5” precision dome on FF with 8-15mm & 1.4TC

Hi All

I hope you are well and getting some diving in!

I Had a test out in the pool with the Canon 8-15mm and kenko 1.4 TC on a full frame camera. I was a bit concerned the image quality would be rubbish.

For my level of photography the image quality seems ok and I am looking forward to getting it in the ocean. 

I have some Nudibranch shots in mind at my local site , so hopefully I can bring those ideas to fruition. 

Finding any info on this exact setup is not easy, if anyone else has some pertinent info to share please do.

I hope to update this thread with some shots when the water clarity allows. 

On 11/21/2020 at 6:30 AM, Chris Kippax said:

Hi All

I hope you are well and getting some diving in!

I Had a test out in the pool with the Canon 8-15mm and kenko 1.4 TC on a full frame camera. I was a bit concerned the image quality would be rubbish.

For my level of photography the image quality seems ok and I am looking forward to getting it in the ocean. 

I have some Nudibranch shots in mind at my local site , so hopefully I can bring those ideas to fruition. 

Finding any info on this exact setup is not easy, if anyone else has some pertinent info to share please do.

I hope to update this thread with some shots when the water clarity allows. 

 

 

Interesting report. For FF sensor the 2x TC would be the optimum for best angles of view (a real competition for the expensive, big and heavy WACPs). Did you try out the 2x TC?

I get very good optical results with Kenko 1.4x TC, Canon 8-15mm and Nauticam 140 (also Zen DP170) with small MFT sensor (EM1II and EM5II). IQ is, more or less, as good as without the TC, but AF becomes quite slow and is not so reliable any more. In addition, without TC the 8-15mm provides already the optimum AOVs for the small sensor...

Just to test the potential for FF (I am planning to upgrade), I purchased the Kenko 2x TC and tested it out over the water (with MFT; of course the 2x TC does not make sense with the small sensor): the result was discouraging: very soft images, even in the center...

Wolfgang

It is very soft with chromatic aberrations on the edges. I had the same experience with Tokina and 1.4x really pretty bad

4 hours ago, Interceptor121 said:

It is very soft with chromatic aberrations on the edges. I had the same experience with Tokina and 1.4x really pretty bad

Tokina 10-17 with 1.4x is clearly worse compared to 1x (best IQ gives Tokina with 0.71x speedbooster). With Canon 8-15 I could not see a difference between 1x and 1.4x. This is my impression from MFT sensor (EM1II), that is smaller and should be more stringend for optical IQ compared to FF, since optical errors get "blown up" with MFT, when the final image is enlarged to a certain physical size...

I also think that Chris's images are soft, but this may well be a result of a wrong dome/extension combination: 180° diagonal fisheye on the small MFT sensor are tack sharp with Canon 8-15 - on the larger sensor they are supposed to become even sharper...

Rating IQ quality of images is difficult here, because of the 1 MB limit for upload. I suggest to post images in DPReviews for IQ judgement, since they allow up to 10 images in full size to upload per posting...

Wolfgang

https://www.dpreview.com/forums/thread/4534175#forum-post-64575727

Thanks for the feedback, its good to hear the opinions of other members. 

Check out the images at original size in this DPR thread.

I used the port configuration specified at underwater camera stuff who makes the dome but I am no expert by any means.

http://uwcamerastuff.com/precision_5_dome.htm

I will keep going and see if I can get some decent results.

Tokina 10-17 with 1.4x is clearly worse compared to 1x (best IQ gives Tokina with 0.71x speedbooster). With Canon 8-15 I could not see a difference between 1x and 1.4x. This is my impression from MFT sensor (EM1II), that is smaller and should be more stringend for optical IQ compared to FF, since optical errors get "blown up" with MFT, when the final image is enlarged to a certain physical size...
I also think that Chris's images are soft, but this may well be a result of a wrong dome/extension combination: 180° diagonal fisheye on the small MFT sensor are tack sharp with Canon 8-15 - on the larger sensor they are supposed to become even sharper...
Rating IQ quality of images is difficult here, because of the 1 MB limit for upload. I suggest to post images in DPReviews for IQ judgement, since they allow up to 10 images in full size to upload per posting...
 
Wolfgang

10 hours ago, Chris Kippax said:

https://www.dpreview.com/forums/thread/4534175#forum-post-64575727

Ah, now I see, you hide the images in the "Portrait and People Photography" subforum (I have a regular look in the "Underwater Photography" subforum, so I did not see your post)... 

The full resoluton images are much better (again I complain that it is not possible to upload images at full resolution here; great forum for discussion but not for image comparison). In the center your images are crisp and tack sharp, at the edge they are difficult to rate, because there is not much except water and the child's extremities are certainly out of focus. But as Massimo says, with the small MFT sensor, we are using only the sweet central 25% area of the image circle, compared to FF, so the performance in the edges may vary...

Wolfgang

14 minutes ago, Architeuthis said:

Ah, now I see, you hide the images in the "Portrait and People Photography" subforum (I have a regular look in the "Underwater Photography" subforum, so I did not see your post)... 

The full resoluton images are much better (again I complain that it is not possible to upload images at full resolution here; great forum for discussion but not for image comparison). In the center your images are crisp and tack sharp, at the edge they are difficult to rate, because there is not much except water and the child's extremities are certainly out of focus. But as Massimo says, with the small MFT sensor, we are using only the sweet central 25% area of the image circle, compared to FF, so the performance in the edges may vary...

Wolfgang

Yes I tend to spend more time in the wildlife & people sub forum as they get a bit more traffic than the underwater photography sub forum

1 hour ago, Chris Kippax said:

Yes I tend to spend more time in the wildlife & people sub forum as they get a bit more traffic than the underwater photography sub forum

 

That is true. I started submitting underwater images to judged photography competition.

Photos with people do better, also landscape shots do well

Pictures with fish portrait score very low and macro near zero

So generally wide angle better if there are people in get more attention from non divers

6 hours ago, Interceptor121 said:

That is true. I started submitting underwater images to judged photography competition.

Photos with people do better, also landscape shots do well

Pictures with fish portrait score very low and macro near zero

So generally wide angle better if there are people in get more attention from non divers

So true! Especially for photo sales!

It should have more or less the same extension as a Nauticam 140mm dome they are both 180° domes  so the centre of curvature is about in line with the flat base of the dome so they should have about the same amount of extension.  The link you provided showed that you need 5510.24 extension - but ikelite don't provide the length of that.  Nauticam specifies a 50mm extension.   Your ikelite extension should be close to that length.

Looks pretty decent in the centre to me.

Thanks Chris appreciate your input,

Bill appears to have put a considerable effort into matching the dome port lengths. I concur about the 180 degree dome similarity but the unknown would be where the camera is situated in the housing? I presume some are further forward/back depending on manufacturer?

I am away from my gear but from memory the port length was quite a bit more than 50mm

I am not too concerned about corner sharpness as I only intend to use it for CFWA and would always try and frame most things against a dark or blue BG.

It is not just the sharpness is the chromatic aberrations you can see green circle around edges. When you then combine them with blurred corners you can have some really weird effect
I wonder if the problem occurs even before you are behind the dome port


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Fair call Massimo, I will give it a test sans TC when I get a chance.

My experience with TCs on high resolution full frame has not been positive. I even bought the latest Kenko HD version, but I still found that the images were soft. I liked the results on cropped sensor cameras, but the D850 really showed their flaws.

Similarly, I would not chose to use a 5" dome with a full frame camera, even with a fisheye. I think the CA that @Interceptor121 notes is probably due to dome size, rather than lens combination. My minimum size is 7" with full frame.

Aperture plays a role here too. If you can always shoot with a small aperture (f/15 or so) you can get away with some things that you can't at f/11!

2 hours ago, adamhanlon said:

My experience with TCs on high resolution full frame has not been positive. I even bought the latest Kenko HD version, but I still found that the images were soft. I liked the results on cropped sensor cameras, but the D850 really showed their flaws.

Similarly, I would not chose to use a 5" dome with a full frame camera, even with a fisheye. I think the CA that @Interceptor121 notes is probably due to dome size, rather than lens combination. My minimum size is 7" with full frame.

Aperture plays a role here too. If you can always shoot with a small aperture (f/15 or so) you can get away with some things that you can't at f/11!

 

Hence I suggested to check performance on land first then underwater. The TC will have issues of its own at times and needs stopping down already on land then of course you need to understand what it does in the dome subject to the residual field of view

While you can check a lens's performance on land, you can't check a dome's...

The issue may be the interaction of the lens and dome rather than the individual components.

As I mentioned, I think the CA is probably due to the size of the port.

While you can check a lens's performance on land, you can't check a dome's...
The issue may be the interaction of the lens and dome rather than the individual components.
As I mentioned, I think the CA is probably due to the size of the port.
 

The curvature of the dome itself can cause CA-and the way the lens combination interacts with the dome can also cause it. This is independent of the DOF issues caused by aperture. 

You can check the lens for CA on land, but not the dome, or the dome/lens combination. The port only produces a virtual image underwater.