Woody's Diopter Test Shots

[rcolman]

I just shot a sequence of test images with a 35mm macro on an e-330, with and without the diopter, through the Ikelite flat port, at a resolution grid.

I will post images shortly, but, here are some quick conclusions:

* no free lunch ... you get what you pay for (US $60 or so)

* significant color fringing everywhere except at the center

* loss of sharpness and resolution

I am going to play with Photoshop CS3 to see if I can reduce some of the chromatic abberation through raw processing.

Rick Colman

 

[jlyle]

Rick,

Did you do your test shots u/w? It may make a difference.

Jim

 

[rcolman]

No, did not do them underwater because it is hard to get my test page down there. However, I don't think it would make any difference in the results. I will post shortly, and it should be obvious.

Whether the quality loss is worth the increase in magnification is a judgement call.

 

[alcina]

I don't think your results are typical. I, and those others I know who use Woody, get excellent results in a wide range of situations.

 

[Gudge]

No, did not do them underwater because it is hard to get my test page down there. However, I don't think it would make any difference in the results.

It will make a difference, the refractive index of water is much much higher than that of air. As a result, underwater the magnification of the Woody dioptre is less and the results you're getting in air will not be anything like you're going to get underwater. I've been using a Woody's dioptre for a couple of years now and won't go underwater without it. I occasionally get some CA in some shots but this is easily removed using filters such as this:

http://flofilters.free.fr/

 

[rcolman]

Here is the link to typical test images IN AIR.

http://www.ocdiving.com/gallery2/main.php?g2_view=core.ShowItem&g2_itemId=10849

The comments about refractive index make perfect sense ... less magnification ... less damage.

Again, the choice is really an artistic one ...

 

[alcina]

Again, the choice is really an artistic one ...

I guess I'm confused...isn't every choice on gear, settings, composition etc an artistic one?

 

[rcolman]

NOT for me. I have a limited budget, limited time, and somewhat limited capabilities.

So, I may choose to accept a lower level of quality because the item is relatively inexpensive (US$ 60 for the diopter vs. $450 for a Sigma 105 macro)

-or -

maybe I want to flexibility of a wet diopter over a shorter lens, giving me more options on a dive.

Please do not misunderstand me. I am not saying anything particularly negative about the web diopter, it is what it is ...

Best fishes,

Rick.

 

[alcina]

So, I may choose to accept a lower level of quality because the item is relatively inexpensive (US$ 60 for the diopter vs. $450 for a Sigma 105 macro)

-or -

maybe I want to flexibility of a wet diopter over a shorter lens, giving me more options on a dive.

Ahh...I see the first sentence as two totally different things. That makes sense.

And the flexibility of a Woody (insert other wet mate option here) is excellent