If I were to order a magnifier+adapter from reefnet; would I be getting the new one or the old one? Does anyone here know?
Yes, you'll get the new 67mm threaded version. The "old" one is no longer in production, and the new ones have been plagued with manufacturing delays, so won't be available until around the end of August... *crosses fingers* Send me an email if you want more information about it.
Phew this thread is a heavy read!
So to try to summarise - a DX (cropped) sensor camera gives greater magnification, however a FX (full frame) sensor will have greater depth of field (1.5x more) than a DX sensor when both are used with the same lens at the same magnification. Could someone please confirm these (seemingly) simple statements without going into a massive amount of mathematics? A simple "yes" or "no" will do nicely.
Incorrect. Sensor size does not affect image magnification. With the same lens, at the same image/object magnification, a DX and FX sensor will have the same depth of field (for a given f-stop).
I think what you're talking about has to do with "apparent magnification", in which case, you are also incorrect. If you produce the same image with a DX and FX sensor, the DX sensor will produce more depth of field, since it will be an image at less magnification than the FX. To explain - at 1:1 magnification, an FX sensor gets filled with a 36mm subject, while you'll be able to fill the DX frame with a 36mm subject at a lower magnification level (1:1.5), since it is 'cropped'. With other characteristics held constant, lower magnification results in more depth of field.
Sorry about the numbers here, but hard to explain without them! I hope this helps!