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

Hello,

I know there are some topics around for the Nauticam 4.33 and 3.5 dome port. However, most/all of the people seem to use the Panasonic 8mm in it.

Since I own the Rokinon / Samyang 7.5mm I would like to buy a dome for it.

Can anybody share some experiences regarding vignetting in any of the domes, please.

Thank you very much.

what camera/system are you talking about?

on the sony nex 7 the 8mm rokinon did vignette on the 4.33 nauticam dome.

According to the specs. at B&H photo the Panasonic 8mm is 35mm longer than the Rokinon, 518mm v. 483 for the Rokinon. This puts the lens further back in any of the 8mm ports which is likely what is causing the vignetting. I don't think you are going to find a port that sites any closer to the housing than the 3.5 inch dome so you may be out of luck.

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...

There is almost no vignetting with this set-up.

Could you please share a picture showing the vignetting on a 4:3 picture ?

Hello guys and thank you for the first input. I plan to use it with my Olympus E-M1 in a Nauticam housing.

The Rokinon is only a 7.5mm. However, I only found some stuff about the 8mm version, which is also mentioned by jmauricio. Probably all the problems with the 8mm are even worse with the 7.5mm.

Anyways, it is very exiting that michaeltsantos uses the 7.5mm set-up.

I also plaid around this the lens on land and had the same idea with F at 11 or higher. With the new 3D-printer technology it is probably also pretty easy to build a fitting focus gear. Otherwise, I would just turn focus peaking on and put it the focus on 0.15, since I would like to take Macro Wide Angle pictures.

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...

It would be extremely nice, if you could share some pictures. I prefer to shoot in 3:2 format, since then there is more space to crop it. Would it be possible for you to upload some in 3:2 and / or 4:3 format?

This would be much appreciated.

Thank you very much

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)

Oly 9-18mm lens with Nauticam zoom gear

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

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

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

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

Hope this helps!

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:

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

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!

Thank you for the tip with the rubber band.

Would have an underwater "focused" image though ?

Wonderfull! Thank you for the pics. I expected it would be worse. Thank you very much.

Thank you for the second picture !

The vignetting is not too bad, like you said. Especially for someone

who would focus close, it is totally useable.

Even when the vignetting occurs, it could be cropped to 3:2. This is

how I would use it anyway.

Sorry guys, don't have a nice pic available. I'll try to do a better test this month and post pictures later.

I bought now the 4.33 and will test it with the 7.5mm as soon as it arrives (Probably the end of next week).

Please, let us know how it goes ! Enjoy your new gear.

Looking forward to your seeing your pictures!

Thanks!

Sorry guys, the housing and port is still at the customs. I will let you know how it works as soon as it arrived.

Today I finally got my housing. Damn German post and their strike!!!

Anyways, I was able to do some quick 'dry' shoots. The 7.5mm is really nice and there is really almost no vignetting.

In Picture one I was just couple of cm away from a wall to have a clean test shoot. Please note that in the lower corners there is just a bit vignetting, a bit hard to see due to the floor.

Picture 2 shows a Micro-Wide-Angle Shoot at f8 and 0.15m. Pretty nice for the first try.

I hope I can test the system soon in the water, but this might have to wait for some more weeks.

Alright guys,

I finally made my first dive with my new housing and the 7.5mm. Here you can see a example picture. Almost no vignetting visible!! Sorry for the bad visibility of the lake

I just tested the 7.5mm during a short walk into the lake. For the dive I used the 60mm macro because of the visibility and because so far I can't focus with it.

Anyways, I am on it to create and print a focus gear for the 7.5mm! But even at 0.25 and F8 it makes pretty nice results. Point and shoot!