Nikon 18-70mm For UW use

So I took my 18-70 lens UW for the first time yesterday. Ikelite D-70 housing, dual 125s. I had a 4x diopter on it and was using a 6" dome.

After shooting with both the Nikon 60mm and the SIgma 10-20mm lenses I was rather disappointed with this one. Granted, the low visibility environment I dove in might not be the best suited for this lens, but overall I found it didn't perform well. I had to keep my aperture open near it limit in order to achieve decent exposure and focus was often soft. I even had to switch to AF-C because I was getting frustrated with it.

Now, I'm still new to using DSLR UW so it could have very well been all user error.

What do you think? Anyone using this lens successfully?

I don't know what would be wrong. Exposure should not matter between lenses. If you photograph a scene and it requires f8 and 1/100 secs shutter speed with 1/2 power flash for proper exposure it won't matter if its a 105mm macro or a 12-24mm WA. Other than the angle of view covered and the width of flash required to cover that angle of view, exposure values are absolute--not lens dependant. For differences in exposure I would look at other factors like available light, ISO setting, shutter speed and strobe power.

Now as for soft focus. You will definately be dissapointed when comparing the super tack sharp prime f/2.8 60mm macro to this lens. Its in a totally different league and doesn't have to do nearly as much as the zoom. The 60mm is my favorite lens. It gets me the most keepers and its super sharp. Zooms have to make a lot more compromises to do what they do. For $300 the 18-70 is a screaming deal and its a great consumer lens but it has to make still more compromises to cut cost. It can't compete in sharpness or low light focus to the 60mm. at 70mm its an F4 lens so the aperture used for low-light focus will be compromised.

Also check your subject distances though. Its easy to get into the habit of shooting things more than a meter out with this lens. Anything will look terrible if the vis is bad and its too far away. Shoot as close as possible to redice the water between you and the subject.

The 18-70 is a good lens all things considered. I used to own one and ports too. I never took it under because I was so enamoured with the 60mm, 12-24mm, 105mm and 15mm. Post some pics and I can comment more.

Check this thread:

http://wetpixel.com/forums/index.php?showtopic=14494

I'm quite happy with it.

Thanks for all the feedback. I think I'll give it another shot

J.C.

I use it with the older 8 inch Ike dome port and found with the +4 it wouldn't focus well. I switched to a +2 and it worked much better.

SD