Sigma 18-50 mm F2.8 EX DC Macro lens for Nexus/Anthis

Sorry if I am a nag, but I see this lens pop up in underwater discussion for time to time without resolution for a Nexus housing. There is a tease on usanexus.com. They have not answered my two e-mail inquires. So, I put it to the gnomes and wizards of wetpixel.

I think it could be a good survey lens, e.g. I have never been on this dive site and have no idea what to shoot! In a dome port for a Nikon digital, it would be ~27 to 75 mm in 35 mm view or 36 to 100 mm in a flat port. While not a “real†macro lens, with the water magnification + .9 wet diopter, the flat port configuration is approaching 1:1.

My concerns are possible vineting in the flat port and fitting a zoom gear over the zoom lock. Has anyone tried this lens in a Nexus (Anthis) or Sea & Sea housing?

I have the non macro version of that lens and I'm a big fan of it. It's a nice versatile lens... With the aperture stepped down, it shoots very well even at 18mm (much better on corners than the canon 10-22 IMHO).

I currently use it in a S&S housing with an Athena Dome and 40mm extension without an diopter. I wouldn't think of using it in a macro port!

But you might want to consider the 17-70mm DC Macro Sigma if you want that extra reach for macro. While it's not a EX lens, the quality of shots coming from that lens I've seen are as good as the 18-50 EX.

I have been using the new 18-50 macro version quite a bit this year. I use it in a Sea & Sea housing with compact dome port and 40mm ring.

It appears to work well. I chose it over the 17-70 sigma, as it is a bit easier to house as the lens extention is not quite so large. I also thought it might work better optically. It is almost unusable behingd a flat port because of vignetting at wide angle settings.

I rate this lens highly for a mid range zoom and have been pleased with image quality. I can focus to within 1 cm of the front of the port. I can think of no other mid range zoom lens that can do this. This is really a lens for those that like the idea of a mid range zoom but are frustrated with poor close focus ability of Nikon and Canon alternatives. I bought it after a true macro lens and fisheye lens so I do not view it as a 'one lens fits all' bit of kit.

I came up with my own zoom gear built out of bits of plastic and rubber -i deas taken from the 'build your own focus gear' in the DIY forum. The zoom lock switch needs to be taken in to account.

Hope that helps

Thanks pakman and tkr for your pompt and helpful replies.

I did the numbers on the Sigma 17-70 mm; the zoom extension is too long for partical use in ports.

tkr,

May I assume you are using a compact dome port ~ 6.5' to 6.7" diameter with the 40mm extenson?

I made a zoom gear from some Ikelite plastic gears for my Sigma 24 to 80 zoom. I like the ideas in the DIY form.

Now, what do I hock to get the Sigma lens????