Ikelite dome...again :)

More about Ikelite domeports...

I own a ikelite housing (canon 40d) and have recently bought a Tokina 10-17 fisheye lens.

Previously I used a Sigma 10-20 behind a 8" Dome and a 5510.16 port body.

Ikelite suggests I should use a 5510.10 (which basically is a shorter port body) with the Tokina.

I mounted the camera with the new lens and used with the regular port body and it seems to work ok without any vignetting. Might add I've only tried it dry so far...

Now the question. Why should I get the shorter port body? Will the lens work better if positioned closer to the dome (which is the case with the shorter port body)???

Hope anyone could help me with this question...

Keep the 5510.16.

Canon's APS-C digital SLR crop is 1.6X which is why you aren't seeing any vignetting. Nikon's 1.5X crop absolutely requires the shorter #5510.10 extension to use the Tokina at 10mm and not see the shade edges.

Even though the lens is back a small amount in the dome I have never noticed any difference. Likely due to the incredible depth of field of the Tokina 10-17mm Fisheye.

If not shooting over / under shots I routinely use the Ikelite #5503.20 6" dome port which has larger cut outs on the shade. Again, on a 1.6X crop Canon dSLR no vignetting at 10mm.....

Good luck!

dhaas

So what is the best distance for the 8" dome to be away from the the Tok10-17 lens with a Canon 1.6 crop? I'm having an adapter made so I can use old 8" Oceanic dome port on my Ike for over and under shots. Has anybody tried adapting the optically coated Sea&Sea dome on an Ikelite?

Bo

Keep the 5510.16.

 

Canon's APS-C digital SLR crop is 1.6X which is why you aren't seeing any vignetting. Nikon's 1.5X crop absolutely requires the shorter #5510.10 extension to use the Tokina at 10mm and not see the shade edges.

 

Even though the lens is back a small amount in the dome I have never noticed any difference. Likely due to the incredible depth of field of the Tokina 10-17mm Fisheye.

 

If not shooting over / under shots I routinely use the Ikelite #5503.20 6" dome port which has larger cut outs on the shade. Again, on a 1.6X crop Canon dSLR no vignetting at 10mm.....

 

Good luck!

 

dhaas