TC-E15ED or generic equivalent? plus telephoto focal length question

[Odysseus]

Hello.

I have a generic telephoto boasting 2x tele but the more expensive and supposed better quality Nikon TC-E15ED telephoto only boasts 1.5x tele. Doesn't seem right to me so I ask:

If any of you guys are an owner of Nikon's TC-E15ED telephoto lens which claims 420 mm or an equivalent I am curious what kind of sample photos you may have to help me in my decision to purchase one.

And: Does anyone have a clue about the focal length of a generic telephoto lens that claims 2x telephoto? I have one, see signature, and if I am correct it provides a focal length two times the length of my present lens fitted to the Nikon CP 8700. Is that correct? The focal range of the CP 8700 lens is 8.9 - 71.2 mm, which is equivalent to 35 - 280 mm...meaning that a 2x telephoto lens should in theory double that? Thus a focal length equivalent to 560 mm?

That sounds pretty nice but the telephoto quality my generic 2x tele produces is nowhere near that of a $1,000+/- 400mm telephoto I could buy for a DSLR.

Where am I misunderstanding? Thanks for setting me straight. :D

[britkev]

A 2x does indeed convert the standard lens to a 560mm equivalent, but you get nothing for nothing in this world, and apart from the $$, you also pay 2 full f/stops for a 2x teleconverter... at full zoom the 8700 lens is f/4.2... screw on the TC and you suddenly have f/8.4. In all but the brightest sunshine you are either going to be dealing with a shutter speed too slow for that length of lens, leading to blurring caused by camera shake, or else you have to deal with the horrible noise levels of ISO800.

I had the TC-15ED with my 8700, but hardly ever used it, partly because of the reasons above, but mostly because of the complete loss of flexibility: it is, of course, only useable with the lens fully zoomed, so as soon as you want anything a little bit wider you have to unscrew it and pack it away, by which time you have usually missed the shot anyway.

You weren't seriously expecting a ~$100 add-on to a $600 point-and-shoot camera to give you as good results as a ~$1,000 lens on a $1,000 body, were you?