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Lens help

Posted: Mon Oct 15, 2012 1:09 pm
by Nwcid
Many know I just bought the Nikon D70 that was listed on here that included a 10.5mm Fisheye lens. While I did get some cool shots with the fisheye the other day I would also like to be able to take better pics of small critters. One reason I was sold on this camera is the fact I own a D90 along with 2 lens for it and they are all compatible.

The "kit" lens that came with my D90 is a 18-105mm and I was hoping to use this in the UW housing. While it does fit I can only "zoom" it to about 30mm before I run out of room. I have not had a chance to try shooting with it underwater so I am not sure if it will do what I want or not.

What I want to be able to do is get some more "close up" pics of some of the smaller critters or even stuff like crabs. So now I am not sure what I need. Looks like I need a fixed mm lens now I am just not sure what one, 40mm, 50mm, 55mm, 60mm? From what I have been reading this should be a decent lens. All the reviews are great and seems to focus quick. http://www.nikonusa.com/en/Nikon-Produc ... -TechSpecs

Re: Lens help

Posted: Mon Oct 15, 2012 1:14 pm
by lundysd
The Nikkor 60mm macro is the easiest and most versatile lens. The Nikkor 105mm macro is also great, but harder to use and more expensive. Both will give you theoretically 1:1 magnification (objects will be the same size on the sensor as they are in real life). These are far and away the most popular 2 macro lenses on the Nikon platform

Re: Lens help

Posted: Mon Oct 15, 2012 1:23 pm
by Nwcid
Good to hear about the 60mm. There is no way the 105mm will fit in my housing.

I also assume it will be a big improvement in "zoom"/distance I can be away from the subject vs ~30mm with the lens I have now. Am I correct in thinking that if I set my zoom lens on 60mm that is the same thing I would see though the lens all the time with a fixed 60mm. I have no experience with fixed lenses.

Re: Lens help

Posted: Mon Oct 15, 2012 1:25 pm
by lundysd
Honestly... you'll probably want to buy a dedicated macro port. They're not that expensive, and they will provide better optical quality. It is also very dangerous to use a macro lens on a dome port because it's very easy to get too close to a subject and scratch your expensive glass :)

Each of the above macro lenses have their respective ports, but both will work equally well with your camera and housing

Re: Lens help

Posted: Mon Oct 15, 2012 2:19 pm
by Nwcid
Ok, so after reading many threads for now it sounds like the dome I have will work for me for now. With the length of the 60mm it will be almost to the end of the dome so we are only talking 1-1.5" further then you might be with a flat port. Also my diving skill is not to the point where I would be that close to a subject without good odds of hitting it. Right now getting within 6-12" makes me quiet happy.

I had fun with the Fisheye the only dive I have done with this camera but even just taking "normal" (non close up) shots the subject seemed distant even when I got close.

Re: Lens help

Posted: Mon Oct 15, 2012 3:26 pm
by dlh
The dome port will have a negative impact on a 60mm or other macro lens. You will lose magnification, negating some of what you want from a macro lens. You really do want a flatport for best results. An Ikelite flatport can be found pretty inexpensively.

Re: Lens help

Posted: Mon Oct 15, 2012 3:55 pm
by John Rawlings
lundysd wrote:The Nikkor 60mm macro is the easiest and most versatile lens. The Nikkor 105mm macro is also great, but harder to use and more expensive. Both will give you theoretically 1:1 magnification (objects will be the same size on the sensor as they are in real life). These are far and away the most popular 2 macro lenses on the Nikon platform
This is really good, sound advice. I have both the 60mm and the 105mm and have found that I use the 60mm almost exclusively for macro and close-up work. A bonus of that is that the 60mm is also less expensive than the 105mm.

- John

Re: Lens help

Posted: Mon Oct 15, 2012 3:59 pm
by John Rawlings
Also, if I remember correctly the set-up that you bought has an Aquatica housing, right?

Aquatica makes a great flat macro/close-up port that I know for a fact will work with both the 60mm and the 105mm. They also make extensions that can be used with a variety of lenses.

Re: Lens help

Posted: Mon Oct 15, 2012 4:12 pm
by Nwcid
Yes it is an Aquatica housing with an 8" dome port.

I am trying to read up on the suggests you keep making so I can get a better feel for what I might need. I understand there are some things that are best. Right now I am looking for workable solutions that I can build on.

If I am going to have to change ports might I be better off for now to buy a port I can use with the 18-105mm lens I have now? Right now I am wanting to take decent all around pics not super close ups. I did decent with my Gopro when we went to HI but the thing I want is to be able to get my "subject" more in the photo vs "see the little yellow speck".

Re: Lens help

Posted: Mon Oct 15, 2012 5:31 pm
by deep diver

Re: Lens help

Posted: Fri Oct 19, 2012 10:27 am
by MikeMeagher
Your wide angle lens is behind a concentic dome port. The curved surface of the dome port mitigates the refreaction of air-port-water interface and keeps your lens "wide". Without the dome, refraction behind a flat port would cause distortion at the extreme edges and narrow your effective Field of View. However, whenever you put a dome into water with air on one side and water on the other, you now create a lens. Try it with a round bottom pyrex baking bowl, slowly push it into a sink full of water. You will see the image. This combination creates whats called a "virtual image". Your wide angle lens is in reality taking an image of a virtual image that is at a focal point just a few inches away from the lens. A dome port works just fine for most wide angle lenses, given that they often can focus close enough to be sharp on the virtual image and also they have great DOF. Sounds like your lens when zooming is no longer able to focus on that virtual image.. thus the blurryness.

For a macro lens.. youre shooting a narrow field of view. You dont need a dome port. Refraction of the image at the edges is no longer a concern given you have a narrow FOV> What you should do is then put your macro lens behind a flat port, not a dome port. You wont have any noticiable refraction so deal with and your lens will focus at all distances.

This is how I shot stills for many years and I now apply the same system to my video work: for wide angle I use a WA lens behind a dome port; for macro shooting I use a a macro lens or close up diopter behind a flat port. You'llhave to pick and configure prior to the dive and plan the dive and dive the plan... and pray that when you have your macro setup that a huge whale doesnt swim by. Another alternative is to break out the VISA card,, take two cameras in the water all the same time. :) I used to do that long ago before I was married and had kids.

Re: Lens help

Posted: Fri Oct 19, 2012 1:58 pm
by Nwcid
Thanks.

The focus issues had to do with a known problem with the AF on the D70. I have that issue fixed now.

As for dome vs flat I am trying to use what I have and slowly build up without having to spent another $1000 right now. I fully get why some things work best and will work on that.

For this weekend I will be trying my 18-105mm set at 30mm as that is what fits under the dome and see what happens. Of course I do have the 10.5mm fisheye too.

Re: RE: Lens help

Posted: Fri Oct 19, 2012 5:00 pm
by DecidedlyOdd
I wouldn't bother buying a port for the 18-105. "All around" lenses on the surface don't work well underwater. Because light drops off fast in water, you need to be close to your subject for decent shots unless you're shallow in clear water.

To get really close there are only 2 options--ultra wide angle (like your 10.5 behind a dome) or macro (60/100 behind a flat port). Shots from other setups tend to look blah or flat because it's hard to get close enough and keep the subject framed well.

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