Above Water Macro lens for underwater use

[cricfanSD]

I am wondering whether this is possible ? I use Nikon 5T/6T macro lens for topside macro. These are multi-coated two element lenses. Will this work similar to the Inon or Fantasea lenses ? Is the primary concern is that there may be water leak into the elements ?

 

[herman]

They will work however due to the different index of refractions of water and air their "power" is cut by a factor of 4. In other words, you need one with 4 times the diopter rating to get the equilivent effect under water so unless you have some pretty high diopters they are of little value. For example, an 8 diopter on land becomes a 2 underwater.

 

[bvanant]

Well, maybe. Depends a lot on which camera/port and the distance between the lens and the entry point of the camera. I use a Canon 500D on the front end of my athena ringstrobe and get way more than 1/4 of the 2x that Herman suggests. Try it and see. In general you get a reduction in magnification UW but at least experimentally in my hands there isn't a magic formula.
Bill

 

[cricfanSD]

Well, maybe. Depends a lot on which camera/port and the distance between the lens and the entry point of the camera. I use a Canon 500D on the front end of my athena ringstrobe and get way more than 1/4 of the 2x that Herman suggests. Try it and see. In general you get a reduction in magnification UW but at least experimentally in my hands there isn't a magic formula.
Bill

4x maginification reduction works for single element lenses. Not sure about the double element. hence the question. Canon 500D is equivalent to Nikon 6T, so I believe it may just work.
Atleast that will be much cheaper solution than Inon macro lenses as I bought my 6T before Nikon discontinued it.