"Cool " Continuious Lighting questions

[kundalini]

I am in the market or at least considering some cool continuous lighting for a light tent intended for product photography. The primary product will be pottery that is highly reflective. I am looking at CFL (Compact Fluorescent Lights) that are set to 5500K.

The question is do I "need a bigger boat"? The bulbs I'm looking at are:
27 watt - 1600 Lumins @ 1m - Equivalent to 100w tungsten
45 watt - 2400 Lumins @ 1m - Equivalent to 150w tungsten
85 watt - 4800 Lumins @ 1m - Equivalent to 300w tungsten

These are meant to light a 28"x28" light tent. I'm just not sure how much is enough. The object to be photographed will range in size but not likely to exceed 20"x 15". I'll post an example after I get off the company computer and can get to photobucket. (Could be a little while as I still have to get a project out tonight...... )

Thanks for your help.

 

[AlexColeman]

I would say get a few of the lower power, so you have no shadows, and since Producht photos are on a tripod, exposure doesn't matter.

 

[kundalini]

and since Producht photos are on a tripod, exposure doesn't matter

Umm, okay, but I would still hazard a guess that exposure is part of the equation.


Okay, here are a couple of examples I have using the speedlights. The hotspot reflections are killing me. That's why after talking to someone about it, the suggestion for continuous light was brought up.

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Thanks again.​

 

[JerryPH]

The hot spots are not the result of the speedlight vs continuous lights but becuase your apparent light size is not big enough. If you swap out flash for continuous and the apparent size of the light is the same, it will give you the same hot spot. Those shadows tell me that this light is very harsh and far from diffused or "apparently large" to the subject.

Back the flashes a couple of inches further away and angle them up so that the diffused light bounces through the diffusion material at an angle and up into another white reflective material on the inside roof of your mini-softbox, thus making the light source as large and even as possible (if using a paper box, make sure the holes on the sides are as large as possible and that the light is as big or even slightly bigger than these openings), and crank up the power to something like a blistering 1/64th or 1/32nd power for F/4 level apertures, 1/32nd to 1/16th for F/8 or smaller apertures... and also no shadows, no hot spots if you do it right... this is assuming your method of diffusion causes both large and diffused light to hit the subject.

If necessary, place a plastic diffuser on the flashes to make the light larger, even and more diffused.

If continuous... well, the same principals apply, of course.

 

[KmH]

That top piece is a lighting nightmare. shudder.

I think you're going to wind up having to get creative with gobo's and flags.

 

[Don Kondra]

For an object that size-ish I would use 2 - 45w and possibly a 27w top or back light.

Having said that, now that I'm using strobes I've only kept the 85w lights, I just move them farther back when using the light tent.

I've even combined umbrella's with the light tent to eliminate/cut down on the hot spots. Chances are there will still be hot spots but you can at least place them where you want them

Cheers, Don

 

[kundalini]

I should clarify..... Those above were not shot with a light tent.

I had a flash on either side of camera at 1/8 power(I think) on stands pointing up to the ceiling (8' A.F.F.) at a reflector and another flash, hand held, pointing at the background trying to blister it at 1/4 power. Pretty sure I was at f/8 and shutter speed to meter zero in ambient light.

There was a great deal of ambient light pouring through four windows and I tried to minimize as best as I could, but it still had some affect.

Thanks for the link a week or so ago Don for Alzo. I like their tents and several other products.

 

[Don Kondra]

Glad I could help.

FYI - When shooting with continuous light I either wait for dark or cover the windows with cardboard.

If you are shooting with flash in manual mode at flash sync speed, the ambient light shouldn't matter.. I usually take a test picture just to be sure cuz it still amazes me

Cheers, Don