Compact 8" DL Ikelite dome

I have a canon SL2 ikelite housing with a canon 15mm lens. I love doing split shots, and I'm able to get them with calm water, however I would love for it to be a bit easier to capture in rougher water. After seeing what my friends Gopro dome port can handle in rougher water, I was a bit jealous.

I don't really want to deal with the size of the full size 8" dome port. Just wondering if the compact version will give me the same ease split shot photography, or, is the small size going to make it relatively similar to the 6" dome.

Should I just be purchasing a wider than 15mm lens?

Anyone use the compact dome and the standard 8" dome that can weigh in?

Would I be better of with a precision 5" half globe dome port?

Hi, I have a Nikon D700 + Sigma 15 FE 2.8 DX.

For split shot I still use the big 8" but this not my favorite type of photo (I never manage do remove all water droplet).

For underwater I use the 5" precision dome (Prec-5in-Nik-ike) + Ikelite 5510.11 but it has a little bit of vignetting (you see the sunshade on some corners) I spoke with Bill who made a new sun shade. It was better but not enough and after that He made a new dome call Prec-5in-Sho-ike but I don't try it. It's not easy to do splishot with it but not impossible.

Today, I mainly use the Prec-5in-Nik-ike + 5510.22 + Sigma 15 + Kenko 1.4.

I have tried the 6" but I find it not good.

Prec-5in-Nik-ike + Sigma 15 :

Canon 15mm lens - the fisheye lens?  there is not much wider apart from a circular fisheye. 

Regarding your choice of port the port charts are your  best first reference, here is the Ikelite DL port charts:

https://docs.ikelite.com/reference/port-chart-dl-system.pdf

You will note it does not list the Canon 15mm, but does list the 8-15, which will be similar but probably needs different extension??  It says:

" Compact and lightweight for travel. Dome shade must be removed. Some vignetting (shadows in the corners of the image) will be present. Zoom gear may alternatively be used to manually focus."

Regarding required extension, the FL port cahrt (older system) lists the same extension for both the 8-15mm and 15mm Canon lenses, so the 75020 extension used for the 8-15 should also match the Canon 15mm.  But contact Ikelite to confirm!  they are supposed to be pretty responsive.

I would think being the same diameter that the compact port should be equivalent for splits to the 8" port, though optical quality may be compromised by not placing the entrance pupil at the radius of curvature, you can see the lens would need to be well forward in the dome to not vignette but the centre of curvature is back behind the dome - a compromise to allow for compactness - would probably impact the corners most - how much you would have to find someone who has used it that way to let you know. 

I made a mistake, i've not the 5510.22 but the 5510.16. Sorry.

Longbord 1 please read this, several miss leading responses are made above.

First the Ikelite housing for the Canon SL2 (and SL1 & SL3) supports the DLM port system not the DL port system. So all of the observations by Chris would not be relevant. 

Only the DL port system includes the Compact 8' port which is much different than the DLM 6" port. The DL Compact eight inch port is excellent when paired with the Canon 8-15mm Fisheye on a full frame camera, see my review of the Canon EOS R in back issue #106 of uwpmag.com. This is a free PDF download and the review was done with the Ikelite housing and Compact 8' dome.

Because your camera has an APS-C and not a full frame sensor the 8-15mm zoom is a large expense unless you intend to move to full frame. The Tokina 10-17mm Fisheye zoom also has problems with zoom range and vignetting with your housing and port selection.

J-S comments reference the Sigma 15mm Fisheye with the five inch Precision dome on a full frame camera. The Precision port and the Ikelite port DO NOT support the discontinued Canon 15mm fisheye because of the large difference in minimum focus distance between the two lenses. The Sigma focuses to around 6.5cm while the Canon is 20cm this makes a huge difference when focusing on the virtual image created by the port. The fact that the Canon 15mm works in your current system does not make it ideal by any means.

I would be more inclined to invest in a new lens rather than a new port.