Laowa 10mm or 7.5mm MFT in 4.33" dome

I don't think anyone will have tested this, but as the 10mm f2.8 MFT lens now has auto aperture and the 7.5mm f2. will get it soon they become more attractive for underwater use. Does anyone thing they're worthwile to take underwater in a 4.33" dome or will the corners be too soft? I would think the chances with the 10mm prime are much better but who knows...

Would certainly beat lugging the 8-18 and 7" dome in terms of travel size. 

They are rectilinears, so no, the 7" is certainly marginal for the 8mm and of 8-18 , so the 7.5mm would need at least as big a dome and 10mm is not that much narrower, so I thing the corners with the 4.33"dome would be pretty ordinary.  People talk about using the Oly 12mm f2 in a small dome though - I think Phil Rudin was a proponent of that combo from memory. 

They're also MF, which I think is an issue, you need to be able to focus the lens and focusing critically can be a problem with wides.

If you want to use a little dome then the fisheyes are certainly an option worth considering - if your pockets are deep you could consider an adapted 8-15mm otherwise the m43 fisheyes are nice lenses.

I am happy with the results at 8mm behind the 7" dome, but I agree that 7.5mm behind the small dome would be a fools hope. My parents use the 9-18mm behind a 6" dome and that's also not that great, so probably the 10mm is out too. I don't think a 12mm prime is really all that wide (I've tried the 12-50mm in the 7" dome). I already have the Panasonic fisheye and 4.33" dome and I am generally very happy with it. I'm just looking for a slightly narrower (doesn't even need to be rectilinear) solution for when the 180° fisheye is too wide. 

The following options seem to be available:

Olympus 12-50mm with MWL-1 (would allow 150-71° FoV according to Nauticams Portchart). This is probably pretty cool although the (very sparse) reviews of the MWL are not that confidence inspiring. Biggest downside is cost and no splitshots, but splitshots are pretty hard behind a small dome anyway. Upside is, you would still be able to also do macro with the 12-50mm macro mode.

Canon 8-15mm and a bunch of adapter and 140mm dome. This combination would probably be the best wide angle image quality wise and would also allow splitshots. Cost is about the same as the MWL-1, maybe a bit more.

Olympus 12-50mm in 4" Wide angle port. This port is I believe a really small cut from a fairly large dome, which is fine for the reduced FoV of a 12mm lens. It also has an option for a flip adapter to add macro wetlenses. No Idea how good a CMC-1 would work in combination with the 12-50mm behind a small dome. This would be quite good as an allround solution for dives where you don't know what you will encounter (same as the MWL-1). It's much less expensive (probably about 800€ for Port&Flipadapter), but obviously gives a much narrower FoV. Like the MWL-1 I've not found any reports online of this solution.

The unanswered question on the MWL is the aperture requirement.  They say it needs f16 on full frame - I've seen no reports on if or how much that could be relaxed on m43.  f16 is well into diffraction territory on m43 sensors.

the little 4"dome is interesting - you'd need to see just how well it fitted the 12-50- you would want the lens to be nice and close to the inside of the dome at 50mm for the CMC to work well I would think and of course no info available on that either. 

So when you say 7"dome - assume you mean the Nauticam acrylic?  I've seen that dome and my Zen 170mm dome is significantly smaller.  Apparently you can use the Zen N120 170mm dome for the 8-18 and the also the olympus fisheye if you have a custom short n85-n120 adapter if I remember correctly- you can't do it with Pany lens as you need zero extension which is not feasible.

The 8-15 fisheye would be nice but not a total  solution that replaces the 8-18mm.   In terms of horizontal coverage angle at 8mm you get 130° field and zooming to 15mm gets you about 70°.  The 8-18 goes from 94° to 72° between 8mm and 12mm.  The fisheye goes wider in the corners but you normally don't have the main subject extending into the far corners.  So it provides a reasonable coverage but obviously you can't do the smaller stuff the 8-18  can do.

I just wish it was easier to try these things out. I've heard that Kraken/Weefine is working on a MWL-1 clone, that will hopefully be a bit cheaper. 2000€ is a bit of a stretch for me, although the MWL certainly does sound very nice.

When considering a zoom fisheye, do not forget the Tokina 10-17mm. My wife and me are using both Canon 8-15 and Tokina 10-17 behind Nauticam 140 and Zen DP170 (maybe your parents have one of these domes, also the Nauticam 180 would work). The Tokina 10-17 with Metabones 1x (only possible with Zen DP170, but not Nauticam 140) provides even more useful angles of view than the Canon and IQ for the Tokina is surprisingly good UW (the Tokina is a terrible "joke-lens" over the water, but UW performance is different).

When wider angles are required (especially with Canon 8-15; Tokina with teleconverter already looses IQ), also the Kenko 1.4x teleconverter can be used...

Wolfgang

On 1/10/2021 at 10:35 AM, ChrisRoss said:

The unanswered question on the MWL is the aperture requirement.  They say it needs f16 on full frame - I've seen no reports on if or how much that could be relaxed on m43.  f16 is well into diffraction territory on m43 sensors.

the little 4"dome is interesting - you'd need to see just how well it fitted the 12-50- you would want the lens to be nice and close to the inside of the dome at 50mm for the CMC to work well I would think and of course no info available on that either. 

So when you say 7"dome - assume you mean the Nauticam acrylic?  I've seen that dome and my Zen 170mm dome is significantly smaller.  Apparently you can use the Zen N120 170mm dome for the 8-18 and the also the olympus fisheye if you have a custom short n85-n120 adapter if I remember correctly- you can't do it with Pany lens as you need zero extension which is not feasible.

The 8-15 fisheye would be nice but not a total  solution that replaces the 8-18mm.   In terms of horizontal coverage angle at 8mm you get 130° field and zooming to 15mm gets you about 70°.  The 8-18 goes from 94° to 72° between 8mm and 12mm.  The fisheye goes wider in the corners but you normally don't have the main subject extending into the far corners.  So it provides a reasonable coverage but obviously you can't do the smaller stuff the 8-18  can do.

The 8-15mm and the 8-18mm are two different solutions for different things

I use the 8-15mm as prime wide angle lens for fish it is very flexible like a Tokina on APSC

The 8-18mm is good for shots with people, wrecks where lines matter and split shots. In fact it is my favourite lens for splits and the one I I use

When considering a zoom fisheye, do not forget the Tokina 10-17mm. My wife and me are using both Canon 8-15 and Tokina 10-17 behind Nauticam 140 and Zen DP170 (maybe your parents have one of these domes, also the Nauticam 180 would work). The Tokina 10-17 with Metabones 1x (only possible with Zen DP170, but not Nauticam 140) provides even more useful angles of view than the Canon and IQ for the Tokina is surprisingly good UW (the Tokina is a terrible "joke-lens" over the water, but UW performance is different).
When wider angles are required (especially with Canon 8-15; Tokina with teleconverter already looses IQ), also the Kenko 1.4x teleconverter can be used...
 
Wolfgang

Nice thing about the Tokina is that it's so cheap. Unfortunately it doesn't fit through the N85 port system and all the adapters make is about as expensive or more so than the WWL-1. The WWL-1 vignettes with my Olympus 12-50 (which is very nice, so I'd like to keep it). The MWL doesn't but it's super expensive and not widely tested. 

For now I will hold off and stick to what I have. After all the main concern for me is a more compact system. In terms of Fisheye, Wideangle and Macro I've got all the bases covered and I don't necessarily need it all on one dive.