Zoom

[thunderkyss]

How do you figure your zoom, or if you have enough zoom?

Say you know most of your shots are going to require zoom.. a softball game, a dance recital, clandestine private eye work.

How do you compare the zoom (magnification) of one lens vs another?

 

[Gaerek]

I guess I don't really understand the question. Focal length (which I believe you are calling zoom) is measured in millimeters (mm). The more mm the closer your subject appears. The less mm, the farther away your subject appears.

If you have one lens that is 200mm and another that is 300mm, the 300mm lens will make your subject appear closer than the 200mm. Thats how we can compare the focal length of lenses.

Zoom just refers to a lens that has an adjustable focal length. Focal length, I think, is the word/phrase you were looking for.

If I missed the mark here, let me know and I'll see if I can explain better.

 

[KmH]

How do you figure your zoom, or if you have enough zoom?

Say you know most of your shots are going to require zoom.. a softball game, a dance recital, clandestine private eye work.

How do you compare the zoom (magnification) of one lens vs another?

Lets use the word reach, where you refer to zoom.

Or, another way to think about it is telephoto or magnification.

The longer the focal length, generally the higher the magnification/reach/telephoto effect. However, you can have a long focal length lens that is not a telephoto.

The apparent focal length of a lens is affected by the image sensor size and the spacing from the rer lens element to the focal plane.

As an example Nikon dSLR's using an APS-C size(DX) image sensor have a 1.5x crop factor. If a 200 mm focal length is used (zoomed to or fixed) the image on the sensor will have the same field-of-view as a 300 mm lens (200mm x 1.5 = 300 mm)on a full frame sized image sensor of any brand (Nikon FX).

Canon APS-C sized sensors are slightly smaller than Nikon APS-C sensors and have a 1.6x crop factor. Cameras using 4/3 image sensors, which are smaller still, have a 2x crop factor.

Professional sports shooters typically use 400 mm lenses on full frame sensored camera bodies for field sports like football, soccer, and baseball. However, they also usually have a second camera body ready with a shorter focal length lens so they are ready for closer in action.

A 200 mm to 400 mm zoom lens: http://www.bhphotovideo.com/c/product/300488-USA/Nikon_2146_200_400mm_f_4_G_AFS_ED_IF.html

A 70-300 mm zoom lens: http://www.bhphotovideo.com/c/product/449088-USA/Nikon_2161_AF_S_VR_Zoom_Nikkor.html

A 400 mm telephoto lens w/no zoom: http://www.bhphotovideo.com/c/product/520639-USA/Nikon_2171_AF_S_Nikkor_400mm_f_2_8G.html

 

[thunderkyss]

So, what would be the equivalent of a P&S camera's 3x zoom, or 4x zoom?

Let's say I was looking at a 200mm lens, what would be the equivalent magnification?

 

[prodigy2k7]

So, what would be the equivalent of a P&S camera's 3x zoom, or 4x zoom?

Let's say I was looking at a 200mm lens, what would be the equivalent magnification?

The "3x" or 4x" is just to tell you how wide the range the zoom is, there is no equivalent.

100-400mm = 4x lens
10-40mm = 4x lens

Lots of "superzoom" point and shoots go from pretty wide to pretty long focal lengths.

Canon PowerShot SX30 IS has a 24-840mm focal length lens and is named a "35x" zoom.

840 / 24 = 35

 

[Derrel]

When the lens gets really long, and really heavy, and a real pain in the butt to carry, then you know you have enough zoom.

 

[thunderkyss]

When the lens gets really long, and really heavy, and a real pain in the butt to carry, then you know you have enough zoom.

That sounds like too much zoom.

 

[Whootsinator]

When the lens gets really long, and really heavy, and a real pain in the butt to carry, then you know you have enough zoom.

That sounds like too much zoom.

Depends on how far away the Russian ICBM launch sites that you're trying observing are.

 

[KmH]

When the lens gets really long, and really heavy, and a real pain in the butt to carry, then you know you have enough zoom.

That sounds like too much zoom.

Nah!

 

[SrBiscuit]

^ right amount of zoooom

 

[Whootsinator]

If there was ever a lens that could end a focal length pissing match, I do believe you've found it.

 

[SrBiscuit]

nope.

wheres the "bigma"?

edit* here it is