Hello there. In this comparison, we will be evaluating two RF lenses – the Canon RF 15-35mm f2.8 L IS USM, which is expensive, and the Canon RF 50mm f1.8 STM, which is far more affordable.

If you’re considering investing in either of these lenses, this review will provide you with an insight into their strengths and weaknesses, helping you make an informed decision.

Aperture & Focal Length

Let’s delve into the subject of aperture and focal length. The Canon RF 15-35mm lens has a maximum aperture of f2.8, whereas the Canon RF 50mm lens has a wider aperture of f1.8. Instinctively, it might feel like the larger number is better, but in the case of apertures, the opposite is true. In this comparison, the RF 50mm lens has the advantage.

The wider f1.8 aperture enables the lens to take in more light, making it a great option for taking clear shots in dimly lit settings.

It’s important to note that a lower f-number indicates a wider aperture, allowing for more light to enter the lens.

The numbers in millimetres refer to the focal length of the lens. The 15-35mm in the Canon RF 15-35mm lens represents its focal range, meaning it can zoom from 15mm to 35mm.

In contrast, the 50mm in the Canon RF 50mm lens signifies a fixed focal length, which means that the magnification of the lens is constant and cannot be adjusted.

Why Prime?

In terms of image quality, prime lenses such as the Canon RF 50mm tend to produce sharper images. Conversely, zoom lenses like the Canon RF 15-35mm offer versatility and convenience with their zoom capabilities.

Zoom lenses provide greater versatility with the ability to adjust the focal length. Different focal lengths, such as 15mm, 35mm, 50mm, and so on, result in distinct images due to their different levels of distortion.

It’s also worth mentioning that the 50mm lens provides a more focused, zoomed-in view than the 15-35mm lens. This means that the 15-35mm lens can capture more in the frame, when compared to a photo taken with the 50mm lens from the same location.

We’ll discuss a bit later in the review what each lens is specifically good at, but up next, how portable are these lenses?

Size & Build

The Canon RF 15-35mm lens measures approximately 126.8mm, or 4.99 inches in length, 88.5mm, or 3.48 inches in diameter, and weighs around 840g, or 1.85 pounds. On the other hand, the RF 50mm lens measures approximately 69.2 x 40.5mm, or 2.72 x 1.59″, and weighs around 160g, or 5.64oz.

Given these measurements, it can be seen that the RF 15-35mm lens is more substantial. What about their build quality?

The RF 15-35mm lens has remarkable build quality. It stands as one of the finest lenses I’ve ever held, which is not surprising given its hefty price tag.

In comparison, the significantly more affordable RF 50mm lens does not quite match up in terms of build quality. Despite being an improvement over the EF 50mm f1.8, it falls short compared to the RF 15-35mm lens.

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Image Quality

Alright, now that we’ve covered the ease of use and versatility of these lenses, let’s dive deeper into their imaging capabilities.

Minimum Focusing Distance

To start with, we’ll take a closer look at the minimum focusing distance, which may be confusing for photography beginners.

In simple terms, the minimum focusing distance is important. It refers to the closest distance for lens focus. For example, consider taking a close-up picture of a flower. As you move closer, the camera might stop focusing. This is because the lens can’t focus on subjects too close.

In other words, a lens with a shorter minimum focusing distance allows you to get closer to your subject while still maintaining sharp focus.

The reason for this is that a lens, much like the human eye, must maintain a minimum specific distance from the subject to achieve focus.

For instance, the Canon RF 15-35mm lens has a minimum focusing distance of approximately 11.02″ (28cm), whereas the Canon RF 50mm f/1.8 lens requires a minimum distance of approximately 11.81″ (30cm).

I understand that the concept of minimum focusing distance can be confusing for those new to photography, so I wanted to clarify it to prevent any confusion. That said, let’s discuss sharpness now.

Sharpness

Typically, budget lenses tend to have inconsistent sharpness, with the centre being sharper than the edges. However, most subjects are usually positioned in the centre of the frame, so this is usually not a major concern.

It’s worth mentioning that the difference in sharpness between the centre and edges only becomes noticeable when significantly magnifying the image.

So the much more expensive RF 15-35mm lens doesn’t show this issue. Its photos are fairly sharp throughout. On the other hand, in the case of the RF 50mm f/1.8 lens, the edges of the frame can be less sharp at wider apertures.

Vignetting

Next, let’s discuss vignetting. This is when the corners of an image appear slightly darker than the centre. While technically considered a flaw, some photographers actually prefer the vignetting effect in their photos, especially for portraits.

The darkened corners can draw the viewer’s attention to the brighter centre, where the subject’s face is typically located. It also adds a three-dimensional look to the image, lending it more depth.

Now, both of these lenses exhibit some vignetting, but if you decide you don’t want it in your photos, you can quite easily correct it in post-production.

Chromatic Aberration

Right, so how about chromatic aberration? When taking photos in low light, if you zoom in on straight edges, you might be able to sometimes spot some colour fringing. It almost looks like some of the colours are bleeding around those edges.

In the case of these lenses, the RF 15-35mm lens can exhibit a tiny bit, while the RF 50mm lens can exhibit somewhat more.

I wouldn’t specifically say that this is an issue, as only photographers tend to spot these optical flaws with photos. A regular person, when looking at chromatic aberration, wouldn’t really recognise it for what it is.

Image Stabilisation

Ok, what about IS, or image stabilisation? Does either of these lenses have it?

The RF 50mm lens does not, but the 15-35mm lens does. Sure, most cameras now have Digital IS, but turning it on is not usually recommended, as whatever the camera does to the footage, it’s final. You don’t get two versions of the footage, just the digitally stabilised one.

You’re always better off just recording something shaky, and then trying to straighten it out in Premiere, or whichever software you use.

In the case of the 15-35mm lens, its IS is optical, so it naturally produces more steady footage, and also sharper images, making them less prone to motion blur when taking photos in low light conditions.

There is, however, an issue with the 15-35’s image stabilisation. When zoomed all the way out, at 15mm, the image stabilisation system will produce noticeable wobbling in the corners of the image.

This is easily fixable by zooming the lens in a bit, to 20mm. That makes it so that the wobbling is no longer visible.

Autofocus

Right, so what about autofocus?

So, the RF 50mm lens has STM in the name, while the RF 15-35mm lens has USM. This will provide us with some clues.

Generally speaking, STM motors can be found on more budget lenses, while USM motors are usually present in higher-end lenses.

The benefit of STM is that it’s more affordable, it focuses fast, and it’s relatively quiet. When comparing the two lenses, both focus very well, and are very quiet.

Compatibility

Ok, so which cameras can I mount these lenses on?

The Canon RF mount lenses are specifically designed for Canon’s new line of mirrorless cameras, such as the Canon R, R5, R6, etc.

If you have an RF mount camera, these lenses will be a great match for you. It’s always good to check the compatibility of the lens and camera before making a purchase.

Vlogging

Right, so what if you want to do some vlogging? Is either of these lenses useful for that?

One is, and one isn’t, and this is for two reasons. First off, the RF 50mm lens is not only zoomed in but also lacks IS.

As a result, if you attempted to do handheld vlogging with it, even if using a Gorillapod, you’ll find that you might be uncomfortably zoomed in. Additionally, due to the lack of IS, the footage will be rather shaky.

On the other hand, the RF 15-35mm lens is not only much wider, but it also has built-in image stabilisation, which would provide you with very stable footage.

YouTubers

Ok, what if you want to just place the camera on a tripod, and film?

If you film while seated and mount your camera securely on a tripod, then the 15-35mm lens’s IS advantage disappears.

In fact, if you are going to film on a tripod, I’d probably just go with the RF 50mm f/1.8.

The lens can open wider, and thus produce nicer Bokeh. It’ll also allow you to film in low-light conditions. Alternatively, you could still use the 15-35mm lens, as it will fit more in frame, but it will have less Bokeh.

Applications

So, what are these lenses actually designed for?

Portrait Photography

When it comes to portrait photography, the 50mm lens is the clear winner. Both lenses can be used for portraits, but the 50mm is better suited for this purpose.

Street Photography

If you’re interested in street photography, both lenses can be used for this type of work as well. However, be aware that the large size and professional look of these lenses can attract a lot of attention, especially when paired with a camera like the Canon R5.

If you plan on taking either of these lenses outside for street photography, it’s advisable to not do so alone, as you may attract unwanted attention.

Product Photography

Ok, what if I want to do product photography?

For product photography and videography, the RF 15-35mm lens is the recommended choice. I currently use this lens for most of my B-roll, including the footage of the RF 50mm f/1.8 lens.

Landscape Photography

For landscape photography, you can use either lens, but starting with a wider lens, like the RF 15-35mm, might be better.

Fashion Photography

For fashion photography, the 50mm lens is the preferred choice. However, if you also want to include handheld videos, the 15-35mm lens would be a good balance between still photography and videography.

However, if you’re using the RF 50mm lens with the Canon R5, you can actually get some very stable footage, especially if you’re going to slow the footage down.

Documentary

For documentary-style shooting, the 15-35mm lens is the better choice. The image stabilizationization provides smooth footage and the ability to zoom in and out slightly makes it more versatile.

Sports or Wildlife Photography

For capturing sports or wildlife, neither lens is ideal as they both have limited zoom capabilities. The 50mm lens might be a better choice, but a lens specifically designed for these types of photography would be more suitable.

Wedding Photography

For event or wedding photography, either lens can be used depending on the desired shot. If you’re looking to capture larger groups, the RF 15-35mm lens with its ultra-wide field of view is the better option. For more focused, detailed shots, the RF 50mm lens with its zoomed-in perspective would be ideal, without the need to get too close to the subject.

General Photography

If you want something that is versatile though, the RF 15-35mm lens is the better choice of the two. It’s my primary lens, and it’s always attached to my Canon R5.

Control

Ok, so how easy are they to use?

Both lenses have a premium feel and are easy to use. They both have manual focus rings with smooth operation and the RF 15-35mm also has a zoom ring. Additionally, the RF 15-35mm lens has a programmable ring that can be set to various functions such as adjusting ISO.

Although the programmable ring is a convenient feature, I personally avoid using it because I’m worried about accidentally altering my settings while shooting. However, having the option is still a nice touch.

Longevity

Right, so how long can I expect them to last? Both lenses have metal mounts, which bodes well for their lifespan. In terms of weather sealing, the RF 15-35mm lens is protected from dust and splashes, but the RF 50mm lens isn’t.

I always attach a UV filter as an extra protective layer to my new lenses. Both my lenses have a Sigma ceramic UV filter that remains on at all times, and I attach it immediately after purchasing the lens. The filter may be costly, approximately 10% of the cost of my 15-35mm lens, but I consider it a valuable investment.

Attaching a UV filter to the lens negates the requirement for lens caps, although one may still use them if preferred.

To mount a filter on either of these lenses, it is important to know the filter size, which is 82mm for the RF 15-35mm lens, and 43mm for the RF 50mm lens. Note that this is distinct from the lenses’ focal lengths, and must be considered while purchasing filters.

Conclusion

In conclusion, which one should you buy?

Making a decision can be challenging, so let’s simplify it by determining the camera you currently have or plan to purchase.

If you choose the R5, which has built-in image stabilization, the absence of IS on the RF 50mm lens becomes less significant, as the camera IBIs will partially compensate for the lens’s lack thereof.

So, what do you intend to do with the lenses? Primarily portraits? If so, go for the RF 50mm lens, as it’s a lot better for portraiture. However, if you need versatility and want to shoot video too, consider the RF 15-35mm lens.

Recommendations

I hope this has been helpful. I invite you to have a look at some of my other articles. We have something for everyone, whether you’re interested in audio, or cameras and lenses. Alternatively, if you prefer video reviews, feel free to have a look at my YouTube channel.

Finally, down below you will find all of the items I talked about in this article.