lenses can both affect how perspective distortion is perceived in your shots.

The Field of View Face-Off: 14mm vs. 14mm

You might assume that 14mm is always just 14mm, but that’s not the case.

When you look through a Rectilinear 14mm lens, you might notice a few feet of space beyond the wall on either side of your shot. However, when you switch to a Fisheye lens at 14mm, David says you’ll see about 15 extra feet on each side.

It seems like the fisheye is the ultimate lens for capturing everything. At the 7mm end of a fisheye zoom, you get a 190-degree field of view. David highlights that you can even see a bit behind the camera at that angle. This is incredible for capturing immersive concert scenes or tight spaces where you can’t move back any further.

Can You Just “De-Fish” It Later?

I know what you’re thinking. Why not just purchase a fisheye lens for that wide view and then adjust the curves in Lightroom? It seems like an economical option, but David has his doubts about this approach.

While it’s possible to correct the curved lines in an image, David points out some significant drawbacks. When you use software to straighten those lines, you’re stretching the pixels like chewing gum, which can degrade quality.

He also notes that you might notice more noise, especially at the edges, because stretched pixels become thinner. Even if the lines look straight, objects or people in the corners can appear oddly distorted. I’ve tried this before, and the results often resemble a distorted funhouse mirror. If you’re aiming for a clean, professional wide shot, David recommends starting with a rectilinear lens instead.

High-Tech Cheating: AI and Filters

David had some fun testing out AI. He tried using ChatGPT to fix fisheye distortion in photos. While he thinks it does a pretty good job, he notes that it can lower the resolution and alter people’s faces.

We’re not quite at the point where we have an easy fix. David also mentions the “Spherize” filter in Photoshop, which can transform a standard photo into a fisheye look. It’s a neat trick, but he points out that it’s not the same as the real fisheye effect.

David also advises against using AI corrections for news or editorial work. It’s a tricky ethical issue. If you’re a journalist, it’s best to focus on the actual images rather than relying on AI adjustments.

When Should You Use Which?

So, which lens should you take with you? In short, consider whether you want the look created by Fisheye and Rectilinear Lenses before making your choice.

The Rectilinear Prime: Your safe choice. David recommends it for architecture, interior design, landscapes, and astrophotography. If you need precise lines and want a flat horizon, this one is the best option.

The Fisheye Zoom: This lens is for the creatives and thrill-seekers. David believes it excels at capturing immersive scenes, concerts, and unique styles that draw the viewer’s attention right into the middle of the shot.

I completely agree with David about the 14mm Rectilinear VCM being the best everyday lens. It’s reliable for almost all wide-angle shots, so you won’t have to worry about your client complaining about crooked walls.

Ultimately, David believes the decision should reflect your own taste. If you’re into bold, wide shots, the 7-14mm Fisheye may be perfect for you. However, if you seek reliable, high-quality images for landscapes or real estate, the 14mm Rectilinear is your best bet. As you can see, the two choices, Fisheye and Rectilinear Lenses, offer different creative opportunities.

Canon is really stepping up its game with these L-series lenses. Whether you want an extreme perspective or just a clean, sharp image, you have choices. Just don’t rely on software to fix what your lens should already capture.

[Fisheye vs Rectilinear Lenses – Ask David Bergman I Adorama; Image credits: Envato]

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