question about 1.7x telephoto converter

[dionx]

So I have the Sony H9 super-zoom camera, which has 15X optical zoom. If I buy the 1.7x telephoto converter, does that mean I will get 25.5X optical zoom?

Is it just as simple as 15X * 1.7X = 25.5X or is there more to it? Thanks.

 

[fuzzybabybunny]

Technically you will still have the same zoom. "Zoom" is an all too common misunderstanding for people unfamiliar with cameras. If you look on the front of your H9 on the lens barrel you'll see "2,7-4,5/5,2-78"

The commas are supposed to be periods, so 2.7 - 4.5 / 5.2 - 78. The 2.7 - 4.5 are your maximum aperture values at 5.2mm and 78mm, respectively. They should be written as f/2.7 and f/4.5. The 5.2 - 78mm is your lens' focal length range, which determines how close or far you can make something appear. This lens is a 5.2 - 78mm zoom lens. A smaller focal length number corresponds to more of a wideangle. A larger focal length number corresponds to more of a telephoto. The 15x is simply 78mm / 5.2mm, or the zoom factor from wideangle to telephoto.

If you add a 1.7x telephoto converter (TC) your focal length range will become 8.84mm - 132.6mm (5.2 x 1.7 and 78 x 1.7). Note that this is still a 15x zoom (132.6 / 8.84 = 15). The difference though is that now your focal length has been increased by a factor of 1.7x, meaning your lens has become more of a telephoto, and can make things appear closer by a factor of 1.7x. So you've gained more reach with your telephoto end but you've lost some of the wideness of your wide end.

Also note that this 1.7x TC will make your maximum aperture smaller, effectively making it harder for your lens to gather sufficient light for a good photo. The f/2.7 - f/4.5 will now be f/4.59 and f/7.65 (larger f-values mean smaller aperture sizes)

All this is probably very confusing to you. It would make more sense if you started out by learning what aperture and focal length really are.

 

[Throckmorton]

Yes, it will be 25.5x

 

[seanc85]

Originally posted by: fuzzybabybunny
Technically you will still have the same zoom. "Zoom" is an all too common misunderstanding for people unfamiliar with cameras. If you look on the front of your H9 on the lens barrel you'll see "2,7-4,5/5,2-78"

The commas are supposed to be periods, so 2.7 - 4.5 / 5.2 - 78. The 2.7 - 4.5 are your maximum aperture values at 5.2mm and 78mm, respectively. They should be written as f/2.7 and f/4.5. The 5.2 - 78mm is your lens' focal length range, which determines how close or far you can make something appear. This lens is a 5.2 - 78mm zoom lens. A smaller focal length number corresponds to more of a wideangle. A larger focal length number corresponds to more of a telephoto. The 15x is simply 78mm / 5.2mm, or the zoom factor from wideangle to telephoto.

If you add a 1.7x telephoto converter (TC) your focal length range will become 8.84mm - 132.6mm (5.2 x 1.7 and 78 x 1.7). Note that this is still a 15x zoom (132.6 / 8.84 = 15). The difference though is that now your focal length has been increased by a factor of 1.7x, meaning your lens has become more of a telephoto, and can make things appear closer by a factor of 1.7x. So you've gained more reach with your telephoto end but you've lost some of the wideness of your wide end.

Also note that this 1.7x TC will make your maximum aperture smaller, effectively making it harder for your lens to gather sufficient light for a good photo. The f/2.7 - f/4.5 will now be f/4.59 and f/7.65 (larger f-values mean smaller aperture sizes)

All this is probably very confusing to you. It would make more sense if you started out by learning what aperture and focal length really are.

Very well said. really not much i can add

the 15x is basically a ratio of your maximum and minimum zoom, it doesn't specify a set mm focal length

 

[Aharami]

fbb, you're like a photography encyclopedia! Great explanation. Technically it is sound, but I can see what the OP is saying. Yes, the zoom # can be quite deceiving as a camera with 28mm WA and 18x zoom will equally magnify a distant object as a camera with 36mm WA and 14x zoom (both 504mm tele). But I can assure you that the public will think that the 18x camera will zoom more than than the 14x one. So people really consider zoom to be the reach of the camera from the photographer (not from the camera's wide angle). Also I doubt people shoot at WA with a tele converter lens on. So in a sense, OP is correct that his zoom (layman's term) will be 25.5x while, technically, as you pointed out, it will not.

 

[fuzzybabybunny]

Originally posted by: Aharami
fbb, you're like a photography encyclopedia! Great explanation. Technically it is sound, but I can see what the OP is saying. Yes, the zoom # can be quite deceiving as a camera with 28mm WA and 18x zoom will equally magnify a distant object as a camera with 36mm WA and 14x zoom (both 504mm tele). But I can assure you that the public will think that the 18x camera will zoom more than than the 14x one. So people really consider zoom to be the reach of the camera from the photographer (not from the camera's wide angle). Also I doubt people shoot at WA with a tele converter lens on. So in a sense, OP is correct that his zoom (layman's term) will be 25.5x while, technically, as you pointed out, it will not.

Yup yup, back in the day I was confused with what zoom meant as well. I was kind of a binocular nut and if you look at how binoculars rate their "telephoto-ness" you'll see that they just use "zoom." It is really quite strange.

For a binocular that doesn't even zoom (a prime in photography terms), it'll be rated at something like 8x25 or 10x40. The 8x and 10x are the binocular equivalents of lens focal lengths. A 10x is more of a telephoto than a 8x.

To make things really weird, those binoculars that actually did zoom were still rating by this system. For example, you'd see zooming binoculars as 8-24x zooms. When I applied this binocular terminology to cameras I got confused.