darth mollusk

I use the Canon 8-15 behind a 140mm dome and find it's the perfect balance between corner sharpness and dome size... just my 2 cents.

That makes sense. Brian Carnathan at 'the digital picture' noted in his review that the RF100 exhibits "moderately strong" breathing. It also exhibits noticeable focus shift when stopping down at close focus distances – this is usually masked by increasing DoF at smaller apertures, but I wonder if it will be a problem with the razor thin DoF even at f22+ when using a UCL... probably. Like you said, only one way to find out.

Thanks Chris – exactly the information I was looking for! An 80mm working distance for the SMC-1 is amazing. I looked up the EF 100 on the Nauticam port charts and it has a working distance of 53–93mm. Considering that the naked EF lens has a min working distance of 146mm, that leaves room for the use of a weaker UCL in the 93 to 146mm gap. As there's only a 5mm gap between the RF 100 (85mm) and SMC-1 (80mm) there's no reason to purchase a weaker UCL. This must be unique to the RF 100 lens design as I've not seen any other examples of strong UCL (+11 / 2.3x or equivalent) focusing right up to the 100mm macro lens minimum working distance. I've also read that the Inon UCL lenses have more working distance than the Nauticam equivalents – though in this case there's not much room to improve.

I've been shooting with the Canon R5 + RF 100 macro. The RF 100 has a minimum working distance of 8.5 cm from the front element – at this distance magnification is 1.4x. I'm considering the addition of a wet close up lens but have some questions: 1. Would a +10 diopter be the equivalent of +15 or more when in front of a lens that already shoots at 1.4x magnification? 2. The older EF 100 minimum working distance is reduced from 14.6 to 6.9cm when behind the Inon UCL 90 (+11 diopter). Would the RF 100 minimum working distance then be reduced from 8.5 to 4cm? I would guess that DOF would be razer thin at this distance... Edit: after writing this I think I've answered my own questions. Seems somewhat obvious now that both statements (1 + 2) should be roughly true. Any recommendations on a sharp +5 or +6 UCL with a reasonable minimum working distance?

Not sure about the Weefine, but Aquatica, Anglerfish, and Hugyfot all use Feelworld monitors – they've just built the housings and branded it as their own. Weefine probably does the same - should be easy to narrow down which one by comparing features. I have the Aquatica (Feelworld F570) and it works great for macro and video work with the Canon R5 (i.e. I wasn't looking for a monitor that records and am not too interested in extra features like false color and focus peaking).

Haven't posted much online recently – but I do have some video (mostly photos) up on Instagram: www.instagram.com/markus.thalassia re: blue moon – agreed, it was a slim hope that I could have an R5 / R5c setup similar to the Nikon Z6 / Z7. I shoot as much above water as I do below, and it would be so nice to have an R5 that's not vacuumed into a housing when wildlife shows up between dives... maybe this is the excuse I need when the R5ii shows up

I am currently shooting underwater with the R5 and shoot 8K RAW when I feel I might need more flexibility in post – particularly for white balance. But in most situations I also prefer shooting at 60 fps... and lose that option at 8K. It would be great to have the option to shoot 5K RAW at 60 fps (added bonus: smaller file size) – that's the only advantage the R5c has that I find interesting. Was also hoping the size difference was going to be small enough I might fit the R5c in an R5 housing – but that's clearly never going to happen.

awesome! nice work benedika. felt familiar but foreign – so many similar species here in BC, Canada. would love to dive in Norway one day!

Was hoping to see something new from either Keldan or Light and Motion at DEMA 2021 – but no such luck. Looking to upgrade to something in the 15,000 to 20,000 lumen range. Anyone know of anything I haven't heard yet? Was leaning towards Light and Motion, but their 15K lights are 3 years old now... should probably just pull the trigger on a pair of Keldan 8x. Also, just got word from a retailer that Light and Motion will be increasing their prices on Dec 1 due to increased part costs.

Hi Brendon, I use the R5 in an Aquatica housing and prefer to use an external monitor – but I do have a solution for you: In the 'custom buttons' menu (orange #3) you can set the m-fn button to switch between VF/viewscreen. You might be able to set other buttons to do the same, but I haven't looked.

Just received an update from Backscatter: Aquatica will be machining a new mini macro port for the Canon RF 100.

Thanks Chris! I had not seen that the working distance at 1.4x reduced to 85mm (makes sense). I estimated where the RF 100 would sit before bumping into the tapered side of the port by measuring dimensions in PS (including the standard 4mm width of the sidewall). I suspect the 18430 mini macro port 'supports' the Nikon lens, but still places it back 3 or more cm from the glass. Considering your very valid points re: working distance I want to be as close to that glass as possible. So far the best option appears to be the Saga (~1.5cm from the glass). Guessing the non-tapered Aquatica macro port would make it challenging to get the strobes in close enough at minimum working distance...

Thanks Tom! Good to hear there shouldn't be much of an issue with the air space – would be painful to lose that crisp image quality that comes with the 100 macro. In the short term I'm not too worried about accessory wet-lenses (1:1.4x with 45MP gives me plenty to work with... for now). I suppose the other consideration is that my port will be ~3cm closer to critters than it would otherwise need to be. Measuring the Saga macro port dimensions in PS it appears I could get the RF 100 within ~1.5cm of the glass (did not know Saga offered an Aquatica mount – great to have another option!) So many epic salmon images on your website btw – nice work!

I will be purchasing the Canon RF 100mm macro and have a few options to consider before I choose a port. I own the Aquatica AR5 housing. Ideally I would use the Aquatica mini macro port – but the tapered design will likely keep the lens ~3cm back from the port glass (the RF lens has a wider diameter than the EF lens the port was designed for). 1. Are there consequences to having 3cm of space between a 100mm macro lens and a flat glass port? Aquatica has a wide (not tapered) flat port option – but this will reduce my ability to get the strobes in close. 2. I've heard some people have used a 100mm fisheye dome with a macro lens (this would be great for travel – one port for fisheye and macro options). Guessing this would impact how close I could focus on the virtual image (the RF 100 has an 11cm working distance for reference). Anyone here tried this with the EF 100 or equivalent? 3. Curious if there are options available to use non-Aquatica ports on an Aquatica housing (I've seen a Sea & Sea adapter – though I'm not sure it's in production anymore). I will be talking with Aquatica (when we get a copy of the lens to test). I shoot with Aquatica for a number of reasons: I'm Canadian (having local contact is great – and I have a preference to support small local business) and I dive in cold, remote locations (Aquatica have a reputation for tough housings). I understand I would have a few more options available if I went with Nauticam... but there are always trade-offs.

Thanks Chris. I have the dome and extension they sent me -- so my data comes from direct measurements. The extension measures 70mm – same length recommended by Nauticam for the RF 15-35. But I also see that Nauticam recommend the same extension for both their 180 and 230mm domes (guess they're rounding to the nearest existing extension). For the centre of curvature I made an assumption that the diameter of the dome port (230mm) is close to what the diameter of the full sphere would be (this will be an underestimate, but close to true). Laying my dome flat to measure the height (85mm) and comparing this to the radius (115mm) I can see that the centre of curvature should be ~30mm back from the opening (35mm if we use the commonly stated 120mm radius). I can move the lens back 30mm and it does not vignette. The front element in this position sits at the dome opening and the lens only has a 110 degree angle of view. I would assume that the manufacturer arrives at the correct extension length using similar calculations and hopefully some testing. But that means I'm wrong – and I don't see any errors in my reasoning. Edit: I've read some incredibly detailed posts by folks here on WP re: lens position in dome ports. Cunningham's law ('the best way to get an answer on the internet is to post the wrong answer to the question') suggests I've not made any mistakes here...