Reply To: EMWL Focusing issues and soft images

[Nicolas]

Hi @rubys_light

So sorry to hear you’re experiencing those issues with the EMWL, it’s a fantastic system, let’s try and sort things out.

To rule out a couple of issues, I suggest you start with the following EMWL settings:

F/18, ISO 500, 1/200th.

There could be a few things at play with the softness you’re seeing in your EMWL images:

• 1/ Motion blur: the many lenses within the EMWL system cut down lots of ambient light, and I’m often finding myself reducing my shutter speed to 1/40th (slower if I am supper stable) while using ISO 800, if I have little ambient light. I’ve happily gone up to ISO 2000 when necessary, modern full frame cameras can take it if exposing properly. By shooting at 1/200th you’ll likely get a black background, but at least you can see if your subject is crispy sharp. On my Nikons, I found that image stabilisation did help, but do toggle it ON/OFF your R5 to see if it changes anything.
• 2/ Diffraction. Like Grace said, at very small apertures this can reduce sharpness, but I’m quite happy with the sharpness I get at F/22 (45 MP full frame sensor like yours). Anyways, troubleshoot at F/18, it’s a good balance of depth of field and lack of diffraction.
• 3/ Back/Front focus: unfortunately, some camera & lens combinations have been known to present back or front focus when used with the EMWL (as reported in my review – see TUC’s blog: https://theunderwaterclub.com/blog/review-the-nauticam-emwl-system-for-bugeye-photography/). For example on my Nikon Z9, I get constant backfocus when using the Nikon Z 105mm MC lens, but zero issues with the older Nikon 105mm AF-S VR lens. Sony camera shooters using older bodies (A7R Mk3 and older) have reported similar issues (with the Sony 90mm), while the issue seems gone with newer Sony cameras (and the same 90mm lens). Unfortunately, I don’t have first hand experience shooting the EMWL on a Canon camera, so unsure if this is what your problem is.

I suggest you shoot your EMWL with the settings I recommended above, try your best to be super stable (must be hard to frame with the inverted view, if you have no relay nor viewfinder) and see whether you have parts of the image with maximum sharpness, and whether that is on the intended subject, or before/after (front/back focus).

As it happens, I might be shooting a Canon camera for the next few weeks and will have a chance to test this myself, but let’s get you sorted out before that.