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michaeltsantos

Member Since 28 Aug 2008
Offline Last Active Yesterday, 09:07 PM
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#362871 Vignetting with Rokinon/Samyang 7.5mm fisheye in Nauticam 4.33 or 3.5 dome port?

Posted by michaeltsantos on 02 July 2015 - 11:09 PM

Hi!  Attached are some some test shots (sorry again for the bad quality).  Will try to do a serious pool test soon.

 

Test Photo 1:

 

P6210023.jpg

No vignetting when the focus area is closest to the camera.

 

P6210024.jpg

Slight vignetting when the focus area is furthest from the camera.

I guess this is because the front element moves in and out during focusing.

 

Hope this helps!




#362870 Vignetting with Rokinon/Samyang 7.5mm fisheye in Nauticam 4.33 or 3.5 dome port?

Posted by michaeltsantos on 02 July 2015 - 10:44 PM

Hi!  I find that it's still important to be able to focus during the dive.  It's very easy to put a focus gear on the Rokinon lens. 

 

Please see the pictures below: (sorry for the bad picture quality, not sure why the images are posted up side down)

 

Rk1.JPG

Oly 9-18mm lens with Nauticam zoom gear

Rokinon 7.5mm lens with rubber band and "shims" (cut from a motorcycle tire inner tube)

 

Rk2.JPG

Rokinon 7.5mm lens with rubber band and "shims" mounted on the focus ring

 

Rk3.JPG

Rokinon 7.5mm lens with Nauticam 9-18mm zoom gear mounted (just the outer ring)

 

Rk4.JPG

Rokinon 7.5mm lens in Nauticam EM-10 housing. Focus can be adjusted with the zoom gear!

 

Hope this helps!




#362840 Vignetting with Rokinon/Samyang 7.5mm fisheye in Nauticam 4.33 or 3.5 dome port?

Posted by michaeltsantos on 01 July 2015 - 09:54 PM

Hi!  I just started using the Rokinon/Samyang 7.5mm fisheye with the Nauticam 4.33 dome port.  This is in combination with the Nauticam housing for the Olympus EM-10.  There is almost no vignetting with this set-up.

 

However, corner sharpness can be a problem.  Since you can't change the aperture during the dive, I usually just leave it at f11 for better corner sharpness.  Still not that sharp, but (in my opinion) acceptable for a fisheye lens.  I just adjust exposure by playing with the SS and ISO.

 

What's more difficult is maintaining proper focus during the dive.  I was able to mount the Nauticam zoom gear for the Olympus 9-18mm on the Rokinon using  thick rubber bands.  I use this, in combination with "focus peaking", to adjust focus during the dive. 

 

I'm still experimenting to get the best settings.  Hope this helps...