wiring lighting inside a valance

[Chris333]

I was ready to use LEDs fr a small shelf layout, but in the end it was a ton cheaper to just get a shop light for $10 and use daylight bulbs. Maybe someday the LEDs will be cheaper.

[DKS]

I do know what David is referring to - Tony forwarded an e-mail from an MRP reader showing a pen standing on end with about eight shadows radiating out from it which had been taken under LED lighting.  I was unable to replicate the effect under my lights.

Here's a couple more examples that are more obvious under my lights.





In some cases it's not noticeable, but in others it becomes a bit of an issue, especially for those of us who do close-up or macro photography. Also, don't forget that, even though the LEDs might have 100-degree dispersion across the axis of the lamp, fluorescent fixtures have essentially 360-degree dispersion that is also completely consistent in brightness; this provides a substantial amount of diffuse fill lighting that helps quite a bit with shadows and also illuminates backdrops more evenly (I had to dedicate two LED bars to light just my backdrop, else the falloff was too obvious--that added cost hurt).

Regarding colour, you have to experiment a bit to find a colour temperature which works for you.  I eventually settled on 3500K; 4100K seemd a bit harsh to me.

The problem with LEDs goes beyond the quoted color temperature; LED specs often refer to it as the "dominant wavelength." LED spectra are pretty wonky overall, and often include IR and UV components that can't be seen but show up in photos (blue LEDs have a considerable UV component, and since white LEDs are based on blues, that component is likely prevalent in most of them).

My LEDs are approximately the same color temperature as the fluorescent fixtures they replaced (loosely called "warm white"), but certain materials wind up photographing very differently. This is because of the specific spectrum and how certain paints and dyes react to it. LED technology is yet to achieve the same kind of spectral control as fluorescent lighting, which has been well-characterized and very finely-tuned for quite a long time.

For instance, here's what the LEDs did to my trees. Before, under fluorescents:



After, under LEDs:



To my eye everything looks the same under either type of lighting, which, ironically, isn't like either image; what I see is actually closer to this:



...which was shot with a different camera (revealing the unique and slightly capricious behavior of camera sensors). One could assume the white balance was wrong in one or both of the first two images, but it was correct, and my attempts to fix the greens in Photoshop were met with failure because the white balance was already correct; correcting for just the trees threw everything else off, and it became a small Photoshop nightmare. I finally had to spray the trees with a dye that compensated for the LEDs.

For most folks, this might not be a big deal, but knowing Tom's propensity for tightly-controlled photography, I could see both the point-source and color temperature issues looming large for him.

One last comment about cost. I don't know what the lifetime of Tom's layout would be, but I would place bets that he could purchase several complete sets of fluorescent lights for the cost of the LEDs at this point in time. Don't forget that it takes several LED light bars to match the light output of one fluorescent fixture, so a $12 shop light is probably equivalent to maybe four (?) LED bars, and that $80 would buy a heck of a lot of complete replacement shop lights (often cheaper than buying parts like ballast).

I'm not putting down LED technology summarily; it's right for some modelers given their circumstances and their budgets. It's just not an option for everybody yet; the technology still has quite a ways to go before it could be considered truly competitive, and the energy savings per lumen versus fluorescents are far too minimal to compensate for the huge cost difference. I'm still kicking myself for making the switch prematurely because I got hooked on what I thought it was a good idea. It wasn't, not just yet.

[GaryHinshaw]

One more vote for lumens.  Color perception is not only a function of source spectrum, but also of total brightness.  Try to pack as many lumens per watt (and dollar) as you can muster.  You'll perceive detail much better under bright lighting too.

[DKS]

One more vote for lumens.  Color perception is not only a function of source spectrum, but also of total brightness.  Try to pack as many lumens per watt (and dollar) as you can muster.  You'll perceive detail much better under bright lighting too.

Totally agree. And one reason I wound up spending such an obscene amount of money on lighting a tiny shelf layout.

[Sokramiketes]

One of my hats includes street light maintenance here, and that industry is pushing so, so hard for LED street light heads.  We've only tested a few, and they were like spotlights and didn't have enough throw to the sides.  Manufacturers are starting to claim better distribution now, with lenses on each separate LED.  But I haven't been impressed yet.  We've also tried some replacement LED bulbs for interior fixtures... the cheap ones burn out quickly, the expensive ones arn't worth the cost. 

I have been impressed by some of our induction lighting tests though.  Picture a flourescent fixture, but with magnetic induction instead of an electronic starter.  10 year warranty instead of LED's 5 years.  Just about the same energy savings. 

[Nelson]

Current affordable LED technology has some real limitations when it comes to lighting, but Organic LED's show a lot of promise. More even lighting (think luminescent panel), better color spectrum, low energy, etc..
Unfortunately it is probably at least 5 years away from affordability, but the push to develop them for more energy efficient big screen TVs is on and that may speed their development.

Nelson

[tom mann]

David, note that Tim has three strips of LEDs - maybe they cancel each other out shadow wise.

If I also need three strips of LEDs, I'm looking at $49 x 3 every 2 feet 

The funny thing is that I don't really want lighting above the layout.  I'm happy with a single light source in the room to replicate sunset.  Above all times of day, I enjoy photography at sunset the most of all.  But I have to admit that a valance makes the layout look more like a permanent fixture in the room, and therefore necessary for look I'm after.

[DKS]

David, note that Tim has three strips of LEDs - maybe they cancel each other out shadow wise.

I have four rows of LED fixtures; each fixture is 18 in. long, and I have two sets of four, end-to-end. Each fixture has 5 ultra-high-brightness LEDs, which are actually clusters of 6 emitters in high-density packages, for a total of 30 LEDs for each fixture, x 8 fixtures, grand total of 240 LEDs. It's just about bright enough for a 15 x 36-inch layout; I'd prefer it to be a bit brighter, but my wallet can't afford another lumen for the layout.

By the way, here's an example of the curious things that happen to shiny objects under LEDs: