Inspired by Massimo and a comment in another thread I would like to gather intelligence for underwater photography in the RF System and point your attention to one of the most unpopular and underestimated wide angle lenses for full frame canon camera bodies:

 

Canon RF16mm F2.8 STM
https://www.usa.canon.com/shop/p/rf16mm-f2-8-stm

is what we talk about.

 

Lens data available at:

https://photonstophotos.net/GeneralTopics/Lenses/OpticalBench/OpticalBench.htm#Data/JP2022-085382_Example03P.txt,figureOpacity=0.25,AxisO,OffAxis

 

Underwater dome port & travel benefits:

1) very low minimum focus distance of just 13cm

2) minimal weight and size ( just 165 g )

3) very affordable price (less than $300)

 

some cons / stuff to watch more closely:

1) the lens moves the npp ( entrance pupil ) more than 6mm during focussing

2) has already some vignetting and chromatic aberration topside, which will not disappear when stopping down

 

Do you shoot it? You like it?

please share your thoughts and test shots in this thread

 

Edited May 5, 20241 yr by Adventurer

I have the 16mm and I use it as a backup lens or when I want something smaller than my other lenses.  As you said - small, light, and "cheap" so if something goes wrong with my other lens then I have a backup. I also really like that I can use zero extension and a 180mm dome for a relatively compact rig.

 

I have not had any issues with focus or anything else on it...however - I also just don't use it that much.  I keep on meaning too but then I almost always end up putting a different lens on the camera: 8 -15 fish for stills, the 14-35 for video or mixed, and when I am feeling lazy, want to shoot wider open, or want very straight lines - the 24mm macro.

 

So, I have nothing but good things to say about it even though I almost never use it.  There is no way I would leave it behind for remote shooting though. It is a perfect backup lens and I have been happy with the image I have collected with it. I also will sometimes just take it as my main lens on a hike...it is really small and light.  I will dig up some photos and post them here in the next couple days (they are not on the computer I am on right now).

Hello @ColdDarkDiver any samples full-resolution update?

6 hours ago, stillviking said:

Also a total surprise and MUST BUY + USE lens is the cheap Canon RF 16 STM. That lens is ULTRA SHARP (even) behind (small) domes. One diver used it the whole trip and it turned out to be surpirisingly flexible. The fact that you can focus on small dome ports allows you to shoot fish portraits with it. It was really amazingly adaptive for a prime lens. There is this kind of semi-macro mode available on that lens, if you get really close. I am going to get one myself; even though I already own the overlapping Canon RF 15-30 ST

There is update and discussion in the above linked thread about that lens.

 

I now own one. But it will take some time to hit the water with it. 
 

There has also been discussion about 10mm and 14mm lenses being very difficult to shoot because of the pincushion distortion. Basically anything below 20mm focal length is prone to dropping edges (even if very sharp and correctly positioned).

 

So why do I like the 16mm so much and was impressed? One of the factors may be that the onboard Canon in-camera lens correction will render this lens FOV (Field of View) close to a 20mm lens without the dramatic pincushion effect.

Edited August 21, 20241 yr by Adventurer

@Adventurer thank you so much, this topic is a masterclass!

 

Can you explain me better what do you mean with "Canon in-camera lens correction will render this lens FOV (Field of View) close to a 20mm lens"? 

 

If I compare a current zoom 16-35 mm at 16mm and this prime RF 16mm 2.8 they will not look the same? It would be the same at 20 mm?

I have owned this lens for quite a while and have used it with both 8 inch and 6 inch domes. I posted about this in Wetpixel with some images a while back if you can get it.

 

For its price It really is remarkably good. No extensions or diopters required. Being so cheap, small and light you cant go wrong. Corner sharpness with a 8 inch dome are fine.  With a 6 inch dome,  apertures smaller than f8 were necessary for acceptable corners. 

 

HTH

9 hours ago, AndreSmith said:

I have owned this lens for quite a while and have used it with both 8 inch and 6 inch domes. I posted about this in Wetpixel with some images a while back if you can get it.

 

For its price It really is remarkably good. No extensions or diopters required. Being so cheap, small and light you cant go wrong. Corner sharpness with a 8 inch dome are fine.  With a 6 inch dome,  apertures smaller than f8 were necessary for acceptable corners. 

 

HTH

 

Thanks, I will check the old wetpixel. I would love to see some full-resolution photos to check the quality before buying.

 

Also, it's pretty weird to me Nauticam chart recommends a huge 230 mm dome for RF 15-35 mm 2.8 L with min. focus of 28 cm and RF 16 mm 2.8 with a with a min. focus of 13 cm. Shouldn't it improve?

Edited August 22, 20241 yr by stillviking

4 hours ago, stillviking said:

Also, it's pretty weird to me Nauticam chart recommends a huge 230 mm dome for RF 15-35 mm 2.8 L with min. focus of 28 cm and RF 16 mm 2.8 with a with a min. focus of 13 cm. Shouldn't it improve?

 

Yes but * indicates the best quality option and probably the behemoth 230 mm is.

 

I see, but Ikelite chart has a smaller dome model for RF 16 mm 2.8 as option 1 that is 6" size (however name is 8" compact).

null