Sightmark 4.5x42S Photon RT Night Vision Rifle Scope Review

If you are looking for a reasonably priced night vision scope, then the Photon RT series is a good place to start. There are 4 scopes in that lineup and they all have their pros and cons, with the major advantage being that they are cheap. Not only they are very budget-oriented but the Photon scopes are also well-respected from hunters all over the country mainly for the fact that they are easy to use and prove to be a reliable field companion when out hunting in the night.

Jack’s Verdict:

The Sightmark 4.5x42S Photon RT Night Vision Scope is one of the few real budget scopes out there currently. It offers a good amount of features and shows a lot of improvement over its predecessor. It isn’t going to help you do a 500 yard shot in pitch black conditions as it only really excels in the 100-200 yard range. Anything above that will require an external IR illuminator. There is an array of additional features that make this scope a great deal for its money but it still falls short compared to its competition from companies like ATN.

For more of my thoughts on some of the best night vision scopes for this year, head over to my full Buyer’s Guide. Now, let’s just jump straight into it!


Right off the bat, the few big improvements in the RT lineup are the ability to save files internally, the external power port, which also doubles as a port for the USB connection between the scope and your PC, the improved IR illuminator, battery life, and finally the ability to wirelessly connect to your mobile device.

There are a few different models in the RT scope series. Each of them has its own advantage, and before I move forward to the features of this particular scope I want to show you guys what is available out there. The four RT scopes can be put into two groups – “S” scopes and “standard” models. Here are the “S” scopes:

  • Photon RT 4.5x42S
  • Photon RT 6x50S

The two standard ones have the same names without the “S” at the end. That letter “S” after your scope indicates that it comes with the 850nm illuminator, while the standard ones have a 940nm version. I will get into these two illuminators and their pros and cons a bit further down this review.

Now, let’s get deeper into the 4.5x42S Photon RT features…

Magnification & Optics

What I like about the 4.5x model is the fact that it gives you a great field of view on sub-100 yard shots at night. After all, that is what matters with these scopes. If you opt for the 6.5x model you will have a really narrow field of view, as the whole scope is geared more towards 150-250 yard shots. That should be one of the main things to help you decide which model to choose. I personally stick to mid-range shots and find the 4.5x42S to be perfect for that.

What is great here is that there is now a digitally enhanced magnification. What this means is that you can zoom in your 4.5x scope to 9.0x. This isn’t done in steps of 0.5x or 0.1x. It is either 4.5x or 9.0x which can feel a bit weird but you have to remember that this is a budget scope and the previous generation didn’t have that zooming option at all, so this is a welcome improvement for a lot of people. It will allow this scope to do 200-yard shots without much issue.

This particular model has a 42mm objective lens which allows for a good amount of light to enter the scope. A bigger lens would’ve been better but that is reserved for the higher magnification model (6×50). This is one of the few places where you really feel the price-cuts in this scope and thanks to those “downgrades” the scope comes at such an affordable price.

There are diopter and focus adjustment rings on both sides of the scope. The diopter adjustment goes from -4 to +4 and is great for scopes that are used on a range by multiple people.


The reticle options here are somewhat good. Most budget scopes offer very limited adjustability when it comes to your choice of reticles but the Photon RT has 6 different ones. On top of that, they can be toggled between 4 different colors. This has been the standard across all Photon scopes for a long time now but I expect them to double-down on the reticle options in their future night vision generations.

Sensor & Screen

Thanks to the 768×576 CMOS sensor you will be able to see a clearer, brighter, and crisper picture out of your scope at night. That upgraded sensor has a 40% better resolution than the previous Photon generations. The sensor works great with external illuminators and can easily detect targets at 200 yards.

It is paired to a 640×480 LCD display which is vivid, accurate and has good contrast. It has adjustable brightness from 10 to 100% although the maximum brightness will drain out your battery really fast, so keep it around the middle.

IR Illuminator

Sightmark 4.5x42S Photon RT Night Vision Rifle Scope Review
Sightmark 4.5x42S Photon RT Night Vision Rifle Scope Review

On the RT generation, the IR illuminator is moved on the right side of the scope. It is adjustable meaning that you can play with the focus. Since this is the “S” model (4.5x42S), your illuminator is the 850nm one and it can help you see up to 250 yards in pitch black conditions

The IR emitter is LED and has a 200mW equivalent IR power. The “non-S” models get a 940nm illuminator and are slightly more expensive. There are two major differences between the 850nm and the 940nm illuminators here…

The illuminators with an IR wavelength in the 800s have a red light inside them that can be visible, even from 100 yards, that is if you know where to look at. According to some hunters, that has been detected by hogs or coyotes at night and they have gotten scared of it. They might have not seen the hunter but they’ve seen the red glow. That is a very slim probability and it is worth mentioning that all premium illuminators operate in that wavelength range as well. That has been the case for decades now.

The 940nm illuminator is marketed as an invisible infrared light model. That cannot be further from the truth, especially with the Sightmark illuminators since there is a faint soft red glow in them that can be seen. Granted, it is very hard to see but it can be actually seen if you look closely in the middle, especially in the night.

Those 940nm illuminators will also limit your maximum scope reach and will only allow you to detect targets of up to 150 yards.

The conclusion is that you will be paying more to see less which isn’t a deal I would have.

Construction & Design

In terms of construction, this scope does an all right job. It isn’t the most durable model out there but at this price, you can’t really expect it to be bulletproof. It is water and dust resistant which always a great thing, although the body doesn’t feel as sturdy as you’d want it to be.

Still, the construction is ultra-lightweight and you will barely feel this scope on top of your rifle, even with an extra battery pack attached to it.

On top, you have your focusing knob and your recording button. On the right side, there is the IR illuminator, as well as the now relocated battery pack. The left side of the scope houses the USB port and the weaver mounting rail which you can use for additional accessories.

At the back of the scope, there is still a rubber eyecup which is removable as it was with the older series. Some people like it but others that wear glasses find it too hard to use the scope with it so Sightmark made it a removable part of the scope.

Mounting It On Your Rifle

As the tube of the scope here is slightly shorter, you will definitely need a Picatinny rail on top of your bolt-action rifle. If you are using an AR-15 style rifle there will be no problem but with the bolt-action ones, you will have to place the scope way back on your rail in order to get the proper eye relief.

One thing that hasn’t changed with the new RT models is that you will still need the same rings. I would suggest you get the quick detach rings from Sightmark primarily because they are built for those scopes specifically and are a perfect fit. The Sightmark SM34002 QD Rings are the ones that are your best bet. If you don’t mind getting rings without the quick-detach feature, opt for the SM34007 Tactical rings. The quick-detach ones come as one piece so you will have to buy two, making that investment even more expensive than the regular ones that come as a pair.

If you want to invest in another brand of rings just remember to not take height index into consideration, as it is often misleading. You will need a very specific height – 3/4 of an inch from the bottom of the ring saddle to the top of the Picatinny rail. Most rings are not that tall, so be careful.

Battery Life

The battery slot is on the right side of the scope where it houses the 4 AA batteries of the scope. The previous generations had that on the top and could only fit two batteries which lead to significantly shorter battery life. This scope here can easily last you 90 minutes when constantly using the IR illuminator, while the previous could only give you a maximum of 45 minutes continuous usage.

The brighter illuminator, the recording features, as well as the wireless streaming, are all things that require more battery power. This is why this model has the extra two batteries to help it out.

If you keep the illuminator on some of its lower settings (4 to 7) you will actually be able to get more than 120 minutes of battery life out of your scope. Screen brightness is another thing that determines how much the scope will last. For optimal performance and results, I suggest keeping the screen at 30-50% brightness.

There is a Pulsar DNV Battery Pack that is available for this scope which is rechargeable and will be able to slot right into the place where the current 4 AA battery pack goes into. It has an improved battery life of 3 hours and is a good addition for anyone that is constantly on the go with his rifle.

What You Get

With every Photon RT you get, you will also be getting a lot of additional accessories. Those are:

  • Carrying case (semi-hard)
  • USB cable for charging and data transfer
  • Spare battery container
  • Pouch for the battery container
  • Lens cloth
  • User manual

On top of that, there is a non-removable objective lens flip-cover at the front and a removable rubber eyecup.

Extra Features

One of the most modern improvements of the Photon series is the wireless streaming with the free app you can get. As long as your device is close to the scope, you will be able to record, take pictures, and control the other functions of the scope through the display of your device.

You will also be able to stream live video to your device from your scope. Basically, whatever you see on the scope, it will be shown exactly as it is on your mobile device. That is perfect for people that hunt in pairs or you have a spotter.

Here is a list of a few other additional features your Photon RT has:

  • Built-in video recorder (AVI format, 320×240 or 640×480 video resolution)
  • Photo format – JPEG (320×240, 640×480, and 1280×960 photo resolution)
  • Internal storage – 8 GB
  • Diopter and focus adjustment rings at both sides of the scope
  • USB port for charging or data transfer

The video recording lasts around 5 hours on a previously empty internal storage. It isn’t as good as the one on the ATN X-Sight II HD Night Vision Scope which records in 1080p at 30fps but it still is decent enough for the money and the image is bright and sharp.

Something I also wanted to do is highlight some of the improvements of the RT series over the previous generations. Here is a comparison between the RT and the older XT line of Sightmark scopes…

Sightmark Photon RT vs. Photon XT Rifle Scopes

The Photon RT series is the official replacement for the Sightmark Photon XT series scopes, as they are now discontinued. Both of these scopes look very similar in terms of overall shape and design. Still, there are quite a few changes made to the newer RT series. The biggest change is the Internal video recording option as well as the still-picture taking. The Photon RT records onto the internal memory and sadly doesn’t record right on an SD card, due to the fact that there is no slot for it. You can either use the 8GB memory or record wirelessly onto your smart device.

As we mentioned, the RT series “S” models get an 850nm IR illuminator, while the standard RTs get a 940nm illuminator. Still, both of those prove a significant improvement over the last generation.

The battery port has also changed from the XT models. It is now on the side of the scope and packs 4 AA batteries. They can last you around an hour and a half to two hours depending on some conditions such as how much you use the illuminator or how cold/warm it is.

The RT series also now has a 2x digital zoom, as opposed to the fixed magnification on the XT series. It isn’t incremental and can only switch between 4.5 and 9.0x, for example.

The newer models also come with the option of being able to plug in an external power source through the USB port. The RT series also pairs wirelessly with your nearby device through the “Stream Vision” app.

Other than those major differences, there are tons of similarities such as the lens cap at the front, the focus adjustment rings, the rubber eyecup, and the overall shape of the scope. The RT series scopes are slightly shorter in the middle and therefore a little bit more compact. They both use the same rings and attachment systems.

How to sight in a Sightmark photon rt

In order to sight the scope, you will need to use the brightness knob, which also doubles as a button to control various features through the menu. When you press and hold it you will see three options. The top one (on the left) is the reticle pattern, the one bellow it will change the color, and the bottom-most option is going to be your sight-in menu. You press that and you will get your windage as an “X”. The “Y” is your up and down. Adjust these two until you place the reticle exactly over the holes you did with the first calibration shots. Once you have narrowed it, hold the button to enter the new settings and you now have a sighted Sightmark Photon RT!

Advantages & Disadvantages

Sightmark 4.5x42S Photon RT Night Vision Rifle Scope Review


  • One of the better budget scopes
  • Very affordable
  • Can detect & identify targets of up to 250 yards
  • Lightweight construction
  • Has an improved IR illuminator
  • The sensor and built-in display have great resolutions
Sightmark 4.5x42S Photon RT Night Vision Rifle Scope Review


  • The is no SD card slot
  • Battery life can use an improvement
  • Some users report that the 850nm illuminator is seen by animals

Frequently Asked Questions

How to mount a Sightmark Photon digital scope to a rifle?

While you can use some fully-adjustable mounts for most digital night vision scopes, this one can be also mounted with Sightmark’s Tactical Mounting Rings. They are also relatively easy to adjust and will keep the scope well aligned for both air guns and normal rifles.

How long does its battery last?

Depending on the batteries you use, you can get around an hour and half out of the scope. That is if the illuminator is on all the time. If it isn’t, you can get slightly more, using in day mode.

Where are Sightmark scopes made?

While the main design work and engineering happen in the USA, Sightmark scopes are surprisingly built in Japan.

Conclusion & Rating

Jack’s Rating: (4.5/5)

As a whole, the Sightmark 4.5x42S Photon RT Night Vision Scope is a budget-oriented scope that surely packs a bunch of useful features into it, such as its 2 times magnification on top of the 4.5x zoom it already has and the wireless streaming features. The scope itself doesn’t have things like an SD card slot but the 8GB of internal memory compensates well-enough for that. If you are shooting at 50-150 yards with an AR-15 style rifle, then this is one of your best bets bellow 1000 dollars.

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Jack Simons

Jack is a retired policeman who loves spending his free time around weapons and hunting across the state of Colorado with friends. His goal is to help newcomers find their way into the world of guns & hunting as well as review all the current best products and accessories for bow and rifle hunting.

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