[ti-force]

This is a review of the new Olight SR51. This light is new to Olight's Search and Rescue (SR) series. This light was sent to my by 4sevens for review purposes.



Here are the manufacturer's specs, taken from Olight's website:

SR51 Intimidator

Feature:

1. World-class super bright Cree XM-L LED

2. Max 900 lumens(OTF),700 meters long throw.

3. Max 10 hours long runtime

4. Anti battery polarity reverse protection

5. Two digitally controlled constant brightness levels and strobe

6. Access to strobe instantly

7. Rugged indestructible aluminum body with anti-scratching type III hard anodization, Engineered anti-slip knurling

for a tightly firm grip

8. Highly water resistant to IPX-8

9. Mil-spec: MIL-STD-810F

10. Mini orange peel reflector offers perfect beam and long throw.

11. Super Strong anti reflex coating lens，99% effective transmission

12. Excellent tridimensional heat dissipation ability

13. Friendly user interface, press and hold the switch for transferring mode.




Here's an image of everything that's included with the light. Like the SR91, this light comes in a nice case for storage and carry. It also comes with a holster, lanyard, spare o-rings, and a diffuser that can be easily installed over the bezel end of the light to convert the light into a very useful flood light.








Here are some images of the light :









Power button:






The business end houses the new Cree XM-L emitter:







The glass seal (red ring) at the bezel end of the light has a slight glow to it after the light is turned off. To notice this you will need to be in nearly complete darkness because it's a very dim glow:






Shown here is the included CR123 primary battery holder on the right, and an optional 2x18650 battery holder on the left:






Here's an image for size reference. From left to right- X10, SR51, S18 and the SR91:








Now it's time for some comparison beam shots against my garage door. All lights were in their highest mode, and all camera settings remained the same for each beam shot taken, and I set the white balance to auto, since we're not comparing tint here, just beam shape. Distance from each light to my garage door is roughly 17ft.

These are .gif's, which I believe help to see the difference between each light better. If you're using a mobile device you may not be able to see the .gif's work properly. If you're viewing it properly you should see two images switching back and forth with each beam shot. Certain browsers also have trouble viewing these:




SR51 without diffuser vs SR51 with diffuser:






SR51 without diffuser vs X10:






SR51 without diffuser vs SR91:







SR51 without diffuser vs S18:










I was able to take some long range beam shots last night. They are not perfect. Bugs kept flying towards my lights, and this can be seen in most of the images. All camera settings remained the same for each image taken. White balance was set to auto. Distance from lights to tree is roughly 90 to 100 yards. NOTE: These images are over exposed. At these distances it has to be done to show the beam profile correctly. The brightness of these images is brighter than the light actually is at these distances. Don't expect these lights to be this bright at these distances in person.






SR51 No Diffuser vs SR51 With Diffuser






SR51 vs S18






SR51 vs SR91







SR51 vs X10








Now it's time for some OTF lumen results. The SR51 was tested using two AW 2900mAh 18650 Li-ion batteries, and since this light is not thermally regulated like the X10 (and others) I didn't test this light in any other method than simply holding the light in my hand by the handle, which is how I expect most users to use this light. I didn't use a cooling fan or any other method of cooling on this light because it didn't get hot enough to worry about heat. I feel like this method more truly represents the lights output and runtime. Below I've posted two images to show an example of how I'm holding the light during the following test (click each image to view full size):







Here are my OTF lumen results for this test. Again, I'm using 2x18650's for this test:




And here is a thermal graph showing the lights exterior temperature throughout the run time test:











I've also decided to include a graph comparing the SR51 to the 4sevens Maelstrom X10. The following test was done using the same method, meaning I held the light by the handle with my bare hand. The X10 starts dropping in output due to thermal regulation. This is a feature that 4sevens has developed into the X10 to protect it from overheating, which could damage the light, and/or injure the user due to heat. The size of the SR51 is the reason it can hold its output without the need for thermal regulation:




And the thermal graph for the previous test:









The X10 can maintain an output closer to its initial output for a much longer duration if the light is kept cool enough. I've demonstrated this in my X10 review. However it's possible that the SR51 could hold a higher lumen output throughout its run time if I were to use the same cooling methods used on the X10, so this is not really a fair comparison, but it gives you an idea of what the X10 can do if the temperatures remain low. Please see the images in my X10 review for images showing examples of the different holding/cooling methods of the X10:




And here's the thermal graph showing the temperature of each light in the previous test:









I hope you enjoyed my review, and hopefully this data was helpful.