10 replies to this topic

[UWphotoNewbie]

I read the article on the front page a while ago about Aquatica's upgraded glass:

http://wetpixel.com/...-lens/#comments

Anyone using these? Does it make a difference? Do other manufactures use optical glass?

Thanks

Edited by UWphotoNewbie, 20 April 2007 - 03:56 PM.

[Iggy]

I read the article on the front page a while ago about Aquatica's upgraded glass:
http://wetpixel.com/...-lens/#commentsAnyone using these? Does it make a difference? Do other manufactures use optical glass? Thanks

Are you asking if the optical coating makes a difference or if the glass makes a difference? I use Seacam ports and glass absolutely makes a difference. In the case of a big dome like the Superdome or Megadome, glass sheds water better so it's quite nice for over/unders. When I switched from acrylic to glass I was shooting an N90s and switched housings but not cameras, so I did have an opportunity to compare one against the other and I found better corners and sharper focus through the glass. This difference is probably accentuated these days given the resolving power fo the cameras we use, but I haven't seen that for myself. My comment is based upon the comparison of film images.

Though I have never broken one of my glass domes (knocking on wood at this very moment ) it's pretty obvious they are more fragile than acrylic domes if a mishap were to occur. And for the cost of these domes that's a significant consideration.

[UWphotoNewbie]

Actually the question was about flat macro ports more than domes. I understand that for domes icorners matter more because of the angle of view. However with macro lenses the FOV should be small enough that maybe you don't have corner issues?

So the question is about optical glass vs. standard glass or acrylic and coatings vs no coatings in flat ports? It seems that Aquatica is upgrading to optical glass. Is it worth the $100 upgrade?

[Iggy]

So the question is about optical glass vs. standard glass or acrylic and coatings vs no coatings in flat ports? It seems that Aquatica is upgrading to optical glass. Is it worth the $100 upgrade?

I believe optical glass is a far better port to use. There are a number of different reasons (nothing polishes like mineral glass and as a result nothing creates as low color dispersion, is as resistant to producing fringing or maintains photochromatic properties over the long term) but the proof is in the images and the power of today's dslrs has really made the quality issues obvious. I'd say the 100 bucks to switch your acrylic port to a glass one is well worth the cost.

Admittedly I don't know enough about the aquatica coatings. But I'd question the advantages of using coatings for flat ports. If you scratch an optical coating it's a bigger problem than if you just scratch the glass (I don't know what happens when you scratch a scratch resistent coating ) and I'm not convinced of the advatanges to coating a flat port. Is it really gonna reduce flare and is flare really that big of a problem if strobes are used and positioned properly?

[RogerC]

uncoated glass transmits only ~95% of light, the rest is reflected. Coated glass transmits more, 98 or 99%. It's all approximate, it depends on the glass, the coating, and the wavelength. The reflected light may or may end up on your sensor as flare or internal reflections. It may not, depends on all the angles.

[Iggy]

uncoated glass transmits only ~95% of light, the rest is reflected. Coated glass transmits more, 98 or 99%. It's all approximate, it depends on the glass, the coating, and the wavelength. The reflected light may or may end up on your sensor as flare or internal reflections. It may not, depends on all the angles.

My comment was more focused, or was intended to be focused, on the need for a coated flat port when I can't recall ever having a flare problem behind one. Given that coatings scratch I'd think there would have to be a pretty good reason for applying one, yet I don't see it for a flat port.

[bvanant]

My comment was more focused, or was intended to be focused, on the need for a coated flat port when I can't recall ever having a flare problem behind one. Given that coatings scratch I'd think there would have to be a pretty good reason for applying one, yet I don't see it for a flat port.

It's true that coatings scratch, but many of the thin film coatings are almost as hard as the glass beneath and of course little scratches matter not (I bet your dome has some small scratches). The advantage of the coatings is color reproduction and transmission. All camera lenses are coated, all our laboratory optics (almost) are coated. Coatings really work, older non-coated large format lenses are very very different than modern lenses even using the same glass formula. I don't know if the Aquatica coatings will be noticeable on every shot, but I am guessing that they will be the difference between good and better for some shots.
Bill

[Viz'art]

[/quote]Is it worth the $100 upgrade?[quote]

Its actually more like 20.00 more for getting the glass version over the Acrylic one. I will not start another debate on the Glass versus Acrylic, both have advantages and disadvantages. Theorical conclusion is something, practical field operational conclusion is another, and that is the reason we still offer both the macro port and dome port in glass or acrylic, so that you have the choice

[meister]

"and that is the reason we still offer both the macro port and dome port in glass or acrylic"
Is the new glass dome port out already?

[Viz'art]

The glass dome is upcoming, we are in the final stage of preproduction, our insistance that it be rated at 300 Feet is delaying production, the flange design is the final hurdle, not the dome. simplicity is never a simple task

[Iggy]

It's true that coatings scratch, but many of the thin film coatings are almost as hard as the glass beneath and of course little scratches matter not (I bet your dome has some small scratches).

The scratch on a flat port that mars a macro image will more often than not have no effect if on a dome shooting a wide angle shot. My domes are essentially full of small scratches, but that is not something I can get by with on my flat ports.