Nauticam Extension Rings with Domes

Nauticam port chart for N120 Canon has several recommendations for extensions and relevant domes to be used with the 16-35 f4 canon lens

My question is:

with a glass 230 mm dome for canon,  extension ring 70 is recommended with the 16-35 F4 canon lens

it also recommends extension ring 80 with the same lens and dome with a foot note saying 'secondary set up recommendation based on optical performance'

Now I already have the 70mm extension. Would it make a herculean or a small difference or no difference at all, if not used with an 80mm extension ring ?

Thanks for any advice/guidance on this.

Diggy

Hey Diggy

I'm sure Nauticam experts will chip-in. But, bottom line, seems to me the issue is are you happy with the results you are getting with the EXR70? Rectilinear lenses are, of course, well known for the difficulty of housing - but you are well into that with the 230 dome. Are you happy with the edges/corners?

it appears the 70 is recommended if you want a focus knob on the extension tube, perhaps they don't make an 80mm tube with a knob. This is a new version of the port chart it has the 16-35 f4 with the WACP-2 as the best performing most optimised combination.  In prior versions I expect the 80mm extension would have been most optimised.

I would think that using 10mm less extension would result in a small loss of corner performance, I can't quantify that for you. 

An alternative to an 80mm tube might be a to add a 10mm tube to your 70mm, that however uses screws to secure rather than a lock.  Nauticam could also have recommended this to go with the 70mm tube with knob but didn't.  I can't be sure but I expect this indicates they didn't think adding the 10mm tube to the 70mm tube with knob was worthwhile. 

I would suggest trying it out with your 70mm tube and adding a 10mmm tube if you feel the corners could use improvement once you try it out.

On 2/24/2022 at 2:03 PM, TimG said:

Hey Diggy

I'm sure Nauticam experts will chip-in. But, bottom line, seems to me the issue is are you happy with the results you are getting with the EXR70? Rectilinear lenses are, of course, well known for the difficulty of housing - but you are well into that with the 230 dome. Are you happy with the edges/corners?

Thanks Tim,

Have yet to try the system. Will be doing so in March. Lets see what the results look like.

Diggy

23 hours ago, ChrisRoss said:

it appears the 70 is recommended if you want a focus knob on the extension tube, perhaps they don't make an 80mm tube with a knob. This is a new version of the port chart it has the 16-35 f4 with the WACP-2 as the best performing most optimised combination.  In prior versions I expect the 80mm extension would have been most optimised.

I would think that using 10mm less extension would result in a small loss of corner performance, I can't quantify that for you. 

An alternative to an 80mm tube might be a to add a 10mm tube to your 70mm, that however uses screws to secure rather than a lock.  Nauticam could also have recommended this to go with the 70mm tube with knob but didn't.  I can't be sure but I expect this indicates they didn't think adding the 10mm tube to the 70mm tube with knob was worthwhile. 

I would suggest trying it out with your 70mm tube and adding a 10mmm tube if you feel the corners could use improvement once you try it out.

Thanks Chris,

I do have the 10 mm extension( the one with the screws). Let me see what the images look like. I would readily add this to the 70 mm but I also have an 8-15mm canon and a 20 mm extension with lock. The extension recommended for this lens is 30mm so would rather add the 10 mm here. Finally I guess go out there and buy another 30 mm extension. 

Diiggy

3 minutes ago, diggy said:

Finally I guess go out there and buy another 30 mm extension. 

 You know you are going to, Diggy! 

I'm guessing with the screws, it's pain to switch that 10mm extension between other EXRs.

14 hours ago, diggy said:

Thanks Chris,

I do have the 10 mm extension( the one with the screws). Let me see what the images look like. I would readily add this to the 70 mm but I also have an 8-15mm canon and a 20 mm extension with lock. The extension recommended for this lens is 30mm so would rather add the 10 mm here. Finally I guess go out there and buy another 30 mm extension. 

Diiggy

I would suggest trying it first - you may be fine with just the 70mm. 

7 hours ago, ChrisRoss said:

I would suggest trying it first - you may be fine with just the 70mm. 

Yup, Thanks Chris, this would be the logical thing to do.

Diggy