Sky Lumen        
Page 5 of 7 FirstFirst 1234567 LastLast
Results 121 to 150 of 203

Thread: Sunwayman D40A (XM-L2, 4xAA) Review: RUNTIMES, BEAMSHOTS, VIDEO + more

  1. #121
    Flashaholic
    Join Date
    Dec 2013
    Location
    Tempe AZ
    Posts
    166

    Default Re: Sunwayman D40A (XM-L2, 4xAA) Review: RUNTIMES, BEAMSHOTS, VIDEO + more

    Thanks SB, and since I've used your reviews for a couple different purchases of late, I'm sending you some battery money. You do excellent reviews and have made comparison shopping so easy!
    Cheers

  2. #122
    Flashaholic
    Join Date
    Feb 2013
    Location
    Texas
    Posts
    120

    Default Re: Sunwayman D40A (XM-L2, 4xAA) Review: RUNTIMES, BEAMSHOTS, VIDEO + more

    Doingoutdoor has the D40A for a much lower price. Free shipping also. I've never ordered from there and just wondering why it's so much cheaper than others that I have used before.

  3. #123
    Flashaholic
    Join Date
    Nov 2011
    Location
    Atlanta, GA
    Posts
    234

    Default Re: Sunwayman D40A (XM-L2, 4xAA) Review: RUNTIMES, BEAMSHOTS, VIDEO + more

    That price/discount is about the same that a some of the other well know online retailers did during the holiday and black Friday sales.

  4. #124
    Enlightened
    Join Date
    Jan 2014
    Location
    Bristol, UK
    Posts
    50

    Default Re: Sunwayman D40A (XM-L2, 4xAA) Review: RUNTIMES, BEAMSHOTS, VIDEO + more

    Sunwayman list a 2-light holiday package that includes a 1020 lumen version of the D40a. Most of the other specs are identical to the 980 lumen version, including throw and run times. Does anybody know whether this will replace the 980 lumen version, or is it just a limited edition?

  5. #125
    Flashaholic
    Join Date
    Feb 2013
    Location
    Texas
    Posts
    120

    Default Re: Sunwayman D40A (XM-L2, 4xAA) Review: RUNTIMES, BEAMSHOTS, VIDEO + more

    I just got my D40a NW and I really like this light. This was my first venture into the higher lumens (I hadn't pushed 300lm yet)
    Even though I like the light, I have to admit that I was disappointed with the turbo vs high. The difference was barely visible. I can't imagine a circumstance where I would need the 980lm vs the 550lm. I was testing the light outside on trees far away. The turbo showed no more detail than the high. I now wish I could just bypass the turbo.
    I have read the threads on lumens and what the human eye can really see, but I still thought 980 would look brighter than 550.

  6. #126
    Flashaholic Dr.444's Avatar
    Join Date
    Jan 2013
    Location
    Egypt
    Posts
    205

    Default Re: Sunwayman D40A (XM-L2, 4xAA) Review: RUNTIMES, BEAMSHOTS, VIDEO + more

    Quote Originally Posted by froggyted View Post
    Sunwayman list a 2-light holiday package that includes a 1020 lumen version of the D40a. Most of the other specs are identical to the 980 lumen version, including throw and run times. Does anybody know whether this will replace the 980 lumen version, or is it just a limited edition?
    They upgraded the LED to XM-L2 [U2] instead of XM-L2 [T6] !

    Maybe this will replace the 980LM version when the christmas combo is sold out .
    . . . . . . . . . . . . . .

  7. #127
    Enlightened
    Join Date
    Jan 2014
    Location
    Bristol, UK
    Posts
    50

    Default Re: Sunwayman D40A (XM-L2, 4xAA) Review: RUNTIMES, BEAMSHOTS, VIDEO + more

    Quote Originally Posted by revscott View Post
    I just got my D40a NW and I really like this light. This was my first venture into the higher lumens (I hadn't pushed 300lm yet)
    Even though I like the light, I have to admit that I was disappointed with the turbo vs high. The difference was barely visible. I can't imagine a circumstance where I would need the 980lm vs the 550lm. I was testing the light outside on trees far away. The turbo showed no more detail than the high. I now wish I could just bypass the turbo.
    I have read the threads on lumens and what the human eye can really see, but I still thought 980 would look brighter than 550.
    Have you tried it in a small room? There should be a very noticeable difference between these two levels, if not maybe your light is faulty. Also, try pointing it at nearer targets rather than targets right at the extreme of the light's range. The least attractive thing about this light for me, judging from spec seems i don't currently own one, is the big jump between 30 lumen and 230 lumen. The 230 lumen setting only gives a quoted 4 hours runtime so i would have liked something nearer the 85-120 lumen mark.
    Last edited by froggyted; 01-19-2014 at 04:59 AM.

  8. #128
    Enlightened
    Join Date
    Jan 2014
    Location
    Bristol, UK
    Posts
    50

    Default Re: Sunwayman D40A (XM-L2, 4xAA) Review: RUNTIMES, BEAMSHOTS, VIDEO + more

    Quote Originally Posted by Dr.444 View Post
    They upgraded the LED to XM-L2 [U2] instead of XM-L2 [T6] !

    Maybe this will replace the 980LM version when the christmas combo is sold out .
    What i really don't understand is that all the run times are exactly the same. Isn't XM-L2 (U2) supposed to be a more efficient emitter? My Fenix LD41 (680 lumen version with U2 emitter) gives a quoted 5 hours 45 min at 240 lumen on 4xAA, yet both versions of the D40a quote 4 hours at 230 lumens, which to me is curious. It hardly seems to have been worth upgrading the emitter for 800 more cd giving a mere 5 metres more throw when every other spec appears identical to the 980 lumen version.

  9. #129
    Flashaholic
    Join Date
    Feb 2013
    Location
    Texas
    Posts
    120

    Default Re: Sunwayman D40A (XM-L2, 4xAA) Review: RUNTIMES, BEAMSHOTS, VIDEO + more

    Quote Originally Posted by froggyted View Post
    Have you tried it in a small room? There should be a very noticeable difference between these two levels, if not maybe your light is faulty. Also, try pointing it at nearer targets rather than targets right at the extreme of the light's range. The least attractive thing about this light for me, judging from spec seems i don't currently own one, is the big jump between 30 lumen and 230 lumen. The 230 lumen setting only gives a quoted 4 hours runtime so i would have liked something nearer the 85-120 lumen mark.
    Yeah I always play around with the lights in my house. Still don't notice much of a difference. I have no need to light up a room like that. I want more light for outdoor use. I was surprised that 980lm didn't seem that bright. Oh well, I still like the light.

  10. #130
    Enlightened
    Join Date
    Jan 2014
    Location
    Bristol, UK
    Posts
    50

    Default Re: Sunwayman D40A (XM-L2, 4xAA) Review: RUNTIMES, BEAMSHOTS, VIDEO + more

    No, i realise that 980 lumens is way OTT for indoor use, i was only suggesting it because it would be more apparent in a room whether or not the light is throwing out significantly more light at turbo compared to high. It is possible that your batteries aren't capable of driving the torch at turbo level, especially if they are alkalines as opposed to NiMh.

    I've just ordered one, and i hope i'm not going to be disappointed with the turbo on mine, since i already have a Fenix 680 lumen LD41 and am expecting the D40A to be signiicantly brighter. Amazon have a very good deal on the Cool White version at the moment for just under £UK40 from ThruNite Store. That's about half the rrp from what i can tell.

    Quote Originally Posted by revscott View Post
    Yeah I always play around with the lights in my house. Still don't notice much of a difference. I have no need to light up a room like that. I want more light for outdoor use. I was surprised that 980lm didn't seem that bright. Oh well, I still like the light.
    Last edited by froggyted; 01-19-2014 at 02:06 PM.

  11. #131
    Flashaholic
    Join Date
    Feb 2013
    Location
    Texas
    Posts
    120

    Default Re: Sunwayman D40A (XM-L2, 4xAA) Review: RUNTIMES, BEAMSHOTS, VIDEO + more

    Quote Originally Posted by froggyted View Post
    No, i realise that 980 lumens is way OTT for indoor use, i was only suggesting it because it would be more apparent in a room whether or not the light is throwing out significantly more light at turbo compared to high. It is possible that your batteries aren't capable of driving the torch at turbo level, especially if they are alkalines as opposed to NiMh.

    I've just ordered one, and i hope i'm not going to be disappointed with the turbo on mine, since i already have a Fenix 680 lumen LD41 and am expecting the D40A to be signiicantly brighter. Amazon have a very good deal on the Cool White version at the moment for just under £UK40 from ThruNite Store. That's about half the rrp from what i can tell.
    I'm using brand new Eneloop XX that I purchased with the light. Mine is the neutral white version so maybe that effects the perceived brightness even more.

  12. #132
    Enlightened
    Join Date
    Jan 2014
    Location
    Bristol, UK
    Posts
    50

    Default Re: Sunwayman D40A (XM-L2, 4xAA) Review: RUNTIMES, BEAMSHOTS, VIDEO + more

    Possibly, although i would have thought there should still be a noticeable difference. I too have XX Eneloops - excellent batteries. Have just ordered a second set plus Sanyo charger. What is your opinion of the lanyard and lanyard positioning? My guess is that the metal crocodile clip will scratch the anodising.

    Quote Originally Posted by revscott View Post
    I'm using brand new Eneloop XX that I purchased with the light. Mine is the neutral white version so maybe that effects the perceived brightness even more.

  13. #133
    Flashaholic
    Join Date
    Feb 2013
    Location
    Texas
    Posts
    120

    Default Re: Sunwayman D40A (XM-L2, 4xAA) Review: RUNTIMES, BEAMSHOTS, VIDEO + more

    Haven't used the lanyard. I think it will help keep the light from rolling off a table. It's a weird position for sure.

  14. #134
    Enlightened
    Join Date
    Jan 2014
    Location
    Bristol, UK
    Posts
    50

    Default Re: Sunwayman D40A (XM-L2, 4xAA) Review: RUNTIMES, BEAMSHOTS, VIDEO + more

    I always use lanyards. I use my lights mainly for hiking and would be afraid to drop it, especially whilst new. I have all my accessories such as water bottle, gps etc. secured to the rucksack either with lanyards, pouches, or a combination of both.

  15. #135
    Flashaholic
    Join Date
    Feb 2013
    Location
    Texas
    Posts
    120

    Default Re: Sunwayman D40A (XM-L2, 4xAA) Review: RUNTIMES, BEAMSHOTS, VIDEO + more

    I'm not even sure how the lanyard attaches now that I've looked at it. The metal clip is too big for the hole. I guess you have to take it apart and feed the cord through. It seems like it was designed to be a wrist strap.

  16. #136
    Enlightened
    Join Date
    Jan 2014
    Location
    Bristol, UK
    Posts
    50

    Default Re: Sunwayman D40A (XM-L2, 4xAA) Review: RUNTIMES, BEAMSHOTS, VIDEO + more

    Quote Originally Posted by revscott View Post
    I'm not even sure how the lanyard attaches now that I've looked at it. The metal clip is too big for the hole. I guess you have to take it apart and feed the cord through. It seems like it was designed to be a wrist strap.
    Interesting. I read somewhere (possibly this thread) that there was a batch of lights with lanyards that wouldn't fit the hole, i thought they'd sorted that out. I will be tempted to source another lanyard from Amazon which doesn't have a metal clip. As long as the lanyard can fit around my wrist without impeding operation it will suit me fine in that respect.

  17. #137
    Flashaholic Disciple's Avatar
    Join Date
    Dec 2004
    Location
    Oregon, USA
    Posts
    435

    Default Re: Sunwayman D40A (XM-L2, 4xAA) Review: RUNTIMES, BEAMSHOTS, VIDEO + more

    Quote Originally Posted by revscott View Post
    Even though I like the light, I have to admit that I was disappointed with the turbo vs high. The difference was barely visible. I can't imagine a circumstance where I would need the 980lm vs the 550lm. I was testing the light outside on trees far away. The turbo showed no more detail than the high. I now wish I could just bypass the turbo.
    I have read the threads on lumens and what the human eye can really see, but I still thought 980 would look brighter than 550.
    You should be able to see the difference between Turbo and High in direct comparison, but it should not appear to be a large difference. Using the cube root formula, which seems to be a reasonable first-order approximation of human vision, and selfbuilt's measurements (940 and 610 lumens), it should only appear (940/610)^(1/3) = 115.5% as bright as High (15.5% brighter). This may come as a surprise if you were expecting a linear perception of the brightness difference. This is the reality of "the law of diminishing returns" as it pertains to flashlights. The formula for throw is a bit more forgiving as it is a square root relationship, so you should get 24% greater throw (distance to equivalent luminance) on Turbo. For this reason I have little interest in replacing a flashlight, for the sake of brightness or intensity alone, unless the replacement yields a four fold increase in output (which would be perceived as about 59% brighter, or a 100% increase in throw).

    Quote Originally Posted by froggyted View Post
    The least attractive thing about this light for me, judging from spec seems i don't currently own one, is the big jump between 30 lumen and 230 lumen. The 230 lumen setting only gives a quoted 4 hours runtime so i would have liked something nearer the 85-120 lumen mark.
    I gave a modified D40A (D40Avn) to my father for Christmas. This light should have an even bigger gap between Medium and Low, since Moon and Low level are unchanged, yet Mid/High/Turbo are boosted. Nevertheless I find the level spacings quite practical. I don't think you should worry unless you are very particular about a certain output level.

    Quote Originally Posted by froggyted View Post
    What i really don't understand is that all the run times are exactly the same. Isn't XM-L2 (U2) supposed to be a more efficient emitter? My Fenix LD41 (680 lumen version with U2 emitter) gives a quoted 5 hours 45 min at 240 lumen on 4xAA, yet both versions of the D40a quote 4 hours at 230 lumens, which to me is curious. It hardly seems to have been worth upgrading the emitter for 800 more cd giving a mere 5 metres more throw when every other spec appears identical to the 980 lumen version.
    The higher flux bin could be used to yield either an increase in brightness at the same drive level or longer runtime at a slightly lower drive level that produces the same brightness. Either way it is a minor incremental increase that only makes a difference on paper in my opinion.

  18. #138
    Enlightened
    Join Date
    Jan 2014
    Location
    Bristol, UK
    Posts
    50

    Default Re: Sunwayman D40A (XM-L2, 4xAA) Review: RUNTIMES, BEAMSHOTS, VIDEO + more

    Quote Originally Posted by Disciple View Post
    The higher flux bin could be used to yield either an increase in brightness at the same drive level or longer runtime at a slightly lower drive level that produces the same brightness. Either way it is a minor incremental increase that only makes a difference on paper in my opinion.
    Hi Disciple, thanks for the detailed reply. With regard to the above point though, the U2 version of the D40A appears to do neither: more max cd resulting in an extra 5 metre throw (!), but otherwise exactly the same lm/runtimes as the 980lm version:
    http://www.sunwayman.com/html/products/201311/146.html

  19. #139
    Flashaholic Disciple's Avatar
    Join Date
    Dec 2004
    Location
    Oregon, USA
    Posts
    435

    Default Re: Sunwayman D40A (XM-L2, 4xAA) Review: RUNTIMES, BEAMSHOTS, VIDEO + more

    It is rated at 1020 lumens instead of the stock 980 lumens. By brightness alone you'd never see the difference, but perhaps it has a better tint (being optimistic).

  20. #140
    Enlightened
    Join Date
    Jan 2014
    Location
    Bristol, UK
    Posts
    50

    Default Re: Sunwayman D40A (XM-L2, 4xAA) Review: RUNTIMES, BEAMSHOTS, VIDEO + more

    Quote Originally Posted by Disciple View Post
    It is rated at 1020 lumens instead of the stock 980 lumens. By brightness alone you'd never see the difference, but perhaps it has a better tint (being optimistic).
    It does make me wonder why they bothered though - can't help thinking they could have done more with the U2 emitter. As it stands it seems just a gimmick so they can quote 1k+ lumens. Anyway, i have ordered the 980lm CW version since there is an offer that is way below rrp on Amazon at the moment (UK£40) and i can't justify paying near the full price. No doubt in a few months time there will be an upgraded model with perhaps better run times and i'll wish i'd held fire. My comments re the low and mid ranges is based on my Feinix LD41 (U2). It has a low mode of 10lm and a mid of 85lm. 85lm is perfect for night walking in woodland, and even 10lm can suffice at a push. I'm a bit concerned that with the 30lm low on the D40A i will be frequently cycling to 230lm, which is overkill for most hiking purposes and will run the battery down much faster. I'm still not sure how Sunwayman only get 4 hours at 230lm whilst Fenix get 5 hours 45 minutes at 240lm (both same emitter). I will report back when i get a chance to test the D40A on a hike. Maybe the 30lm low will do the job better than i anticipate.

  21. #141
    Flashaholic Disciple's Avatar
    Join Date
    Dec 2004
    Location
    Oregon, USA
    Posts
    435

    Default Re: Sunwayman D40A (XM-L2, 4xAA) Review: RUNTIMES, BEAMSHOTS, VIDEO + more

    I hope you are pleased with the light. Run-times are often stated to 10% output, therefore a light that quickly drops to 11% and holds it will have a far longer run-time than a light which is flat regulated. I don't know what the situation with the LD41 is, but as you can see from selfbuilt's testing the D40A compares favorably to other 4xAA lights; I doubt the LD41 gets to 5:45 flat-regulated.

  22. #142
    Enlightened
    Join Date
    Jan 2014
    Location
    Bristol, UK
    Posts
    50

    Default Re: Sunwayman D40A (XM-L2, 4xAA) Review: RUNTIMES, BEAMSHOTS, VIDEO + more

    The LD41 has regulated output, and as far as i understand it maintains the stated lumens for the quoted runtime. Certainly from my experience with the light that appears to be the case.

  23. #143

    Default Sunwayman D40A (XM-L2, 4xAA) Review: RUNTIMES, BEAMSHOTS, VIDEO + more

    Quote Originally Posted by Disciple View Post
    ....Using the cube root formula, which seems to be a reasonable first-order approximation of human vision, and selfbuilt's measurements (940 and 610 lumens), it should only appear (940/610)^(1/3) = 115.5% as bright as High (15.5% brighter)...
    I'm not sure the cube root formula is correct. That would imply that 900 lumens appears only twice as bright as 100 lumens. I personally use the same formula, but in square root, since to my eyes 4x lumen increases feel 2x brighter. Technically though, I thought I read around here that the Stevens/Weber/Fechner brightness perception laws derived something around 3x lumen increase is ~ 2x perceived brightness. If that's where you were were getting your "cube" number from, then I think the formula should be (940/610)^(2/3) or something like that....

    Quote Originally Posted by froggyted View Post
    .....I'm still not sure how Sunwayman only get 4 hours at 230lm whilst Fenix get 5 hours 45 minutes at 240lm (both same emitter)....
    You can't really compare spec sheets like that, there's all sorts of conservatism, exaggeration, interpretation, and gaming going on between the different manufacturers and the ANSI rules are wide enough to drive a truck through - here's my favorite "ANSI" example, see output runtime graph on first post:

    http://www.candlepowerforums.com/vb/...shlight-Review

    You must either use Selfbuilt's comparative data, or test it yourself (even a free smartphone light meter app will be more accurate/objective than your own eyes). SB found here the D40A to run near 25% over its 4 hrs spec (almost 5hrs flatline), and while he hasn't tested the Fenix, I think we both noticed another Fenix (LD12) fell quite short of its spec claims, even extrapolating for the high capacity cells Fenix likes to test with. I have tested the D40A on its low and moonlight mode and believe them to be pretty conservative on their numbers.

  24. #144
    Enlightened
    Join Date
    Jan 2014
    Location
    Bristol, UK
    Posts
    50

    Default Re: Sunwayman D40A (XM-L2, 4xAA) Review: RUNTIMES, BEAMSHOTS, VIDEO + more

    Hi reppans, thanks for your reply. I thought i'd read somewhere on this forum that Fenix were fairly honest with their stated spec? That is, within the accepted margin for error, which if i understand correctly is 10%? Could the difference be something to do with Sunwayman designing their light to step down to Low a bit earlier in order to preserve some usability at 30lm, whereas, from my limited usage so far, the Fenix tends to max out the levels and then step down from Turbo to Low fairly quickly, although to be fair the light then runs on Low for approx 4 hours before the low battery warning (i have reviewed my experience with the LD41 in further detail on one of the relevant threads).

    I read Selfbuilt's review of the D40A and noticed the longer runtime in High mode, and hopefully mine will perform similarly when it arrives. In your own tests, when you say the stated spec is conservative are you agreeing with Selfbuilt re extended runtime or are you saying it delivered more lumens, or both? I would also be interested in approximately how long you can run the D40A at Turbo by repeatedly reselecting after step down before the light will no longer run in this mode.
    Last edited by froggyted; 01-25-2014 at 03:42 AM. Reason: corrected 'Low' to 'High' in para 1, sentence 1.

  25. #145
    Enlightened
    Join Date
    Jan 2014
    Location
    Bristol, UK
    Posts
    50

    Default Re: Sunwayman D40A (XM-L2, 4xAA) Review: RUNTIMES, BEAMSHOTS, VIDEO + more

    Post deleted.
    Last edited by froggyted; 01-20-2014 at 08:59 AM.

  26. #146
    Enlightened
    Join Date
    Jan 2014
    Location
    Bristol, UK
    Posts
    50

    Default Re: Sunwayman D40A (XM-L2, 4xAA) Review: RUNTIMES, BEAMSHOTS, VIDEO + more

    Quote Originally Posted by reppans View Post

    You can't really compare spec sheets like that, there's all sorts of conservatism, exaggeration, interpretation, and gaming going on between the different manufacturers and the ANSI rules are wide enough to drive a truck through - here's my favorite "ANSI" example, see output runtime graph on first post:

    http://www.candlepowerforums.com/vb/...shlight-Review
    That's dreadful! So after about 10 minutes it runs at 10%, which would actually be lower than the Low mode?! I would never knowingly buy a light from such a disingenuous manufacturer. Maglite are totally overhyped anyway, as are Lenser, who seem to adopt a similarly fluid policy to their specs.
    Last edited by froggyted; 01-20-2014 at 09:00 AM.

  27. #147
    Enlightened
    Join Date
    Jan 2014
    Location
    Puerto Rico
    Posts
    35

    Default Re: Sunwayman D40A (XM-L2, 4xAA) Review: RUNTIMES, BEAMSHOTS, VIDEO + more

    Quote Originally Posted by revscott View Post
    Doingoutdoor has the D40A for a much lower price. Free shipping also. I've never ordered from there and just wondering why it's so much cheaper than others that I have used before.
    Seems like it's just a temp promo, they even state as much (says promotional something or other right at the top)... In any case, I ordered one from them yesterday so I'm looking forward to it... Leap of faith based on having read posts from others ordering there without issue around last summer.

    Hasn't shipped yet tho, Illumination Supply and Fast Tech are definitely besting them in that regard, I placed different orders at all three places simultaneously... Got a ZL SC52 coming as well along with some other minor stuff. I bought the D40A as a larger/throwier alternative to the SC52 with longer runtimes at similar lumen...

    Not quite sure if I made the right choice since these are really the first two premium lights I've bought but we'll see. I expect I'll use the SC52 more often while the D40A will be the one I reach for when the power goes out during hurricane season or when I need light for a longer task...

    Got kinda paranoid it'd be too throwy for a lot of tasks so I already ordered a little silicon diffuser for it without even trying it out.

  28. #148

    Default Re: Sunwayman D40A (XM-L2, 4xAA) Review: RUNTIMES, BEAMSHOTS, VIDEO + more

    The Olight M22 diffuser works well for the D40a, and the choice of SC52 and D40a is what I would go for right now if I had to start out over again or trade in all but two of my lights. Very good choices.

  29. #149

    Default Re: Sunwayman D40A (XM-L2, 4xAA) Review: RUNTIMES, BEAMSHOTS, VIDEO + more

    The discussion here about ANSI specs and runtimes gets back to why it is so important to visually compare runtime graphs done under the same conditions and scales (preferably by an independent source).

    FYI, I discuss this on my website a bit further:

    http://flashlightreviews.ca/method.htm#Runtimes
    Full list of all my reviews: flashlightreviews.ca. Latest hobby: whiskyanalysis.com. New: Selfbuilt's MID-RANGE MYSTERY BOX Sale
    Gratefully accepting donations to my battery fund.

  30. #150
    Flashaholic Disciple's Avatar
    Join Date
    Dec 2004
    Location
    Oregon, USA
    Posts
    435

    Default Re: Sunwayman D40A (XM-L2, 4xAA) Review: RUNTIMES, BEAMSHOTS, VIDEO + more

    Quote Originally Posted by reppans View Post
    I'm not sure the cube root formula is correct. That would imply that 900 lumens appears only twice as bright as 100 lumens. I personally use the same formula, but in square root, since to my eyes 4x lumen increases feel 2x brighter. Technically though, I thought I read around here that the Stevens/Weber/Fechner brightness perception laws derived something around 3x lumen increase is ~ 2x perceived brightness. If that's where you were were getting your "cube" number from, then I think the formula should be (940/610)^(2/3) or something like that.
    I have read (here) that perceived brightness curves depend greatly on ambient illumination. The formula I used is based on the Wikipedia page for Stevens' Power Law, which lists: Brightness 0.33 5° target in dark. It may be preferable to ignore subjective (perceptual) brightness due to the ambiguity and look instead at the formula for throw which is a simple inverse-square relationship that matches your subjective appraisal.

Page 5 of 7 FirstFirst 1234567 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •