Blurry adges - again....

[Ido]

Hi

I  shot this image with Nikon Z7 2 (Isotta housing and 2 Sea&Sea strobes) lens: 14-30 iso 250 1/125 f11 

I love the image however I always get these blurry edges (the lower part of the frame). The dome is suitable for this lens and it was with f11. 

Any ideas ? Or the only way is using wet lenses ? 

Edited February 25 by Ido

[Ido]

Here is another example. 

 

 

[TimG]

Hi Ido

 

I suspect it’s the usual issue of housing a full-frame wide-angle lens.
 

Even though a manufacturer recommends a lens/port combination, you can’t be certain that it will work perfectly to give edge sharpness 

 

Id try stopping down more - to f16. If that doesn’t work you might need a bigger dome; or one of the Sea&Sea correction lenses. I know others who have had to do that. 

[Ido]

 

Edited February 25 by Ido

[Ido]

1 minute ago, TimG said:

Hi Ido

 

I suspect it’s the usual issue of housing a full-frame wide-angle lens.
 

Even though a manufacturer recommends a lens/port combination, you can’t be certain that it will work perfectly to give edge sharpness 

 

Id try stopping down more - to f16. If that doesn’t work you might need a bigger dome; or one of the Sea&Sea correction lenses. I know others who have had to do that. 

Thanks. Unfortunaly the Sea&Sea correction lens is out of stock every where ..

[TimG]

Yeah I thought that might be the case. They doubled in price about two years ago. Bummer. 
 

It could be then Ido, that the only solution is a bigger dome: 230mm. But even that might not give you perfect edges if that’s what you want. I don’t know of any other solution. 

[Architeuthis]

Were the photos made at 14mm? If yes, I believe the edges are, more or less, normal (what does "null" mean? When I look at the photos both have slightly blurred edges, pretty much the same)...

Not all of the "blurriness" I see there is due to domeport optics. To some extend it is just a depth of field issue, as the substrate in the edges is closer as the central object is. There is also some kind of "rectilinear" distortion in the edges, that can be observed even without a domeport, when you make comparable photos over the water...

WWL/WACP will improve "domeport blurriness" and "rectilinear distortion", but cannot help with out of focus issues. It will also introduce some kind of "fisheye distortion", that is, however, regarded as pleasant by many...

 

Wolfgang

[Guest]

The nikon 14-30 is classic wide angle lens that doesn’t work well at close range

the minimum focus distance is 28 cm the lens is not very big resulting in a required dome over 6” radius

the isotta domes are on the small size but frankly this lens is not something to consider for close focus shots

 

lenses that work best focus at 20cm

A cheaper topside lens can perform as result much better than an expensive one that focusses far

 

[Ido]

2 hours ago, Architeuthis said:

Were the photos made at 14mm? If yes, I believe the edges are, more or less, normal (what does "null" mean? When I look at the photos both have slightly blurred edges, pretty much the same)...

Not all of the "blurriness" I see there is due to domeport optics. To some extend it is just a depth of field issue, as the substrate in the edges is closer as the central object is. There is also some kind of "rectilinear" distortion in the edges, that can be observed even without a domeport, when you make comparable photos over the water...

WWL/WACP will improve "domeport blurriness" and "rectilinear distortion", but cannot help with out of focus issues. It will also introduce some kind of "fisheye distortion", that is, however, regarded as pleasant by many...

 

Wolfgang

Thank you. the "null" was just a typo. sorry.. For the WWL/WACP - I am using Isotta housing - So unfortunately - I can't use these.  

[Barmaglot]

2 hours ago, Ido said:

Thank you. the "null" was just a typo. sorry.. For the WWL/WACP - I am using Isotta housing - So unfortunately - I can't use these.  

 

Sure you can, if you're prepared to put a hurting on your credit card 🙂

 

https://www.backscatter.com/Isotta-Adaptor-Ring-B120-for-Nauticam-N120-Ports

[Chris Ross]

If you want to use a WWL you get the nauticam port and lens combination and change the lug ring over.

 

Regarding your shots, what are you focusing on?  Depth of field is 1/3 in front and 2/3 behind your focus point.  If you focus on a closer point you may get a little more in focus.  Also try shooting at f13/14/16 and compare corner performance.

 

A further option is using a fisheye, you would need the Nikon 8-15 as the the most straight forward option and you could use your existing dome and only buy a different extension ring.

 

 

[Ido]

17 hours ago, Chris Ross said:

If you want to use a WWL you get the nauticam port and lens combination and change the lug ring over.

 

Regarding your shots, what are you focusing on?  Depth of field is 1/3 in front and 2/3 behind your focus point.  If you focus on a closer point you may get a little more in focus.  Also try shooting at f13/14/16 and compare corner performance.

 

A further option is using a fisheye, you would need the Nikon 8-15 as the the most straight forward option and you could use your existing dome and only buy a different extension ring.

 

 

Thanks. I do have the Nikon 8-15. I'll try it as well and I will compare results. 

[TimG]

35 minutes ago, Ido said:

Thanks. I do have the Nikon 8-15. I'll try it as well and I will compare results. 

 

It should be much better, Ido.

[Ido]

Hi all - this is the reply that I got from Sea&Sea about the correction lens:

 

Hello Ido,

Thank you for your contact.

About M82 internal correction lens:

Both M77 and M82 internal correction lens have been discontinued. Because our actual supplier has been closed during covid-19 pandemic.

We have a plan to reproduce them but it is not so soon. Let's say in July or August..

We will keep you updated. Once they are ready, we will announce to public.

We are so sorry for your inconvenience.

Best regards,

Kaz Okada
International Sales
Sea & Sea Co., Ltd.
2F,4-8-11 Nagasaki, Toshima-ku, Tokyo 171-0051 Japan
Tel: 81-3-5926-9320
Mob:81-80-3276-7203
 

Edited March 1 by Ido

[TimG]

Thanks for posting that, Ido. Good to know. I'm sure there are a few folks who would be inserted to know when the lens becomes available again.

[Diver4fun]

It doesn't look too bad IMO, maybe try to add some vignet to make it less apparent