The difference between the telescope ED and BAK4

In addition to the objective lens (the big one) and the eyepiece (the small one), the telescope also has a prism inside the lens barrel. BAK4 refers to the material of the prism, and ED refers to the lens that is the material of the eyepiece objective, both of which are relatively good optical glasses.

The material used on the telescope can improve the imaging effect a lot. As for your question, there is no comparison between the two, just like asking which is the difference between steamed bread and stir-fried vegetables, one is a side dish for rice, the other is to fill the stomach, they can be eaten together, ed and bak4 can be used together for a telescope, how do you compare? I can only tell you that the prism BAK4 is better than the BAK7, the lens ED is also a good lens, the food tastes good, and the steamed buns are also chewy.

If you want to know the difference between the various materials in detail, you can do it yourself, I don't actually understand this.

Both ED and BAK4 have their own characteristics in telescopes.

ED lenses (objective lenses) are mainly used to improve the resolution of telescopes. The BAK4 prism (inside the lens tube) improves the color reproduction of the telescope and makes the image clearer.

Taken together, both ED and BAK4 can improve the imaging effect of telescopes, but their roles are different and there is no direct comparison. In practice, they can be used in combination to optimize the imaging of telescopes.

Since you swipe the screen to ask questions, I will swipe you. Don't try to advertise in this way.

It should be said that in a complete optical system (e.g. telescope), the ED lens is not an option or insert, so your question "Is there a big difference between a telescope with an ED lens and no one" is rather nonsensical, or that a telescope with an ED lens is basically not comparable with a telescope with ordinary optical glass (the so-called universal elimination mirror).

<> if you insist on comparing, for example, make a PK of an 80 caliber, F 6 universal elimination mirror and an ED-APO mirror with the same 80 caliber and F 6 at the same magnification - then it can basically be said that the latter's chromatic aberration control, sharpness, contrast calling block, usable magnification and other properties have the advantage of crushing the former.

Finally, the telescope is not a necessity of life, and it is not suitable to use indicators such as "cost performance" to measure it - who is more cost-effective than the general consumption that can be bought for a few hundred yuan, or the ed-apo mirror that can be bought for tens of thousands of yuan? Matter.

The advantages and disadvantages of ED lens telescopes are these:

EdextraLowdispersion Lens: Effectively solve the problem of dispersion caused by general lensesAlthough the general optical lens has a low spherical aberration, relatively speaking, it will also be accompanied by a large light scattering, that is, chromatic aberration chromaticaberration, mainly because the different color wavelengths of visible light red, blue and green are different, and the refraction rate of the optical lens is also different, and it cannot converge in the same plane position. Especially on telephoto lenses with long focal lengths, red and blue are prone to obvious chromatic dispersion due to different wavelengths, which greatly affects image sharpness and color vividness. ED ultra-low dispersion lenses are an innovative lens designed to address other types of high-performance lenses such as fluoride calcium compound lenses.

Tips for using telescopes:

1. The left and right eyepieces are rotated and adjusted separately. That is, the left and right eyes observe the distant target separately, and rotate the left and right eyepieces respectively until the target is the clearest.

2. The center adjustment mechanism and the right eyepiece are rotated to adjust. The method of using this adjustment mechanism is to upgrade the code Xun: the first step selects a clear target of about 1000 meters, first by adjusting the middle handwheel to make the left eye see the target clearly, the second step rotates the right eyepiece to make the right eye see the same target clearly, through these two steps, the visual defects of the user can be compensated correctly, and the observation of different distance scenery only needs to rotate the intermediate handwheel later.

This kind of visual adjustment of the telescope is generally called "distance to the mode of filial piety". <