50mm with dome

[thiebautla 0]

Hi there!

 

I was wondering what to expect with a 6" dome and 50mm on a full frame.

I'm especially looking to do split shoot.
Does a 6" dome will be enough ?

Does someone already try it ?

 

Cheers

[Tom_Kline 127]

The main problem with your idea is that you will be able to either focus on what is above water or what is under water at one time unless you use a split diopter close-up lens (attached to front of 50mm lens). Keep in mind that the virtual image of the underwater portion of your picture is on the order of 0.3m from the image (sensor or film) plane. Focusing on the virtual image and what is above water at the same time is what is challenging to do without a fisheye lens.

[miguelpereira 0]

I've tried once a 50mm in a 230mm and it was not good. Very poor performance (I didn't tried split shots but I think that would have been even worst). I've seen someone get good results from a 50mm lens but in a 500mm custom dome! I think your 6" dome won't be big enough I'm afraid.

[thiebautla 0]

@Tom_Kline

I don't know wich diopter should I choose. +1 +2 +3 ?

Edited September 10, 2018 by thiebautla

[Tom_Kline 127]

Here is some theory: https://www.scubageek.com/articles/wwwdome.html

 

Focusing distance of a diopter lens (if in proper diopter units) = 1/diopter in meters. So a +2 lens focuses at 1/2 meter and a +3 at 1/3 meter with the prime lens set at infinity. So one of these will work with most domes. Try a +2 first but if you cannot focus close enough to your underwater subject try a +3.