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...
40139
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.
518034
1/2 a cup exactly then subtract 3 1/2 tsp. I use a syringe type dropper made for oral medicine to measure. Your results may be a little different... but this is a really good place to start. For me this makes round death stars. If you add too much you get fun house mirror death stars shaped all cone like on the top. (which is the bottom of the mold)
1340325
The first number is the power of the lens, that is how much it will magnify the image. The second number represents the diameter of the lens in mm. They work together to calculate a number called the "exit pupil" or "exit ratio". Take the lens size and divide it by the power to get this number. The higher the number, the brighter the image. For example, 10x50 will give an exit ratio of 5.0, 8x42 would be 5.25, 10x42 would be 4.2. In my opinion, the exit ratio is more important than the power. My favorite binoculars are 8x50 (6.25) but I also just bought 10x50 as a gift who is delighted with that configuration. Stay away from high-power binoculars. They, for me, are too hard to keep steady due to the high magnification. I hope this helps. -Norm
1193218
The 1.25 dimension is the standard telescope eye size for most scopes. I to have a C90 and purchase a "hybred-diagonal" (.965 to 1.25). This allows me to use all of my 1.25 eye pieces on my C90. Hope this helps.
1471639
It depends on both the scope and the eyepiece. While the Barlow will increase the magnification by that amount you don't want to exceed the resolving power of the scope since you'll lose image quality and not gain additional detail. There are web calculators available that can help you figure out magnification and resolving power.
1253935
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.
21263
i would get the -3 that way you don't cause disorientation, because water as is does have refraction, so i would go with the lowest diopter.
1503374
The 25 and 36 refer to the size of the lens opposite the eyepiece in mm. The larger the lens the more light it gathers. This of course makes for a heavier monocular and a larger one. I have a 10x25 and it is fine. You have to have a steady hand though in using the devise.
1922935
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 :)
1951961
There are three lenses which can be stacked for greater magnification. Using the first lens only it's about 8-8.5 inches. Add the second lens and that drops to about 4 - 4.5 inches. Add the circular lens (for the right eye only) and it drops to about 3/4 - 1 inch. Hope this helps.
1515978
I have found no differences between the different diffraction glasses that I have purchased from Amazon. I have been buying large quantities for a couple years now to pass out to 8th grade science students in an Expanding Your Horizons project that I volunteered for. We use them to describe how Optical Emission Spectroscopy works in our lecture called "Chemistry of Light" I have never even tried them under black light, but will look into that for future reference. Not sure about the actual diffraction grating sizes being used but we are just looking to get the children's interest sparked so we haven't been very scientific about it. I have found no differences between the different diffraction glasses that I have purchased from Amazon. I have been buying large quantities for a couple years now to pass out to 8th grade science students in an Expanding Your Horizons project that I volunteered for. We use them to describe how Optical Emission Spectroscopy works in our lecture called "Chemistry of Light" I have never even tried them under black light, but will look into that for future reference. Not sure about the actual diffraction grating sizes being used but we are just looking to get the children's interest... » Read More I have found no differences between the different diffraction glasses that I have purchased from Amazon. I have been buying large quantities for a couple years now to pass out to 8th grade science students in an Expanding Your Horizons project that I volunteered for. We use them to describe how Optical Emission Spectroscopy works in our lecture called "Chemistry of Light" I have never even tried them under black light, but will look into that for future reference. Not sure about the actual diffraction grating sizes being used but we are just looking to get the children's interest sparked so we haven't been very scientific about it. « Show Less
1746
That is the strength of the reading glass. The higher the number the greater the magnification. It is not at all about the size as it will fit your head.
676547
I don't know how to measure parallax, but at 25-30 yards, parallax is not a problem. I have excellent clarity throughout zoom range. Worth the money!
2259983
I have found it only to be a slight adjustment. If you take it off the camera then move it in front of something close to focus on. Adjust the ring and you will see a slight difference. Personally I don't use the diopter after initial focus.
349530
It does refer to the diameter of your lens, if you are unsure or want to double check, look on the inside of your lens cap!
2033673
Michael, Not sure exactly how much 1.2 is, but the adjustment is fairly large on the right eyepiece both + and - As a test .. I set the right eyepiece at max (-) and used my reading glasses 1.75's in the eyepiece to bring the field back to normal focus, ie left in focus, right at max - and the 1.75's on the right bring them both back to even focus. They are great binoculars and they perform very well for the weight and compact size. Hope the info helps.
1645861
Paul, thank you. From the specs alone, I agree, but I think there must be some significant difference between the two sets. The only thing I can see from the specs is something about the eyepiece adjustment.