M4/3 CFWA Wide-angle Macro with Mini-dome Zen DP-100

[JohnC]

Curious if anyone has tried CFWA with an Olympus 8mm F1.8 for CFWA, with either a Nauticam or Zen mini-dome? The Zen DP-100 with a 30mm extension ring is listed as the correct dome port setup from the chart, but I see the dome shade on the top and bottom of the frame. It's easily cropped out by changing the aspect ratio to 3:2 instead of the native 4:3. Do similar mini-dome setups share this issue?

[Chris Ross]

7 hours ago, JohnC said:

Curious if anyone has tried CFWA with an Olympus 8mm F1.8 for CFWA, with either a Nauticam or Zen mini-dome? The Zen DP-100 with a 30mm extension ring is listed as the correct dome port setup from the chart, but I see the dome shade on the top and bottom of the frame. It's easily cropped out by changing the aspect ratio to 3:2 instead of the native 4:3. Do similar mini-dome setups share this issue?

I have used the Panasonic lens with the Zen DP-100 and it doesn't show the dome shade.  The Olympus with the 30mm extension should not be showing it either.  There should only be one N85 port from Zen, assume you are using the DP-100-N85 model with the Nauticam 30mm mini extension ring?  The dome shade is non removable on this one so really can't be rotated incorrectly.  Perhaps post a pic of your setup?

 

 

[JohnC]

Thanks, Chris. Yes, it is the N85 DP-100 and Nauticam 30mm ext. The lens/port position looks right to me, i.e., not too far behind or forward of the dome flange. See the attached photo of the setup and a bathtub shot showing the lens shade and corner vignetting of the dome.

[Chris Ross]

[Chris Ross]

13 hours ago, Chris Ross said:

Well, I typed a bunch of stuff to go with these pics but it's now disappeared?

 

Looking at your pic , your dome seems to have some extension built in.  Compare a pic of my dome with yours, you can see where I have circled it that there is a straight bit that continues on from the dome shade on your dome that is not there on mine. 

 

To allow comparing the domes I measured from the shade edge to the port flange as shown in second pic, eye balling with a ruler the distance from the dome flange on mine to edge of the sun shield is around 21-22mm.  If yours is more than that it is the problem.

 

You should be able to see the outer edge of the front element when sighting perpendicular to the dome across the section of the dome shade that I circled.

 

Did you buy this one new?  I'm not sure which model it is but it doesn't seem to be a DP-100 N85 model.

[JohnC]

It’s a DP-100 N85 alright, possibly an early version. It looks undived. Thanks for highlighting the difference to yours - I’ve just sent an email to Zen support to see if they can help…

[Chris Ross]

I'm not sure what this one actually is, but the solution is less extension.  I think there are lmited extensions available in N85 so possibly a 20mm?  I measured 22mm from the dome shade, this one has ~22mm from seam below the dome shade to the flange.

[JohnC]

Thanks again; my thoughts precisely! I have a 20mm extension and have just tried it with some bathtub art 🙂 The front of the lens does seem to be well inside the dome but I have sharp focus from a few cm (10ish) to about a metre, which I think is fine for CFWA. Still waiting on official word from Zen...

[JohnC]

The word from Zen is: "So that is actually a DP-100-S3 (Subal Type 3) with a PA-S3-N85 port adapter on it. The adapter converts the Subal Type 3 mount to the Nauticam N85 mount. This was the very first generation of a DP-100-N85, which was designed around the Panasonic 8mm lens. Unfortunately, that will not be compatible with your Olympus 8mm."

[Chris Ross]

3 hours ago, JohnC said:

The word from Zen is: "So that is actually a DP-100-S3 (Subal Type 3) with a PA-S3-N85 port adapter on it. The adapter converts the Subal Type 3 mount to the Nauticam N85 mount. This was the very first generation of a DP-100-N85, which was designed around the Panasonic 8mm lens. Unfortunately, that will not be compatible with your Olympus 8mm."

As I suspected, though I'm not sure what the basis for saying it is not compatible is as it clearly works with a 20mm extension and will be quite close to the correct position for your lens.  Without actually having your dome in hand it looks to have the same dome shade as mine and the adapter adds about 10mm of extension, so it is pretty close to the right extension for your Olympus 8mm.  Perhaps the translation of their response is we haven't done the testing/measurements for your lens and this particular version of the dome?