Rookie question: 105mm Nikon + Diopter for tiny stuff?

Rookie question. So have been playing with my new Nikon 105mm macro lens and it works great. I know Macro Mate makes a 2:1 lens, $500, that would work with my Aquatica flat port. If I am planning a dive to shoot real small stuff could I use a Diopter, -$500, (is this the right word?) something that doubles the magnification? Will it and the 105mm fit in my D100 Aquatica housing with its flat port and extension ring? Dumb idea? Possible?

I'm wanting to a formal comparison of wet diopters since I own the macromate plus others. For now I'll just comment.

First, the macromate doesn't go inside the port. It mounts outside and is removable underwater. There is room inside the port for a diopter but that's a simple Nikon 3T or 4T. I think you can use a 3T most, if not all, the time.

The claims of 2:1 with the macromate and a 105mm are just plain false. The best I could achieve was nowhere near 2:1 but in line with what you'd expect from a diopter on that lens. Perhaps 1.3 or 1.4. Granted I used the Canon 100mm but that makes little difference. My results were not scientific but some day I'll measure it.

In addition, it's expensive, heavy, easily damaged and does not travel well with your rig. It's also tedious to take on and off. I got nearly as good performance out of the cheap woody's diopter and I'll add that Inon makes a +3 achromat wet diopter for far, far less money. Granted you have to adapt it to your rig but it should tell you what the value of the $500 piece is when Inon's goes for $150.

Ultimately, if you need high power you should use more focal length. Get a Nikon 3T for your lens plus try to adapt a woody's diopter. If that's not enough then use a 1.4x teleconverter or switch to the Sigma 150.

I quite often use +1, +2 and +4 dioptres with my 105mm. These all go on inside the port - so can't be changed once you are UW. So you loose flexibility, but they work well and are much cheaper than a wet dioptre. Plus you can't loose them UW!

IMO when shooting super macro is that you want you whole rig optimised for the technique - strobe positioning, spotter torch etc. Better to dedicate 1 dive to super macro and one to standard macro?

Alex

Like the idea of a wet "diopter" but am willing to commit to shooting "super macro" for a whole dive, of course that’s when a whale shark, Lock Ness Monster show ups but oh well. When I want to get 2:1 is the device called a diopter or teleconverter? Typically buy from B&H Photo, what should I look for?

When you say 2:1 do you mean apparent? Are you using a DX sensor camera?

Let's say you want a frame width of 18mm, that's 2:1 apparent, and you are using a DX sensor camera. With a 105mm and a Nikon 6T you can get that since the crop factor is 1.5 and the lens with diopter will do about 1.3. That's about all you can get out of the 105 alone.

For more you could use a 1.4x teleconverter with your 105mm and get down to about 17mm or combine the teleconverter with the 6T diopter and get down to about 13mm. Shooting frames that small becomes very difficult!

Now, if your camera is full frame then you lose the crop and 2:1 apparent becomes much harder. That's not the case for many here but it explains why you might need the longer macro lenses like the 150/180/200.