Pop-up flash booster

This looks an interesting bit of kit for $35- only works with lenses longer than 10mm though.

link

This does look good - I took from the link though that it is designed to work at 100mm and above - presumably by narrowing the beam and projecting it at a narrower field of view it concentrates the power, giving you more distance and / or power. Of course, it only mentions the other camera brands, , but I can't see why it wouldn't go onto a Pentax DSLR?

I meant to wtite 100mm.....missed a zero out.

The blurb days it works on most Dslr's, I would imagine it will work on a Pentax.

looks okay but when would u use it...

When you need more distance or power from the built-in flash.

the only issue I can see with putting it on a Pentax is going to be physically attaching it, the pop-up flash/pentaprism housing is probably a different shape which might make matters difficult, or might not be an issue at all, deppending on how the mounting works.

"8x more power" - total poppycock!

All it is, is a lens to narrow the beam angle - exactly the same as the lenses that attached to the Pentax AF400. As for the size, properly engineered it would be a lot smaller than that monstrosity.

It is possible isn't it? I mean, the '8x' extra power would only apply to the narrow field of view area covered by the long zoom - ie 8x more power at that distance for that particular narrow field of view than you would get at that exact spot without any narrowing of the beam.

This is the same principle with flash head zooms - they 'zoom' to reduce the beam coverage to match the field of view of the long lens, and you don't need as much power then for correct flash illumination - recycle times are shorter and batteries last longer. Assuming that the built-in unit will fire at full power it is possible that the effects of concentrating the beam in such a way would be equivilent to '8x' the total power, is is not?