Canon RF 18-45mm f/4.5-6.3 IS STM Lens for Underwater Photography Review & Results

Canon's RF 18-45mm f/4.5-6.3 lens is packaged together with their EOS R100, R10, and R7 compact mirrorless camera bodies. What can you really do with a standard kit lens underwater?

John Brigham went diving with it recently in Grand Cayman and as it turns out, this unassuming lens is quite sharp and capable. It's perfectly suited to shooting a wide variety of mid-sized subjects when used behind a dome port. 

All photos in this gallery were taken with the Canon EOS R100 camera, dual DS51 strobes, and TT5 Canon TTL Fiber Optic Transmitter # 44701.

All images © 2024 John Brigham

 

The corners are surprisingly sharp at the lens' widest open aperture. • f/4.5 • Shot at 18mm • 1/125 • ISO 100

 

With a minimum focus distance of 7.87" (0.20m) throughout its zoom range, you can get quite close to your subject... if it lets you. • Shot at 18mm • f/4.5 • 1/125 • ISO 100

 

A mid-range zoom lens is perfect for shooting larger fish like this beautiful French Angel • Shot at 28mm • f/5.0 • 1/125 • ISO 100

 

At wider settings there can be slight curvature around the edges of the frame but the detail is still well defined. • Shot at 21mm • f/7.1 • 1/160 • ISO 100

 

 

The lens' built in image stabilization can cause a tiny amount of clipping at the corners in certain situations. It's corrected in-camera but can be seen if you import images into Lightroom without the camera's corrections applied. In this image, we used Photoshop Content-Aware Fill to remove it in post production instead. • Shot at 18mm • f/6.3 • 1/125 • ISO 100

 

A super wide angle lens is generally preferred on wrecks but with the right vantage point a mid-range zoom can hold its own. • Shot at 21mm • f/4.5 • 1/160 • ISO 100

 

 

It's not the brightest lens in our bag, but still capable of pulling of shots in very low-light environments. • Shot at 21mm • f/4.5 • 1/160 • ISO 250

 

Canon's eye detection AF works well on fish and makes it easier than ever to come home with a winning shot. • Shot at 18mm • f/8 • 1/125 • ISO 100

 

The kit lens is a great all-around reef lens when you don't want to commit to a "macro dive" or a "wide angle dive." • Shot at 27mm • f/8 • 1/125 • ISO 100

 

Even on a crop sensor an 18mm lens can easily capture large animals like this resting nurse shark, so long as you're shooting it behind a dome port. • Shot at 18mm • f/5.6 • 1/100 • ISO 100

 

A good set of strobes is essential to bringing out color and clarity when shooting with any lens underwater. • 32mm • f/5.6 • 1/125 • ISO 100

 

There's relatively little distortion of the straight lines in the wheelhouse of the Doc Poulson wreck even though they're pushing the edges of the frame. • Shot at 18mm • f/4.5 • 1/125 • ISO 100

 

Our good friend and Ambassador Gary Burns, wondering if he should consider one of Canon's new compact mirrorless cameras. • Shot at 21mm • f/8 • 1/160 • ISO 100

 

John swimming past the Kittiwake with the Canon EOS R100 underwater housing and dual DS51 strobes. Taken with Sony a7C II © Jean Rydberg

 

 

Additional Reading

The Best Canon RF-Mount Lenses for DLM Underwater Housings

Canon RF 85mm f/2 Macro Underwater Review and Tips [VIDEO]

Canon Mirrorless Lineup Explained for Underwater [VIDEO]

Custom White Balance for Underwater with Canon Mirrorless Cameras [VIDEO]

The Most AFFORDABLE Pro Quality Underwater System // Canon EOS R100 Housing [VIDEO]

Canon R100 Underwater Photos & Video // California & Grand Cayman [VIDEO]

Canon EOS R100 Underwater Photos

Canon EOS R10 Underwater in La Paz Mexico / Bahamas / Florida [VIDEO]

 

 

John Brigham is the Vice President & head of product development at Ikelite. He was born with a flair for design and an entrepreneurial spirit as son of Ikelite founder Ike Brigham. He worked his way up in the business and is a natural fit in the R&D side of things. John dives the equipment as much as possible to test product and put himself in the "fins" of the user. You may also find him on the other end of an email or phone call when you reach out for product advice and support. When he's not underwater he's flying drones, setting off rockets, training his German Shepherd "T2", and spending time with his family.