Stacking Extension Rings - Aquatica + Canon 17-40mm

Hi Guys,

I've just realised that according to the Aquatica lens chart I should be using extension #18457 (67mm) with the 5D3, 17-40mm and 8" dome.

As I don't want to travel with yet another extension ring, can I'm wondering if I can stack the ones I already have and need to get a solution. With what I have, I can make a 63mm, 70mm or 75mm long stacked extension.

I'm guessing the 70mm solution will be the way to go, but my dome theory is a little rusty so looking for some advice.

thanks, damien

I don't shoot with an Aquatica but I frequently stack Nauticam extension rings. Upsides are a more flexible, weight saving solution when travelling and less cost (I should take my own advice as I have 2x20mm, 2x30mm, 2x40mm, 2x50mm, 2x60mm & 2x70mm). Downsides are a marginally heavier rig and an extra o-ring seal to worry about!

Thanks for the validation.

After a few beers I had the idea to jump in the pool and test out the setup. So that I can keep one extension for using on another rig, I tested the 75mm stack and it appeared to work fine. More vibrant subject matter is required, but I'm going with that for now. For Internet archive reference, it was one #18453 & one #18456.

Kind regards,

damien siviero

Damien

The 18457 is actually 54.5mm extension (67mm overall). You have to minus 13.5mm from overall length to get the extension length. I stacked 2 x 18453 (28.5mm) to get 57mm and it worked fine. I used the 18453s with the macro port with the 100L and extension tubes and extended accordingly.

Thanks Drew for the correction.

Seemed to work in the end, image quality didn't seem to be an issue with the stacked setup.