Why is the 140mm Glass Dome Recommended vs the 230mm Glass Dome for the Canon 8-15mm and all other fisheye lenses?

[Architeuthis]

Left: dome #1, right: dome #2

Top to bottom: center to corner

Yes?

 

 

Clearly the left image at the bottom is sharper. Maybe a small difference in the middle. Same IQ in the top…

 

 

I would say: left is DP230 and right is Nauticam 140, but the small improvement in IQ in the corner is not really worth the upgrade from 140 to 230 (except for split photos, but this is a different story)…

 

 

But maybe Massimo is right with his "wrong positioning story" and it is the opposite (left= NA140; right=DP230)?

😋

 

 

Wolfgang

 

[Guest]

Left is zen right is 140

 

Centre performance 140 better than 230 the hint is the edge of the ruler where you need contrast is invisible on the zen

Off centre same as above 140 better 230 has less constrast

Extreme edge the 230 has a little benefit however the image has chromatic aberration look at the helix both left (green) and right (purple) as the dome is not positioned correctly (it cant it would vignette)

 

Based on this very basic test there is no reason to get the larger dome and Nauticam MTF measures are indeed aligned. IN their test tank the extreme edges are outside the field of view

 

By the way the forum resolution makes it impossible to distinguish much so your eye goes to the image that look brighter

Edited May 6 by Interceptor121

[Architeuthis]

2 hours ago, Interceptor121 said:

Left is zen right is 140

 

Centre performance 140 better than 230 the hint is the edge of the ruler where you need contrast is invisible on the zen

Off centre same as above 140 better 230 has less constrast

Extreme edge the 230 has a little benefit however the image has chromatic aberration look at the helix both left (green) and right (purple) as the dome is not positioned correctly (it cant it would vignette)

 

Based on this very basic test there is no reason to get the larger dome and Nauticam MTF measures are indeed aligned. IN their test tank the extreme edges are outside the field of view

 

By the way the forum resolution makes it impossible to distinguish much so your eye goes to the image that look brighter

 

Indeed a small difference. I doubt that one can see a difference in real world WA photos, certainly not worth going for the larger domeport...

 

And there is some chromatic aberration with the Zen DP230, probably a result of incorrect positioning, as you outline in the EMail you have sent to me (are the images corrected for CA, BTW?)...

 

=> Thank you, Massimo, for this very interesting test series (confirms for my usage, that NA140 is way enough for the Canon 8-15mm)...

 

 

Wolfgang

Edited May 6 by Architeuthis

[Guest]

1 hour ago, Architeuthis said:

 

Indeed a small difference. I doubt that one can see a difference in real world WA photos, certainly not worth going for the larger domeport...

 

And there is some chromatic aberration with the Zen DP230, probably a result of incorrect positioning, as you outline in the EMail you have sent to me (are the images corrected for CA, BTW?)...

 

=> Thank you, Massimo, for this very interesting test series (confirms for my usage, that NA140 is way enough for the Canon 8-15mm)...

 

 

Wolfgang

No in real world photos you will be at mercy of depth of field

 

If you are very close to a subject and you want the distant background to be sharp you need to stop down the lens more with the small dome especially as the small dome lets you get very very close this is where you need your f/14 or f/16

In terms of depth of field advantage considering that with a large dome you can no longer get close you have a benefit of 1/3 stop for an increase of radius of 5cm so definitely not worth it.

For close focus wide angle you can even get good results with the 4.33" acrylic port if you are not interested in the antireflective coatings