Sea and Sea port options

For the current Nikkor 18-55 and 18-70 kit lenses which Sea and Sea port options would be best?

The Sea & Sea lens chart indicates flat ports but users here seem to favour a dome.

If anyone is using the Sea and Sea compact dome with either of these lenses which if any extention ring is best - the 40mm or the shorter SX ring?

The cheaper 18-55 looks to have a better close focus ability than the 18-70 lens.

Also, is there anything to be aware of with the close focus ability when using either of these lenses behind a dome - any dioptre required?

Hi TKR and welcome to wetpixel.

If you wish to preserve the 18-70 as a mid-range zoom, then you'll want to use a dome port and you'll need an appropriate diopter.

If you want to shoot it as a fish photo and pseudo macro lens, then a flat port is better.

As for the 18-55, I haven't used it, but I think the 18-70 is a vastly superior lens.

HTH

James

HI

I use the 18-70 DX to great effect on my Sea & Sea DX70

combo is

Compact Dome port with 40 extension ring & +4 Dioptre.

see images below for samples

I dont think sea & sea make a zoom gear for 18-55, 18-70 is covered as i use it.

18-70 is the better choice

regards

craig

For my style of shooting, compact dome, 40mm extension, +4 diopter is the most appropriate choice too...

James' advice is spot on re: the flat port.

There are probably loads of posts concerning diopters on wet pixel but I'll ask anyhow.

What exactly goes wrong if I don't use a diopter on an 18-70 or 18-55 behind a dome port. Is it just close focus ability that is compromised or is there more to it than that?

Why a +4 ?

If anyone has the energy to reply on such a topic I'd be grateful.

In your case (the 18-70) it is the close focus ability. But for some zoom lenses that can focus closer, photographers that advocate the use of diopters will tell you that you will have sharper corners with the diopter even if your lens can focus without it behind a dome.

Luiz

I'm reading this post with interest as someone who has only borrowed a housed SLR once to use underwater. I've trawled back through previous posts for anything to do with zoom lenses with diopters behind a dome.

The theory is not too confusing: - the camera focuses on a virtual image - the mid range zoom invariably can't focus close enough on the much closer virtual image - the diopter is needed to recorrect for the much closer virtual image - the diopter may help overcome the curved plane of focus caused by a dome - improved corner sharpness. etc. etc. At least I think I understand some of it!

It seems though that there is a blanket recommendation by many to use a +4 diopter on the 18-70 Nikkor and various other similar mid range zooms behind a 6 inch dome. Some say that if the lens will not focus at less than 12 inches then for a 6 inch dome a +4 is required. Others say this might be too strong and further experimentation is required to get the best set up.

It all sound quite inexact to me considering the expense of some of these housed zoom lenses. Perhaps fixed focal lengths lenses would take some uncertainty out of getting a guaranteed good optical quality?

Hi Trevor

I've actually been back and forth with using zooms

I first started out using zooms, then required better image quality and moved onto Fixed lenses.

Now in the days of Digital I actually find it very nice to use a zoom again from time to time.

I use zooms when i'm not sure what i'm going to encounter whilst underwater.

If i make the decision to shoot wide but dont know the dive site or marine life, i tend to use a zoom like 18-70 as this can cover quite a lot of shots.

If i know what i'm shooting (work) then i tend to use a fixed focal like 15mm or 20mm or 10.5mm as most of my work involves divers so CFWA and quality is what i need.

I do however find myself going for the zoom more often than not, the quality is still just fine for upto A3 prints and magazine articles at A4.

I've never had a magazine turn down any image that i've shot with a zoomer, I dont think they would even know in fact.

There is nothing in-exact about it, you use what works for you, +2 or +4 or no Dioptre.

Most of the new wide zoomers out these days will work without the addition of a filter, But and there is a BUT, there are people and Alex is one that will vout for using close up filters as they actually serve to improve image quality and edge sharpness.

You just have to do some testing with your own setup until you reach what your happy with.

I've just got a 12-24mm, i'm sure its going to become a favorite. testing will begin without using a filter and i'll move on from there.

But i think most will agree, there is a certain QUALITY which comes along with Prime lenses.

regards

Craig

Hi Craig,

There is clearly a bit to learn about this and a lot of seems to involve going diving and taking pictures to find out what works.

Just out of interest what sot of diopters do you use. The cheaper sort or the multi element type?

It looks like Sea and Sea do a zoom gear for the newish 18-55 zoom now. This seems to have a close focus of 28cm against the 38cm of the 18-70. Does that sound useful in the diopter issue or no big deal?

Regards from someone else stuck in the UK midlands,

Trev

Hi Trevor.

Nice to conversate with someone so close to home.

As for you question on the 18-55, I'm sure it will work without a dioptre, as the 18-70 does anyway and from your figures it will focus a little closer.

Nice of S&S to produce a gear, I've bashed them for a month now to get it together and produce 10-20mm and 12-24 tokina zoom rings. without success.

would i be correct in thinking that you have a D50 in mind ?, only reason i say is because the 18-55 is being shipped with that camera.

Back to the dioptre. you are only going to need a +2 if anything on the 18-55 for sure as it focuses quite close anyway.

I use Hoya close up's just the normal ones. you'll find that trying to get a HMC Hoya in anything above 62mm is quite hard.

I use warehouse express for all my filter needs, they have a huge stock range and excellent service.

regards

craig

In my recent research in purchasing a housing I have learned but not confirmed that many 8" domes are not a true 8" but were sized metrically and are actually smaller than 8" around 7" and change. Thus a diopter helps in the corners. I prefer to have less glass in front of my lenses so I do know Aquatica is a true 8" not sure about other manuf. but I suspect those using dipoters depending on the lens may not have a true 8". I am sure this varies by lenses but thought I would share this.

Knowledgeable types say I can no longer refer to it as "Da Bigga Doma" but the radius is same as Aquatica............