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50mm with dome


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#1 thiebautla

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Posted 08 September 2018 - 12:06 PM

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



#2 Tom_Kline

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Posted 08 September 2018 - 12:13 PM

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.


Thomas C. Kline, Jr., Ph. D.
Oceanography & Limnology
Currently used housed digital cameras: Canon EOS-1Ds MkIII, EOS-1D MkIV, and EOS-1DX; and Nikon D3X. More or less retired: Canon EOS-1Ds MkII; and Nikon D1X, D2X, and D2H.

Lens focal lengths ranging from 8 to 200mm for UW use. Seacam housings and remote control gear. Seacam 60D, 150D, and 250D, Sea&Sea YS250, and Inon Z220 strobes.

http://www.salmonography.com/

 


#3 miguelpereira

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Posted 09 September 2018 - 09:57 AM

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.

#4 thiebautla

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Posted 10 September 2018 - 04:26 AM

@Tom_Kline 

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


Edited by thiebautla, 10 September 2018 - 04:26 AM.


#5 Tom_Kline

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Posted 10 September 2018 - 09:08 PM

Here is some theory: https://www.scubagee...es/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.


Thomas C. Kline, Jr., Ph. D.
Oceanography & Limnology
Currently used housed digital cameras: Canon EOS-1Ds MkIII, EOS-1D MkIV, and EOS-1DX; and Nikon D3X. More or less retired: Canon EOS-1Ds MkII; and Nikon D1X, D2X, and D2H.

Lens focal lengths ranging from 8 to 200mm for UW use. Seacam housings and remote control gear. Seacam 60D, 150D, and 250D, Sea&Sea YS250, and Inon Z220 strobes.

http://www.salmonography.com/