On 4/28/2021 at 6:15 PM, adamhanlon said:
Based on the images above, you definitely need an extension ring.
The lens's nodal point needs to sit in line with the dome port's back panel. The issue is not vignetting (although it may do this too) but it will be optically poor if it is incorrectly positioned.
I would consult with you Aquatica dealer to see what they recommend.
Adam
Hello Adam....
I needed some advice
English is not my first language, so please understand if there is word bad.
I already wrote it, but you are my big fan. Your writing and video helped me a lot with the theory of underwater photography.
Aquatica sent me messages first and exchanged a few emails.
I believe that button manipulation problems will be corrected.
As you may have already read, it's about the 8-15 lens extension.
At first, I received an e-mail from Aquatica that they would talk to the engineer about the 8-15 lens and let me know.
The next e-mail I've received is...
"For the 8-15 lens,we have some customers using without an extension ring and some use with one of our shirsest rings,both getting good results.
For sure with an extension ring you will need to remove the dome shade,so you will not get vignetting.
Next week I do have an order shipping to my dealer in Korea,in the shipment we can include this short extension ring,and you can give it a try."
"shirsest" is probably a typo. shortest
So I compared all the expansion rings of other brands. Of course, I expect the difference in distance from the sensor to be different for each brand, but just for my reference.
First of all, the Canon 8-15 and Nikon 8-15 use the same extension ring for most brands (Nauticam has 10mm longer Canon).
But I think Aquatica's extension ring is probably the shortest 48456 (16.5mm/65in).
By the way, there is a port chart in Aquatica to use 48463 (21.5mm/.82inch) for Canon 8-15 lenses.
So it's the weekend and it's dawn in Canada, so you won't get a reply, but I sent you an e-mail saying I want to test two, 48456 (16.5mm) and 48463 (21.5mm) if possible.
But there are some questions here.
1. As Aquatica said, if vignetting occurs when using a short extension ring at 15mm, we should use it without an extension ring. Diving would be hard without a dome hood.
2. According to the Nikon 8-15 lens review, I saw a post in your article that the vignetting got worse because of the expansion ring. July 6, 2017
https://wetpixel.com/forums/index.php?/topic/60171-nikon-8-15mm-in-the-house/
Could you share your opinion on this?
3. For reference, compared to Aquatika's Canon Lens Chart, Canon 8-15 does not have any benning for the dome hood, but I actually do not understand if Nikon expects that even 5 mm short expansion rings will cause vignetting.
I want you to let me know your opinion. Thanks a lot.
And I always watch your posts and YouTube well. Thank you.