Alex_Mustard

The Zeiss one is definitely more complicated. The front (main) part is not simply plano-concave. But it two elements sandwiched together, with the outer element being slightly convex. Also the internal lens is not a simple positive lens - but matched to the outer lens. Worried about loosing this lens, we measured its strength and made a simple replacement matched to the same strength, which didn't work anywhere near as well (showing there is something more in the design). I know that I shared a lot of stuff about it on Wetpixel at the time. That Tom also contributed to. Search Ivanoff on Wetpixel forums - e.g. https://wetpixel.com/forums/index.php?/topic/54681-full-frame-slr-wide-angle-corrector-port-tests/&tab=comments#comment-356001

That photo shows my camera before a blackwater dive, but the strobes are not in their shooting position - they are in their carry to the boat position! I generally shoot BW with the strobes pushed out wider than this, just in front of the port (as shown) and aimed in at around 45 degrees (again pretty much as shown). Ideally translucent subjects show up best with the light coming through them from behind, whereas more solid subjects show up better with more front lighting. This position is a good compromise for both (as a starting point). When shooting the MFO-3 as a main lens on BW, yes, I would have the strobes a little further forward still. Hope this helps,

Here is a photo of my port and internal lens (not attached to housing or lens): When searching my phone for the word Zeiss (to find the picture) this one came up of another one of the shots from it in print: And here are a couple more from my website that I didn’t share previously: In the UK, the older guys who used these in the 1960s and 1970s always called them Ivanoffs. I suspect that this was because they didn’t like Rebikoff personally, probably because of his commercialisation of the idea! That’s why I always call it an Ivanoff or simply a Corrector Port - as I was taught about it from these guys. My setup works very well. And I have faith in this idea for people or manufacturers to develop. It definitely has a corner sharpness advantage over a dome at more open apertures. But once you get to f/13 or more closed down - I think it performs very similarly to a dome. I was always slightly frustrated that I could not get my 16-35mm @ 16mm to perform as well as the 20mm did - it would go blurrier towards the corners. I haven’t adapted the Corrector to my Mirrorless camera (yet). This is partly because I use the Nikonos 15mm (a 20mm equivalent) with my Sony - which kind of does the same job (and is more travel friendly). And this is partly because I don’t have many Sony wide angles of my own to test - and don’t want to spend money buying lenses that I am not sure will work. Added to this, I would never shoot rectilinear as my main wide angle underwater - I just find the look of the images too low impact for my taste. I much prefer barrel distortion (fisheye distortion) compared to rectilinear for underwater shooting - so would always choose a WACP or WWL over a 16-35mm or similar for shots in this FoV range. Which means spending money on this solution is hard to justify.

Illustrated review of shooting the Sony 100mm in Lembeh is up on YouTube:

I'd agree with that from practical experience. That this is relative to flat port, not a dome port, which of course, is what we’d be using these wide angle lenses behind these days.

I am excited to see Seacam exploring this idea. And keen to see more sample images - as the one test shot on their website looks both distorted and with very poor corner performance. Which I find somewhat surprising as I found this technology gave good optical performance (up to a 20mm wide angle on full frame). I shot with an Ivanoff style port for several years, and was very happy with its performance, but have not bothered adapting it to my current housing yet - and have been using the smaller Nikonos 15mm to fill this niche instead. Here it is on my Nikon D5 in 2015. I used the optic quite a lot for a couple of years and took many well known images with it. Such as this photo from the Wildlife Photographer of the Year: Wildlife Photographer of the YearRig diver | Wildlife Photographer of the Year | Natural...Diving beneath the oil rig, Alex had to anticipate when the cormorants would burst through the fish shoal. The birds hide behind the legs of the rig after they plunge into the dark waters, gaining the And also this photo, which will be seen widely in the coming months as it is the main promotional image for the forthcoming BBC Blue Planet 3 series: Could you be a part of Blue Planet III | BBC EarthWe are currently on the lookout for captivating and unusual animal behaviours from the marine world, and would love your help. Some memorable BBC nature sequences began as observations by wildlife entAs well as others. Rebikoff was the one to claim extreme depth of field for this lens (see figure 6.13 in Mertens 1969) but I never felt this was especially evident in my pictures. This is shot with the port - and shows minimal depth of field can be achieved: https://www.amustard.com/library/fifteen/CAY15_am-101945.jpg For me the downside of the system is that the look was too rectilinear! Topside photographers always think that fisheye distortion is something that we'd want to avoid underwater - but actually it is the barrel distortion of fisheye lenses than makes many underwater wide angle pictures immersive. Non-fisheye wide angle images often feel stand-off-ish. So carrying the weight of this port around for the few wide angle shots I don't want to have a fisheye look, is the main reason I'm not currently using mine. But overall I am excited to see this option being explored and developed. If it works it would be easy to adapt to any housing. I look forward to some sample images that show decent corner performance on 16mm wide angle lenses. Mine gave exceptional image quality with my 20mm lens - but the corner performance was not great when I used my 16-35mm with it.

I've shot over 3000 underwater images with the Sony 100mm now. It is definitely the best macro lens that I have tried on my Sony. And arguably the best macro lens on the market. That said it is small gains over other options, rather than this being a whole new world. AF better, especially tracking and difficult subjects. Sharpness excellent, but not that different. Bokeh more attractive. The 1:1.4 range makes it very versatile - you can definitely do so much with the lens and MFO-1. Works very well with MFO-3, SMC-3 and EMWL-160 (although I find I get a bit more camera shake than with 90mm - despite stabiliser - need to check settings). The most impressive thing to be me is the performance with teleconverter. AF is amazing with TC.

I had the chance to shoot it in Lembeh, last week, while the Backscatter boys were in town. Matthew and I will surely chat about it when I am back.

Focusing Unit 3 working perfectly with the EMWL.

O-ring from an old Inon strobe.

Quick update on the ports. Nauticam's new port for the lens made it to Lembeh today - and it obviously fits the 100mm perfectly. I've only tried it briefly, but the 90mm port is problematic - as the front part of the 100mm lens does not fit neatly into the inside of the Nauticam port for the 90mm, so the lens ends up not being able to get right up to the front glass. Which won't be an issue for most things, but I suspect would impact using the EMWL. I will test more in the coming days. I have a shorted Nauticam flat port here (32 - I think) - which accommodates the front of the 100mm lens better. And this plus a lot of a port extensions might be better for accommodating multiple macro lenses, while keeping travel bulk down. Ultimately, though, the new 100mm port is not heavy - so maybe the best thing might just be biting the bullet and getting the new port. Although as Pietro notes above - maybe shooting through water limits how far this lens stands above the 90mm Sony - and especially the 90mm Tamron.

Nauticam's own tests with their dedicated port say UNIT 3 is best. It will be tricky to get it to work with a converted port from the 90mm as the spacing has to be perfect to avoid vignetting. UNIT 2 works too, but with some very small vignetting at some focusing distances. I'll test it with Unit 3 this week - assuming I get the port. But if I am using the adapted 90mm port I'll probably just stick to testing the 1.4 x TC (I don't own a 2x), MFOs and SMCs this time. Been busy testing other gear so far this trip so far.

One thing I meant to say yesterday was to always be careful when lenses end up very close to the glass - I’ve seen a few times problems when the housing compresses underwater (more port sections - more o-rings - more compression), the port then pushes the lens and camera back in the housing enough that the push buttons on the back of the housing start activating.

Sorry for the slow reply. Yes, I had those Saga port extensions custom made. Quite a lot of people got the 16mm one - as it was perfect for adding the Nikon 5T lens to the 90mm (in the days before the MFO-1). TIP: if you do get one - put a little mark on it - so you know where to line it up when taking it off (you'll thank me every time you have to take it on and off - every saga port extension I have owned is always super tight fitting!)