I read on another site that: 1/2 the cylinder measurement + the sphere measurement = diopter strength. Because I have a lot of astigmatism this changes the measurements quite a bit (-3.25 cylinder, -3 sphere). Has anybody else used this equation to...
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That's the method we used when buying my daughter's goggles. She ended up with -3.625 (R) and -4.25 (L) so we split the difference with a -4 prescription. She says they work well enough for her, and she has to be read a white board to get her workout during swim practice.
1469254
I use the 3 and higher for imaging Planets, thet 2X can be used for doubling the power at the eyepiece. The 127 eq is a great scope you should have lots of fun. I had a C5 at one time loved it.
2042953
A 6mm eyepiece will give you about 75x magnification. I get better views of Jupiter in my scope with 4mm and 3.8mm eyepieces at about 115x. I don't like using a Barlow.
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After using it, you can inspect it with a magnifier. I saw no problem and continued to use it on my lenses and filters. I'm happy with mine.
325774
An ounce or two is nothing if it works for you. I love it. I put it on my crossbow to see if it gave more light and my bad eyes could see better. I love it. will put it on a 556 for distance now.
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You need to know your glasses prescription. If you're nearsighted, (need correction for distance sight your rx will be a negative number. The lenses come in 0.5 increments. For example I have a -3.75 correction. Since it is in between correction options I ordered a -3.50. (If your in between order the lesser strength). If you are far sighted the correction will be a +.(ie reading glasses). Hope that helps.
1632329
Hi, The focusing distance is always measured from the sensor. Therefore, subtract the distance from the sensor to the front of the lens barrel (approximately 3 inches), and you are left with actual "working distance" of about an inch. Hope that helps.
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Thanks for taking the time to reply. I suspected as much, so I have just been using one at a time. Nice to know that I needed to, and should continue to, in the wide angle range.
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If you pull out the viewfinder you'll find a small dial. That's the diopter adjustment. It's great when you go from glasses to no glasses. Before you set it make sure you've actually had the camera properly focused on something first.
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So you have the option to have a different strength for each eye? I did not when getting swim goggles and went with something in the middle, so in your case, either 2 or 2.5. I have one eye too strong, one not enough, but that does not seem to be a problem.
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Because of the difference I would suggest buying 1 pair in each of the diopters you need and swapping out the lenses. For me the difference was only 1 point so I went up a half. They've worked out great.
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Her is two thoughts, 1st you can use a minus 1 and that may give you the rsange you want but I took the 2nd way which I purchased a -2, that way I can use the plus adjustment to get the proper adjust. Don't to purchase an eye cup for the corrective lens.
2030132
Hello Joyce, The "mm" measurement refers to the size lens the filter is meant to fit. Most lenses should have this measurement written on them, and it refers to the diameter of the end of the lens where the filter screws on, not the "35mm equivalent" of the zoom, so it is important that you get the right size for your lens and there is only one correct size. This specification should be listed under the specs for the lens as well, and is specific to that particular lens..other lenses will have different diameters...Hope that helps!
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Yes - this pair allows for diopter adjustments, which you calibrate when you first use them out of the box (it may make focusing difficult for other eyes than your own, like when you lend your binos to someone else). I think the paperwork included has directions, and if not you can google how to do it :)
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The numbers 1.25, 1.5 etc refer to the maginification of the lens, the reading glass strength. The frames are all sized the same, for a unisex head shape. The temples are adjustable in length assuring a comfortable fit on a wide variety of head sizes. You'll need to know which power (+2.0? or +1.5? ect) you'll need for the lens of course. Thanks,
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Its actually not bad. I sighted in at 25yds and at 50yds. At 50 it was a little faint but you could definitely see it.. make sure you're not using a bright white paper to sight though as it will wash out. I really wasnt even expecting that for the price. It's worth the 12 bucks.
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I ordered a pair for myself and 1 pair for each of my sisters in new mexico and texas. We all decided they were not user friendly for us. I don't know the strength but I can tell u this, you cannot see anything unless u hold the item about 1/8th of an inch away from our eyeglasses (we all wear glasses. we were hoping we could get splinters out but we all decided that they would not work for that either. all 3 pairs were thrown in the trash. they just did not work for us. hope this helps u