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Bifocal mask conundrum


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#1 wydeangle

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Posted 11 December 2013 - 11:00 AM

First, I'm not sure which forum this belongs in, so move it if it needs it! I do video so maybe this is a good spot for the question...

 

Here's the problem: My bifocal mask has a visual "dead spot."

 

Say I'm approaching a video subject, and tracking it using the distance portion of the mask. At some distance, say a few feet, the subject is too close for me to focus my eyes on it. The bad news is that it's too far away for me to use the bifocal part of the mask which focuses well at about one foot.

 

The distance figures are not necessarily exact, but are intended to give the idea that from about three feet to around one foot, there's nothing in focus through the mask. Too close for the distance part of the mask lens; too far away for the bifocal part. If I try to see through the monitor back using the bifocal lenses, it's a bit too small sometimes...

 

I thought about making the bifocal part of the lenses focus at two feet instead on one foot - that would make it difficult to see the monitor back on the housing - sort of running into the "arms too short" problem most of us experience as we accumulate birthdays.

 

You younger divers with eyes that can still adjust to see at all distances, just move along :sick:  On second thought, if you dive for enough years you'll probably develop an interest in this question!

 

I asked Seavision if they could make me a trifocal mask lens or a progressive mask lens and they said no. And they didn't know of any one who does...

 

So I ask: is there a place where such a lens can be obtained? Or are there other options?

 

Tom



#2 Aquapaul

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Posted 11 December 2013 - 12:11 PM

It's a bitch to get old….. Have you tried prescriptiondivemasks.com  ? They are out of California, I don't have the trifocal yet but they would know if it's possible.


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#3 wydeangle

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Posted 11 December 2013 - 01:02 PM

Paul,

 

That's what my brother reminds me: getting old isn't for sissies.

 

I've sent an e-mail to prescriptiondivemasks. Thanks for the pointer.

 

Tom



#4 Walmyr Buzatto

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Posted 11 December 2013 - 05:35 PM

Try these guys, too: http://www.sportviz.com/home They do progressive lens as well. Sent from my iPad using Tapatalk HD

Edited by Walmyr Buzatto, 11 December 2013 - 05:36 PM.

Using Tapatalk

#5 wydeangle

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Posted 12 December 2013 - 04:35 PM

Thank you Walmyr; I sent them an inquiry. Their masks presently seem to be limited to 100' with a deeper capability coming in "early 2014." So we'll see if I'm going to be a pioneer... (you know, the guy with all the arrows in his back - grin)

 

Tom



#6 peterbkk

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Posted 12 December 2013 - 05:33 PM

Hi Tom,

I'm in the same boat (pun intended). If we still lived in caves, the tribe would have put me out in the snow on a cold winter night because I could not see the wooly mammoths well enough to spear them anymore.

I tried SeaVision but, at best, it was an approximation solution.

So, I tried Prescription Dive Masks (Rx.Divemasks@mail.com) and have been very happy with them.

Firstly, you start with your own mask so it is a mask that you like. Given the cost, you might want to buy a new one of your favorite mask.

Secondly, you visit your optometrist with the mask and some instructions from Prescription Dive Masks. Your optometrist checks your ideal prescription for the distances (short and long) that you want to be in ideal focus. For long distance, I went for 10 to 20 meters and for the short distance I did the eye tests for about 80cm but its good out to about 1.2 meters. Your optometrist also marks your mask so that the fitted lenses align with your pupils.

You send the mask to Prescription Dive Masks and it comes back a few days later with an insert lens invisibly glued inside the mask.

Of course there'll always be that transition distance where you can either look up or down through either of the lenses but, if the lens is well suited to your eyes and aligned to your pupils, that'll be minimal.

Regards
Peter

#7 wydeangle

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Posted 14 December 2013 - 06:05 AM

Peter,

 

Thank you for the added potential source of a prescription dive mask - the site appears to be: http://prescriptiondivemasks.com/

 

If not please advise!

 

If I read your post correctly you did one of the options I was considering - put the "middle" part of the progressive lens as the "distance" part. That way the gap between distance and bifocal essentially goes away. I'm debating whether it's worth giving up the distance spotting of hammerheads etc (beyond normal video/photo range anyway) in favor of getting rid of the out-of-focus part of the near distance. Oh, well, all life is some sort of compromise...

 

I even thought about having two masks with me for that reason: clip off the distance mask and switch if I decided it was better at a given moment. Just what I need; something else to hang off my BC!

 

Still in the drum-roll on this one...

 

Tom



#8 peterbkk

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Posted 14 December 2013 - 05:27 PM

Yes, that's their website.

The best way to do this is to get your optician involved. I spent some time explaining to my optician what I was trying to achieve. She watched the video on http://prescriptiondivemasks.com/. Then she was able to write the prescription and mark the mask for the best compromise.

regards
Peter

#9 okuma

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Posted 18 December 2013 - 06:32 PM

I've been dealing with PrescriptionDiveMasks for 10 - 12 years and always the best service.

I have bifocals and know about the 'dead spot'.

In shooting stills, I trust the Nikon 'in focus' icon in my view finder much more than my eyes!

 

Ask for Linda; she is the owner.

 

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