Photo box problems

[Dave Humphries]

This is an interesting idea Pops,

I think whether it is relevant may depend upon where in the world Missnibbles is, or more specifically, what her line voltage is; 110v or 220/230v.

I am going to discuss the technicalities with a colleague tomorrow, but it potentially throws up a difference between how fluorescents work on those two line voltage bands - not something I had ever considered before and I'm an ex-engineer - "ex" because I do web things these days

Thanks for a stimulating idea,

[Colin Southern]

I'm wondering what happened to her - one minute we were posting almost "real time" and then ... gone. Hope she's OK.

The pics were interesting - I thought that the colour temp would be consistent, but it appeared to vary over quite a range - and yet ironically, tungsten seemed the "closest fit".

[PopsPhotos]

I've noticed before that the tungsten setting is better when using "daylight" or "full-spectrum" fluorescents. It makes sense, but is not intuitive.

I'm in the process of writing a lesson plan for my photography class covering temperature ranges for light. Because this class is for 4 through 6 grades, I have to simplify a lot. I figure, if I can understand it, a fourth-grader should be able to get it.

Pops

[PopsPhotos]

I think whether it is relevant may depend upon where in the world Missnibbles is, or more specifically, what her line voltage is; 110v or 220/230v.

I don't think there will be a difference created by line voltage. The difference will be the line frequency. At 60Hz, the lamp is off 30 times per second and on 30 times per second. Thus, 1/30th exposure can trigger during the off period at one shot and during the on period at another shot. At 50 Hz,, 1/25th shutter speed is sync-possible. Adjusting shutter speed to half the off cycle rate (1/15 for 60 Hz) will counter this effect.

Incandescents don't display this phenomenon because they glow during both halves of the cycle.

I wonder if using the camera's TTL detection for admitted light would keep the shutter open through a full cycle.

Pops

[Colin Southern]

I'm in the process of writing a lesson plan for my photography class covering temperature ranges for light. Because this class is for 4 through 6 grades, I have to simplify a lot. I figure, if I can understand it, a fourth-grader should be able to get it.

It reminds me of the father who sits his son down and says "Son - it's time for us to have a little chat about the 'birds and the bees'" - son answers "sure Dad - what would you like to know?"!