I have now had Marelux 60 lens for about a month. I bought it for the specification of focusing well beyond the ~1 meter MFO-3 limit. The MFO-3 had been on my radar since the announcement. I was about to buy the MFO-3 about the time Phil wrote his blurb on the Marelux lens here on Wetpixels. I then looked on the Marelux site and contacted them to verify this specification which they did so I ordered it right away as I have one use case here in AK and it was due about 1 month after the solstice: the arrival of Pink Salmon in an intertidal creek near where I live. For a few days sea lice stay attached and I wanted to shoot them with a normal focal length.

We had a lot of rain from several storm systems during July. When it cleared up the residents along the creek told me they had been there for just a couple of days and it looked like the whole run entered at once likely triggered by all the rain. So I had my chance. This was also my first salmon shoot with the new Maxi strobe which I had pre-ordered way back when. See pix. One is square crop of a D800 image showing the flank of a Pink Salmon. Note the bug near the center. I looked at it at 300% and did a frame grab which is attached as well. This is an early stage of a sea louse. Prior to the big rain I attempted shooting it in the nearby lake on a sunny day. Although it looks calm there was enough of a swell to cause the algae I was shooting to sway so those pix had to be binned.

The other pix show how I used the lens on a Seacam housing. I used a Nauticam bayonet adapter and bayonet holder on a Saga port. I bought a cheap 77mm thread petal lens shade that has a plastic thread so is semi-disposable. I would avoid using metal-metal threads in seawater. The rubber shade used on my first trial (in pic) did vignette.

Edited Sunday at 06:38 AM4 days by Tom Kline

15 hours ago, Phil Rudin said:

Both the Nauticam and Marelux lenses have a 0.9X max magnification and on full frame are generally assumed to be suitable for 90mm, 100mm and 105mm macro lenses. So AOV's of 27 degrees, 24 degrees and 23 degrees. With the MFO-3 and MV-60 in place the result is an AOV of around 47 degrees+/-, 40 degrees and 38 degrees. Nauticam states it was tested with the Nikon Z 105mm macro and has a working distance of 0-1500mm or 59 inches. The Marelux MV-60 was tested using a 100mm macro so 24 degrees and 40 degrees with a working distance of 0-infinity, spec's from each websites.

I am sure many will say that shooting beyond 59 inches/1500mm is a waist of time however what shooting to infinity points out is the large difference in lens design between these two lenses. My guess is that having a flat front element allows the MV-60 to focus to infinity while the curved front element of the MFO-3 restricts working distance. This may also explain a difference in AF speed although this is purely speculative. Different camera systems have a wide verity of AF choices and to have a relevant comparison you would need to be using the same system with the same AF setting I would think.

The max magnification varies depending of focal length for the MFO3 with the Sony 90mm reporting 0.8x from the port charts. All lenses focus between 0 and about 1500mm with the MFO3 added . The stated design from Nauticam is that the MFO3 corrects for having a flat port so has better corners than what a 50/60mm macro would have through a flat port and also shifts the the focus range of the so that in common 0.5x to min magnification range corresponds to the lens focusing to infinity and the fact the lens is out in the range where AF is fast and snappy on the bare lens, so AF improves. In my case with the olympus 60mm macro my limit is 0.5x - but for what I use the MFO3 for - it's a non issue.

I've certainly found my MFO3 to be snappy when focusing once the lens racks out to the focal range needed after I first attach it, beyond that I don't even think about AF, it just snaps on. Whether or not the corners improve - I have not done any sort of detailed comparison, I'm just very happy with what it does.

In terms of sharpness crushing - a lot of people are using the MFO2 now it seems and I don't recall anyone complaining about sharpness. These lenses are being used with Canon/Nikon/Sony top line macro lenses which are as a rule no slouch optically, seems to me it would be a hard ask for a different supplementary lens to claim to be crushing relative sharpness performance when using the add-on lens unless Nauticam is destroying it. As good as the bare lens or a little better - sure seems quite plausible. I haven’t used the Marelux version so don't know how it performs but have no reason to doubt it produces top notch images.

Needs someone to spend some pool or test tank time shooting resolution targets to put the question to bed. Me personally - I'd rather go diving - but would certainly review the results with interest if someone was keen enough to produce some images to compare. Any volunteers?😅