Chris Ross

I should add that I would think it would be worth at least trying it out in a pool or lake before travelling, what seems perfectly practical can end up causing unanticipated issues which may be difficult to fix in the field. For example I set my rig before I travelled to be near neutral and I had a 690 gr and a 210 gr float arm on each side. I found it took lots of torque to twist up and the solution was swapping out the 210 gr arms for standard arms and diving with it about 450gr negative. I'm going to try out a bottom float of about 400 grams on my next trip. Stills of course is a lot less demanding than video when it comes to trimming and I'm just trying for near neutrality without a lot of torque to aim up.

I think the big advantage of the 8-15 with 2x is it's versatility. it goes from a 175-180° full diagonal fisheye through to about a 28mm equivalent. I use the 8-15 with my OM-1 which gives the same range as available on FF with the 8-15 plus 2x. You would need to have a gear printed with the 2x but that should not be a major obstacle. It is effectively a 15mm fisheye, WWL-WACP with 28-60 and 14-28 lens in one package, albeit with some barrel distortion throughout the range. And it seems at least as sharp as the WACP/28-60 combination. My calculations suggest the WWL-WACP/28-60 combination has the about the reach of a 32mm lens at 60mm compared to the 28mm reach of the 8-15/2x which is pretty close and I suspect would be sufficient for most users. In fact I'm wondering if Nauticam could have perhaps worked with someone like Metabones to develop a custom 2x converter tuned to the 8-15 lens rather than developing the FCP port. It might avoid the limited depth of field the FCP seems to have at close focus. You could have a 1.5x model as well which could be used on APS-C and would also find application on full frame. All of this is possible due to the high optical quality of the Canon 8-15.

Good questions, It's hard to say till you try, the basics are relatively simple - the floats want to be on top and the housing/weights below and generally speaking keeping it symmetrical. In principle when trying to keep the whole thing neutral, I expect adding weight is probably easier than subtracting buoyancy. and ideally that weight could become your trim as well. The issue you may run into could be that float arms are more or less vertical while the float between the rail is horizontal so the distribution of buoyancy shifts when you tilt the rig. Same thing with your monitor - if it's behind the housing it's like an extension of the housing and can be balanced with sliding weights. If it's above as you tilt it over it's going to start pulling down. Perhaps you could mount a buoyancy block behind the monitor with the other block directly below it? In principle making the monitor also neutral would free up where you position it. Once you decide how to mount your monitor then you can think about where to place the buoyancy I think.

I think not exactly apples to apples comparison, this tests out the sharpness but does not consider the barrel distortion which tends to pull the subject forward in the frame in comparison to the edges. This effect becomes increasingly less obvious as you zoom in. @Alex_Mustard has chimed in when I have been comparing fields of view between fisheyes and other lenses with this observation on a number of occasions Counting squares in the centre crop looks like the image scale is 1.16x for the WACP at 60 over the 8-15 @ 30mm which could be handy for some marginal objects but with MP available I think hardly noticeable in details captured. Interestingly my calculations say almost the same thing 1.16 vs 1.17 image scale factor. To me the 8-15/2x combo has sharpness advantage in the corners at least at the wide end (just really looking at the 140mm - the 180mm as expected is a little worse).

I think if you add half the required buoyancy at the rails at the bottom and the other half in float arms it should be a lot closer to balanced. The other thing with rails is if place your dome balance weights at the end of the rails they have more leverage to pull the dome down than if the weight is around the neck of the port. The other consideration is having some small excess of the buoyancy above which means this is the natural floating position, if the excess is below then it will want to be on top.

My take is it is more useful on FF than APS-C at least from what has been presented so far. Alex likes it specifically as a small increase in magnification. The EF 100mm increases magnification to 1.2x with the MFO. In one of the videos on close up lenses a while back Alex mentioned that his most used diopter was about a +3 unit and it had about a 1.2- 1.3x magnification and this was the original premise of the the MFO. The diopter Alex used was a standard 2 element doublet design, the MFO optics will be superior to this type of diopter more than likely as the MFO has built corrections for the flat port interface. The problem as you go up in magnification is specifically finding small enough subjects to use them on. If you stay at APS-C then you've already got a 1.6x crop factor over full frame if you use the same lens, so even less critters findable that can use that type of magnification.

Unfortunately the forum software reduces these images to 1200px wide - even if you donwload the image it's 1200 px wide. The best way to compare views seems to be as follows: Open link in dropbox go to top RH corner and choose magnification I picked 50% gives you a better sense of image sharpness I think Scroll around in top LH corner of each image to bring up a polyp that appears to be in focus. swap between tabs to compare. Here's a small crop snipped from each of 24 and 26 images side by side. I just picked an area with polyps that looked in focus. Top LH corner. To me there's not much to pick between them, maybe an edge to 24, you can make out texture on the polyp arm coming up towards mid frame.. Didn't include 28 as it has a quite different image scale.

Agree, when I first started I had the idea to use TTL as it works so well on land, but soon found manual was nowhere near as hard as it seemed, the key is recognize that the flash exposure remains constant if the distance doesn't change to your subject. Realistically for most macro subjects from fist sized down to small nudis, the distance doesn't change that much and as you get closer the increased magnification reduces the exposure somewhat (varies with the lens you use of course) which kind of compensates. The end result is I rarely change flash exposure very much on a dive - maybe only when I'm shooting something like the size of a weedy sea dragon and opening up the aperture to do that is viable as you don't need as much DOF.

Looks like a great project, presumably the idea is to get the rig neutral and move the weights to change from horizontal trim to pointing up/down. It's an interesting 3-dimensional balance problem, the weights/housing want to stay at the bottom and the floats want to stay at the top so it takes increasingly more torque to twist the whole rig to point upwards. I discovered how much using about 1.4kg of floats on my strobe arms with my rig - it was close to neutral but did not want to point up. The point is if your angles are small then it won't take much to change the trim but pointing something like 30-45° up will be more of a challenge. If you increase the weight of the balance weights to assist you need more buoyancy up top which makes things worse. I faced a similar issue balancing a fork-mount astronomical telescope - they work best if well balanced and you can point them anywhere in the sky and they will stay with only slight friction on the clutches when done properly. I had a smaller guide scope piggy-backed on top and to achieve balance I needed weights equivalent to the weight of the guide scope on the opposite side of the main scope and a much smaller sliding trim weight. Thinking about how to achieve something similar if that's your aim you would need to split your flotation 50/50 between above and below the housing. An additional complication is if you have lights on arms, the balance will change every time you move them. The solution might then be to make the lights neural with a float collar on each of them. You could for example make your lights neutral, then balance the housing with buoyancy split between the arms for the lights and the other 50% strapped to in the inside of your rails. you could move the bottom floats back and forward to help with front/back trim. Just some thoughts on how to make it balanced in most positions.

The CMC-1 is slightly more powerful than the SMC-1 as I recall and the CMC-2 a bit less powerful. In previous versions of the port charts there were a few lenses listed with both SMC and CMC and you could see slightly more magnification with the CMC-1 compared to SMC-1.

Did you read the MFO thread? mixed opinions there but seems most useful for full frame, though it does add an extra lick of magnification which may be useful depending on your subject.

The issue is the D2000 won't sync without the magnet, you can buy replacements. Might be easier to just start using the MF-2. it will force you to use manual, though it's really only a macro flash. If you do nay wide angle , you will need a different strobe/strobes.

Good to hear you are getting it sorted. What was the damage for the housing service? Assume it's a Nauticam?

You didn't say which camera you were using, generally it has to be set up correctly along with the trigger and the strobe. The camera knows nothing about the strobe and the strobe nothing about the camera so all settings need to be sorted out. If you have an MF-2 and don't have an Olympus camera and you want to use the MF-2, manual is the only game in town unfortunately. I think if you want to make use of the MF-2 you probably need to bite the bullet and work out how to use manual and you might as well do that now with the D-2000 as well. An outline of manual mode - first on the camera set it to manual SS/Aperture, pick your aperture maybe f11 on a Sony APC-C maybe 13-16 on FF, choose your ISO. Shutter speed should start at your flash sync speed assuming macro and no ambient contribution Set your trigger to manual - I assume this will only emit a single flash from your trigger - No pre-flash Set the strobe to manual and pick a high to mid range setting. On the D-2000 you want the magnet in. Take a photo with the rig setup in a mirror pointing the strobe straight ahead - you should see the flash in the image. This confirms sync. Take a test shot of a small 3D object about the size of your usual subject - setup on a table so you can repeat easily and adjust exposure up or down till you get the subject properly exposed. This is you starting exposure for macro. For things around this distance that exposure stays constant . If you double the distance from the strobe either open up one stop or increase flash power one stop. For wide angle with the D2000 try it out at maximum on the dial without going around to full power on the mode dial. If you are using the MF-2 on manual it reads the first exposure to work out if it needs a take into account a pre-flash or not. Until you get used to things keep your aperture constant and just adjust flash strength - it's one less thing to think about - once you feel confident start moving the aperture around if desired.

There's some discussion of using the 140mm dome with the 10mm in the thread on the Laowa 10mm here: If I recall correctly @DreiFish did some testing of the lens as well, might have been in a 180mm dome.