Is it necessary to use a +4 diopter close up lens with the DR lens kit? It focuses at 0.9 ft, which is less tha 12". Is anybody using this setup? What has been your experience? I was told that it is NOT needed with the lens kit because of this. I will be diving in Belize next month and want to have all necessary lenses and accessories purchased and mastered by then. Please post responses, as well as e-mail me at:

jasonfelipe@sbcglobal.net

Thanks all for your help!!!!

That depends not on the lens, but on the port you use. Using a domeport you will need a +diopter because the dome is working like a negative diopter lens under water. And without you will not be able to focus sufficiently close. If you use a macro port no diopter will be needed.

Daniel

I will be using an Ikelite Housing with a 3"dome port to accommodate the lens. Again, I was told that if the lens focuses at less than 12", then a +4 diopter lens is not needed, yet on Ikelite's website, it says that it IS needed???? Help!!!!

Disclaimer: I am no expert, new to the Rebel as well!

If you are referring to the #5503 dome port (What they recommend for the kit lens) it is not really needed. At full zoom I can down to about 10 inches from the dome UW (estimate) without a diopter. I have thought about testing one though.

I have done a lot of pool testing with this setup before my next trip (Two weeks and I can't wait!!! ), some of the results here: http://www.digitaldiver.net/yabbse/index.p...y;threadid=5946 shows shots about as close as the lens will focus without a diopter.

Hope this helps,
Dave

But then again, if you spent lots of bucks on dive trip and $400) + on the rest of your rig then you might not want to take the chanses on having a little $20 piece of glass being the missing link... I had the same question and bought it. Certainly does not hurt.

Ooops that should ave been $4000 + No I did not get a $400 super deal

I was at my camera store to buy my D70 and they only had a set of 4 promaster diopters for around $100. What brand/where can you get just the +4?

Thanks

No a diopter is not needed for the Kit lens in an Ikelite housing and 5503 dome port. I know because I dive with this setup every weekend. I ordered a diopter assuming that it was going to be needed but when I tryed it out in the pool both with and without the diopter there was no difference so on the 5 dives I have made with the kit lens I have not used the diopter and have had no problems.

William - When you say that there is no difference, what do you mean? This is only possible if the kit lens can already focus on the front of the dome without the diopter. Is that what you mean?

A +4 may also make it so you cannot focus at infinity underwater. You certainly will not be able to on land.

Dave,

Using the kit lens and the ikelite housing and dome, what is the closest object you can focus on underwater?

I believe this is shown in your photos, but I'm lazy...:-)

Cheers
James

I am sure there are many options, but I got a B+W NL-4 from B&H. This was not part of a "set" of diopters.

I mean that underwater it can focus at infinity with or without the diopter and that underwater the diopter does not noticably decrease minimum distance either. Yes above water it cannot focus at infinity with the diopter.

This picture is with the kit lens at 18mm withOUT a diopter.
http://www.wetpixel.com/PNphpBB2-viewtopic...ic-t-4862.phtml

That is very strange, William. There is a huge difference when I use a +4 with a 16-35mm zoom in my Canon setup. Go figure.

You are going to need the +4 diopter with the Ike dome to get the closest focus the lens is capable of. As other mentioned you might test it without the diopter to see how close you can focus. If it is close enough for your purposes then you might not need it.

James,

No scientific measurements, but it seems to be around 8 to 10 inches from the dome, at full zoom - 55mm. I have not really tested close at the wide end, no reason I thought. It does focus closer than I thought would for a dome, believe this is attributed to how close the lens extends to the port at full zoom.

There IS a point to where the camera will not focus if too close. And that distance the subject appears closer to me in the resulting photograph than what I shot, I have always just attributed that to the 'apparent' image that the dome creates as opposed to what I see when taking the shot (Might be just error in my perception of what I thought I saw and what was actually taken). Any of that make sense?

Warning though if a diopter is used, watch how far you zoom out. I use a 58mm UV haze filter to protect my lenses as many do. The first time I loaded the camera I left it on and it will strike the dome. Since the dome is acrylic it could cause a mark from the serrations on the end of the filter. :shock:


Dave