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darth mollusk

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About darth mollusk

  • Rank
    Clownfish

Contact Methods

  • Website URL
    www.thalassia.ca

Profile Information

  • Location
    Quadra Island, British Columbia, Canada
  • Interests
    Marine ecology and conservation

Additional Info

  • Show Country Flag:
    Canada
  • Camera Model & Brand
    Canon R5 / RF 15-35 / RF 100 macro
  • Camera Housing
    Aquatica AR5 / 230 dome / mini macro port
  • Strobe/Lighting Model & Brand
    Retra Pro X

Recent Profile Visitors

1558 profile views
  1. Just received an update from Backscatter: Aquatica will be machining a new mini macro port for the Canon RF 100.
  2. 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...
  3. 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!
  4. 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.
  5. 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...
  6. I've recently sold my compact camera setup and decided to take my R5 underwater. There are some new considerations for me here – and I would appreciate some peer review. I've just watched Dr. Mustard's excellent presentation: 'Beyond the Dome – Dome Port Theory' to wrap my mind around the basics, and read other threads here on WP re: these topics (dome position, pupil location, etc.) but wanted to pull it all together here. I want to be sure – to the best of my knowledge – that I've positioned the RF 15-35 correctly in the Aquatica 230mm megadome. Manufacturer guidance is to use a 70mm port extension. The lens sticks ~30mm into the dome (at 15mm zoom) with this extension. To check this was positioned correctly I needed to know the entrance pupil location. I measured this using a standard 'point of no parallax' test often used by panorama photographers. The measurement agrees with where I can see the pupil, sitting ~113mm from the base of the lens (right at the 'L series' red line) or ~30mm from the front element. Set in the housing with the 70mm port extension, the pupil is parallel to / sits at the dome opening. As I understand: the entrance pupil should be positioned at the dome's centre of curvature. The dome is not a full half: the centre of curvature is ~3.5cm back from the dome opening (ironic – considering the attached figure used in Dr. M's presentation – the 'wrong extension' here was 3.5cm off). Either I've missed something, or I need another extension to move the lens back. Related (but I don't want this to hijack the thread): not interested in the WACP (that's taking cost a little too far). I will likely purchase a fisheye lens as well – but would prefer a native RF mount, so might be waiting for a few years (and I'll still need to position it correctly... )
  7. Update on cost to order Retra Pro's from Retra in the EU: DHL International must be reading this thread – I only got charged tax (12% here in BC) and an $18 border service fee. No duty. Exchange rates are effectively the same for EU and US conversions at the moment – if that's still true when you read this, order from Retra...
  8. Thanks Ian, all good information to know! I had two options ordering the Retra strobes – Backscatter or Retra. Neither offered a postal option so I went with Retra (slightly better exchange rate and I prefer directly supporting small business when possible). We'll see if I get nailed with ridiculous brokerage fees – should know by the end of next week. I'lll post here for others who might also be wondering... Markus
  9. Thanks Chris. For those who might find this later – based on the numbers from Ian and the gov calculator I expect to be charged tax, 5% duty, and a brokerage fee (hopefully not exorbitant). I've ordered straight from Retra as the duty charges are based on where the item is manufactured not purchased (so I would be charged the same from Backscatter -- only difference is exchange rate (EU vs US) and a different courier).
  10. @ianmarsh Hi Ian. I'm about to pull the trigger on a pair of Retra Pro X strobes from Backscatter (I live in BC). You mentioned $420 in fees from DHL – would I be correct with my math in saying ~$100 of this was duty and brokerage fees (i.e.: not taxes)? Thanks!
  11. That's a good point. My other concern is finding the space to run a cable inside the housing – might have to remove a few pieces. Might be easier to convince Sealife to adapt it themselves. I imagine the market for a $400 underwater monitor housing would be big enough to make it worth their while.
  12. I'm looking to add a monitor to my underwater setup – but not happy with the options available. SmallHD and Atomos are great monitors but cost thousands to take underwater. The dedicated underwater monitor options have received less than enthusiastic reviews from others I dive with... and still cost a few thousand. Not sure why someone hasn't put together a housing for an iPhone with a port for an HDMI cable. It would serve only to provide a larger articulated screen for macro or video – but that's all I need. Any thoughts on rigging the Sealife Sportdiver iPhone housing ($300) for this purpose – it has a threaded vacuum port, but not sure if it would be possible to replace or covert to an HDMI connection.
  13. This was posted 5 years ago, without any great recommendations at that time. Anything new out there? So many resources for underwater photography, so few for video. I found this: http://www.jeffgoodman.co.uk/Book.html– published 5 years ago. Curious if there are others I've missed.
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