S&S MDX-D300 help needed: Nikkor 12-24mm & 10.5mm w/teleconverter

[bfdc]

You'll want the 20mm SX extension ring with the nikon 10.5 + tele, or the tokina 10-17mm.

Regarding the +2 or +4 diopter, most people will test this themselves, the right answer can vary depending on the particular port, housing and extension ring. A quick pool test should do the job! - Scott

thx Scott...I think I have all the possible combinations covered now...a +2 and +4 plus a 20mm and 40mm extension. The hard part will be finding a pool in November! I may have to visit the local shop and see where they are teaching their next certification class to get access to a indoor pool.

 

[Magrone]

Hi....doing some upgrades and considering trying different types of shots with my existing Nikon D300/S&S MDX-D300 setup and need some confirmation of port/extension combos before I start spending money.

I have Nikon 10.5mm and Nikon 12-24mm lenses. I have the S&S NX Fisheye Dome port (acrylic, large dome, NOT compact)

Question 1: CFWA or WA Macro

I would like to put a teleconverter behind the 10.5mm to try some of really cool fisheye "macro" shots I have been seeing on the web. By itself, the 10.5mm works great with my NX dome. I assume if I put a Kenko 1.4TC behind it, I will need to put a port extension on the NX dome. Is that true? If so, which one? One educated guess said it looked like the S&S SX extension would do the trick.

Can anyone confirm or let me know what they use?

Question 2: Improving Performance of 12-24mm:

As many have noted in the past, the 12-24mm seems to have soft corners when use without "aids" in the NX dome. I have searched, but I can't seem to pin down a consensus about what combination of port extensions and/or diopters are needed.
-Port Extension Only (and which one)?
-Diopter Only (and which one)?
-or port extension and diopter combo (which ones?)

I have seen suggestions of SX extension only/no diopter; I have seen 40mm extension w/ +4 diopter; and I think a +4 or +2 diopter only.

Any thoughts? (I just hope then answer isn't "any of the above...maybe") ;-)

thx for your time
Paul

In regards to question 1, in my opinion, there is not much point in trying to put a TC on the 10.5 with a big dome for wide angle macro, for 3 reasons. 1.You won't be able to get very close to your subject because of the size of the dome 2. You won't be able to get low enough on the subject because of the size of the dome 3. Lighting will be a pain in the @ss because you will have to pull your strobes way in order to light the front of the subject, which most likely will result in flair or backscatter... because of the size of the dome. If you really want to shoot wide angle macro, I reccomend the zen mini dome, and possibly the Tokina 10-17 instead of the 10.5. The Kenko TC on the 10.5 will only get you as close as the Tokina at 17mm, which is still pretty wide for macro. The Kenko on the Tokina gets you significantly closer, but most of the pictures I see with this combo look a little soft.

At the very least, I suggest a smaller dome.

 

[bfdc]

thx for the feedback Magrone...I am aware of those challenges and I wouldn't disagree. The small dome is ideal, but it seems to me to be a one trick pony for most of the diving that I do. From my internet browsing, my "concerns" for the small dome and/or tokina:
1. doesn't handle non-fisheye wide angle lens, so I would have to travel with both
2. is a worse performer than my big dome for normal 10.5mm fisheye pics...particularly available light. Needs to be stopped down quite a bit to sharpen it back up. A challenge on deep wrecks/lower light situations
3. cost $899
4. Tokina has the same issue as #2....and with my normal diving, I find my "fin" zoom works very well with my 10.5mm - wrecks don't move much! I know the 10-17 is extremely popular, but I love my 10.5
5. Tokina cost $500-600 additional plus zoom gear, etc
6. there has been some interesting "reduced FOV" uses of the 10.5mm/TC/big dome combo which don't require that extremely close positioning of the dome for larger stuff.

...I will give it try and see. I may end up passing on the TC. UwP - a big experiment of throwing money into the ocean to see what works! ;-)

 

[bfdc]

The purpose of the extension ring is put the lens' entrance pupil at the center of the partial sphere
of the dome. That allows the lens to look out perpendicularly to the dome which helps to keep the
corners sharp.

The purpose of the diopter is to allow the lens to focus on the virtual image which is a much closer
apparent distance than the actual subject.


Chuck

a followup....and stupid question....I see where folks say that putting a diopter in front of a lens may impact on that lens ability to focus on the virtual image when at infinity. I think a +4 will have a bigger impact than a +2. In practical terms, what does this mean? I assume it doesn't mean "exactly" at infinity, but it must impact distances shorter than infinity...say beyond 10' or 15' on the Nikon 12-24? It has a very short focus "throw" I am curious just what the range reduction would be. There is probably a formula somewhere

thx

 

[Chuck Tribolet]

The virtual distance to virtual image is a function of the dome port radius (smaller radius, shorter virtual distance, IIRC) and real distance to the subject. Someplace I'm sure there's a formula.

I'm pretty the diopter Adm. Linda uses with her Nikkor 12-24 and 10-24 in an 8" Aquatica dome is a B+H +4. It's worked fine. I can verify the strength of the diopter this weekend.

Chuck

 

[bfdc]

The virtual distance to virtual image is a function of the dome port radius (smaller radius, shorter virtual distance, IIRC) and real distance to the subject. Someplace I'm sure there's a formula.

I'm pretty the diopter Adm. Linda uses with her Nikkor 12-24 and 10-24 in an 8" Aquatica dome is a B+H +4. It's worked fine. I can verify the strength of the diopter this weekend.

Chuck

Thx for replying
I am just trying to figure out if there are "distance" pictures that I won't be able to take because I have a diopter on the lens and does this get worse if you move from +2 to +4 diopter

dont want to miss that NAT geo cover shot of mating orcas because the camera can't focus at 15-20 ft!

all this will move from virtual/above water to real world underwater next week, but really hate to travel across the world and waste a dive "testing"

 

[bfdc]

Some above water tests: a +2 diopter on the 12-24mm reduced the "maximum distance" focusing to only those things inside 3 or 4 feet; beyond that, no focus. for +4, that maximum distance focusing dropped to 1 to 1.5 ft feet. minimum distance for both was 3-4 inches in front of the lens

 

[Chuck Tribolet]

Above water and below water results will be very different/

Chuck