The 2x designation is nothing other than marketing. It is happily regurgitated by those who won't make the effort to measure and denigrate others who do by calling them pixel peepers and measurebators. Thankfully, engineers who develop these products are willing to measure.
I assume that was directed at me. First off, I meant no offense in my comment re. pixel peeping, and if my comments came across that way, I apologize. My reference to pixel peeping pertained to the optical quality aspect, and I put it there to make it clear where my particular preferences lie - so that people can put my stated opinion in its proper context and take it for what it is worth.
As an engineer myself, I agree with you regarding the value of proper, scientific testing. But my engineer brain also tells me to test in a manner that is appropriate to the required performance. My required performance is "sharp large prints" - the first thing I did when I got this adapter is take a few shots and make some prints. Loved the results.
I dont make the effort to measure specs that dont make a difference to my shooting. IQ with and without the Macromate is irrelevant to me - I will never be doing A/B comparisons of prints. So I am sorry if my opinion doesn't meet *your* specific standards of scientific rigorousness - but since no one is paying me to do any tests for them, I'll stick to measuring the performance that is relevant to *me*.
And FWIW, I think a lot of people spend far too much time obsessing about minute optical differences that are only relevant under testing conditions or at 100%, and I'll stand by that. I have yet to have *anyone* look at a good image I have taken with a $200 lens and go "that is lacking in critical sharpness" - nor has anyone taken a look at a lousy image I have taken with a $6000 lens and gone "that is a lovely, sharp image." Comparing performance with and without TCs and diopters makes no sense to me - that is my opinion, and I state it not to provoke but to make my own biases clear. Those who disagree with it can then ignore the rest of my opinions.
The Macromate claims that it can achieve 2:1 macro in combination with a 100mm lens, thus the 2x label. My own testing with the original version showed this to be highly optimistic with my port and lens. With a 50mm lens, there's no way it is anywhere close to 2x.
This is good to know. I'll refrain from calling it a 2x from now on.
In the simplest terms, diopters work by modifying focusing distance, but there's more to it. As the diopter is moved further from the lens, magnification increases. A lot of the benefit of a Macromate, or other wet diopter, comes from being fairly far from the end of the lens. You can play with one and see the effect. It's basically an expensive magnifying glass.
And this is exactly how I find it to be most useful. You can shoot at 0.5x - 0.75x at much greater working distances, thanks to the greater magnification of the lens.
I think a Macromate, or similar, is great to have for when you need it but it is not a substitute for taking right lens on the dive. I feel the same way about teleconverters.
That's generally my approach when I am shooting at home - I can afford to go after 1 specific subject a day, and so take the 100mm macro when that is needed.
But when traveling, where one doesnt always have the luxury of going after 1 subject per dive, it adds flexibility. For example, in Lembeh, it was invaluable, as it let me shoot everything from reef octopus to tiny nudis with the same lens. And I have been getting good enough results *for me* (again, without any scientific testing, so feel free to ignore my opinion) with the 2x that more and more, even at home, I find myself taking the 50mm + Macromate instead of the 100mm (unless I specifically have small critters and nothing else on the agenda).
Good grief, I sound like a shill for Macromate here. It is positively embarrassing, so I'll just shut up now. I am just really thrilled with this accessory, that's all. It has been a HUGE help for me, given the way I photograph. YMMV.
V.