ReviewTheLight: Olight ST25 Baton

Bigmac_79

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Olight makes a wide variety of high-end flashlights, and they've recently added the ST25 Baton to their lineup. The ST25 takes two AA's, with a long thin form factor. It features an electronic side switch, and it's highlight is the silent and hidden rear switch.


Thanks to Olight and GoingGear for providing the ST25 for review.


I'll be reviewing the ST25 in two sections: first, I'll discuss the light objectively (the facts about the light itself), then I'll discuss the light subjectively (my impressions about the light's performance when used for specific applications). If you have any other specific applications you'd like the light tested for, let me know and I'll see what I can do.

Video Review

Below is a video review of the ST25. Due to my old image hosting site closing down, I've got new restrictions on image uploads and have replaced the "Construction" section of my reviews with a more detailed video review.


This video is available in 1080p HD, but defaults to a lower quality. To select the playback quality click the settings button (looks like a gear) after you've started the video.


Objective

Manufacturer's Specifications

Price: 60 USD




Dimensions





User Interface

The ST25 is controlled by two switches: the electronic side switch and the silent tail switch.

The main control is by the side switch. A single click to the side switch turns the light on in the last regular brightness mode you used (this included Moonlight, Low, Medium, High, and Turbo but does not include the Strobe mode). When the light is on, holding down the side switch advances the light to the next mode in the sequence Low -> Medium -> High. While the light is on, a double click will activate the Strobe mode. To turn the light off, use a single click. When the light is off, holding down the side switch for about a second will turn the light on directly in Moonlight mode, or a double click will turn the light on directly in Turbo mode.

The silent tail switch has the ability to turn the light on and off only. Press the switch once and the light will turn on in the mode you used last (including Strobe). Press the switch again and the light will turn off.

Just to be clear: the mode memory of the ST25 will memorize the Strobe mode only if you activate it by the side switch, turn the light off by either switch, then turn it on and off using the rear switch. If you activate the Strobe, turn the light off, then turn it back on by the side switch the Strobe mode will be forgotten and it will use whatever brightness mode you were using before activating the Strobe.


Action Shots

You can click on any of these shots to see them full size.

Light in Hand


White Wall (Moonlight, Low, Medium, High, Turbo)
ISO 100, f/3.5, 1/20"


BeamSlice


MugShot


Indoor Shots (Moonlight, Low, Medium, High, Turbo)
ISO 100, f/3.5, 1"


Outdoor Shots (Moonlight,
Low, Medium, High, Turbo)
ISO 100, f/3.5, 2.5"


Long-Range Shots (
High)
ISO 100, f/3.5, 5"



Performance

Submersion: I submersed the ST25 under a foot of water for about an hour, clicking the switch several times (only the side switch, I didn't try the hidden rear switch). I found no evidence of water entering or damaging the light.

Heat: The ST25 gets very hot after about 20 minutes on Turbo.

PWM: I could not detect pulse width modulation on any of the brightness modes of the ST25.

Drop: I dropped the ST25 from about a meter onto various surfaces (including grass, carpet, dirt, and hard wood), and found no cosmetic or functional damage.

Reverse Polarity Protection: I can find no claims by Olight of reverse polarity protection on the ST25, so to be safe make sure you insert the batteries correctly.

Over-Discharge Protection: This is not an issue for a light that does not use lithium-ion battery chemistry.


Spectral Analysis


All light that we see as white is actually made up of several different colors put together. The relative intensities of the different colors in the mix are what determine the tint of the white we see. For example, cool white LED's have a lot of blue, and warm white LED's have more red or yellow. This measurement was done on a home made spectrometer. The plot below the picture is corrected for the spectral sensitivity of the human eye. Note: the peak in the 900nm region doesn't really exist, it's a piece of the second-order spectrum that's showing up here because of the high intensity of the light source.

Output and Runtime


ANSI FL-1 runtime ratings are the time it takes for a light to fall to 10% of it's original output (counting from 30 seconds after turning the light on).

The vertical axis of the graphs below represents a relative brightness measurement using a home made light box. The horizontal axis is time in hours:minutes:seconds. Runtimes are stated in hours:minutes:seconds. These graphs may be truncated to show detail.

Mode Comparison


Turbo


High


Medium



Throwing Distance

ANSI FL-1 standard for stating a light's throwing distance is the distance at which the peak beam intensity (usually at the center of the beam) is 0.25 lux. I calculate throwing distance and candela (lux at 1 meter) by measuring peak beam intensity at five different distances and using the formula lux*distance^2=constant.


Peak Beam Intensity: 4506 cd
Throw Distance: 134 m


Subjective Review

Quick break down:

+ Great regulation
+ Instant access to Moonlight or Turbo from off
+ Silent tail switch
+ High brightness for it's class
+ Slim profile
+ Sub-lumen moonlight mode
+ Good beam profile
+ Good clip design
+ Accepts common batteries

- Slightly complex interface
- Too long

Olight has proven they make high quality lights, and the ST25 is no exception. I don't tend to use AA lights very often, preferring lithium ion cells, but it's certainly useful to keep a light around that accepts commonly available batteries.

The ST25 has a lot going for it, starting with it's instant access to Moonlight or Turbo modes. Few things annoy me more than being forced to pass through a high brightness or flashing mode on my way to the low brightness I want. So, I really appreciate the ability go from off directly to the mode I choose. I often find it practical to go directly to Moonlight, then increase the brightness if necessary. Theoretically, there will be situations where it would be useful to go quickly and directly to Turbo, though I haven't encountered one yet while testing this light. I expect the control (two quick clicks) would be pretty easy to activate quickly in an emergency.

550 lumens may not sound like much if you've been looking at other modern lights (some reaching >1000 lumens off a single battery), but for a 2xAA light it's actually near the high end of what's reasonably possible. The ST25 can't maintain that level for more than a few minutes before dropping to 370ish, but if you plan on needing high output for longer than that you'll want something other than a AA light anyway. The Moonlight mode, at <1 lumen, is excellent for getting around in dark places without drawing attention or completely ruining your night-adapted vision. A good very low output level is something not appreciated as much as it should be, so I was very glad to see Olight include it on the ST25. This Moonlight mode pairs nicely with the next topic I'll cover.

One of the more unusual features of the ST25 is it's silent tail switch. Most flashlights have a switch that makes a distinct (and sometimes fairly loud) "click" sound when pressed. Both mechanical and electrical switches have this tendency. The tail switch of the ST25 makes no sound, and in fact isn't even easy to identify as a switch if you don't know what to look for. This silent switch has obvious advantages for situations where you need to activate the light without being noticed.

As always, Olight has ensured all the little details that make a good light a great light. The knurling is Olight's smooth rectangle pattern, grip is incorporated into the body shape, stainless steel bezel, deep pocket clip, blue o-ring in head, etc.

My only real negative with the ST25 is that the interface is a bit complex. It's pretty simple once it's known, and the average person can access most of the functionality when they're just handed the light, but in order to find the Moonlight or Turbo mode you'll probably need to be told what to do. This is a bit off from what I imagine as the ideal usefulness of a 2xAA light--one that can be used easily by anyone of a household in an emergency. Like I said, it does the job fine, but I'd prefer to see the Moonlight and Turbo modes included in the regular sequence. The other negative is the length, but that can't really be helped when using 2xAA batteries are used in a row.

Overall, the ST25 is one of the top lights in it's class. If you're looking for a high-end light that takes a common battery type, the ST25 has excellent Moonlight and Turbo modes that can be accessed directly from off, and a silent switch in addition, making this a great option.


Long Term Impressions
I'll fill this part in after carrying the light for a while. If nothing get's added here, either I find nothing else worth noting about the light, or I end up not using it often.
 
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Mr Floppy

Flashlight Enthusiast
Joined
Feb 19, 2007
Messages
2,065
Thanks for the review. Glad to see the 2xAA format getting some love again. Used to be my favourite form factor.

I do think the 550 lumen turbo is just not worth it. Might as well start it at 370 and have a lower high, and a longer running medium. Is the turbo a timed step down or something that takes advantage of the higher voltage when the cells are fresh?
 

Bigmac_79

Flashlight Enthusiast
Joined
Jun 3, 2011
Messages
1,511
Location
Kansas
Thanks for the review. Glad to see the 2xAA format getting some love again. Used to be my favourite form factor.

I do think the 550 lumen turbo is just not worth it. Might as well start it at 370 and have a lower high, and a longer running medium. Is the turbo a timed step down or something that takes advantage of the higher voltage when the cells are fresh?

I'm not sure about that, I'll pop in some low voltage cells and see how it behaves.

Here's a partial run with some batteries at about half charge, compared to the fully charged Turbo:


So, it looks like it takes about the same time to reach 400 lumens in either case, though the fully charged run spends more time at higher outputs before getting there. Both seem to level off at about the same output before dropping again at the end of the run. From that I'd say it seems the initial decrease in output is timed, but that with fully charged cells it takes advantage of the extra voltage to give higher outputs.
 
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Overclocker

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Aug 13, 2005
Messages
1,585
Location
Philippines
thanks for the review!

it would be interesting to see how long it could actually MAINTAIN ~500 lumens. perhaps you could zoom in on just the first 3 minutes...

by the looks of it the advertised "550 lumens TURBO" is totally not available for any decent amount of time
 

Bigmac_79

Flashlight Enthusiast
Joined
Jun 3, 2011
Messages
1,511
Location
Kansas
thanks for the review!

it would be interesting to see how long it could actually MAINTAIN ~500 lumens. perhaps you could zoom in on just the first 3 minutes...

by the looks of it the advertised "550 lumens TURBO" is totally not available for any decent amount of time


Here's the first few minutes:
 
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