I stumbled across this video and was amazed! I don’t know if this is a UK-based underwater equipment dealer or a photographer, but kudos!!!

This is by far the best must-watch and well-illustrated video to get your head around dome port theory and positioning. The author uses really clear graphics and small animations, and I was genuinely impressed by how logically and neatly he covers every aspect - in exactly the right order.

Very educational - and even better than Dr. Mustard’s “Beyond the Dome” talk - which (imho) had a tiny hint of Nauticam-flavoured mysticism. In contrast, the recommendation above feels pretty timeless and pleasantly light on branding - even if the creator might be in the industry, it comes across more like genuine enthusiasm than a sales pitch.

Thanks for pointing this out. Excellent clip, as is his Part 2 on domes.

Yeah, really good. Such a clear explanation.

At the end of the day, it's about compromises......

Hi all, does anybody know the author / anchorman of these four videos ?

At first I thought he is affiliated with the former British camera store OceanOptics, because of the channel name. That however seems wrong. The channel origin seems to come from The Netherlands and I think that this might be confirmed by a slight Dutch accent I am hearing.

I am interested to learn more about his uw photographic works and if he maybe is a well established pro or even a waterpixeler 😉 ?

having found the optical centre of a lens and the theoretical centre of the curvature of the dome...

• how critical is the approximation of the two? Spacers are available for ports but seem to come in say, 10mm increments

does being off by 2-3 mm make a critical difference? or is within a centimetre or so acceptable?

12 minutes ago, Mike Saunders said:

having found the optical centre of a lens and the theoretical centre of the curvature of the dome...

• how critical is the approximation of the two? Spacers are available for ports but seem to come in say, 10mm increments

does being off by 2-3 mm make a critical difference? or is within a centimetre or so acceptable?

You will note in an example in the video, the lens used a 17mm extension added to if I recall correctly a 30mm ring. However the video notes that the combination vignetted, so the suggestion was to just remove the 17mm ring and just use the 30mm. This gives you an idea of what you can get away with. IMO an ultra wide rectilinear lens (14mm FF equivalent or less) will be more sensitive than a fisheye lens. I think it likely also depends on the lens in question. A marginal performer might show more issues if the spacing is less than optimal. I think the right answer is get as close as you can within the limitations of your housing system. Some systems have 10mm increments others the extensions go up by 5mm.

53 minutes ago, Adventurer said:

Hi all, does anybody know the author / anchorman of these four videos ?

At first I thought he is affiliated with the former British camera store OceanOptics, because of the channel name. That however seems wrong. The channel origin seems to come from The Netherlands and I think that this might be confirmed by a slight Dutch accent I am hearing.

I am interested to learn more about his uw photographic works and if he maybe is a well established pro or even a waterpixeler 😉 ?

I don't know him, but he definitely has a Dutch accent.

Edited yesterday at 10:46 AM1 day by waso

It is worth watching the video even just for his shirt!

P.S.

Jokes apart, great video and explanation indeed

11 hours ago, Mike Saunders said:

having found the optical centre of a lens and the theoretical centre of the curvature of the dome...

• how critical is the approximation of the two? Spacers are available for ports but seem to come in say, 10mm increments

does being off by 2-3 mm make a critical difference? or is within a centimetre or so acceptable?

This is a great question, but difficult to answer except by saying 'do the best you can' based on what extensions you have available. In practical terms I aim for <10mm misalignment for a typical WA rectlinear lens, and preferably c. 5mm.

Something new to me in his clip was his method of checking alignment (of OC and CC) by viewing the reflection of your eye in the dome at an angle (on land) and seeing how close it is to the apparent position of the aperture diaphragm.

Anyone tried this? I will when I get around to it.

One point he made in his flat ports clip which at this stage I can't endorse is his assertion that domes work well with longer macro lenses. I asked him about this but he hasn't replied. I have tried to get the Sony 90 and 100 macros working with a correctly aligned dome, but I run into mis-focusing issues (with AFC). There is also the problem that due to the size of these lenses and position of their EPs (CC) you need a large radius dome (c. 100mm or better) to get within a bull's roar of alignment.

But large radius domes are typically only available with large diameters (eg. Nauticam 180), so their bulk gets in the way for macro.

I would love to be proved wrong on this, and hear from someone who is successfully using a dome with either of these lenses! (And details of their rig).

@dentrock I don't have experience with the Sony 100, but I have done a little testing of the Sony 90mm, Tamron 90mm, and Sigma 105mm behind domes. The entrance pupils of the Sony 90mm and Sigma 105mm are very far back (near the rear mount), so I think they will require something like a section of a 300mm diameter dome (or larger) to have a chance of working well (they don't work well with the smaller domes I have on hand). On the other hand, the Tamron 90mm entrance pupil is much closer (near the center of the lens), and it works very well behind dome sections typically used for macro lenses (such as the dome from the Zen WA-100 port, which is a section of a ~170mm diameter dome).

Edited 17 hours ago17 hr by Isaac Szabo

Thanks. Another problem with the Sony 90 is the EP moves a lot; in fact much closer to the camera when focusing close, so it ends up very far back.

This is not the case with the Sony 100 - the EP only moves a little as you focus close in. I estimated it at 84mm from the lens flange mount. But with a small diameter port (Nauticam 140 / 70mm diameter) the best I can get is 17mm mis-alignment (OC forward of EP). For my one dive test so far, I used a total of 75mm extension with Nauticam 180 port (110 D). Theoretically I needed another 6mm. But as I mentioned, still some mis-focus problems using AFC and tracking.

If I can't use tracking, I'll stick to a flat port for this lens, but I may test some more / hoping some one else has got it humming.

My goal was to emulate the sharpness right across the frame I can get with the 50 macro and 140 dome.

2 hours ago, Isaac Szabo said:

(such as the dome from the Zen WA-100 port, which is a section of a ~170mm diameter dome).

So the Zen WA-100 port is only for Olympus housings (different from the fisheye port which has a smaller diameter)?

@dentrock The entrance pupil moves a fair amount with focus with all the macro lenses I have tested (from around 15mm to as much as 35mm+). So I measure it at multiple points from 1:1 out to a reasonable underwater shooting distance like 50cm and pick a spot in the middle of the range to center the dome around.

It's promising that the EP may not move much with the Sony 100mm and that it seems to be located in an ideal place (not far back like the Sony 90mm and Sigma 105mm). How are you measuring the EP?

I should note that I can't speak to the focusing issues you're experiencing. I'm just looking at sharpness in my testing. The Tamron 90mm with Zen WA-100 dome indeed gives me edge to edge sharpness like the Sony 50mm behind the same dome. Did the Sony 100mm behind the 180 port give edge to edge sharpness when you did manage to get shots in focus?

I must admit I'm a little confused by you saying "Nauticam 140 / 70mm diameter" and "Nauticam 180 port (110 D)". I'm not very familiar with the Nauticam ports, but do you perhaps mean radius for the second numbers? Or maybe I'm just missing something?

Again, I'm not very knowledgeable on Zen ports, but yes, I believe they also make fisheye ports with a smaller diameter dome. It was Matt Sullivan who first had me make him a macro port using the dome from the Zen WA-100 port, and it worked so well that I wanted one for myself as well.

4 hours ago, dentrock said:

But large radius domes are typically only available with large diameters (eg. Nauticam 180), so their bulk gets in the way for macro.

I would love to be proved wrong on this, and hear from someone who is successfully using a dome with either of these lenses! (And details of their rig).

@Alex_Mustard had some posts on using a dome port with macro lenses, he typically used one of those small section domes for this, here's one article on this:

Inside Scuba

Shooting Macro With A Curved Port

Explore the benefits of curved macro ports for underwater photography, including improved image sharpness and a wider angle of view.

I remember some posts on Wetpixel possibly, but can't find them right now.

2 hours ago, Isaac Szabo said:

I must admit I'm a little confused by you saying "Nauticam 140 / 70mm diameter" and "Nauticam 180 port (110 D)". I'm not very familiar with the Nauticam ports, but do you perhaps mean radius for the second numbers? Or maybe I'm just missing something?

Sorry, I meant radius!!! 140 D has 69-70 R and 180 D has 110 R.

I am estimating EP by looking from the front and marking off the apparent position on the outside of the lens, then measuring this distance back to the flange.

1 hour ago, Chris Ross said:

I remember some posts on Wetpixel possibly, but can't find them right now.

I think Subal make some large radius / small diameter domes. Nauticam makes or used to make the same kind of dome for a particular 35mm lens, in N100 size. But it costs c. AUD $800 plus would need an extension which I don't have, at another $800 or so. So unless I can get the 100 macro working with the 180 dome, I can't justify buying the more compact large radius dome, since I don't need it for the 50 macro.

6 hours ago, Chris Ross said:

@Alex_Mustard had some posts on using a dome port with macro lenses, he typically used one of those small section domes for this, here's one article on this:

Inside Scuba

Shooting Macro With A Curved Port

Explore the benefits of curved macro ports for underwater photography, including improved image sharpness and a wider angle of view.

I remember some posts on Wetpixel possibly, but can't find them right now.

As far as I understand, the MFO-1 lens corrects for the optical aberrations introduced by using macrolenses behind planports and should have similar IQ to a macrolens behind domeport (?).

For longer focal length (e.g. 90mm on FF), however, these aberrations are pretty small and neglectible. For shorter focal length (e.g. 50mm or smaller for FF), a domeport may increase IQ noticeably...

Anyone can confirm this from real life experience?

P.S.: I am using Sony 20-70mm (FF) and was using Zuiko 12-40m (MFT) behind Zen DP170 domeport (not for real macro, but for fishportrait). At the short end IQ is very good and certainly better compared to planport, but I am not shure whether the domeport brings improvement at the long end...

Edited 8 hours ago8 hr by Architeuthis

This video is gold, thanks for sharing! I was looking for something like this for so long!

2 hours ago, Architeuthis said:

Anyone can confirm this from real life experience?

With a 100mm lens (Canon) I can see a significant decrease in image quality due to CA and some softness in the corners.

48 minutes ago, waso said:

With a 100mm lens (Canon) I can see a significant decrease in image quality due to CA and some softness in the corners.

Hi Warmuth,

Is this observed decrease in IQ, when you compare the lens behind flatport to the lens in air? Or does IQ decrease when using domeport and compare to IQ with planport? Or is it MFO-1 & planport vs. plain planport?

Thanks, Wolfgang

10 minutes ago, Architeuthis said:

Hi Warmuth,

Is this observed decrease in IQ, when you compare the lens behind flatport to the lens in air? Or does IQ decrease when using domeport and compare to IQ with planport? Or is it MFO-1 & planport vs. plain planport?

Thanks, Wolfgang

Hi Wolfgang,

unfortunately I can only compare it underwater and above water, but there it's clear.

I've never used a macro lens behind a dome port – even though its use seems plausible in many cases.

But since I lose the option of using close-up lenses, I would only do it in special situations – and whether the investment would be worthwhile is another question.

7 hours ago, Architeuthis said:

As far as I understand, the MFO-1 lens corrects for the optical aberrations introduced by using macrolenses behind planports and should have similar IQ to a macrolens behind domeport (?).

For longer focal length (e.g. 90mm on FF), however, these aberrations are pretty small and neglectible. For shorter focal length (e.g. 50mm or smaller for FF), a domeport may increase IQ noticeably...

Anyone can confirm this from real life experience?

I recently compared the Tamron 90mm (on full frame) with a flat port, MFO-1, and dome port. I was shooting at a large aperture (f/4), mainly because I was shooting without strobes in my test tank and didn't want to use a high ISO. With the flat port there was good sharpness across the central 50% of the horizontal frame. The MFO-1 improved it to around 80%, and the dome improved it to around 95%. So yes, with this setup at least, the MFO-1 provided a significant improvement in edge sharpness over the flat port, though the dome provided a more significant improvement.

Edited 38 minutes ago38 min by Isaac Szabo

22 minutes ago, Isaac Szabo said:

I recently compared the Tamron 90mm (on full frame) with a flat port, MFO-1, and dome port. I was shooting at a large aperture (f/4), mainly because I was shooting without strobes in my test tank and didn't want to use a high ISO. With the flat port there was good sharpness across the central 50% of the horizontal frame. The MFO-1 improved it to around 80%, and the dome improved it to around 95%. So yes, with this setup at least, the MFO-1 provided a significant improvement in edge sharpness over the flat port, though the dome provided a more significant improvement.

Which dome port did you use for this comparison?

14 minutes ago, waso said:

Which dome port did you use for this comparison?

I made a custom port using the glass dome from the Zen WA-100 port.