I have graduated lenses - Would I be best advised to order bifocals? And, how do you incorporate Cyl and Axis measurements?
282297
Hi Todd, I did not see option to order bifocals so I can not comment. Best..
282298
I do not know what 'cyl' and 'axis' measurements are, but, here is what we did:1. when ordering Speedo goggles, we got the +/- number, from our opthomologist.2. when ordering the ProMate snorkeling mask, we selected the the color and then selected the appropriate eye-adjustment (my son is nearsighted) from the "size" pull-down menu on the ProMate scuba options.3. My 13 year-old son loves the mask and was our family underwater photographer in Cozumel.
282299
I have graduated lenses also; however, I just went with single vision lenses in my mask. Don't know about Cyl and Axis ... I didn't bother (even tho I have an astigmatism) and they worked great
282300
I wear trifocals and the single lens correction worked just fine. I wasn't close enough to need the extra correction even when I was about 3 feet away.
391216
I think the 10mm & 20 mm eye piece comes with the telescope, & a basic laser finder, you may find it more enjoyable to order a 2x barlow extension, That mostly makes it a complete setup for the quality the scope
107887
My daughter's prescription is -7.0 in one eye and -7.25 in the other. I purchased the -7.0 for her and they work great. For you I bet that the 9 would be better as you are already very nearly there at -8.75.
1635572
What I was told with 3.5X loupes is the focal distance should be at least 24-36". I must admit, I was "off" until I finally got myself to hold my head away from the patient at least that distance. Otherwise, everything is blurry. I'm also trying the 2.5x loupes now.
1387443
My advice is to go to Nikon's website where there should be a lens compatible chart or do a Google search.
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A laser collimator. It'll help to make sure your mirrors are aligned. It's pretty easy to do. Look on Youtube for "Collimating your Newtonian" to see how it's done. You'll usually want to check it before each viewing as they can get out of alignment with bumps. If your mirrors are out of alignment, things will get blurry. The Orion Shorty Barlow is a good accessory too if you don't want to buy extra eyepieces. It'll effectively double your eyepieces (turns your 9mm into a 4.5mm and your 25mm into a 12.5mm). Better eyepieces will make it a better scope as well. Superplossls are much better than what's included.
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2.8 will provide a wider view, reference the link for a relative example. http://learnphotographywithtomgrill.blogspot.com/2011/05/lenses-introduction-to-focal-lengths.html
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.
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I can't specify "field of view," but what I can tell you - that I think is important for you to know - is that when I replace a 10x eyepiece in my low-power binocular microscope (1x objective), the image is greatly magnified from what it would appear through the eyepiece . . . perhaps about 5x as much (50x total?). I really would have liked it to stay the same, but I can understand why it doesn't. If you have a 40 or 50x eyepiece (or so) that you replace with the camera, my guess is you will see about the same picture as you see through the eyepiece. The clarity is good. Of course, it could be better, but probably not for the same price. Now that I understand the limitations, etc., I am quite pleased with it. I built my own lens and stand for it, using the barrel of a cheap flashlight and a double convex lens that just happened to fit the tube perfectly (24mm). I added a diaphragm to increase depth of field, and a baffle between the lens and camera to minimize "splash" within the tube. These are all held in position within the tube by O-rings (from Harbor Freight). The added diaphragm requires an additional light source, which I got from eBay for $3.50 (music stand LED lights on flex arms). Works pretty good!
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They do have a 2.5 and 3.0, but they are all bifocal. The upper part of the lenses are plain, no correction.
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To clarify, order one lens of each strength. You should have two line items showing single lens purchases.
8522
Hardy,Thanks for the info about getting better lenses. I just "bit the bullet" and bought the 24-105mm L lens. I have heard this same wise advice from other photographers, and I am looking forward to getting sharper photos with the new lens, and I will try to get only L lenses from now on. In the end, you truly get what you pay for.
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Perhaps the best guide for A-mount lenses can be found on the Dyxum website: http://www.dyxum.com/LENSES/INDEX.ASP
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I recently had cataract surgery and I am now farsighted. Standard 5X magnification didn't help at all, so I went for the highest one I could find. If a 5X doesn't work at all for you, go for the highest magnification.
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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.
1159087
What are you trying to achieve in your star gazing? Although 12 x 36 IS are helpful, optics that let in more light i.e. bigger diameter front lenses, are necessaary for faint objects. However, if you are hoping to see nebulae, galactic clusters, Messier objects, or galaxies, no binocular is good enough. For that activity you need large and powerful telescopes. My Canon binocs are great for bird watching and boating, or for folks who have difficulty holding anything steady. Remember that if you fall into the trap of high magnification, as the primary concern, any slight movement on your part is magnified by the same amount. My telescopes are 60 x 70 and a large 18 inch dia. Even those, securely mounted, are barely able to capture some of the astronomical wonders I would like to see.
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Amazon sells spectacles that function like binoculars. You might be able find a pair that will focus to 3' away but be careful. I ordered a pair of really cheap one and the field of view was too small to be useful. I threw them away. They make much, much better ones that cost much, much more. The issue is can you find a pair that will satisfy your needs at price you can afford.