Architeuthis

Here I have found an article by two very serious UW photographers about this issue (also available as video): Inside ScubaMastering Underwater Autofocus with Alex Mustard and Matt...Expert tips from Alex Mustard and Matthew Sullivan on mastering autofocus for underwater photography. Learn the best settings for macro and wide-angle.It seems even these guys have different preferences regarding this aspect (but I think what they say regards modern, up-to-date cameras)...

I am not sure that I am a "serious" UW photographer, but since I read about dumb focus in Alex Mustards book, years ago, I use it and it helps a lot. I should add that I always had Nauticam housings that have a special lever for it, just placed were the dumb of the right hand is located... Wolfgang

In my view (from someone who was owning Olympus MFT and is now using Sony FF), the difference in size and weight exists, but depends to a great extend on the type of lenses (there are differences between the FF mount systems; I cannot comment on APS-C systems, I never owned one and have zero overview there (also acryl ports or ports from other companies with comparable parameters will work, of course)): #1.: Fisheye w/wo zoom capability: Zen DP100 for MFT vs Nauticam140 (or similar) for FF. => MFT wins (Tokina 10-17mm fisheye with Metabones 0.7x speedbooster and Zen DP100; similar to Zuiko 8mm, that, however, has no zoom out capability)). I, personally was using the, optically superb, Canon 8-15mm with Nauticam 140 - almost no difference in size and weight then. #2.: WA wet lenses: work more or less on both MFT and FF (at present, Sony FF seems to have no WWL-C compatible lens and is the exception (WWL-C was developed for compact cameras; I am not sure about IQ on FF)). => No difference in practice. #3.: rectilinear WA: ZenDP170(or Nauticam180) vs Nauticam230 for FF. there are, however, exceptional lenses like Tamron 17-28mm that work very well behind DP170 (I have one, but almost never use it, since i use adapted canon 8-15mm fisheye with 2x Sony TC). In this case no difference to MFT. I do not know, whether this lens is available in Nikon Z, but Google does. => MFT wins (but not miles ahead); no difference compared with Tamron 17-28mm on FF. #4.: Intermediate focal range for fish portrait (normally seldom used): I am/was using Zuiko 12-40mm f/2.8 pro for MFT as well as Sony 20-70mm f/4 G behind Zen DP170. Both delivered excellent IQ. Now replaced by MFO-3 that also delivers very good IQ and is not flexible, but portability when travelling is so much better. => No difference #5.: Macro: here comes the really big difference: Macro rig with Zuiko 60mm or Panasonic 45mm extension (one can use the 45mm Nauticam port for both, 60mm needs an additional 20mm extension) is such a tiny and smart rig compared to the Nauticam rigs with Sony 90mm or, now, 100mm GM macrolens. In my MFT days the WA rigs (type #1, #3, #4) used to be the biggest and heaviest, while now the situation is reversed. The macro rig is the biggest and most monstrous rig I assemble with my Sony A7R5 (I use #1, #2 (WACP-C), #3 (I do not own a 230mm dome), #4). => Only type where MFT is a clear winner in my eyes (when focus is totally correct and no motion blurr, one gets excellent IQ in both systems (FF offers more postprocessing power, but this makes little difference in practice).

This item is sold now...

In case you want to go near 1:1 it depends on the shyness of the critter and on the clearness of the water which focal length to use, in good vis the focal length cannot be long enough. In my MFT days I had both the Pana 45mm and the Oly 60mm (I did not have a 30mm macro), but prefered almost always the 60mm. 45mm only in bad visibility, but the compromise is reduced working distance. The problem with the 60mm (and also with 45mm, but to a less extend) comes when one makes fish portrait from medium to large size fishes. Then the working distance is really big and IQ detoriates a lot, because of the water. In these days people use the Nauticam MFO-3 (often on flip holder) for that purpose that greatly reduces the focal length of a macro lens...

I use MFO-3 wit Sony 100mm GM on A7R5 (I am a little bit late to the party). It is a great extension of capability with o.k. IQ (MFO-3 sits an a single flip mount, can easily be switched in and out). If someone is out for the ultimate IQ, the Sony 20-70mm f/4 G lens behind Zen 170 domeport is still better for intemediate focal length, but who, except puristic professionals who are out for just this single shot, would be willing to lug lens, extension and domeport arounf half of the world for this seldom used focal lengths? Since I have MFO-3, the DP170-N120 stays at home. Sony 20-70mm f/4 and Tamron 50-300mm I take with me, but for over the water; I think I need soon a second body, A7R5 is sitting all the time in the Nauticam housing and over the water photography is rudimentary)... Wolfgang

Expectedly, you will need a lot of shares of the coppermine... 😄 Seriously talking, I would go second hand in your case (it will need monthes until the new models will become available, if this will ever happen). It is just important to decide now into which system to go (Canon, Nikon, Olympus, Sony; MFT, APS-C, FF), then later you can upgrade with intermediate expense (just 10% of a coppermine (estimated))...

In case you intend to buy new and wait for the OM1-III to appear: There are wild rumors that Nikon will offer an APS-C model based on Z8/Z9 technology this year - in case this turns out to be drue, this is certainly very worth a consideration for a small sensor UW-camera system... mirrorlessrumorsThe APS-C Camera Wars Are Here: Fujifilm X-T6, Canon R10...Nikon Canon and Fujifilm are about to unleash three new High End APS-C cameras! Fujifilm X-T6 is coming on September 3 Nikon “mini Z9” is coming in autumn with 45MP stacked sensor Canon R10II with newIn case you go second hand, anything starting from Olympus EM1II and upwards is a very good way to get started with an MFT system (upgrade Nauticam housing and camera at a later stage)... Wolfgang

I think it means that you can use the monitor only when the DSLR is in "live view" mode, when the mirror is panned upwards and the sensor delivers the "live view", e.g. on the back LCD (or an external monitor). Not when you view through the lens via the mirror (what is the "normal" mode of operation of a DSLR). All functions, especially AF, work only as good as they are in the "live view" mode (you can test easily by yourself with your Canon 7D, how happy you are with the "live view" mode; just use the back LCD, that would be mirrored by an external monitor, on some dives for framing and producing photos)... It is also important to note that AF of the "new" mirrorless cameras is regarded on par with the top DSLR models (e.g. Nikon D850) only since Sony A7R5, Canon R5 and Nikon Z8 and newer models. Before these models, AF was regarded to be inferior compared to the top DSLRs (I have no idea where the 7D stands in this comparison)...

A little but off-topic, but here is an interesting review from an UW phorographer, who was using a monitor for 5 months: https://theunderwaterclub.com/blog/underwater-stills-photography-with-an-external-monitor-pros-cons-and-verdict/?utm_source=scubaboard.com&utm_medium=community&utm_campaign=scubaboard-2026-07-external-monitor

Here is an old tread about the viewfinder issue (it seems both 0.8:1 and 1:1 work on Z8, but 0.8:1 is recommended; better ask there again):

Is this book available also in conventional form (I would prefer to have it on my shelfs)?

I think that AI got it right (this time). It seems to me that Sea&Sea and Isotta are totally compatible, but there are also different port sizes and this has to be taken into account also (but again - it is important to check with manufactureres/dealers before investing a single cent)... I found two dealers that praise this cross-compatibility in their advertisements (maybe ask these dealers in addition for specific camera/manufacturer/port combinations?): Backscatter states that "Many Port Options Isotta housings use a simple port system, which is identical to Sea & Sea's method. The good news here is that Sea & Sea brand ports are fully compatible, so if you have any in your arsenal they will carry right over. You could also run a Nauticam port as long as it has a Sea & Sea style bayonet mount on it, so right out of the box you have tripled your port options. Isotta also makes a full suite of domes and flat ports, along with extension rings so that you can dial in just about any lens combo you would want for underwater imaging. There are two port sizes, one for DSLR and full frame mirrorless cameras, and another for micro 4/3 cameras." https://www.backscatter.com/reviews/post/Introducing-Isotta-Underwater-Camera-Housings Underwatercamerastore states "7. Wide Range of Port Options Isotta uses a simple and effective port system compatible with Sea & Sea ports, meaning photographers can easily transition to Isotta without needing to invest in entirely new port setups. Additionally, Nauticam ports with a Sea & Sea-style bayonet mount are also compatible, providing even more flexibility. Isotta also manufactures a full range of domes, flat ports, and extension rings, ensuring compatibility with nearly any lens combination. Isotta Underwater Housings | Premium Red Aluminum Protect...Discover Isotta underwater housings, featuring premium red anodized aluminum for superior camera protection. Perfect for deep diving, these housings offer...

There was a tread about his distance, maybe you can get the required information from there: Furthermore, the Google AI says that Isotta and Sea&Sea are "cross-compatible", since they have the same distance - but this MUST be confirmed by Isotta, Sea&Sea or owners here, before building on this: "How big is the difference in flange distance between Isotta, Sea & Sea and nauticam housings for underwater use of FF cameras? In underwater photography housings, the "housing flange distance"—the mechanical measurement from the camera’s actual lens mount to the front opening of the housing where lens ports or extension rings attach—varies considerably across brands. [1, 2] Isotta and Sea & Sea share an identical native port mount design, meaning their housing flange distances are effectively the same, while Nauticam stands apart with a significantly longer flange distance on its standard full-frame (N120) housings. [1, 2] The Flange Distance Comparison When comparing housings designed for Full-Frame (FF) mirrorless cameras (such as Sony E-mount, Canon RF, or Nikon Z), the approximate mechanical distances from camera mount to housing port opening are: Isotta (B120 Mount): ~38 mm Sea & Sea (Custom Bayonet): ~38 mm (Native cross-compatibility with Isotta) Nauticam (N120 Mount): ~60 mm (ranging between 58.8 mm and 66 mm depending on the specific camera model’s native body depth) [1, 2, 3] The difference in housing flange distance between Nauticam and Isotta / Sea & Sea is roughly 22 mm. [1] Why This Difference Matters Because Nauticam positions its housing port opening roughly 22 mm further forward, it changes how lenses align inside the port system: [1, 2] Port & Extension Ring Lengths: If you cross-adapt a port between these brands, you cannot use the same extension ring sizes. A lens setup that requires a 40 mm extension ring on an Isotta/Sea & Sea housing will typically require a much shorter extension ring (or no ring at all) on a Nauticam housing to keep the lens elements perfectly aligned with the dome port's optical center. [1, 2] Native Cross-Compatibility: Because Isotta and Sea & Sea share the exact same physical bayonet system and flange depth, their native ports, extension rings, and dome ports can be swapped directly between housings without any adaptation. [] Using Nauticam Ports on Isotta/Sea & Sea: You can use Nauticam N120 ports on Isotta or Sea & Sea housings by swapping out the port's rear lug plate for a Sea & Sea style lug plate. Because the Isotta/Sea & Sea housing is shallower (~38 mm) than the Nauticam (~60 mm), the adapted Nauticam port will sit closer to the camera. To compensate, Isotta offers specific adapter rings (like the H18 and H26 B120-to-N120 adapters) which physically space the Nauticam port forward by 18 mm to 26 mm to perfectly recreate the correct optical distance. [1, 2, 4, 5] If you are trying to calculate a specific configuration, what camera body and lens model are you planning to use? I can help you look up the precise extension ring math or official port charts for your setup. [1]"

According to the posting below, Sea & Sea ports can be used on Nauticam housings via adaptors or minor exchanges at the ports basis: