Re: Olight M21 ( Luminus SST-50 ) Review : RUNTIMES , BEAMSHOTS and more !
Written by jcalvert on 12-22-2010 10:28 AM GMT
Hello Eric,
First off, thank you for all the hard work you put into your reviews. I have a couple of questions I hope you don't mind answering.
First, although I know you do not endorse any products and I won't ask you to do that. However, I'm in search of a predominantly floody, mid-size (5"-7"), general purpose light such as I believe the M21 may be, within a $120 budget, that also offers enough useful throw (at least 50 yards+) to make it an ideal trail walking light in heavy woodslands. Would you be able to offer any other products to suggest that I could look further into that are predominantly flood-based lights of the type previously described that I may also consider, so that I can make a fully informed choice?
Second, is there a way to translate lux to feet or yards. For example, if you have measured the M21 SST-50 to have a lux measurement of 6,700, how can I translate that to feet or yards so that I know how far the light throws its beam and to also make accurate comparisons with other lights?
Thank you in advance for your feedback!
All the best,
John Calvert
Re: Olight M21 ( Luminus SST-50 ) Review : RUNTIMES , BEAMSHOTS and more !
Written by
selfbuilt on 12-22-2010 12:02 PM GMT
jcalvert said:
However, I'm in search of a predominantly floody, mid-size (5"-7"), general purpose light such as I believe the M21 may be, within a $120 budget, that also offers enough useful throw (at least 50 yards+) to make it an ideal trail walking light in heavy woodslands. Would you be able to offer any other products to suggest that I could look further into that are predominantly flood-based lights of the type previously described that I may also consider, so that I can make a fully informed choice?
The The M21 is a good walking light in my opinion, due to the broad hotspot and good spill (i.e. I don't like playing "follow the bouncing ball" of a tight hotspot when walking at night). The Lumapower D-mini VX Ultra (SST-50) with 18650-tube is another good option for this type of beam (with optional TurboForce head if you want more throw).
But there are now a number of XP-G R5 lights you might also want to consider, like the Eagletac T20C2-II or Fenix TK12. These are not overly throwy, but do have a tighter hotspot than those above.
Whatever light you go for, see if you can get a properly fitting diffuser for it. That way, you can have pure flood whenever you want.
Second, is there a way to translate lux to feet or yards. For example, if you have measured the M21 SST-50 to have a lux measurement of 6,700, how can I translate that to feet or yards so that I know how far the light throws its beam and to also make accurate comparisons with other lights?
Yes, you can do this easily - but you have to decide what is a minimally acceptable lux level first. Yes, you can do this easily - but you have to decide what is a minimally acceptable lux level first.
The ANSI FL-1 standard "beam distance" is based on distance calculated to yield 0.25 lux. This is considered the ground level illumination of a full moon. The calculation is simple: divide lux at 1m by 0.25 (i.e. 6,700/0.25 in this case) and take the square root (to give you 163m in this case).
Personally, I find 0.25 lux to be rather low. More realistic might be to go with something between 1-5 lux as the minimum output need to make out what you are looking. 1 lux is simple - it is just the square root of lux at 1m (i.e. sqr-rt of 6700 = 82m). 5 lux would be the sqr-rt of (6700/5) = 37m.
Again, it doesn't really matter which one you go with - as long as you are consistent in comparing lights.
Re: Olight M21 ( Luminus SST-50 ) Review : RUNTIMES , BEAMSHOTS and more !
Written by
jcalvert on 12-23-2010 05:03 AM GMT
selfbuilt said:
The M21 is a good walking light in my opinion, due to the broad hotspot and good spill (i.e. I don't like playing "follow the bouncing ball" of a tight hotspot when walking at night). The Lumapower D-mini VX Ultra (SST-50) with 18650-tube is another good option for this type of beam (with optional TurboForce head if you want more throw). Thank you so much for your help, I really like the quality and features of my M20S, so the M21 is next for me and I will give the M20S to my wife and teach her how to use the instant-on strobe for defensive purposes.
But there are now a number of XP-G R5 lights you might also want to consider, like the Eagletac T20C2-II or Fenix TK12. These are not overly throwy, but do have a tighter hotspot than those above. I little OT, but I purchased the ET T20C2 MKII last summer and absolutely loved the output and beam, but at that point it was only my first high-end light and I wanted to be able to use it as a bedside light as well. The one and problem I had with the ET was that you couldn't get to the low mode for use in the middle of the night w/o going through the high or medium mode first and then bezel turning it to get to the low mode. Beside the hassle of going through the mode switching when your dead tired, my wife wasn't real happy with being woken up with the higher modes coming on first. So I sold it awhile ago and I now have a Klarus NT20 as a dedicated bedside light...I appreciate the NT20 so much I have two (the other is a winter coat EDC) and I'm getting a third. My question finally is this, why do you think ET would not have placed the low mode in with the constant light group so that owners could set the memory to low? It just doesn't make sense to me and if they change the low mode to the constant light group one day allowing memory, if I didn't have the M21 that I'll be getting, I would buy another T20 in a second for its quality and wonderful beam.
Whatever light you go for, see if you can get a properly fitting diffuser for it. That way, you can have pure flood whenever you want. I wonder if Olight has one for the M21 or if there is another brand's diffuser that will fit.
Yes, you can do this easily - but you have to decide what is a minimally acceptable lux level first.
The ANSI FL-1 standard "beam distance" is based on distance calculated to yield 0.25 lux. This is considered the ground level illumination of a full moon. The calculation is simple: divide lux at 1m by 0.25 (i.e. 6,700/0.25 in this case) and take the square root (to give you 163m in this case).
Personally, I find 0.25 lux to be rather low. More realistic might be to go with something between 1-5 lux as the minimum output need to make out what you are looking. 1 lux is simple - it is just the square root of lux at 1m (i.e. sqr-rt of 6700 = 82m). 5 lux would be the sqr-rt of (6700/5) = 37m.
Again, it doesn't really matter which one you go with - as long as you are consistent in comparing lights. Thank you so much for your easily understandable explanation. Armed with this knowledge really helps me make better and more informed decisions. I will likely just use the simple 1 lux measurement initially and when I receive the M21, I'll measure out 82' and with my son's help, see how much detail I can make out on him at that distance to determine if using 1 lux is just right or if I need to adjust my basis lux number up or down based on the amount of detail I can make out with my eyesight.
Eric,
Thank you very much for taking the time to help me out and for all the wonderful information you provide in your reviews. As much time and effort you must put into these reviews, you must really enjoy doing it. If you ever need some volunteer help that can be done by tele-commuting between your location in Canada and myself in Michigan, please feel free to PM me and I'll provide you contact information.
Thanks again for everything and I wish you a Merry Christmas and Happy 2011!
All the best,
John
Re: Olight M21 ( Luminus SST-50 ) Review : RUNTIMES , BEAMSHOTS and more !
Written by
selfbuilt on 12-23-2010 08:54 AM GMT
jcalvert said:
My question finally is this, why do you think ET would not have placed the low mode in with the constant light group so that owners could set the memory to low?
No interface is perfect - I guess they didn't attach as much weight to that option. No interface is perfect - I guess they didn't attach as much weight to that option. :shrug: Personally, I like a light that comes on in moonlight mode (for middle of the night). But I still find the T20C2-II an excellent dog-walking light (in General mode, with option for Turbo when you need it).
I will likely just use the simple 1 lux measurement initially and when I receive the M21, I'll measure out 82' and with my son's help, see how much detail I can make out on him at that distance to determine if using 1 lux is just right or if I need to adjust my basis lux number up or down based on the amount of detail I can make out with my eyesight.
Let us know how it works out for you! Curious to hear your findings. And happy holidays to you as well. Let us know how it works out for you! Curious to hear your findings. And happy holidays to you as well. :wave:
Re: Olight M21 ( Luminus SST-50 ) Review : RUNTIMES , BEAMSHOTS and more !
Written by
jcalvert on 12-27-2010 07:11 PM GMT
selfbuilt said:
No interface is perfect - I guess they didn't attach as much weight to that option. :shrug: Personally, I like a light that comes on in moonlight mode (for middle of the night). But I still find the T20C2-II an excellent dog-walking light (in General mode, with option for Turbo when you need it).
HI again Eric, HI again Eric,
First, I hope you had a wonderful holiday.
Like you, I really liked my ET T20C2 MKII when I still had it earlier this year and now ET dealers are offering 15% off until December 31st, so I'm tempted to replace the one I sold earlier with the XPG-R5 for now. However, another poster believes that the T20 is getting an XM-L drop-in here very shortly and suggested that this set-up would provide greater flood and throw than the M21. Also, rumor has it that the Maelstrom G5 may be coming out shortly with an XM-L version.
The question is, based on your expertise and knowledge of the T20 and the G5, do you think either or both of these XM-L upgrades, if they happen, will provide a broader flood hotspot and also more throw than the M21. Even though I assume that that the throw of the M21 will be sufficient for woods walking and room-filling, do you think that either the T20 and/or the G5 w/XM-Ls be even greater than the M21? The T20 at $85 minus 15% or $72.25 is very tempting versus $108 after 10% CPF discount for the M21. Even adding an XM-L drop-in would still be less in total for the T20 than the M21.
I apologize for all the questions as to whether the M21 will be the right choice or not, but I'm a bit of a recovering perfectionist and I hate making returns/exchanges and wasting return shipping charges.
Anyway, thanks in advance for your help. You are a treasure to this forum as I'm sure you are to your family. Take care!
John
Re: Olight M21 ( Luminus SST-50 ) Review : RUNTIMES , BEAMSHOTS and more !
Written by
selfbuilt on 12-27-2010 09:14 PM GMT
jcalvert said:
The question is, based on your expertise and knowledge of the T20 and the G5, do you think either or both of these XM-L upgrades, if they happen, will provide a broader flood hotspot and also more throw than the M21.
Hard to say without seeing them. But in general terms, the XM-L has a smaller die size than the Hard to say without seeing them. But in general terms, the XM-L has a smaller die size than the SST-50, so it should throw further with a standard-size reflector (although that depends on the specific reflector design). The G5 is designed for throw, so I expect a XM-L version would be relatively throwy. But there are a lot of unknowns, until the lights are actually produced.
Re: Olight M21 ( Luminus SST-50 ) Review : RUNTIMES , BEAMSHOTS and more !
Written by
jcalvert on 12-28-2010 05:11 PM GMT
selfbuilt said:
Hard to say without seeing them. But in general terms, the XM-L has a smaller die size than the SST-50, so it should throw further with a standard-size reflector (although that depends on the specific reflector design). The G5 is designed for throw, so I expect a XM-L version would be relatively throwy. But there are a lot of unknowns, until the lights are actually produced.
Thanks Eric, Thanks Eric,
Well I guess I have hopefully just one last question that may help me out. Since we have lumens to measure output and lux to measure throw, do we have some designation for flood that I can research and use to make apples-to apples comparisons between lights? Thank you!
John
Re: Olight M21 ( Luminus SST-50 ) Review : RUNTIMES , BEAMSHOTS and more !
Written by
selfbuilt on 12-29-2010 09:26 AM GMT
jcalvert said:
Well I guess I have hopefully just one last question that may help me out. Since we have lumens to measure output and lux to measure throw, do we have some designation for flood that I can research and use to make apples-to apples comparisons between lights? Thank you!
The simplest measure is simply the ratio of throw (square-root lux) to output (lumens, or some such). The lower that ratio, the less the light is focused for throw (and hence, The simplest measure is simply the ratio of throw (square-root lux) to output (lumens, or some such). The lower that ratio, the less the light is focused for throw (and hence, more floody).
Of course, that tells you nothing about the overall spillbeam width - for that, you need to check comparative beamshots taken under the same conditions/distance. For most people, "flood" indicates how bright the spillbeam is relative to the center-beam hotspot. But hard to come up with an a simple measure - best is to look at the actual beamshots.
I have enough on my hands with all the new lights everyone keeps sending me. 
