# Thread: how to calculate the number of times a zoom is?

1. ## how to calculate the number of times a zoom is?

how to many the zoom in mm to the "x" one?

eg, what is 12x zoom equivalent to? 12x = 300mm??

actually, how to calculate one?

2. take the most tele end of the zoom divide by the the widest end.

55-200mm = 200/55 = 3.63 zoom

35-350mm = 350/35 = 10 zoom

28-135mm = 135/28 = 4.8 zoom

3. Originally Posted by Paul_Yeo
how to many the zoom in mm to the "x" one?

eg, what is 12x zoom equivalent to? 12x = 300mm??

actually, how to calculate one?
depends on the widest angle. there's no fixed value for cameras.

it's different for binoculars where the base is 50mm.

4. Originally Posted by Paul_Yeo
how to many the zoom in mm to the "x" one?

eg, what is 12x zoom equivalent to? 12x = 300mm??

actually, how to calculate one?
Use your longest end and divide by the widest end .... for example .... 28 - 300 = 300 / 28 = 10.7 = 11x

5. OK got it! thanks

so my lens is
24-120 => 120/24 = 5x zoom
70-300mm => 300/70 = 4.2X zoom

6. Originally Posted by Paul_Yeo
OK got it! thanks

so my lens is
24-120 => 120/24 = 5x zoom
70-300mm => 300/70 = 4.2X zoom
Yeah, but pretty useless to calculate in zoom factor.

Your 70-300 is longer reach than your 24-120VR and yet it's only 4.2x vs 5x.

7. I have a couple of 1x zoom..

8. Originally Posted by majere2sg
I have a couple of 1x zoom..
Hahaha....
But u should be the richest.

9. Originally Posted by Paul_Yeo
OK got it! thanks

so my lens is
24-120 => 120/24 = 5x zoom
70-300mm => 300/70 = 4.2X zoom
As ESPN says, for SLR lenses, is a pretty useless measure. More relevant to talk about focal lengths.

10. so, it is more for compact camera huh.

i asked bcos i saw one Panasonic camera got 12x zoom.... that;s why me asked what's the "mm" equvialent loh.

11. Originally Posted by Paul_Yeo
so, it is more for compact camera huh.

i asked bcos i saw one Panasonic camera got 12x zoom.... that;s why me asked what's the "mm" equvialent loh.
if you meant the panasonic fz20, its a 36-432mm lens (35mm equiv) lens. It is actually only 6-72mm but can achieved 36-432mm (35mm equiv) due to the 6x cropping from a smaller sensor size.

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