Potential problems of using the wrong lens for your port?

[pdks]

When you use a fixed focal lens that wasn't designed for the port you're using on your housing, what are some of the possible problems (this assumes it fits, of course!).

- eg: using a 60mm in a port designed for a 105mm?



Thanks for your indulgence with what might be a silly question!

 

[Eskasi]

Dead space for one....the working distance for 1:1 on the 60 is already pretty close. Placing it in a longer port like the one for the 105 would cut it down by that much more..... Having said that, I MAY try it for the new Nikon 60. I's just under a couple of cm shorter than the 105VR I think

 

[TheUWPhotographer.com]

I've been online looking for some technical info about this topic for an upcoming presentation and I came across several great websites that explains this quite well.

Cameras Underwater: Lenses and Optics. and scubageek.com - scroll down to the lens optics part

I think you'll find your answer here.

 

[jcclink]

A possible problem with your example (60mm in 105 port) is vignetting since the 60mm angle of coverage is greater than the 105mm. Just check it in a tub of water - only the face of the port needs to be wet.

 

[advertiser]

Wow thanks for this post it really help me... just one quick question, it is alright to use a compatible lens as long as they are the same size? pardon me for my ignorance.

Sam Milby
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[Eskasi]

Well...you should do research on whether the lens will fit the port....not just the length but also the diameter. Some lenses also zoom out and extend. Take that into consideration.

Apart from that, you may need to make sure that you can modify a zoom/focus gear to fit if non are available to buy off the rack. Remember, each brand of housing will have their own different port options.

Some lenses perform better than others underwater from what I understand. This forum and wetpixel.com are good places to do your lens research. Check with the retailer too.

 

[scottfiji]

I shoot the 60mm lens and my 105mm VR lens in the same port...(D80, S&S housing)

this makes travelling easier and saved me $300, and makes changes lenses from the 60mm to the 105mm and vice versa easier on a boat.

I have never noticed any problems at all. I have no vignetting, no working space issues - I can shoot 1:1 and get proper lighting no problem. keep in mind I use 2 arms on each strobe when shooting macro, just like I do for wide-angle, which helps.

I have also borrowed a 60mm port, and have not noticed any difference in image quality when shooting my 60mm lens in a 60mm port or a 105mm VR port. However, I've heard conflicting opinions on whether the IQ (image quality) should be any different, and I plan on doing some tests in my pool in the next week or two to verify this issue.

scott

 

[Fota]

When you use a fixed focal lens that wasn't designed for the port you're using on your housing, what are some of the possible problems (this assumes it fits, of course!).

- eg: using a 60mm in a port designed for a 105mm?



Thanks for your indulgence with what might be a silly question!

Actually I would say it's the other way around. I've done some dives with my 60mm AF-D in a 105VR port and the shots were the best I've taken (I did it by mistake as I got the 105 for when using 60mm + teleconverter but I forgot to add the teleconverter!). Well, technically that is.
More colors, great exposure, great sharpness.

I think this is because with a longer port you get less water between the lens and the subject. So in dark water with low viz (where I tested) this probably matters more.

The drawbacks are of course that sometimes you don't want to get your port as close as possible to the subject. It may scare it and makes it a little harder (just a little, and far from impossible) to lighten it, point the focus light etc.


/Fota

 

[scottfiji]

I think this is because with a longer port you get less water between the lens and the subject. So in dark water with low viz (where I tested) this probably matters more.

/Fota

I wondered about that too, that maybe having air instead of water is a good thing!

 

[kkgodiving]

When you use a fixed focal lens that wasn't designed for the port you're using on your housing, what are some of the possible problems (this assumes it fits, of course!).
quote]

I hv asked this question in another thread but will repeat it here. The sea & sea 2008 system chart states the AF 20mm with NX Compact Dome Port needs the SX Extension Ring (on MDX-D300). I hv not taken any pic with the AF 20mm + NX Compact without the SX. Has anyone tried it? Result? Thx.