Alright don't laugh but I can't find a straight answer on this anywhere. I'm thinking of getting a new lens for my camera and I need to know if I get a 2.0x telephoto lens and my camera has 20x optical zoom. Will it double my optical zoom to 40x? Or will it just give me 2x more optical zoom?
Looking at your profile, I see that you use a Sony DSC-HX1. Not sure if there's an accessory that you can screw on your lens, but if there is a x2.0 magnifier you should be able to double the focal length to 40x.
Try to test it before buying it to avoid disappointments. Not sure what level of quality you can get out of such lens.
Quoted Message: Alright don`t laugh but I can`t find a straight answer on this anywhere. I`m thinking of getting a new lens for my camera and I need to know if I get a 2.0x telephoto lens and my camera has 20x optical zoom. Will it double my optical zoom to 40x? Or will it just give me 2x more optical zoom?
Neither. If it's a 2x teleconverter it will double your focal length, not your zoom. So for instance, if you had a 50-500mm lens (a 10x super-zoom for a DSLR) it would change those focal lengths to 100-1000mm, which is still "10x zoom".
I looked up your camera model, and this is what it says your focal lengths are without the conversion lens:
28-560mm equiv.(4:3), or 31-620mm equiv. (16:9)
That's what makes the 20x zoom (28mm x 20 = 560mm, or 31mm x 20 = 620mm).
If you add a 2x teleconverter lens, your equivalent focal lengths will then become:
56mm - 1120mm (4:3) or 62mm - 1240mm (16:9)
This is still a 20x zoom, but at a much tighter crop.
As Afagundes says, you will also lose light... with a DSLR a 2x teleconverter will lose you two stops of light. Not sure if you'll lose exactly the same light, but what this means is that your camera will have to shoot at a much slower shutter speed to obtain the same exposure.