Pixapro/Glow 70 degree Magnum reflector vs standard 7 inch reflector

Started 1 month ago | User reviews thread
OP Scrollop Contributing Member • Posts: 768
Re: Pixapro/Glow 70 degree Magnum reflector vs standard 7 inch reflector

ronscuba wrote:

You mentioned the magnum is more tightly focused. Is that really true or is the darker background a result of the magnum being more efficient ?

I used a light meter at the right eye with half-bulb down, pointed at the bulb.

Thus, If you compare the shots taken at 75 cm from bulb to head, I assume that we're nulling the efficiency of the modifiers by metering to the same exposure at the eye (though I may be wrong and confused!).

So then we can (perhaps) compare light fall off without confounding the comparison with differing light efficiencies (maybe this is wrong).

Also, if you compare the shots taken with diffusion sock and without, the shots without diffusion are quite tightl (as though a grid were being used), whilst with the sock on, almost the entire frame is well lit.

I assume this is because the scalloped interior of the Magnum focuses light forward more (on a youtube video by Profoto on their channel they say the interior is essentially tiny mirrors bouncing light forward - is it true?) (similar to a parabolic relflector?), and the greater depth ensure there are less stray light rays escaping off too much of an angle.

Add a thickish sock, and these somewhat parralel rays refract (is that the correct term for light passing through a diffusion material?) in all directions, leading to a final light fall off picture similar to the standard reflector.

Perhaps someone with more knowledge of light mechanics can comment.

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