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Saturday, 18 December 2010
Saturday, 11 December 2010
I am interested in buying the 700x60 Refractor Astronomical Telescope, with 28x to 315x magnification, and the Nipon 20-60x70 spotting scope. Is there a need to have both and can a camera be fitted to each one?
Answer from Nipon Support: Hello, thanks for your enquiry about these scopes. The 700x60 refractor telescope is designed for astronomical observations with high power, while the Nipon 20-60x70 zoom scope is a spotting scope which is mainly used for viewing objects on land. It can take a little time to set up the 700x60 scope so it is best to be kept in the same place if possible, while the 20-60x70 scope is very easy to set up so you can take it around and set it up in seconds. So you may need both of them if you have got the interests in both aspects.
Both scopes can be fitted with a digital camera (using a universal adaptor for example) or with a digital eyepiece. Please do not hesitate to contact us should you need further information.
Question: Thank you for getting back to me. Do you sell the connections (adaptors) I would need? My camera is a Nikon D60.
Answer from Nipon Support: Hello again, thanks for your new message. With the further information that you have provided about the type of camera that you wish to use for digi-scoping, here are some technical aspects for you to consider:
For your Nikon D60 camera, there are two options to connect it to the scope: one is to use a camera adaptor which is specially designed for Nikon cameras (click here to view this device); the other option is to use a universal camera adaptor with extended stand (click here to see it), which can not only connect this Nikon camera, but also other types of cameras to scopes.
With the first option, you replace the camera's lens with the Nikon camera adaptor and then connect the adaptor to the scope’s 1.25” eyepiece holder. With the 2nd option, you do not need to remove your camera’s lens, but attach the camera to the scope’s eyepiece by using the universal adaptor.
However, for the images through the telescope to be visible from the camera’s large lens, you would need to use a larger eyepiece on the scope. We recommend a 32mm eyepiece as a minimum. This large 32mm eyepiece can be directly inserted into the eyepiece holder of the 700x60 telescope, but for the 20-60x70 zoom scope, you would need to replace its zoom eyepiece with a specially made eyepiece adaptor so that other types of eyepieces such as the 32mm eyepiece can be inserted to the adaptor.
It seems that the 2nd option (i.e., using a universal camera adaptor with extended camera stand in order to fit your camera model) is more practical because you will have a flexibility of connecting different types of cameras, and there is no need to remove the camera lens. However, you may also wish to consider the 1st option if you prefer. Please do take your time to understand these technicalities and contact us again should you have more questions. Best regards from Nipon Support Team.
700x60 telescope Nipon 20-60x70 spotting scope
Question: Thank you for getting back to me. Do you sell the connections (adaptors) I would need? My camera is a Nikon D60.
Answer from Nipon Support: Hello again, thanks for your new message. With the further information that you have provided about the type of camera that you wish to use for digi-scoping, here are some technical aspects for you to consider:
For your Nikon D60 camera, there are two options to connect it to the scope: one is to use a camera adaptor which is specially designed for Nikon cameras (click here to view this device); the other option is to use a universal camera adaptor with extended stand (click here to see it), which can not only connect this Nikon camera, but also other types of cameras to scopes.
With the first option, you replace the camera's lens with the Nikon camera adaptor and then connect the adaptor to the scope’s 1.25” eyepiece holder. With the 2nd option, you do not need to remove your camera’s lens, but attach the camera to the scope’s eyepiece by using the universal adaptor.
However, for the images through the telescope to be visible from the camera’s large lens, you would need to use a larger eyepiece on the scope. We recommend a 32mm eyepiece as a minimum. This large 32mm eyepiece can be directly inserted into the eyepiece holder of the 700x60 telescope, but for the 20-60x70 zoom scope, you would need to replace its zoom eyepiece with a specially made eyepiece adaptor so that other types of eyepieces such as the 32mm eyepiece can be inserted to the adaptor.
It seems that the 2nd option (i.e., using a universal camera adaptor with extended camera stand in order to fit your camera model) is more practical because you will have a flexibility of connecting different types of cameras, and there is no need to remove the camera lens. However, you may also wish to consider the 1st option if you prefer. Please do take your time to understand these technicalities and contact us again should you have more questions. Best regards from Nipon Support Team.
What are the Bak4 and Bk-7 prisms? Is there a difference when they are used in scopes and in binoculars?
Both Bak4 and Bk-7 are common types of brown glass used in prisms that fold the light path inside the scopes and binoculars. “Bak” represents “Barium light Crown” glass, while “Bk” represents “Borosilicate Crown” glass.
In general terms, Bak4 prisms are more expensive and are considered better because they give a smooth, rounded “exit pupil”, due to a slightly higher level of refraction than Bk-7. Bk-7 prisms are also good quality, but brightness falls off slightly at the edge of the field compared to Bak4, so they create a slightly square exit pupil. Sharpness and clarity aren't affected by using BK-7 and only the outer edges of the exit pupil are shaded (blurred). If your eye pupil is closed to a size that fits within the unshadowed diamond shape inside the exit pupil there is no loss of light at all with BK-7 prisms compared to Bak4.
However, BaK4 is preferable to BK-7 as a prism glass only when the focal ratio of the objective lens falls below about f/5. Virtually all scopes have focal ratios above f/5, so there's no disadvantage in using BK-7 prisms. It achieves total internal reflection just as well as BaK4. In some telescopes it's actually a slightly better choice because a prism made with BK-7 has a little less spherical overcorrection and chromatic aberration at blue/violet wavelengths than BaK4.
For binoculars, their objective lenses are mostly around f/4 or less, so BaK4 is preferred for their prisms to achieve total internal reflection at the edges of the fast f/4 light cone. Whist the binoculars with the Bk-7 prism would look no difference to the Bak4 in daylight condition, as the light levels drop, and the eye pupil expends, you start to observe the effects of the shaded regions as the image quality drops and becomes prone to chromatic aberration around the periphery of the image.
In general terms, Bak4 prisms are more expensive and are considered better because they give a smooth, rounded “exit pupil”, due to a slightly higher level of refraction than Bk-7. Bk-7 prisms are also good quality, but brightness falls off slightly at the edge of the field compared to Bak4, so they create a slightly square exit pupil. Sharpness and clarity aren't affected by using BK-7 and only the outer edges of the exit pupil are shaded (blurred). If your eye pupil is closed to a size that fits within the unshadowed diamond shape inside the exit pupil there is no loss of light at all with BK-7 prisms compared to Bak4.
However, BaK4 is preferable to BK-7 as a prism glass only when the focal ratio of the objective lens falls below about f/5. Virtually all scopes have focal ratios above f/5, so there's no disadvantage in using BK-7 prisms. It achieves total internal reflection just as well as BaK4. In some telescopes it's actually a slightly better choice because a prism made with BK-7 has a little less spherical overcorrection and chromatic aberration at blue/violet wavelengths than BaK4.
For binoculars, their objective lenses are mostly around f/4 or less, so BaK4 is preferred for their prisms to achieve total internal reflection at the edges of the fast f/4 light cone. Whist the binoculars with the Bk-7 prism would look no difference to the Bak4 in daylight condition, as the light levels drop, and the eye pupil expends, you start to observe the effects of the shaded regions as the image quality drops and becomes prone to chromatic aberration around the periphery of the image.
How to align the finder scope with the main scope?
The finder scope only works to its purchase when it has been aligned with the main scope, so the two are aiming at exactly the same spot. This is easy to do.
It is more convenient to align the finder scope while it's still light outside. A good time to do it is after the telescope has been set up but before the Sunset.
First, put a low-power eyepiece (with long focal length) in the eyepiece holder (focuser) of the main telescope. Looking into the eyepiece, centre a distant object in the field of view — the top of a telephone pole, a treetop, or a chimney on a house. The object should be at least a quarter-mile away. Now look through the finder scope and see if the object appears in the centre of the finder's field of view (where the crosshairs intersect). If it does not, use the adjustment screws on the finder scope bracket to adjust the aim of the finder until the object is centred. Then, look back into the telescope eyepiece and make sure the object is still centred there as well. If so, you're done. If it is not, repeat the procedure, being careful not to move the main telescope while you're adjusting the finder scope positioning.
When the distant object is centred in both the main telescope and the finder scope, the finder scope has been properly aligned and ready to use. Verifying the finder's alignment should be one of the steps you go through each time you set up for an observing session.
It is more convenient to align the finder scope while it's still light outside. A good time to do it is after the telescope has been set up but before the Sunset.
First, put a low-power eyepiece (with long focal length) in the eyepiece holder (focuser) of the main telescope. Looking into the eyepiece, centre a distant object in the field of view — the top of a telephone pole, a treetop, or a chimney on a house. The object should be at least a quarter-mile away. Now look through the finder scope and see if the object appears in the centre of the finder's field of view (where the crosshairs intersect). If it does not, use the adjustment screws on the finder scope bracket to adjust the aim of the finder until the object is centred. Then, look back into the telescope eyepiece and make sure the object is still centred there as well. If so, you're done. If it is not, repeat the procedure, being careful not to move the main telescope while you're adjusting the finder scope positioning.
When the distant object is centred in both the main telescope and the finder scope, the finder scope has been properly aligned and ready to use. Verifying the finder's alignment should be one of the steps you go through each time you set up for an observing session.
Why an image seen through a Finder Scope is often upside-down?
A “finder scope” is included in some telescope packages, such as the NIPON 350x70 and NIPON 700x60 telescopes. A finder scope is a small telescope that is attached to the main telescope. Its purpose is to aid in aiming the main telescope toward objects of interests such as a particular star. A finder scope is built with low magnification (eg. 2x, 3x, 5x etc.) but with a wide field of view (5 degrees or more), thus allowing you to see more of the sky than you can through the main telescope. Therefore, the finder scope enables you to locate a star more easily and centre it on the crosshairs, you can then view more details through the main telescope.
Beginners are often surprised that the image in a standard finder scope is upside-down when viewing objects on earth. That’s normal for any refractor used without a correction prism. For most astronomical observation, it makes little difference if an object is seen upside-down or at an otherwise odd angle because there is no “right side up” in space, since all you are trying to do is to centre the object on the crosshairs so that you can view it through the main telescope.
A relatively new type of finder scope is known as a reflex sight, or "Red Dot" scope (as included in the Nipon 800x60 telescope package). It is a non-magnifying device that displays a red, LED-lit bull's-eye pattern or red dot in the center of the field of view. The red dot appears superimposed on the sky, showing exactly where the telescope is pointed (once the finder scope and the main telescope are properly aligned, of course).
Beginners are often surprised that the image in a standard finder scope is upside-down when viewing objects on earth. That’s normal for any refractor used without a correction prism. For most astronomical observation, it makes little difference if an object is seen upside-down or at an otherwise odd angle because there is no “right side up” in space, since all you are trying to do is to centre the object on the crosshairs so that you can view it through the main telescope.
A relatively new type of finder scope is known as a reflex sight, or "Red Dot" scope (as included in the Nipon 800x60 telescope package). It is a non-magnifying device that displays a red, LED-lit bull's-eye pattern or red dot in the center of the field of view. The red dot appears superimposed on the sky, showing exactly where the telescope is pointed (once the finder scope and the main telescope are properly aligned, of course).
Should I go for zoom or fixed power scopes?
Most Nipon scopes are available with zoom or fixed power eyepieces which can vary from 9x to 78x. Scopes with zoom eyepieces have become popular in recent years especially for many bird watching. It's easier to find your object at low power (which gives a wider field of view) and then zoom in to see more details. This gives you much convenience and saves you trouble changing eyepieces for different magnifications.
However, it should be noted that even though zooms are optically very sharp, they have a relatively narrower field of view as compared with fixed power eyepieces at the same magnification level. Looking through a scope with a fixed wide angle eyepiece (eg. 32mm) is a joy with a bright and wide visual field! If you put two scopes together, one with a 20-60 zoom set at 30x power, the other with a 30x fixed power eyepiece, the difference is striking. You can actually get a wider field of view in the 30x fixed power eyepiece than you will with the zoom eyepiece even when the zoom is set at 20x.
In addition, at the higher end of the zoom power, the image tends to become fuzzy or blurred. This is normal because the amount of light which comes through the objective lens remains the same regardless of the zoom levels. As the image is magnified, the amount of information that contained within the same area of the image is reduced. Therefore, to get a good quality image, either zoom out, or use a fixed power eyepiece.
That's why we have provided a set of fixed power eyepieces as optional accessories in our store, with 16mm, 26mm and 32mm focal lengths. They can add greater values to your scope.
However, it should be noted that even though zooms are optically very sharp, they have a relatively narrower field of view as compared with fixed power eyepieces at the same magnification level. Looking through a scope with a fixed wide angle eyepiece (eg. 32mm) is a joy with a bright and wide visual field! If you put two scopes together, one with a 20-60 zoom set at 30x power, the other with a 30x fixed power eyepiece, the difference is striking. You can actually get a wider field of view in the 30x fixed power eyepiece than you will with the zoom eyepiece even when the zoom is set at 20x.
In addition, at the higher end of the zoom power, the image tends to become fuzzy or blurred. This is normal because the amount of light which comes through the objective lens remains the same regardless of the zoom levels. As the image is magnified, the amount of information that contained within the same area of the image is reduced. Therefore, to get a good quality image, either zoom out, or use a fixed power eyepiece.
That's why we have provided a set of fixed power eyepieces as optional accessories in our store, with 16mm, 26mm and 32mm focal lengths. They can add greater values to your scope.
What's the difference between angled and straight eyepieces?
The Nipon 20-60x70 scope comes in either straight (horizontal) or 45 degree angled eyepiece designs. Straight scopes used to be the norm of these scopes, but angled scopes seem to have taken over for a majority of users nowadays.
With a straight eyepiece design, you can view the target in line with the central line of the scope. It is thus convenient to use the scope with straight eyepiece to locate and track a target, especially when the target or the viewer is moving.
Angled scopes can better accommodate people of different heights, and they seem to be easier to use for digi-scoping (eg. to mount a digital camera). Nevertheless, either option is strictly a personal choice, and both options are available from this shop.
With a straight eyepiece design, you can view the target in line with the central line of the scope. It is thus convenient to use the scope with straight eyepiece to locate and track a target, especially when the target or the viewer is moving.
Angled scopes can better accommodate people of different heights, and they seem to be easier to use for digi-scoping (eg. to mount a digital camera). Nevertheless, either option is strictly a personal choice, and both options are available from this shop.
How to calculate the field of view of your scope?
1. Find out the value of the apparent field of view of the eyepiece. Every eyepiece has its own value of the apparent field of view and this value is supplied from the manufacturer. For the optical eyepieces PL16, PL26 & PL32 as mentioned in the above example, their apparent field of view is 52 degrees.
2. Find the value of magnification. This is calculated by dividing the focal length of your scope by the focal length of the eyepiece. For the Nipon 26-78x78 scope (focal length=780mm) with a 16mm eyepiece, for example, its magnification will be: 780/16=48.75.
3. Divide the value of the apparent field of view by the value of magnification. For the above example, 52/48.75=1.06 degrees. This is the value of the field of view for this scope using this eyepiece.
2. Find the value of magnification. This is calculated by dividing the focal length of your scope by the focal length of the eyepiece. For the Nipon 26-78x78 scope (focal length=780mm) with a 16mm eyepiece, for example, its magnification will be: 780/16=48.75.
3. Divide the value of the apparent field of view by the value of magnification. For the above example, 52/48.75=1.06 degrees. This is the value of the field of view for this scope using this eyepiece.
How much magnification do I really need to get a good image?
If the visual condition is good (eg. on nights when the sky is clear and stable), the top usable magnification for a 60mm (2.4 inch objective lens) scope will be around 2x60=120x. This is more than enough to see the rings of Saturn, cloud belts on Jupiter and many star clusters and nebulae. So, 60mm scopes have been the standard size for a wide range of applications. Two types of these models are available at nipon-scope.com, one is Nipon 15-46x60 Spotting Scope, the other is Nipon 700x60 Telescope.
With a 70-80mm scope, however, the amount of light it gathers is about 55-65% more than a 60mm scope. This improves image quality especially when viewing at high powers and under low light. A selection of these models includes Nipon 20-60x70 spotting scope, 70/300mm refractor scope, 70/350mm refractor scope, and 26-78x78 compact zoom scope. In general, larger scopes outperform smaller ones, but they also tend to be bigger and heavier, and more expensive.
With a 70-80mm scope, however, the amount of light it gathers is about 55-65% more than a 60mm scope. This improves image quality especially when viewing at high powers and under low light. A selection of these models includes Nipon 20-60x70 spotting scope, 70/300mm refractor scope, 70/350mm refractor scope, and 26-78x78 compact zoom scope. In general, larger scopes outperform smaller ones, but they also tend to be bigger and heavier, and more expensive.
How to decide the smallest eyepiece a scope can use?
Based on the Mmax value as calculated above, you can decide the minimum eyepiece focal length that you may wish to use for a scope. The equation is:
f = F / Mmax
Where: f is the minimum eyepiece focal length (mm); F is the focal length of the scope; Mmax is the maximum usable magnification of the scope.
For the Nipon 26-78x78 scope, the minimum eyepiece which can be used is: f=780/156=5 mm. This would provide about 156x power which is nice for viewing Mars or resolving the rings of Saturn. To resolve Saturn's rings, you may only need about 30x power, but to see them more clearly, higher magnifications are required.
f = F / Mmax
Where: f is the minimum eyepiece focal length (mm); F is the focal length of the scope; Mmax is the maximum usable magnification of the scope.
For the Nipon 26-78x78 scope, the minimum eyepiece which can be used is: f=780/156=5 mm. This would provide about 156x power which is nice for viewing Mars or resolving the rings of Saturn. To resolve Saturn's rings, you may only need about 30x power, but to see them more clearly, higher magnifications are required.
What is the maximum magnification power a telescope or spotting scope can achieve?
As described above, the higher the magnification level, the dimmer an image becomes. There is thus a golden rule for the maximum usable magnification (Mmax) of any scope: Mmax=2 x D (mm)
Where: D is objective lens diameter measured in mm.
For example, for the Nipon 26-78x78 compact zoom scope, its objective lens is 78mm, so the maximum usable magnification power of this scope is 2x78=156 times.
Where: D is objective lens diameter measured in mm.
For example, for the Nipon 26-78x78 compact zoom scope, its objective lens is 78mm, so the maximum usable magnification power of this scope is 2x78=156 times.
How to calculate magnification (or power) of a Nipon scope?
1. Identify the focal length of the scope. This is often marked on the body of the scope or it should be given in the user manual. For example, the Nipon 26-78x78 scope's focal length is 780mm.
2. Find the focal length of the eyepiece. For example, for the PL16, PL26 and PL32 eyepieces as listed at nipon-scope.com, their focal lengths are 16mm, 26mm and 32mm, respectively.
3. Divide the focal length of the scope by the focal length of the eyepiece to get the magnification of the scope. For example, if you wish to use a 16mm eyepiece to replace the 26-78x zoom eyepiece of the above Nipon scope, the magnification of the scope will become: 780/16=49x.
It is desirable to have a range of eyepieces with different focal lengths to allow viewing over a range of magnification levels.
Please keep in mind that, as a fundamental law of optics, at higher magnification powers an image will always become dimmer and less sharp. With every doubling of magnification you lose about half the image brightness and 3/4 of the image sharpness.
Therefore, it is best to begin viewing with the lowest power eyepiece (with longest focal length, eg. 32mm of the above example) or with the zoom eyepiece being adjusted to its lowest power level. This will provide the widest true field of view which will make target finding and centring much easier. After you have located an object, you can switch to a higher power eyepiece (with smaller focal length) to see more detail (if atmospheric conditions permit). If the image you see is not crisp and steady, reduce the magnification by switching to a longer focal length eyepiece, or for a zoom eyepiece, zoom out. In general, a small but well-resolved image will show more detail and provide a more enjoyable view than a dim and fuzzy, over-magnified image.
Please refer to "How to calculate the field of view" for more related information.
2. Find the focal length of the eyepiece. For example, for the PL16, PL26 and PL32 eyepieces as listed at nipon-scope.com, their focal lengths are 16mm, 26mm and 32mm, respectively.
3. Divide the focal length of the scope by the focal length of the eyepiece to get the magnification of the scope. For example, if you wish to use a 16mm eyepiece to replace the 26-78x zoom eyepiece of the above Nipon scope, the magnification of the scope will become: 780/16=49x.
It is desirable to have a range of eyepieces with different focal lengths to allow viewing over a range of magnification levels.
Please keep in mind that, as a fundamental law of optics, at higher magnification powers an image will always become dimmer and less sharp. With every doubling of magnification you lose about half the image brightness and 3/4 of the image sharpness.
Therefore, it is best to begin viewing with the lowest power eyepiece (with longest focal length, eg. 32mm of the above example) or with the zoom eyepiece being adjusted to its lowest power level. This will provide the widest true field of view which will make target finding and centring much easier. After you have located an object, you can switch to a higher power eyepiece (with smaller focal length) to see more detail (if atmospheric conditions permit). If the image you see is not crisp and steady, reduce the magnification by switching to a longer focal length eyepiece, or for a zoom eyepiece, zoom out. In general, a small but well-resolved image will show more detail and provide a more enjoyable view than a dim and fuzzy, over-magnified image.
Please refer to "How to calculate the field of view" for more related information.
What is the USB digital eyepiece/camera for Nipon scopes?
This is a digital device which can fit the Nipon 26-78x78 scope, and the Nipon 70/350mm scope, and connect the scope to a desktop/laptop computer through a USB cable. You can see a distant object on the computer screen, adjust the scope's magnification power from your computer and take pictures. You can also make a video recording of distant scene and save the video file (.avi) into the computer. This digital eyepiece has a standard fitting interface with eyepiece adaptor (i.e., diameter=1.25" or 31.75mm) that can be fitted to a spotting scope or telescope as long as the scope has such a 1.25" eyepiece holder.
This digital device comes with relevant software programme and it works under Windows 2000, XP and vista. There is also a detailed user guide about how to set up and use the system. Please view the Product Details page for more information about this product.
This digital device comes with relevant software programme and it works under Windows 2000, XP and vista. There is also a detailed user guide about how to set up and use the system. Please view the Product Details page for more information about this product.
Can I attach a digital camera to the scope?
There is an increasing requirement for attaching digital camera to a scope to take pictures of distant objects. You can achieve this by hand holding the camera, for example, or mounting the camera on a tripod next to the telescope eyepiece, building or buying an adapter to hold the camera over the eyepiece, using a universal camera adapter (available from this shop), or using an eyepiece with built in adapter to attach it directly to the digital camera. Or simply, you can use a digital eyepiece which takes pictures and video footage directly through the scope.
The Nipon 26-78x78 compact scope has a built in eyepiece adapter with a 1.25" (31.75mm) slip socket as an eyepiece holder. With this adapter, you can either fit a digital eyepiece/camera or fixed power optical eyepieces to this scope (these products are available from this shop). This adapter also allows a standard-design T-mount SLR and camera adapters (with 1.25" fitting) to fit into its eyepiece holder.
Alternatively, you can use a universal digital camera adapter to connect your camera to the scope. Please browse the product category "Universal camera adapters" for more information.
The Nipon 26-78x78 compact scope has a built in eyepiece adapter with a 1.25" (31.75mm) slip socket as an eyepiece holder. With this adapter, you can either fit a digital eyepiece/camera or fixed power optical eyepieces to this scope (these products are available from this shop). This adapter also allows a standard-design T-mount SLR and camera adapters (with 1.25" fitting) to fit into its eyepiece holder.
Alternatively, you can use a universal digital camera adapter to connect your camera to the scope. Please browse the product category "Universal camera adapters" for more information.
Why are some binoculars brighter than others?
One of the most important factors affecting the image brightness is known as Exit Pupil, which is a bright circle visible when the eyepiece array is viewed about 10 inches away from the eyes. A larger Exit Pupil gives a brighter image. The value of Exit Pupil (mm) = Objective Lens Diameter / Magnification Power. So, for a pair of 10x40 binoculars, its Exit Pupil is 40/10=4mm. For the Nipon 10x50 binoculars, the Exit Pupil is 5mm. The larger the objective lens, the bigger the Exit Pupil, and thus the brighter the image viewed. However, larger objective lens also means heavier and bigger the binoculars' body.
Binoculars for common use such as sightseeing and birding from near to medium range, an exit pupil size of 4-5mm is considered to be adequate for image brightness.
Binoculars for common use such as sightseeing and birding from near to medium range, an exit pupil size of 4-5mm is considered to be adequate for image brightness.
What is centre focus?
Binoculars with centre focus system use one knob in the middle of the binoculars to move both lenses for fine focusing precision. This allows you to follow the action and switch from one object to another quickly. Binoculars with centre focus normally have one eyepiece (often the one on the right-hand side) which is independently adjustable to accommodate any difference between the two eyes.
What is eye relief?
This is the distance (in mm) the binoculars can be held away from the eye that still allows the user to see the entire full field of view as designed. Binocular users who wear eyeglasses for near- or far-sightedness can remove their glasses while observing clearly through the binoculars because the binoculars can fully correct for these eye defects. However, the users with astigmatism may need to wear their glasses in order to maintain sharp imaging through the binoculars. In this case a longer eye relief will become advantageous for these users, who cannot get as close to the eyepiece.
As a rough guide, an eye relief of 10-15mm should fit most users if this function becomes necessary. However, you may not need to look for this specification because most binocular models allow the eyecup to be either folded or twisted/pushed down to enable eyeglass wearers to enjoy an improved field of view.
As a rough guide, an eye relief of 10-15mm should fit most users if this function becomes necessary. However, you may not need to look for this specification because most binocular models allow the eyecup to be either folded or twisted/pushed down to enable eyeglass wearers to enjoy an improved field of view.
What are lens coatings for?
An uncoated optical glass lens or prism reflects about 10% of the light incident on one of its surfaces, thus allowing only about 90% of the light to pass through. Nowadays most binocular lenses are coated with invisible coverings that work to improve the amount of light transmitted from the front lens to the eyepiece. Standard full coatings can reduce the level of light reflection to about 4% or lower; and more sophisticated multi-coatings can ensure 99% or more light transmission through the lens and prism.
What is field of view?
Field of view (FOV) refers to the size of the area that can be viewed through the binoculars. This can be described either in degrees or in the width of the area visible (by ft. or m) at 1000 yards or 1000 metres. Given the same size of objective lens, the lower the magnification the binoculars have, the wider the FOV.
What is Porro Prism or Roof Prism system?
Since the objective lenses form images that are both upside down and reversed left for right, prisms are used to invert the primary image.
Porro prism and roof prism are two most frequently used systems for such a purpose. Porro prism binoculars are characterised by the eyepieces being offset from the objective lenses, while roof prism binoculars' objective lens and eyepiece are positioned in line for a more compact feature and reduced weight. Either type of prism system, properly manufactured, gives excellent optical performance.
Porro prism and roof prism are two most frequently used systems for such a purpose. Porro prism binoculars are characterised by the eyepieces being offset from the objective lenses, while roof prism binoculars' objective lens and eyepiece are positioned in line for a more compact feature and reduced weight. Either type of prism system, properly manufactured, gives excellent optical performance.
What do the numbers mean in the binoculars title?
In a binocular name, the first number indicates the magnification power and the second number is the diameter of the objective lens in mm. For example, for a pair of Nipon 10x42 binoculars, it has 10x magnification (i.e., an object will be enlarged 10 times; or an object 100m away will look like 10m away through the binoculars), and its objective (front) lens is 42mm in diameter.
How to adjust binoculars?
Our left eye and right eye can be different in their vision and focusing capability. Therefore, to use binoculars properly, we must compensate for such a difference, and centre-focusing binoculars have an adjustment mechanism to achieve this. You can find that almost all the binoculars listed in our store have one eyepiece (usually the one on the right-hand side) which is independently adjustable with a marked scale.
To adjust binoculars, first, use a lens cover or your hand to cover the right objective lens which is on the same side as the adjustable eyepiece (note: better to keep both eyes open to avoid distortion by squinting). Look through the binoculars and use the central focusing mechanism to focus on a distant object until it is sharp and clear.
Second, transfer the lens cover to the other lens on the left, again with both eyes open, but this time adjust the focus on the same object using the adjustable eyepiece only, until it is clear. Your binoculars are now properly focused for your use. Adjust the distance between the two eyepieces so that they in the centres of your eyes (i.e., when the two cycles merge into one). You can now use the central focusing mechanism to focus on objects at different distances, but you should keep the adjustable eyepiece at the same focus setting unless it is accidentally moved or the binoculars have been used by someone else.
To adjust binoculars, first, use a lens cover or your hand to cover the right objective lens which is on the same side as the adjustable eyepiece (note: better to keep both eyes open to avoid distortion by squinting). Look through the binoculars and use the central focusing mechanism to focus on a distant object until it is sharp and clear.
Second, transfer the lens cover to the other lens on the left, again with both eyes open, but this time adjust the focus on the same object using the adjustable eyepiece only, until it is clear. Your binoculars are now properly focused for your use. Adjust the distance between the two eyepieces so that they in the centres of your eyes (i.e., when the two cycles merge into one). You can now use the central focusing mechanism to focus on objects at different distances, but you should keep the adjustable eyepiece at the same focus setting unless it is accidentally moved or the binoculars have been used by someone else.
Monday, 6 December 2010
How to choose an ideal pair of binoculars?
To choose a right pair of binoculars, you would need to consider your main purpose of use. Here are some examples:
If you are looking for a handy pair of binoculars to carry around easily in your handbag or in the pocket, and to use it in numerous occasions such as stadium sports, indoor or outdoor concerts/plays, travel and birding, and you also want to keep the cost down, you may choose a compact model such as 8x21, 10x25 or 12x32 compact binoculars (Fig.1), depending on which magnification level you wish to choose. Such a model has all the functions required for these purposes and they are light in weight. These products have a unique feature with new optical coating technology (fully multi-broadband coated green lenses) which greatly reduces light reflection over a wider spectrum and increases image sharpness.
Fig. 1: 8x21 Compact Binoculars
In addition to the applications as mentioned above, if you wish to obtain a brighter image over a wider observation range while keeping the binoculars reasonably small, you could choose a pair of binoculars with bigger objective lenses, such as 8x35, 10x40 or 10x42 compact binoculars. The larger the objective lenses, the more light they let in, thus the brighter the images. These binoculars have advantages of observing objects under low lighting levels over a greater distance. In addition, some of these binoculars are built with large eyepieces (15mm diameter or larger) to provide a very comfortable and clearer view.
Fig. 2: NIPON 8x35 Binoculars
A top choice of this category is the NIPON 10x42 waterproof model which gives you the best image quality and tracking performance, and it is water/fog proof (Fig. 3). But it is also slightly more expensive. The prices of these binoculars reflect the optical quality and overall manufacturing costs of these products.
Fig. 3: NIPON 10x42 Water/Fog Proof Binoculars
If you care more about the image clarity over a further observation distance and do not mind a slightly larger size of the binoculars, you may well go for a 7x50, 10x50 or a 12x50 binoculars model (Fig. 4). These binoculars have larger objective lenses (50mm diameter) which allow more light into the eyepieces, making them ideal for seeing more object details and also for use in dim light conditions. The Nipon 7x50 and 10x50 binoculars are built with large 20mm eyepieces for a much more comfortable view. These binoculars are considered to have the best balance between magnification, image brightness and image stability.
Fig. 4: NIPON 10x50 Binoculars
If you would like to have an added function to zoom in/out during the observation, you may also consider a pair of zoom binoculars such as a 6-13x22 or 10-30x50 model. These binoculars have an adjustable magnification (power) ranging from 6x to 13x for the first example or 10x to 30x for the second model. Therefore, you can get a closer view of the target being observed. Please note that the zoom binoculars always perform better at the lower power level than they do at the higher power settings. This is because the front objective lens cannot enlarge to let in more light as the power is increased, so the view gets dimmer as the power is increased. In addition, given the same specification (i.e., size of objective lens and power level), the image clarity of a fixed power binocular is almost always better than that of a zoom binocular.
Overall, it is often not recommend to have a pair of hand-held binoculars with their magnification power greater than 30x. This is because that along with the magnified object, any movement or vibration will also be enlarged, including your own shakes and tremors. So the higher the power, the harder to hold the binoculars steadily. 10x or 12x power are adequate for most people for observations over a reasonable period of time, and zoomed function to higher powers is ideal for relatively shorter time observations.
Larger binoculars with greater magnification power should be fitted to a tripod. The NIPON 20x80 giant observation binocular is a typical example with amazing performance.
Fig. 5: NIPON 20x80 giant binoculars
If you want to view targets over a distance which is beyond the reach of binoculars, a spotting scope or a combined spotting scope/telescope is designed for such a purpose. Please view the "Scopes FAQs" page for more information.
by Nipon Optics
If you are looking for a handy pair of binoculars to carry around easily in your handbag or in the pocket, and to use it in numerous occasions such as stadium sports, indoor or outdoor concerts/plays, travel and birding, and you also want to keep the cost down, you may choose a compact model such as 8x21, 10x25 or 12x32 compact binoculars (Fig.1), depending on which magnification level you wish to choose. Such a model has all the functions required for these purposes and they are light in weight. These products have a unique feature with new optical coating technology (fully multi-broadband coated green lenses) which greatly reduces light reflection over a wider spectrum and increases image sharpness.
Fig. 1: 8x21 Compact Binoculars
In addition to the applications as mentioned above, if you wish to obtain a brighter image over a wider observation range while keeping the binoculars reasonably small, you could choose a pair of binoculars with bigger objective lenses, such as 8x35, 10x40 or 10x42 compact binoculars. The larger the objective lenses, the more light they let in, thus the brighter the images. These binoculars have advantages of observing objects under low lighting levels over a greater distance. In addition, some of these binoculars are built with large eyepieces (15mm diameter or larger) to provide a very comfortable and clearer view.
Fig. 2: NIPON 8x35 Binoculars
A top choice of this category is the NIPON 10x42 waterproof model which gives you the best image quality and tracking performance, and it is water/fog proof (Fig. 3). But it is also slightly more expensive. The prices of these binoculars reflect the optical quality and overall manufacturing costs of these products.
Fig. 3: NIPON 10x42 Water/Fog Proof Binoculars
If you care more about the image clarity over a further observation distance and do not mind a slightly larger size of the binoculars, you may well go for a 7x50, 10x50 or a 12x50 binoculars model (Fig. 4). These binoculars have larger objective lenses (50mm diameter) which allow more light into the eyepieces, making them ideal for seeing more object details and also for use in dim light conditions. The Nipon 7x50 and 10x50 binoculars are built with large 20mm eyepieces for a much more comfortable view. These binoculars are considered to have the best balance between magnification, image brightness and image stability.
Fig. 4: NIPON 10x50 Binoculars
If you would like to have an added function to zoom in/out during the observation, you may also consider a pair of zoom binoculars such as a 6-13x22 or 10-30x50 model. These binoculars have an adjustable magnification (power) ranging from 6x to 13x for the first example or 10x to 30x for the second model. Therefore, you can get a closer view of the target being observed. Please note that the zoom binoculars always perform better at the lower power level than they do at the higher power settings. This is because the front objective lens cannot enlarge to let in more light as the power is increased, so the view gets dimmer as the power is increased. In addition, given the same specification (i.e., size of objective lens and power level), the image clarity of a fixed power binocular is almost always better than that of a zoom binocular.
Overall, it is often not recommend to have a pair of hand-held binoculars with their magnification power greater than 30x. This is because that along with the magnified object, any movement or vibration will also be enlarged, including your own shakes and tremors. So the higher the power, the harder to hold the binoculars steadily. 10x or 12x power are adequate for most people for observations over a reasonable period of time, and zoomed function to higher powers is ideal for relatively shorter time observations.
Larger binoculars with greater magnification power should be fitted to a tripod. The NIPON 20x80 giant observation binocular is a typical example with amazing performance.
Fig. 5: NIPON 20x80 giant binoculars
If you want to view targets over a distance which is beyond the reach of binoculars, a spotting scope or a combined spotting scope/telescope is designed for such a purpose. Please view the "Scopes FAQs" page for more information.
by Nipon Optics
Sunday, 5 December 2010
Welcome to Nipon Scope & Optics
Welcome to this site. Nipon Scope & Optics is an online store to provide quality optical instrument including telescopes, spotting scopes, binoculars, monocular/pocket scopes, microscopes and accessories. Please visit our online store at www.nipon-scope.com/shop
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