Rochester Precision Optics is an optics manufacturer based in Rochester, New York known for producing the lightweight optics found in PVS-31, GPNVG-18, and various other military programs. In the commercial space they are known for their 2.0 and 3.0 Milspec+ PVS-14 compatible variants. Recently we had the privilege to test and review pre-production samples from their new NVD-Next Gen Optics program set for release some time in mid 2025.
Objective Lens Weight: 39 grams
Eyepiece Lens Weight: 25 grams
NVD-N Total Weight: 64 grams
Competitor Total Weight: ~110 grams
The objective lens is longer and closer to a standard Milspec length, but optically it is identical to their 3.0 objective lens. The locking rings and locking mechanisms look identical, as do the internal shelves and contours on their aspherical elements. RPO has confirmed the optical design is identical, so the rest of this article will focus primarily on the eyepiece.
The eyepiece lens is in our opinion is the best PVS-14 spec eyepiece yet to be made. RPO changed from an aspherical bonded doublet in the 3.0 eyepiece to a more traditional doublet with singlet eyepiece design. In past consultations with RPO we suggested looking at the performance characteristics of the Ether eyepieces that they OEM to improve upon the 3.0 design. Ether eyepieces had a generous eye box and a flatter focal plane with good off axis performance maintaining resolution with low distortion. They also had good distortion matching with their objectives. Distortion matching is creating an eyepiece that is able to "reverse" or "de-code" the distortion caused by the prescription of the objective lens and produce a flatter, more natural image. The downsides of the Ethers were that they were non collimating and non Milspec compatible in terms of mechanical specification. RPO seems to have followed these recommendations as improvements can be found in all these aspects of the new lens.
These new NVD-N eyepieces are much longer than their old 3.0 and follows a more standard cell size that works perfectly with a standard Milspec diopter adjust assembly, whereas 3.0 required a custom diopter to work optimally. RPO is also expected to offer their lenses with a Milspec diopter.
Confirmation of Collimation on our Hoffman ANV-126A
The new NVD-N eyepiece has the most generous eye box of any current Milspec offering. This is something that is immediately felt during use, but much more difficult to depict using images. To show the longer eye relief (25mm is Milspec requirement) we offset our camera by 37.25mm from our test eyepieces using a 3D printed cylindrical spacer to compare the RPO NVD-N with a Fujinon lens, which is the current standard for Milspec systems.
To Clarify:
Eye Box is the cone shaped area behind the eyepiece where one can have a comfortable viewing experience without the corners blacking out (vignetting). At the end of the eye box the eye must be centered, but when viewed closer the eye can sit a bit off axis and still view comfortably.
Eye Relief is the maximum distance your eye can be away from the eyepiece while still maintaining a comfortable view without corners blacking out or vignetting.
The following are all tested using the same tube
RPO NVD-N Eyepiece at 37.25mm Eye Relief
Fujinon Eyepiece at 37.25mm Eye Relief
As can be seen, the NVD-N eyepiece is still able to see a full field of view at 37.25mm, whereas a standard Milspec Fujinon eyepiece is losing field of view and exhibiting vignetting. Note that this does not mean the Fujinon eyepiece is bad, it is excellent. There is no need to start telling your friends Carson is un-useable with eye pro or gas masks, it is just being tested outside of its designed performance envelope. It is easy to manipulate results from faux lens tests in this manner.
In terms of a flatter focal plane is not actually flat, it is just perceived to be flatter and this is even more difficult to depict through video. In essence, most lenses have a curved focal plane that extends a radiused distance from the lens itself. Tube image plates are also concave to try to match that. However this means that as the viewing pupil is moved out of center, the image distorts like viewing the inside of a bowl. If your eye is moved off center because your helmet shifted while you were running, you are in an unconventional position, etc. the bowl will distort in a different way. The NVD-N eyepiece does a better job of giving the user the feeling they are looking at a flatter screen projected further away.
Fujinon Right, RPO NVD-N Left
The previous RPO offering, 3.0, did have some more distortion than the Fujinon. However the NVD-N eyepiece is a significant upgrade in that the distortion matching is the best we have seen, on par with Ethers. RPO was able to achieve this as well as a longer eye relief by slightly reducing the eyepiece magnification which has a side benefit of making the image closer to true 1x, as most night vision lens systems (including Milspec ones) tend to be slightly magnified.
In line with the theme of a flatter image, the RPO NVD-N also produces a flatter image brightness where the image is a more even brightness throughout, whereas Fujinon tends to have a significantly brighter center and a more vignetted effect overall.
The following were all tested with the same tube with matched lens systems
RPO NVD-N Objective and Eyepiece with Group 5 Centered
Fujinon Objective and Eyepiece with Group 5 Centered
Center resolution is very similar, with RPO marginally sharper. Note that the bottom element (Group 5, Element 6) is marginally clearer with RPO. This test was manually focused with multiple photos taken for each, only the best result for each was selected.
RPO NVD-N Left, Fujinon Right
Closing Thoughts:
Fujinon/Carson/Noctis/Standard Milspec:
- Excellent all around performance
- Good eye relief
- Good lens flare suppression
RPO 3.0
- Lightest weight system
- Higher transmission, slightly more lens flare
- Milspec eye relief, slightly shorter than Fuji
RPO NVD-N
- Excellent all around performance
- Best eye relief and eye box with flattest focal plane
- Higher transmission than standard milspec from Fuji, etc
- Lighter weight with clear all around upgrades and performance benefits over other systems
We have used this system in a binocular for about a month in regular outdoor use, force on force training, driving, etc. and we have no real complaints. This is the lens system the market has been asking for: a lightweight offering that is a clear all around upgrade over a standard Milspec system. This is a clear upgrade over the 3.0 offering, and in our opinion will be one of the best optical systems on the market come 2025.
We also tested the NVD-N eyepiece paired with Fujinon, Qioptiq, and Edmund objective lenses with great success. We believe RPO should offer the NVD-N eyepiece as a standalone upgrade eyepiece over standard Milspec systems. Another bonus is the ease of upgradeability on existing RPO 2.0 and 3.0 systems. Since they are already distortion matched, a 3.0 system essentially just needs an eyepiece swap to upgrade to NVD-N.
A big thank you to RPO for allowing us the privilege of testing and reviewing their new piece of hardware. When time allows, we will update this blog to add some more aesthetic outdoor photos.
