Canon RF 16 mm f2.8, anyone tried?

Hello wetpixels,

I was curious if anyone has tried this very small new gem underwater?

Physical Specifications · Filter Diameter (mm). 43 · Max. Diameter x Length (mm). 69.2 x 40.2 · Weight (g). 165.

Also curious bout this.

Would this be an alternative to Canon EF 8-15?

I don't think it wold be an alternative to Canon 8-15mm per se, as ultrawide (weitwinkel) rectilinear lens and fisheye lens are two very different beast. But I can certainly see why this small package can be attractive. It can focus quite close (13 cm) and offer a good magnification (.26) which are nice attribute for CFWA.

Price and size is a big plus, image quality underwater I'm really curious..!

I was also interested in this and picked one up which I will get in the water shortly.  I also figured with a full frame, even if it is not sharp at the edges in a 230 or 180 dome (highly unlikely to be sharp in the corners with a 180), it can be used in a 1.5 crop mode or for those times when a slightly smaller package is more important than 16mm with full frame.   Or when shooting pelagics where they will be front and center (in theory).  It seems like from the existing port charts, it will use no extensions - which is also nice. Plus at that cost, no reason not to just throw one in your bag for trips in case your primar zoom lens decides it doesn't want to work.  I'll let you know how my logic plays out when I have the lens underwater.

I just got back from putting the 16mm RF through its paces.  This was in a Marelux housing, R5, with the 180mm dome port with no extensions on it.  It was a very poor weekend to test this setup as the visibility was bad (<1m with very large particulate) and it was dark (think night dive during the day) so everything was heavy strobe. This was not an opportunity to look at wide-angle and corner sharpness but also really not an easy shooting scenario for a camera. Having said all that, the lens was just a pleasure. Frame, fire, adjust lighting, frame, fire - no lag, every shot in focus.  In fact, every shot that wasn’t a keeper was due to strobe placement and backscatter not the lens itself. I was shooting High ISO with too small of an aperture (F10-11) but the sharpness was impressive for just taking photos. I also ended up shooting in 1.6 crop mode for a lot of it, mostly due to the water conditions.

From a handling standpoint, for such a large setup it is very compact.  I.e. the lack of extension makes it feel like a much smaller rig than it is.  Would I take the RF 16  on a trip as a backup lens? Yes - without a doubt.  Would I treat it as my main workhorse lens?  Yes. Honestly, it was the easiest setup I used that weekend allowing me to focus on composition rather than…well pretty much anything else.

Here are a couple - I didn’t crop so you can see the whole image. No sharpening was added in post.

Wow ColdDarkDiver thanks for update!!

That's very nice to hear, keep us update if you do more tests in "easier" conditions to check corner sharpness.

Only had one wide angle dive on my recent Anilao trip. Tried out the new RF 16mm lens. Like previously mentioned an affordable wide angle option and nice to be able to use without extensions or close up lenses. I used it with an 8 inch Aquatica dome port.

Some softness in the corners bit not too bad???

Doesn't look bad at all!

On 6/10/2022 at 1:39 AM, AndreSmith said:

Only had one wide angle dive on my recent Anilao trip. Tried out the new RF 16mm lens. Like previously mentioned an affordable wide angle option and nice to be able to use without extensions or close up lenses. I used it with an 8 inch Aquatica dome port.

Some softness in the corners bit not too bad???

Which F did you use here?

Anyway using this little beast can give us more feedback?

I had the opportunity to try the RF 16mm again recently at Sodwana in South Africa.

The images are all uncropped and shot at f8.0.  I still think my go to wide angle lens will be my 8-15mm as the corners are are definitely better. However the 16 is very acceptable imo for the center 80 per cent of the image. So for the dolphin dive it was great and very convenient being so small and light and not requiring any extensions. Throw in the very reasonable cost and you have a good reason to have it in your arsenal!

@AndreSmith thank you so much! Could you upload the full-resolution files to check them? (forum resizes the photos).

Also, do you find Canon 8-15 with distortion correction ON in lightroom (straight imagine) stills have better corners than RF 16mm or just without distortion correction?

My apologies for the belated reply. I was going to do some more pool testing on the RF 16mm and also  the RF14-35 and see how they do in a 6 inch dome port as well ( the previous ones were in a 8 inch dome) but the diving didnt materialise. So I had to revert to the old laundry tub test.

I am happy to say that the 16mm is pretty darn good even in the 6 inch dome port! I have included a tub picture uncropped at f11.

The 14-35 at 14mm is great in a 8 inch dome at f8'  but in the 6 inch dome you need at least f11. The housing manufacturers are all over the map with their recommendations for port extensions for this lens in smaller domes for good reason. I  tried multiple length combinations without finding a particularly sweet spot. Needless to say, the more you zoom in, the less of a problem you have.

To answer your question about the lens profile corrections, it helps for distortion and vignetting  but does not help you with soft corners. 

Awesome post AndreSmith, could you upload the RF 16 mm samples full-resolution (link outside forum).

RF 16mm looks really a gem and 0.13 m focus distance looks pretty good for UW!

Ok here are some: https://www.dropbox.com/sh/schlffne45f8u5r/AAC3Aogu6nkMhHxdK8Jeyrh8a?dl=0

All uncropped, f8, Compressed RAW shot in 8 inch Aquatica Acrylic dome'

HTH

27 minutes ago, AndreSmith said:

Ok here are some: https://www.dropbox.com/sh/schlffne45f8u5r/AAC3Aogu6nkMhHxdK8Jeyrh8a?dl=0

All uncropped, f8, Compressed RAW shot in 8 inch Aquatica Acrylic dome'

HTH

13cm working distance measn this lens should work fine with the 6" dome

The 14-35 with a working distance of 20 cm and the constriction it has will require 3cm larger radius

The 14-35 with the 6 dome will not work well and will not be able to focus close the 16mm will focus right on the dome with the 6"

At 16mm the 16mm lens will be better than the 14-35 with any size dome

It is just a consequence of the construction of the lens with a much smaller working distance

When it comes to edges the field of curvature effect should not differ between the two however the 16mm will allow more focus range because it will always focus on the dome

Generally 14mm is too wide to have edge sharpness regardless how big your dome is

Using rectilinear lenses has a sweet spot between 18-20mm 

16-17 is amber zone large dome may cure things

12-15 is red zone no matter how big your dome is the field of view means the field of curvature will be extensive you can do whatever you like the edges wont be sharp

Something to bear in mind

I think this 16mm is a very interesting lens in the Canon echo system definitely one to get and forget all the other rectilinear options

19 hours ago, Interceptor121 said:

At 16mm the 16mm lens will be better than the 14-35 with any size dome

I own and use the 14-35mm and the 16mm.  There is more to lenses than their sharpness or min focusing distance.  I always reach for the 14-35 when given the option of the two.  I just find the pictures in the end more exciting, pleasing, and what I was going for.  That is not to say that the 16 is not a great lens (AndreSmith posted some wonderful images with it as proof!)

So when we use the word "better" the question is for what?  I capture images to tell a story so the lens that is better is the one that lets me do that.  I always bring the 16mm with me, and wouldn't steer anyone away from it but I would not consider it better. It is wonderfully small and packable.  A great backup lens and capable of wonderful images as a primary lens, as well.

I own and use the 14-35mm and the 16mm.  There is more to lenses than their sharpness or min focusing distance.  I always reach for the 14-35 when given the option of the two.  I just find the pictures in the end more exciting, pleasing, and what I was going for.  That is not to say that the 16 is not a great lens (AndreSmith posted some wonderful images with it as proof!)
So when we use the word "better" the question is for what?  I capture images to tell a story so the lens that is better is the one that lets me do that.  I always bring the 16mm with me, and wouldn't steer anyone away from it but I would not consider it better. It is wonderfully small and packable.  A great backup lens and capable of wonderful images as a primary lens, as well.

Very good review from dpreview

https://www.dpreview.com/videos/8537620039/dpreview-tv-canon-rf-16mm-f2-8-stm-review

On 3/2/2023 at 4:16 PM, Interceptor121 said:

Very good review from dpreview

https://www.dpreview.com/videos/8537620039/dpreview-tv-canon-rf-16mm-f2-8-stm-review

Not impressed by sharpness and huge chromatic aberrations in this review, but I will give it a try underwater for sure!