Information about Binocular

Tuesday, June 17th, 2008

Travel Binoculars

Binoculars are most often used by people who travel. Binoculars are mainly helpful in journey travel, such as traveling to national parks or safaris, where the explorer might want to view wildlife. Travel binoculars are usually lighter and more solid than usual binoculars. They effortlessly fit in a carry on bag, and some are tiny enough to fit in a pouch.

Machinery of Travel Binoculars

It’s always good to know the working of binocular before you choose.

With the help of you see the images right-side-up when looking through the binoculars. Travel binoculars usually have roof prisms, which are present inside the optical tube of the binoculars. It reduces the space and makes it great to travel.

Lens Coating

Glass surfaces are coated that touch the outside air. The coating helps transmit the light. Its better to look for binoculars which are fully coated. Multicoated binoculars reduces glare.

and Objective Lenses

is the power of the binoculars. is usually confirmed in two numbers, such as 8 x 25. The first number means how much the binoculars magnify an object. An 8x means that the object looks eight times closer than natural eyesight. The second number is the diameter. The lesser the diameter, the more compact your binoculars are for travel. However, the larger the diameter, the more light you will have entering your binoculars. The is the lens that faces the object.

The is the lens by your eye. If you hold the binoculars at arms length, you will see a small spot of light through the eyepieces. This is the .

You will have a limited , which is the area you can see when looking through your binoculars. This area is measured in degrees. If you are going to be watching moving objects, look for a large .

Source: http://www.travelequipments.com/travel-equipments-articles/discount-binoculars.htm

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A guide on Choosing Binoculars

Tuesday, February 19th, 2008

 

How to Choose the Right Pair of for You

There are several factors to consider in making a good choice of .

How important each binocular factor is to your selection will depend on how you plan to use them.Important binocular properties;

are almost always identified as number with X then a second number, such as ‘7X50?. in this example is 7X. Natural expectation for people is to want higher but higher comes at a price more than money. The higher the the harder it is to hold what you are looking at steady. Since most uses of are hand held, having excessive is not desirable.

The second number after is the example above 7X50 is the diameter of the ‘objective’ lens in millimeters. The are the larger ones on the far side of the (see diagram courtesy of Nikon below). The size of the is important to as the larger they are, the more light they are gathering for your eyes at the other end. If you think of photons as a quantity of ‘information’, the more photons the lens gathers and bring to your eyes, the more ‘information’ your brain will have to enjoy. However the trade off for larger are the will be more heavy and bulky.

The light that does get to your eyes has an effective area called the ‘’. This can simply be calculated using the 7X50 specification if you divide the 50 ( diameter in mm) by the (7X), which in this case is slightly more than 7mm. The pupils of your eyes are less than 4mm wide in bright daylight so in this case there is ample efficiency. However in low light situations the pupil expands to 7mm when you are younger (not as much as you get older). So if you are older than 40 and using 7X50 in a low light situation you will likely see a darker view than with a pair of 7X35 with a 5mm .

Weight is not an optical property but can be a crucial factor in how useful the you choose are. As mentioned above having high won’t mean much if they are too heavy to lug and hold steadily up to your eyes. More expensive lighter lens materials can offset this if you can afford it. Also more expensive “” are more compact are an option again if you can afford it.

for is most often expressed as ‘X’ number of feet at 1000 yards. The higher the the smaller the will be. You can improve for a given with more expensive “” . For birdwatching or Astronomy 300 to 400 feet at 1000 yards will be acceptable. It is a challenge for 10X to be above 300 feet at 1000 yards.

  • (lens, prisms, and coatings) Quality
  • Ideally you want to avoid poor quality , start with good quality, and then decide later if you want to move to superb quality . There is no point to buying bargain basement or poorly maintained used as your experience will be disappointing. Preferably all are coated and better still multi-coated. Coated improve light transmission. Look for the phrase “multi-layer coated ” and be wary of the phrase “fully coated ” as this might mean that only external air to glass surfaces are fully coated but other internal lens and prisms may not be. Light transmission loss occurs at all surfaces without anti-reflective glass coatings. I will explain how to visually check for coatings in a later post.
  • – High quality lens provide good color fidelity, are free of optical aberrations, and provide excellent detail.
  • Stabilization

Expensive electronic ‘gee-whiz’ adjusting system that noticeably improves the view, especially in hand held use targeting moving objects. An interesting experiment is to take a ‘value priced’ pair of and look at the moon holding them as steady as you can. Then mount the same on a steady camera tripod and look at the moon again. You will be shocked at the extra detail that you can see due to stability.

Having rubber overmold on the binocular body does not always mean they are . Search for drop specifications if is important for how the will be used. is important for hunting and marine use as well as . is specified usually in a JIS or IEC 529 rating (click on the link to understand more about ratings). An IEC rating of IP64 will suffice or look for IP67 if you want to take your swimming. have the air inside replaced with a gas such as Argon or Nitrogen.

you are most likely to be familiar with are with a system moving the two light paths from the closer together on the way to the two eyepieces you look into. “Roof” are “straight through” looking. This lens system is more expensive but has the advantage of allowing for smaller compact configuration and storage. They also look better as a fashion statement if that is important.

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Choosing Binoculars

Sunday, February 17th, 2008

How to Choose the Right Pair of Binoculars for You

There are several factors to consider in making a good choice of binoculars.

How important each binocular factor is to your selection will depend on how you plan to use them.

Important binocular properties;

Binoculars are almost always identified as number with X then a second number, such as ‘7X50′. in this example is 7X. Natural expectation for people is to want higher but higher comes at a price more than money. The higher the the harder it is to hold what you are looking at steady. Since most uses of binoculars are hand held, having excessive is not desirable.

The second number after is the example above 7X50 is the diameter of the ‘objective’ lens in millimeters. The are the larger ones on the far side of the binoculars (see diagram courtesy of Nikon below). The size of the is important to as the larger they are, the more light they are gathering for your eyes at the other end. If you think of photons as a quantity of ‘information’, the more photons the lens gathers and bring to your eyes, the more ‘information’ your brain will have to enjoy. However the trade off for larger are the binoculars will be more heavy and bulky.

The light that does get to your eyes has an effective area called the ‘’. This can simply be calculated using the 7X50 specification if you divide the 50 ( diameter in mm) by the (7X), which in this case is slightly more than 7mm. The pupils of your eyes are less than 4mm wide in bright daylight so in this case there is ample efficiency. However in low light situations the pupil expands to 7mm when you are younger (not as much as you get older). So if you are older than 40 and using 7X50 binoculars in a low light situation you will likely see a darker view than with a pair of 7X35 binoculars with a 5mm .

  • Weight & Bulk of Binoculars

Weight is not an optical property but can be a crucial factor in how useful the binoculars you choose are. As mentioned above having high won’t mean much if they are too heavy to lug and hold steadily up to your eyes. More expensive lighter lens materials can offset this if you can afford it. Also more expensive “” binoculars are more compact are an option again if you can afford it.

for binoculars is most often expressed as ‘X’ number of feet at 1000 yards. The higher the the smaller the will be. You can improve for a given with more expensive “” binoculars. For birdwatching or Astronomy 300 to 400 feet at 1000 yards will be acceptable. It is a challenge for 10X binoculars to be above 300 feet at 1000 yards.

  • (lens, prisms, and coatings) Quality
  • Ideally you want to avoid poor quality , start with good quality, and then decide later if you want to move to superb quality . There is no point to buying bargain basement binoculars or poorly maintained used binoculars as your experience will be disappointing. Preferably all are coated and better still multi-coated. Coated improve light transmission. Look for the phrase “multi-layer coated ” and be wary of the phrase “fully coated ” as this might mean that only external air to glass surfaces are fully coated but other internal lens and prisms may not be. Light transmission loss occurs at all surfaces without anti-reflective glass coatings. I will explain how to visually check for coatings in a later post.
  • – High quality lens provide good color fidelity, are free of optical aberrations, and provide excellent detail.
  • Stabilization

Expensive electronic ‘gee-whiz’ adjusting system that noticeably improves the view, especially in hand held use targeting moving objects. An interesting experiment is to take a ‘value priced’ pair of binoculars and look at the moon holding them as steady as you can. Then mount the same binoculars on a steady camera tripod and look at the moon again. You will be shocked at the extra detail that you can see due to stability.

Having rubber overmold on the binocular body does not always mean they are . Search for drop specifications if is important for how the binoculars will be used. is important for hunting and marine use as well as . is specified usually in a JIS or IEC 529 rating (click on the link to understand more about ratings). An IEC rating of IP64 will suffice or look for IP67 if you want to take your binoculars swimming. binoculars have the air inside replaced with a gas such as Argon or Nitrogen.

Binoculars you are most likely to be familiar with are with a system moving the two light paths from the closer together on the way to the two eyepieces you look into. “Roof” binoculars are “straight through” looking. This lens system is more expensive but has the advantage of allowing for smaller compact configuration and storage. They also look better as a fashion statement if that is important.

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