Is Flourescent flickering caused by the bulb or fixture?

J

Jackson Miller

Well-known member
So I am considering various kinds of flourescent fixtures (not the kino flow type bulbs, the cfl and big cfl shaped ones), and was wondering if I would experience more flickering depending on the fixture/ For example, the socket fixture things I used for china balls from home depot were super cheap and I experienced no noticeable flickering. I assume then that I would be ok ordering one of these cheap folding softbox fixtures:
http://www.cowboystudio.com/product/c09/p0907-31.php and would experience no more flickering than if I used one of the cool lights fixtures like this:
http://www.coollights.biz/clsft1p-speed-softbox-5600k-stand-p-134.html

I am assuming then that it is the bulb quality that determines flickering because cfl's have build in ballasts?

My only confusion is that I saw a review of various cheap kino flo like lights and some flickered while others didn't which they used as a basis to say which lights were good and bad. Couldn't you just buy better bulbs and have a flicker free kino flow type bulb or do kino flo bulb ballasts work differently? Finally, how can I make sure I am getting high quality bulbs? Is it worth the extra price over just buying the 30W and 108W cfls at home depot?
 
The flickering in all cases is caused by the ballast not having a high enough output driving frequency. If the ballast is in the bulb itself (self-ballasted bulb) then from a certain point of view you could say the bulb was flickering (but its still the ballast). If the fixture contains the ballast, and if there is a flickering effect, then it would be the fixture causing the flickering. The actual fluorescent bulb itself in either case isn't the cause ever for flickering.
 
Since I'm looking into DIY lighting, I've looked at the instore offering from Home Depot, and for the most part, the options are pretty poor. The bulbs are put out on the floor in terms of 'tungsten' wattage, which for the most part can actually vary from the nominal 1700 lumen (approx) output of a 'real(tm)' 100 W tungsten bulb. Then there's the color of the light given off, and the CRI, which often is either not stated, or buried in fine print on the package... typically around 80 or so.

Since I'm thinking about presenting in B&W, I'm not worried about certain types of color shifts due to lower CRI, but the recommendation seems to be for bulbs that have at least 90+.

From the data on the Cool Lights bulb in the package you referenced, it seems that it is a CRI 90 bulb with an output of '600 - 700' W Tungsten equivalent... damn why not just state lumen output... and lists as 'flicker free'.

You will not get even that clear a spec from the Home Depot version...

At that point testing is the only reasonable approach.

Home Depot (or most other bulb retailers) typically don't have any clue about what frequency the 'ballast' is running at. And even going to a more industrial distributor doesn't get you any more information on this sort of thing.
 
The lumens on our 200w bulb will be about 10000. I imagine the specs aren't clear on many commercial bulbs because the customers don't care or know about CRI in most cases.
 
Thanks guys.

Richard - I love how you are super helpful and never seem to push people towards choosing cool lights over other manufacturers. I think I am going to get one of your 650 fresnels.
 
Cool Lights said:
The lumens on our 200w bulb will be about 10000. I imagine the specs aren't clear on many commercial bulbs because the customers don't care or know about CRI in most cases.
Click to expand...

The question I'd have then, is the 'heat' generated by your 200W approximately the same as a 250w Halogen? The 250 W Halogen is what my strobes use as a 'finder' light, and I've been wanting to make a fixture
for my Photoflex softboxes to use continuous light. Because they are 'strobe' softboxes, they not designed for the heat of 'real' high wattage lamps. The Halogen is a 15mm bayonet base type, and is set in the middle
of the flash tube housing.

Because the Halogen seems to be from various specs to be about 5000 lumens, and a low 3000 K. So with your 200W at 10000 and higher K, it seems that would be worth it.
 
The heat of a 250w halogen should be much higher than the 200w bulb. It probably would be interesting to see what the real difference is in terms of heat generation. My guess is quite a bit. You can still touch the bulb and its base of the 200w unit. Its not comfortable but you can touch it and part of the issue will be the size of the 200w bulb and how it efficiently radiates whatever heat its generating over a larger area than the 250w bulb. As I recall, you can't really get all that close to the 250w halogen and there is also the issue of infrared as well--that's why tungsten is such an efficient heater element.
 
Cool Lights said:
The heat of a 250w halogen should be much higher than the 200w bulb. It probably would be interesting to see what the real difference is in terms of heat generation.
Click to expand...

Then I'll look into ordering one when I get my fixture made. The halogen bulbs are a hassle, and incredibly hot when one is breaking the setup down... and even when cold, replacing them required not touching
the glass to avoid leaving any oil (my skin is an untapped oil resource...) that could cause problems later...
 
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