See my review of the 22mm Nagler. Further, this lens has less contrast and apparent sharpness that the 22 nagler. Nevertheless, I like the eyepiece.

I own the whole nagler type 4 line & really like them all! there is a small blackout problem with this & the other t4 eyepieces, but nothing terrible. id put this eyepiece against any other 12mm eyepiece for contrast, fov & pinpoint stars across the entire field of view. in a 8 f10 scope this eyepiece is amazing!!! the instajust eyeguard is a great addition to the tv nagler line! nothing but a 10 for this one!!

This is the truest spacewalk EP I own. I was expecting black-out effects, however they were negligible, and once I learned the proper pupil placement - nearly non-existant. I have compared it to the 13mm T6, which was less engaging - it didnt give that same feeling of wow (even though eye placement was less critical). This is an EP others can be measured against.

This eyepiece was a disappointment, especially considering the $300+ price I paid. On my 11 SCT, the views are wide, but heavily washed-out with internal glare. I had to recheck the stats to see if they claimed blackened edges on the glass. They do, but you wouldnt know it by the results. The sharpness is acceptable on my 4.7 refractor, but is well below the performance of my Axiom eyepiece on the 11 SCT. I will be selling the 12mm Nagler, and getting another lens.

You want to love this ep...you really do. When you position your eye...just so...it has fantastic contrast. Its well made, but tricky even so. Screw in a filter too tightly and try to unscrew it: watch out as the whole lower assembly will unscrew with it. The next sounds you hear could be very expensive as itsy bitsy lense elements lurk ready to fall! The Insta-just eyepiece shield is next to useless. There IS ghosting and the kidney bean, but the latter is less an issue the longer you work with this ep. If you have a 1.25 compression ring diagonal the hybrid 1.25-2 barrel is a true hassle to use. But on nights of so-so seeing this is a wicked good ep for planets and M42 etc, and some of my best views have been thru this ep. Go figure!

This is my first Nagler so I have only the plossls that came with my scope to compare it with. It gave me a big wow feeling to look through! Also, I may add, it does great barlowed (TV 2xBarlow). I do not wear eyeglasses, so I leave the eyeguard all the way down - getting those huge sharp views! I have an Orion 10XTi Dob that I use this with - no balance issues. This is a real keeper - I will be looking into getting the 17T4 in the future!

I compared the 12mm t4 with a barlowed 22mm t4 on Saturn during a very calm (great seeing) night. I was surprised when I saw a sharper image with the barlowed 22mm t4 than with the 12mm t4. This was confirmed by another observer that night.

To put it plain and simple...I dont like it. Stars seem washed out with internal reflections. For $300+ I am deeply disapointed and expected much better. Im giving it a 2 for craftsmanship. For about half the price my Radian is superior.