2x telephoto lense converter/light question

[troop]

Ok, I'm pondering buying a 58mm 2x telephoto lense converter for my S6000. I'm assuming light won't be a problem outdoors BUT how much light do these things cut down indoors ? Is it a drastic amount ? Not a terrible expense but still some $$ if it won't be a convenience to have. Input please ? Thx, troop

[timmciglobal]

You can't use them indoors.

You can barly use them outdoors.

The quality and the light fstop is big (3 stops usuaully on crappy 2x)

Tim

[mattdm]

As I understand it, there's nothing magical about the loss of light. Each full stop, at 1.4x the previous one, lets in 1/2 the amount of light. A 1.4x teleconverter "costs" you one stop, a 2x teleconverter 2 stops, and a 3x teleconverter more than 3 stops. Not coincidentally, the effective new number can be calculated simply by multiplying the f/stop of the lens by the multiplication factor of the teleconverter.

(Which makes total sense when you think about it: the f/stop aperture numbers are calculated by dividing focal length by aperture diameter. Double the effective focal length, and this result naturally doubles.)

[Sintares]

Umm, I thought front mounted tcons for non dslrs, didn't cost light ?

[mattdm]

I'm pretty sure the logic above still applies. Think of it this way: you're getting an effectively longer lens, but not correspondingly gaining the ability to physically open the aperture wider.

[Razr]

Umm, I thought front mounted tcons for non dslrs, didn't cost light ?Absolutely correct when front mounted on a P&S.

[Sintares]

Got an excellent answer to the question of light loss and point and shoots over at the dpreview forums.

http://forums.dpreview.com/forums/readflat.asp?forum=1018&message=21122721