plossl vs kellner

Plossl VS Kellner [Which One is the Best Eyepiece?]


In the world of lenses and eyepieces, it can be confusing to pick the right one. Both of the eyepieces work wonderfully.

But who will win the fight of Plossl vs. Kellner?

Both brands of eyepieces work perfectly with your telescope or microscope. But Plossl eyepieces are better than Kellner ones. Plossl eyepieces have a better FOV and better eye relief. On the other hand, Kellner’s has more lenses and is inexpensive. At the same time, Plossl is a bit more expensive. 

We have given both short and detailed comparisons of the factors of both brands. If you are considering purchasing one, this article can guide you in the right direction. 

Short Comparison

The Plossl and Kellner eyepieces are made to see the wonders of the night sky. But there are some differences between the two eyepieces. However, you need to know how to use an eyepiece on a telescope

In the table below, we have presented the key factors of each of the eyepieces. There are some similarities and differences between these two products. Could you check the key elements? 

factors Plossl Kellner
No. of Lenses 3 4
Type of Lens Achromatic Achromatic
Field of View 35-50 Degree 50-56 Degree
Eye Relief 13mm Focal Length = 28mm 20mm Focal Length = 28mm
Price Expensive Not so Expensive

These are the key differences. As we said, you can see some basic differences between the two. Also there are some similarities as well. 

Extended Comparison

Now that you know why each eyepiece differs, let’s get down to the details. Below you will find detailed information about each of the factors. We have presented elements of both. 

Number of Lenses

The number of lenses matters when it comes to eliminating the chromatic effect. The chromatin effect is when you see a glare while looking through the eyepiece. 

Although the number of lenses doesn’t always determine the magnification level, you can use Barlow or Powermate lenses to get a better magnification Barlow Barlow or Powermate lenses

Also, multiple lenses are used in the case of better magnification. The Plossl eyepiece has three lenses, whereas the Kellner has 4. So, Kellner is a better option if you are looking for better magnification. 

Winner: In the case of having more lenses, Kellner is the clear winner. 

Type of Lenses

In both of the eyepieces, achromatic lenses have been used. The job of this lens is to reduce the chromatic effect. This also eliminates the spherical aberration when looking through the lens. 

The lens corrects the wavelength of light. Usually, the red and blue wavelengths are converted. In the cases of Plossl and Kellner, both brands use this type to eliminate the chromatic effect. 

Winner: In this level, it is a draw between the two eyepieces. 

Field of View

The field of view is the maximum area you can see through the eyepiece. The field of view can also be labeled as FOV. The term field of view is used in cameras, binoculars, and all the places where lenses are used. 

Here, the Plossl eyepiece has a 35-50 field of view. That means the angle will be measured at the point where the eye sits. So, the field of view is wide at a 35 to a 50-degree grade.

But this does mean the magnification is maximized at a point. So you can see further with greater focus. Although, how far you can look through a telescope depends on other factors. 

On the other hand, we have Kellner, which has 50 to 56 degrees of field of view. So much larger surface can be observed with this eyepiece. 

Winner: The clear winner, in this case, is the Kellner eyepiece. 

Eye Relief

The term eye relief is used in optical instruments. Eye relief means the distance of the last part of the eyepiece, which the user’s eye the full view. 

The lower the focal length, the light the magnification of the eyepiece. So, the Plossl eyepiece has a 13mm focal length. Usually, eyepieces come on 20 to 25mm of focal length. 

On the other hand, we have the Kellner eyepiece. It has a 20mm focal length. Which is high than Plossl, but that means it has lesser magnification. 

Winner: Here, the Plossl is the clear winner. 


Price is a big factor regardless of a product’s quality or bad. Cause price is what determines the value of the products.

Plossl is Cheaper than Kellner eyepieces. Usually, you can find Plossl eyepieces for 30 to 300 dollars. 

On the other hand, we have the Kellner eyepieces. Kellner eyepieces are considered better products, but they do cost more. Kellner’s eye can cost around 20 to 200 apiece. 

If you are thinking to buy Plossl or Kellner eyepieces, check the link below. You never know when can they go on sale. We always update the price listed below. 


These are the best deals you can get on these eyepieces. 

That’s all the factors of both of the eyepieces. 

Final Verdict

It all comes to which one is better. So, Plossl eyepieces are better than Kellner eyepieces. But they are substantially more expensive. 

Plossl eyepieces are the more expensive cause, their more complex and have better quality. But there are good and bad models available from both brands. So, the purchase decision depends on your budget. 

If you are a professional, Plossl might be a better option for you. But, for beginners, Kellners are good to be with. 


Questions: What are the differences between eyepiece and objective lens?

Answers: The objective lens shows the real image to the eyepiece. This lens sits close to the object. On the other hand, the eyepiece lens sits close to the eye. 

Question: What is the purpose of an eyepiece?

Answer: The purpose of the eyepiece is to magnify the image which sits close to the lens. It projects and magnifies the real image to the eye sensor. 

Question: Is using an eyepiece mandatory in a telescope?

Answer: Using an eyepiece is mandatory for telescopes. The eyepiece puts the object you are viewing in focus. It also magnifies the object you are looking at. 


That is everything you need to know about, plossl vs kellner. Both of the eyepieces are wonderful.

Both professionals and beginners can use the eyepieces to analyze their subject. 

Have fun observing!

Astromania 1.25-Inch 6mm 12.5mm 20mm Plossl Telescope Eyepiece Set - 4-Element Plossl Design - Threaded for Standard 1.25inch Astronomy Filters

as of June 17, 2024 3:48 am

Konus Kellner 20mm; 1.25" Eyepiece

as of June 17, 2024 3:48 am

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