One Dive, One Lens // Canon RF-S 18-150mm Lens Review for Underwater [VIDEO]

Featuring Jean Rydberg
Images © Matt Dowse

The Canon RF-S 18-150mm proves that sometimes the most unassuming lenses can deliver the most versatile performance. For Canon crop sensor shooters, it offers a huge range of subjects in a single compact package. It's practical, versatile, and ready to handle almost anything you encounter underwater.

Watch the video below, or scroll down to read the video transcript. 

 

We're taking a closer look at the Canon RF-S 18-150 millimeter IS STM lens for shooting underwater. Now initially, I wouldn't have picked this as an underwater lens because of its really long zoom range, but I was blown away by the images that Matt Dowse came back with. So let's dive into it.

 

The sweet spot for sharpness on this lens underwater seems to be between 50-90mm. Canon R7 + RF-S 18-150mm F3.5-6.3 IS STM lens at 59mm • 1/80 • f/11 • ISO 100 © Matt Dowse

 

Streamlined Setup

As an RF-S lens, it's designed for Canon's crop sensor cameras, like our favorites, the R7, the R10, the R100. When you attach it to the camera, you can backload it into the housing with a dome port attached. This makes a really streamlined setup and you don't have to put anything on or off underwater. Compared to one of these systems where you're trying to attach a heavy wide angle wet lens to the front of your housing underwater, I find this system will be much more compact, lightweight, easier to pack, easier to travel with, and more comfortable to handle underwater. It's perfect for the beginner photographer who wants something that's really easy to work with.

 

Zoom Range

With this extended zoom range, 18-150mm, you can move from capturing a reefscapes to looking for small details all on the same dive. And this lens really shines in that macro range, which is also the easiest place to start for beginner underwater photographers.

I find 18mm plenty wide to shoot landscapes and the larger reef life, like turtles, sharks, schooling fish, and all of those beautiful larger things that you're going to encounter underwater.

 

The 18-150mm allows for creative freedom underwater. Go from wide shots like this turtle to macro shots of nudibranch all on the same dive. Canon R7 + RF-S 18-150mm F3.5-6.3 IS STM lens at 44mm • 1/125 • f/13 • ISO 320 © Matt Dowse

 

Autofocus

Underwater autofocus performance can really make or break a lens, but the 18-150mm is quick and reliable. It's responsive to sudden changes with the newer Canon autofocus engines I find that it really can do really good subject tracking.

The sweet spot for sharpness seems to be between the 50-90mm range. That's where you find the ideal mix of the working distance, the crop detail, pleasing background separation. And when you're tracking a moving subject or fish, it holds its own.

 

+4 Diopter

So let's talk about the need to add a +4 diopter to this lens to shoot it behind a dome port underwater, and that relates to the close focusing distance of this lens. It's only 7 inches (17 cm) at the wide end, but at 150 millimeters it jumps up to 18 inches (45 cm). You'll need to add the +4 diopter to the front of the lens and that will shorten your minimum focus distance. 

You won't see any effect of this underwater, in fact it might even sharpen your corners a little bit. But you will lose the ability to focus at infinity on the surface, so you can't use this lens to shoot split shots where you're half in half out of the water.  If you're really set on shooting those type of pictures, you're going to want to choose something like Canon's 10-18mm or the 15-30mm. For all other types of photos, you won't notice the difference. The +4 diopter is easy to put on the front and it'll work perfectly underwater.

 

This lens shines particularly at the macro level. Canon R7 + RF-S 18-150mm F3.5-6.3 IS STM lens at 62mm • 1/80 • f/11 • ISO 100 © Matt Dowse

 

Edge Sharpness Troubleshooting

With any lens, the edges of your image can go soft at wider focal lengths underwater, and the 18-150 is not immune to this, but the fix is simple. Stop down to F/8 or smaller to bring that edge to edge sharpness back. Smaller apertures also help to increase your depth of field for macro images.

 

Conclusion

The Canon RF-S 18-150 millimeter proves that sometimes the most unassuming lenses can deliver the most versatile performance. For Canon crop sensor shooters, it offers a huge range of subjects in a single compact package. It's practical, versatile, and ready to handle almost anything you encounter underwater. If you have any questions about this lens, shoot us an email to ikelite@ikelite.com. Thanks for reading and happy shooting.

 

Additional Viewing

Why Your Lens May Need a +4 Diopter Underwater

Canon RF-S 18-150mm f/3.5-6.3 IS STM Lens Micro-Review & Results

Featured Customers | Matt Dowse From the Canon 7D to the Canon R7

The Best Canon RF-Mount Lenses for DLM Underwater Housings

Canon R10 vs R7 // Best Crop Sensor for Underwater Photography [VIDEO]

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

 

Jean Rydberg is the President & CEO of Ikelite. She has lived her whole life in landlocked Indianapolis, Indiana, but is no stranger to the water as a daughter of Ikelite’s founder Ike Brigham. She has traveled around the world shooting and testing gear and enjoys new challenges in both photography and diving. Jean loves to learn about the creative ways photographers achieve their visions. More than anything she wants to show aspiring underwater photographers that excellence is attainable with any system. When she's not working she's spending time with her husband and two daughters.

 

 

Matt Dowse is an electrician, diver, and underwater photographer. He has been diving since 1990 and completed his PADI Divemater's course in 2008. He's been a Canon DSLR 7D shooter since 2010 and recently upgrade to the Canon R7 mirrorless system which he pairs with the Ikelite DS160 dual strobes. When he's not traveling to dive you can find him at the Swansea Bridge. Follow Matt on Instagram @matt.d71, watch Matt and his colleague Pete's underwater videos on their YouTube channel, Vimeo, or check out Matt's Redbubble page.