100mm dome image quality

Has anyone done any comparison tests, using a fisheye lens behind one of the new 100mm or 4" domes (Zen or Subal) and comparing to results with the same lens and a standard 200mm or 8" dome?

I'm wondering if the advantages of the smaller dome with smaller size, lighter weight, and easier strobe placement for CFWA come at a cost of image sharpness, particularly in the corners.

Hi.

Here's a good starting point!

Adam

Just as clarification, Subal is importing and reselling the Zen 100mm dome in Europe, so there is no difference between these models.

Regarding pelagic use:

on DX cameras they were performing very well in the Bahamas with the dolphins.

But on FX I think that the corners will be more troublesome.

Alex

(quick reply - in a departure lounge!)

Now at home, so have time to expand.

On the Wetpixel July 2010 - Sharks & Dolphins trip about half the group had 100mm domes (usually in addition to a standard dome). On the DX cameras they performed remarkably well for big creature photos. They were particularly popular for the dolphins - because of the reduced drag and therefore greater chasing speed. Nobody (all DX users) felt that their images were compromised significantly by the corner performance to want to put on their bigger dome. People were either using Tokina 10-17mm or Nikon 10.5mm.

On FX cameras, my limited testing has made wary of using a mini-dome for anything other than CFWA or WAM. But I haven't actually tested it for pelagic stuff. There are also physical fit issues of mini-domes with 16mm and 15mm fisheyes. Although fisheye + TC combos should be easier to accommodate.

Alex

Thanks, Alex & Ryan, and to Adam for pointing out Alex's excellent article on the subject. Subal also makes a couple of 6" domes (the SWB and SWC). Being midway in size between the 4" and 8" domes they would seem like a useful compromise in characteristics between the mini and standard domes, but please post if anyone has experience or tests showing that the curvature or other design factor of the smaller 4" domes gives them any kind of advantage in image quality over the 6" domes. Cheers, Doug

Hi Alex.

In your reviews on mini domes you were saying that the corner sharpness wasnt acceptable to you at say f7.1 and acceptable at say f14 with the Tokina 10-17mm and DX camera. Which basically means your really limited to CFWA and WAM with the 100mm domes and Tokina 10-17mm/10.5Nikkor DX camera combination.

Now your saying that the mini domes are performing remarkably well on the big stuff without a significant compromise to the corner performance.

I would be interested in a review of the 100mm domes with Tokina 10-17mm/Nikkor 10.5 and DX cameras on larger subjects like sharks and rays. I personally and presume alot of others out there buy these fisheyes with the larger domes primary to shoot larger subjects and landscapes (reef scenes) and would like to compare the two directly. Especially after the suggestion that the 100mm domes are ideal for travel. Are they still ideal for travel when shooting large stuff or will it be a compromise also?

Regards Mark

In your reviews on mini domes you were saying that the corner sharpness wasnt acceptable to you at say f7.1 and acceptable at say f14 with the Tokina 10-17mm and DX camera. Which basically means your really limited to CFWA and WAM with the 100mm domes and Tokina 10-17mm/10.5Nikkor DX camera combination.

 

Now your saying that the mini domes are performing remarkably well on the big stuff without a significant compromise to the corner performance.

I wanted to add these comments - because I was particularly impressed with the quality that the other photographers on board were getting from their mini-domes, which I felt was additional info to what i had written in the review. They were certainly performing better than might have been expected. Have a look at Frank's dolphin shots - which were all taken with the Zen DP-100:

http://www.bluereefphoto.org/p689195285/h21a43722#h21a43722

But note, that my comments above relate to pelagic use with dolphins - and importantly this means that the corners of the images will be blue water and any loss in detail is not really going to adversely affect the image. Furthermore, in the bright Bahamanian sun, the photographers were generally able to stop down.

For reef use - where soft corners will be more noticeable - it is important to have enough light to stop down (say to f/14). This is made possible when you can get close to your subject, but may be difficult with some larger creatures that might not want to come in close.

Alex

Hi Alex.

I had a look at Frank's collection and indeed he has some stunning images there.

I am interested in the shots similar to Frank's Tiger sharks shots (ie 10mm at 1/125th f8). Do you know if these were taken with the 100mm mini Dome?

I am interested mainly in comparing the performance of the 100mm domes vs 200mm+ domes in not so clear water, in not so bright natural light, and deeper than 15-20m and shooting at around f8 on large animals like sharks.

Regards Mark

The Subal SWB and SWC domes are not a full hemisphere, which is less than ideal for fisheye lens use. I expect they'd work at the 17mm end of 10-17, but you'll see vignetting or aberration at 10mm.

I've struggled to document this well because our test charts aren't big enough (they are 8 ft wide), but the corner sharpness with 100mm domes improves markedly as you back away from a subject. They are at their worst in CFWA situations, and image quality is quite well documented in those situations. As you back away corner sharpness improves.

For Information. I have been experimenting with my Canon 15mm fisheye and both the (Seacam) WidePort (WP) and Fisheye Macro Port (FMP). The Canon 15mm lens does not operate as a CFWA behind the FMP. It does work and seems pretty good (although I've not done exhaustive tests) with the FMP at small apertures but won't focus particularly close. In fact it seems to operate more as a CFWA behind the WP and I've posted pix from this combination before, although there are some corner issues even at small apertures at minimum focus which is as expected. I've loaned the FMP out and am told that it works well with the Tokina 10~17 though.

I used the Zen minidome on the Nauticam 7D housing with the 10-17mm all weekend in the Farne islands and am very happy with the corners on the shots.

This one was taken at F3.5 !!