CANON RF 15-35MM F2.8 L IS USM – LENS REVIEW

I have been waiting so long to write this review. As primarily a Canon user, early adopter of the Canon EOS R/RF system and slightly obsessed Nightscape photographer I have had my eye on the Canon RF 15-35mm f2.8 L IS USM since it’s release and have been itching to review it for Nightscape Photography.

There are plenty of reviews of this lens out there, in this review we will focus purely on it’s performance and suitability for capturing the stars.

Before we get into it I would like to say a big THANK YOU to Canon Australia for sending the lens to me for a few weeks so I could capture some images and and write this review. No I am not sponsored by Canon in anyway, but the lens was supplied by Canon Australia for the review.

So lets start with a quick look at the lens, it’s features and specifications.

The Canon RF 15-35mm f2.8 L IS USM is a zoom lens with a focal length of 15mm at it’s wide end and 35mm at the long with a constant fast aperture of f2.8 across the whole range. The lens is RF mount, built specifically for Canon’s full frame mirrorless camera’s and is Canon’s widest lens with the RF mount so far.

For nightscape photographers this is a very useful range covering popular focal lengths with the one lens such as 15mm, 20mm, 24mm, 28mm and 35mm and all with that constant f2.8 aperture, you can use this lens for capturing wide scenes in one shot at say 15mm or use a longer focal length such as 24mm or 35mm for multi image milky way panoramas possibly doing away with the multiple lenses a lot of us use to capture nightscapes.

The lens is weather sealed, dust and water resistant, another great feature for those dewy nights on the beach.

BUILD QUALITY

The Canon RF 15-35mm f2.8 L IS USM is built really well as you would expect from a Canon L series lens, this lens is part of their professional line of lenses and the lens definately reflects that in it’s build quality, solid feel and smooth operation. The lens looks amazing, the modern lines matched to the new modern mirrorless cameras, I love the look of this lens, the way the camera body seamlessly flows into the silver of the lens mount, into the modern black lines of the lens barrel ending at the control ring with big red ring around it, signalling this is an L series lens, Canons best.

SPECIFICATIONS

Focal Length & Maximum Aperture	15-35mm f/2.8
Minimum Focusing Distance	0.92 ft./0.28 m
Maximum Magnification	0.21x (at 35mm)
Lens Construction	16 elements in 12 groups
Special Elements	3 Aspherical lenses, 2 UD lenses
Filter Size Diameter	Ø82 mm
Aperture Blades	9 (circular)
IS (CIPA Standard Correction Effect)	5 stops
Focus Drive System	Nano USM
Minimum Overall Length	Approx. 4.99 in. / 126.8 mm
Maximum Diameter	Approx. Ø3.48 in. / Ø88.5 mm
Weight	Approx. 1.85 lbs. / 840 g

SOME IMAGES

From this angle you can see the manual/auto focus switch, stabilisation switch and from right to left zoom ring (largest and closest to the camera body), focus ring and control ring. The zoom and focus ring have a rubber cover for grip.

The lens is quite chunky due to it’s zoom range and large aperture but feels quite light and very well balanced on the Canon EOS R

The lens has claimed stabilisation up to 5 stops. I did not test this as I just don’t need it for the type of photography I do but if you were photographing the city at night this would be a fantastic feature allowing hand held shots.

Canons control ring, another feature I did not use during this review, the control rings function can be set in camera allowing another method of controlling settings. This works in well with the focus and zoom rings and did not get in my way while I was shooting at night, like the rest of the lens it is built well and operates nicely, with slight positive clicks..

The front element extends from the lens barrel slightly at its widest focal length.

The lenses 82mm front filter thread means that fitting filters is easy, it can accept 82mm standard screw on filters or 100mm square filter systems like the Haida M10 system shown, handy if you want to use a light pollution filter or filters for long exposure and landscape photography. This is an advantage over quite a few of the wider lenses available as a lot of them can only accept large 150mm filters and dedicated holders.

PERFORMANCE

The Canon EOS R, RF 15-35 f2.8 L IS USM mounted on the IOptron SkyGuider Pro, this set up is fantastic for wide field astro and tracked milky way images.

It’s all well and good to look great and be built well but how does the lens perform? From a sharpness point of view the lens is sharp there is no denying that, not once did I feel this lens wasn’t sharp enough, if you want to see close up details and lens charts you will have to look elsewhere as this isn’t something I will go into here, I think the example pics at the end of this review will be enough. Let’s focus more on coma and vignette performance as this is quite important for nightscape and astro photography.

The next few images are all SOOC with the RF 15-35mm f2.8 and Canon EOS R mounted on my IOptron SkyGuider Pro star tracker so we can take images with no star trailing and see the coma performance of the lens better. These will all be taken at an aperture of f2.8, we are paying a premium for that fast aperture so let’s see how it performs.

Lets start at a 15mm focal length and work or way up.

15MM

The first shot above is taken with the following settings 15mm, F2.8, ISO1600, 80 seconds. The stars look nice and sharp but we are seeing a fair amount of vignetting in the corners wide open at 15mm. Let’s take a closer look at the stars in the top left hand corner and see what they look like.

Looking at a 100% crop of the top left hand corner we can see some of the stars showing a bit of coma, not terrible but it is there especially out near the edge, top left. When we look at the bottom right corner that is pretty much the centre of the main image the stars look great, nice pin point stars. We also can not see any purple fringing etc. The lens looks to perform quite well at 15mm for a zoom lens.

20MM

The shot above is taken with the following settings 20mm, F2.8, ISO1600, 80 seconds. Again the stars look nice and sharp and we are still seeing vignetting, let’s take a closer look at the stars in the top left hand corner.

Looking at a 100% crop of the top left hand corner at 20mm we can see some of the stars showing a bit of coma, again not terrible. As we look across into the right of the frame the stars are not showing any coma, again we are not seeing any fringing.

24MM

The shot above is taken with the following settings 24mm, F2.8, ISO1600, 80 seconds. Again the stars look nice and sharp and we are still seeing vignetting, let’s take a closer look at the stars in the top left hand corner.

Looking at a 100% crop of the top left hand corner at 24mm we can see some of the stars showing a bit of coma, again not terrible. As we look across into the right of the frame the stars are showing a tiny amount of coma, looking very critically I can also see a little bit of fringing, but I really have to look hard to see this and it’s not noticeable in the full image.

28MM

The shot above is taken with the following settings 28mm, F2.8, ISO1600, 80 seconds. Again the stars look nice and sharp and we are still seeing vignetting, let’s take a closer look at the stars in the top left hand corner.

Looking at a 100% crop of the top left hand corner at 28mm we can see some of the stars showing a bit of coma, again not terrible and it looks like the at this focal length the coma is very much at the very edges of the frame. As we look across into the right of the frame the stars are showing a tiny amount of coma, looking very critically I can also see a little bit of fringing. I’ll bet no one reading this can see it I’m looking that closely, it’s definately not noticeable in the full image.

35MM

The shot above is taken with the following settings 35mm, F2.8, ISO1600, 80 seconds. Again the stars look nice and sharp, at 35mm we are getting a much better look at those centre stars and they look great. We are still seeing vignetting, although to me it doesn’t look quite as noticeable as the wider focal lengths. Let’s take a closer look at the stars in the top left hand corner.

Looking at a 100% crop of the top left hand corner at 35mm we can see some of the stars showing a bit of coma if being really critical and again it looks like the at this focal length the coma is very much at the edges of the frame. As we look across into the right of the frame there seems to be no coma, I can’t see any fringing at 35mm.

Before I talk more about the lens let’s have a look at an image that is not tracked for comparison.

The above shot was taken at 15mm, F2.8, 13 seconds, ISO 6400 straight out of camera. Again let’s look closer at the top left corner.

Above we have a 100% top left corner crop of the tree image. Looking at this un tracked image you can see a slight bit of star trailing, this star trailing is hiding the small amount of coma we could see in the tracked shots and is the reason I wanted to share as it is how most would be shooting the stars with this lens, wide open straight off a tripod. This looks really good for a wide zoom lens.

As we can see in all of the above images there is a small amount of coma, not bad in any case and barely noticeable unless looking at crops critically, I’m really happy with this performance. There is vignetting at all focal lengths but I have not used any lens correction so this may be a non issue for those that do, I generally add vignetting in post processing to my images so it really isn’t something I am fussed about. The only time this would cause me an issue would be if I was shooting images for panoramic milky way as the dark areas in the vignette can cause uneven exposure in the final pano, but again lens correction would likely fix this.

I’m very happy with the performance of this lens in all the areas above, yes there are a few primes that handle coma a little better, a little being the key word, but this lens is a 15-35mm zoom giving you multiple useful focal lengths and of course the ability to easily adapt filters.

Before we move on I also took images at 24mm testing the various apertures to see if performance changed much, again I used my IOptron Skyguider Pro to track the stars. I kept the settings the same just changing aperture between shots, so the exposures are slightly different but it does give us an idea of performance, let’s have a look.

ABOVE – 24MM AT F2.8, FULL IMAGE.

ABOVE – 24MM AT F2.8, TOP LEFT CROP.

ABOVE – 24MM AT F3.2, FULL IMAGE.

ABOVE – 24MM AT F3.2, TOP LEFT CROP.

ABOVE – 24MM AT F3.5, FULL IMAGE.

ABOVE – 24MM AT F3.5, TOP LEFT CROP.

ABOVE – 24MM AT F4, FULL IMAGE.

ABOVE – 24MM AT F4, TOP LEFT CROP.

In the images above taken at 24mm we can see both vignetting and coma improving as we start stopping down, the exposure difference makes it a little hard to notice the vignette change but it does even up as we stop down. We won’t go into any more detail on that I just wanted to include more samples for those that really want a close look at how the lens performs.

A NICE SURPRISE

I have never been a fan of focus by wire (electronic manual focus) on lenses for nightscape and astro photography for a few reasons, you lose the depth of field scale on the lens, the focus by wire lenses I have used have always been quite easy to bump out of focus and I have found the electronic depth of field gauge in camera not very reliable. I’ve used three mirrorless systems and quite a few focus by wire lenses designed for mirrorless and have always felt this, hence still using my traditional focus and fully manual lenses for Night photography with the EOS R, along with fully manual lenses when I was using Sony and Fujifilm.

But what a surprise the Canon 15-35 was in this area, it didn’t feel twitchy and easy to bump out of focus, instead it felt nice smooth and predictable, I didn’t once bump it out of focus like I have with other lenses and the electronic depth of field gauge was accurate and reliable, honestly this is the first lens I have used with focus by wire that I could be confident in, I really can’t say if all Canon’s RF lenses are this good but I hope so. The other thing I found that was interesting is I could set infinity on the electronic depth of field gauge, change focal length and the lens would still be focussed on infinity making it very easy to quickly change the composition and not have to re-focus, nice!

SOME IMAGES I CAPTURED WITH THE CANON RF 15-35MM f2.8 L IS USM

Unfortunately my time with the Canon RF 15-35mm f2.8 was very short. I only had two clear nights to capture the images for this review but I did manage to use it in a few different ways as you will see in the following images.

Above, a simple single shot, foreground lit with a Lume cube 2.0 on it’s lowest setting, very minimal post processing. Settings 15mm, f2.8, 20sec, ISO6400.

Above is a simple single shot taken under a full moon, very minimal post processing, settings 15mm, f2.8, 15sec, ISO1250

Above, the milky way over my home town of Sale, Victoria. This image is created from 12 indentical images stacked in Starry Landscape Stacker to reduce noise and create a clean image. Settings for each image 15mm, f2.8, 13sec, ISO6400. (You can see how I stack images using Starry Landscape Stacker here)

Above, the milky way rises directly above an old vehicle rusting away in a paddock. Again I took multiple identical images out in the field and stacked them in Starry Landscape stacker for noise reduction.

You can see see exactly how I stacked this image, learn what I do out in the field and download the images to work along over on my Starry Landscape Stacker tutorial found here Starry Landscape Stacker tutorial .

Above, a wide image of the milkyway core. This image is a stack of 14 images tracked with the IOptron SkyGuider Pro and stacked in Starry Sky Stacker to bring out the detail and reduce noise. Each individual image was taken with the following settings, 24mm, f2.8, 90sec, ISO1600.

Above, I saved my favourite to last. This is a composite of the the old truck image taken under the full moon and the tracked milkyway core image. I thought this would be a good way to show an example of how you could use the multiple focal lengths of the RF 15-35 f2.8 L. The foreground is taken at 15mm, the sky taken at 24mm, this helps create a dramatic milkyway image with a wide “in your face” foreground.

CONCLUSION

As you can see the Canon RF 15-35mm f2.8 L IS USM lens is a very good performer for Nightscape photography and can be used in many different ways. I wish I had more time with it to get out and shoot in more scenarios, for example night cityscapes and time-lapse but a combination of the crazy year, short loan time and poor weather limited what I could do for this review.

The time I did spend with the lens impressed me. I would happily own this lens myself and hopefully will in the future, it would definately reduce the size of my kit. I carry three lenses everywhere for my nightscape and landscape photography, this lens could replace all three and not give up much performance wise, in fact it would improve my kit in quite a few ways.

I’ve heard a lot about the price of this lens, but you are paying for a professional quality, fast aperture wide angle lens that could replace multiple prime lenses in your kit, has all the latest tech and Canon’s new RF lens mount. The RF mount and mirrorless is where all the new development and tech will be going from Canon, so this lens will also serve you well into the future.

Would I recommend this lens? Yes, if you are using Canon’s full frame mirrorless cameras and want to buy an ultra wide angle lens for nightscapes or landscapes this would be a perfect addition to your kit if you have the budget.

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