dentrock

I test dived the 20-70 with A7RV, Nauticam housing, 140 dome and a total of 75mm extension (25 adap + 50 ext) as per Phil's rig. I really, really wanted to say it worked out well... but it didn't. Pros: 1. At approx 5440g exc arms and flashes, rig is approx 450 g lighter on land (cf 180 dome rig in my post above). Doesn't sound much, but I noticed it on my shore dive. 2. Smaller dome makes it easier to line up a small subject before you take the pic. Cons: 1. Noticeably more negative underwater. Some will want to add floatation, whereas I don't think the 180 rig needs that. 2. Max mag down. MFD at 20 still approx 50mm from dome, increasing to approx 100mm at 70. I estimate the mag at 70 MFD has dropped from 1:2.6 achieved with 180 rig, to around 1:3 - 1:4 with 140 rig. 3. Corner sharpness noticeably worse than with 180 rig; or more precisely, the central circle of acceptable sharpness viewed at 100% does not approach the centre of the long sides of the 3:2 frame (my benchmark). Even at f8, the 180 rig noticeably outperforms the 140 rig at f16. This is no doubt because the optical centre of the 140 dome is approx 19mm in front of the lens EP (just a few mm difference with the 180 rig). 4. FOV likely also affected by misalignment, but I won't try to measure this. I could use a shorter extension to improve corner sharpness, but that would drastically affect close focus ability. Verdict: hmmm. OK at 70 if your subjects are not too small (say, 60mm up). OK for shooting larger subjects you come across. Not OK if you are shooting mainly WA. If you want to use the 20-70 a lot, the 180 rig is a better option.

All lenses and also battery packs for A6400 housing now sold. Price drop on housing bundle to $1800 without vac valve or $2000 as listed exc battery packs. That's AUD....

Phil Rudin has posted plenty of WA photos for this lens. Here is a close-up of a 40mm male Nesogobius pulchellus, moderate cropping and minor processing (I tried and failed to upload uncropped version), at 70mm. Not too shabby for a do-everything zoom, so might satisfy fish nerds and perhaps blackwater dudes:

Finally got to test mine this morning with A7RV and Nauticam, and following the N port chart recommendation (35 adap + 35 ext + N120 180 dome). In addition to Phil Rudin's positive reports: Positives: 1. At 20, focuses to within approx 50 mm from dome. 2. At 70, approx 65-75 from dome. Specs say 1:2.6 max mag; MFD 30cm at 20 to 25cm at 70, so N recommendation is sound. 3. Heavy rig on land but quite well balanced UW. 4. Successfully shot 40mm gobies as well as a bit of boring WA in the conditions. 5. Very sharp for close-ups and fast focus. As sharp as my macro lenses on gobies. 6. Corners pretty good (no complaints from me, but obsessives can obsess). Besides, for WA I rarely shoot with smaller ap than f8. 7. Zoom is operated by the housing knob and gear. No need for adapter with knob. 8. Terrific lens for general use on land. Negatives: 1. As above, rig is very heavy on land at 5913 g, excluding strobes and arms. Actually, shocked me coming from APS-C A6400 rig. Not ideal for shore dives, depending on difficulty of entry. Options to reduce weight include: a) shoot with A7CR (1.1 kg lighter, comprising 200 less for body and 900 less for housing) b) try with 140 dome (save another 500g). Will do so weather permitting. 2. 35mm adapter used as recommended, but adapter knob gets in the way of housing knob. Because of the profile of the housing face (not flat), cannot mount upside down to get the knob out of the way. What was Nauticam thinking?????? If I was buying the bits to use this lens again, I'd use the hideously expensive 25mm adapter (no knob) + 50mm N100 ext. Or if I owned the N100 version of the 180 dome, no need for adapters. Just use extensions... 3. For close-ups of small, slow moving or static subjects, I like to sight the camera in externally first, then move to the EVF, focus, recompose and shoot. This is fine with a comparatively narrow macro port, but impossible with the big 180 dome. Using 140 dome may help.

Phil, in earlier posts this distance (lens flange to port flange for your Marelux) has been quoted as 43mm. If it is in fact approx. 30mm, that is good news and makes perfect sense. It also means that whatever best extensions you come up with for your Sony FF Marelux rig, we can apply to Sony FF Nauticam rigs, as the measured lens flange to port flange distance for the latter(26-28 depending on who measured and which model) is close enough to the Marelux figure. No need to add that 15-17mm extra for Sony / Nauticam, as quoted earlier in this thread. Perhaps the 43mm is for sensor to housing flange? The only remaining variable is where the optical centre lies for the Marelux 140 dome. I'm making the (bold) assumption that this is also close enough to the Nauticam 140 figure (6-7mm behind the dome port flange) as to not make any further difference, for the purposes of calculating necessary extensions. I am keen to see how you go with reducing your extension from 35 to 30. Perhaps we can get to a compromise where corners are sharp enough with a shorter-than-theoretically-ideal extension - and we don't need to remove the 140 port shade! Apologies for all this measurebating, but I can't dive my Laowa 10 until next week at the earliest. Still, we have a great starting point!

Kenko sold (ebay). Will (politely) consider all offers on adapter!

All lenses except Sony 30mm macro now sold (Gumtree and ebay). I can see I will have to drop the price on the housing bundle, so all offers will be considered (and no offence will be taken on lowball offers)! Will also consider all offers on my N85 to N120 50mm adapter (in other ad). Thanks

I think 121 said the 'built-in' ext was 25mm, with the optical centre still being a further 25mm behind the flange.

This is very helpful Phil! Many thanks. I had assumed the 20-70 would not focus close enough to be worth the trouble with the smaller 140 dome, so good news it can be used with the 20-70 and 10. I have the 25mm adapter and will try it with the 10. Thanks again.

Notes on vignetting (on land), applying my above figures: 1. With 35mm adapter and no other extension plus 140 dome, vignetting is slight - say, 2-3mm of shade visible top and bottom. This could be easily cropped in post - or I could remove the shade. At this stage, I prefer to keep the shade and try this combo in water, in about 3 weeks or so. 2. With 180 dome plus 35 adapter plus 20mm extension, vignetting is substantial - shade plus internal port. The shade is fixed, and I doubt removing the 20mm ext would fix things (and that much mis-alignment would seriously compromise the corners). I won't be testing this in water any time soon. 3. With 20mm extension plus 35 adapter and using the 8.5 inch acrylic dome, vignetting is moderate (in between the above two options). The shade can be removed but this won't quite remove the slight corner cutoff. which I would put up with. Regarding this dome's calibration, I think 121 said the optical centre was 26mm behind the flange, so much the same as for the 180 - I can't confirm this figure. Someone else to advise and confirm???? Regrettably, if I want to use both the 20-70 and the 10 behind one dome on a trip, the 8.5" with shade removed is the only solution, unless I buy yet another larger dome, which really, really, isn't going to happen.

So I have just got my Laowa 10. And since no-one else has volunteered an EP measurement, here is my estimate: 61mm from lens flange to apparent position of diaphragm, when viewed from the front of the lens (just below the blue ring on the lens). Others should check this and let us know what they think, as I found it reasonably difficult to estimate for this lens; but I expect my figure to be within 2mm. Now, using EP=61mm and a flange distance of 28mm for my Sony A7CR (use 27mm if you like); plus a figure of 7mm for location of optical centre behind dome flange for Nauticam 140 FE dome (use 6mm if you like), an extra 5mm extension is theoretically required plus the N100 to N120 35mm adapter to align the EP with that dome's optical centre. Since there is no 5mm ext available, try none, which may reduce any vignetting. Or try a 40mm adapter if there is one and you can be bothered.... For the Nauticam 180 WA dome (and using a figure of 25mm from old mate now departed for location of optical centre behind that dome's flange), required extension for Sony mirrorless is theoretically 23mm (plus the 35mm adapter). These figures are starting points only, and do not take account of any vignetting (not tested yet).

I just re-measured my Nauticam A7CR rig and it still came out at 28mm. I also measured my Nauticam A7RV and that was 27mm; both using two rulers. I suggest people measure their own rigs... to see if there's any variation. I noticed the tray position is not so precise, so could account for maybe 1mm. Regardless, to make best use of these flange measurements, we will need EP measurements for various lenses (distance from aperture location as viewed from the front, to lens flange); and distance of optical centre behind dome port flange. If you accept that the radius of the Nauticam 140 dome is 70mm, that distance is 7mm (or if you agree with old mate now departed), it's 69mm radius making the variation 6mm. I'll volunteer an estimate of the EP for Sony 20-70 at 77mm, at 20mm (decreasing towards tele end). I wish someone would estimate the EP for their Laowa 10! It's not hard to do! Within a couple of mm will be fine for now. I have EPs for various E mount APS-C lenses, but not much interest in those.

It was a "dirty" measurement, made only for the purpose of calculating required extensions for various off-chart applications, so maybe within 1-2mm which is fine for that purpose. Regarding possible diff measurements for Nauticam / Sony rigs, note that they list 3 diff port charts for Sony N100 ports. Go figure! I have been using the A7RV etc chart and ignoring the others, because it's the most comprehensive. Regarding Chris' comment about Nauticam gear meshing, note that although the gears themselves have only a very small tolerance for misalignment (max approx 1mm) there is a bit of variation possible depending on where you mount the gear on the lens.

I did a quick measurement on my Nauticam A7CR rig when I bought it and came up with 28mm. I think our erstwhile and now departed friend arrived at the same figure for whatever Sony he was using. FYI any A6xxx users following this, the same measurement for my Nauticam A6400 rig was 13mm. Has anyone asked Nauticam to reveal their port / ext recommendations? They should have tested the Laowa 10 by now.

I have a 25mm N100-N120 adapter. 20mm ext might work with that, if 10 ext + 35.5 is a pia??? Still waiting, waiting on my 10 Laowa.

PS: also have not seen a measurement for EP from lens flange for the Laowa 10. I have one on order but goodness knows when it will turn up. Any chance of a quick estimate for that too (method estimating apparent position of diaphragm is fine if you are reasonably careful)?

Thanks for the tests. But what's your measurement for sensor to housing port flange for your Canon R5C (so we can estimate performance for other brands)?

That's an interesting accessory - thanks for bringing it to our attention. Pricey though, like all Nauticam accessories. A question: does the housing hold the vacuum when you remove the bulkhead cap to charge / download the camera? If not, a virtually cost free alternative could be to coil up within the housing a short USB cable already attached to the camera, and whip the back off to download etc (still no need to remove camera and lens).

Price drops: Nauticam adapter now AUD $400. Kenko 1.4 now AUD $130. Offers considered.

Price drop on housing bundle: now AUD $2300. A6400 body, Sony 70-350 and Sigma 18-50 are now sold (Gumtree). Offers considered on all items.

Housing c/w body cap, case, tools. Very good condition. NB: one corner of plastic fibre cable mount filed down to allow N85-N120 34.7mm adapter to fit. No effect on housing integrity as it is a 'wet' (removable) block. Also included: 2 Nauticam battery packs with cables, #25624 M14 Vacuum Valve II (fitted) inc. pump and tool; #83213 M67 to bayonet mount converter, inc installation tool. Total new prices (Scubapix Cairns) AUD$3,981. Asking AUD $2,500. Also for sale (not worth posting details here, so message me if you want anything): A6400 body VGC low shutter count Sony E 18-135 Sony E 16-55 G Sony E 70-350 G Sony E PZ 10-20 G Sony E 30 Macro Sony FE 100-400 G Master Sigma 18-50 DC DN for Sony E All the above in excellent to near mint with original boxes, paperwork caps etc. All will be advertised on Gumtree and some on eBay.

When I uploaded the photos, the system deleted all my text... Trying again: For sale: Nauticam N85-N120 50mm adapter very good condition AUD $420 Kenko N-AF 1.4X Teleplus Pro 300 DGX teleconverter for Nikon AF DSLR, very good condition AUD $ 150 Thanks to all who manage to view this ad! (Why can't we delete a stuff-up??????????)

Phil, thanks for your help, especially regarding the 20-70 and flat port.

I have been pondering this question for some time, and was wondering about shooting the 20-70 behind a flat port, IF I could get say, 35-70 happening. Can't tell without getting my hands on one. I do have the now-discontinued Nauticam Compact Port system which has a larger port window compared to their macro ports, which may help. If I do buy the 20-70, it will only be because I want to shoot it on land as well. Couldn't justify it for purely UW use. I also considered that Tamron 35 1:2, but all the reviews say while it has decent IQ, its AF is poor, which is a deal breaker for me for fish photos. Amazingly, despite a huge number of 35mm options, none focus decently close (except for the Tamron). For now my go to lens is the 40mm Zeiss CF f2.0. Its max magnification is just under 1:3, or to be more precise, a subject approx 112mm long fills the frame horizontally at minimum focus. If you include some background for context, then the minimum practical subject size at minimum focus is say half that (55mm), or a bit less if you crop. Working distance is satisfactory for small gobies.