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300mm = 10x ???

PostPosted: Fri Jul 01, 2005 10:24 am
by Chazman1981
HI
i have a basic question cause i am deciding on get a spotting scope to attach to the D70 or just a way bigger lens. but what i wanna know is.

the spotting scope say the are 40x zoom so is that the same as a 1200mm lens?

does it measure like this

300mm = 10x

600mm = 20x

900mm = 30x

1200mm = 40x

and so on


the reason why i ask is cause i have seen some spotting scopes that are rated at 40x zoom which is alot a lens rated at 2600mm so if i m right that would be equal to like a 85x zoom???

Cheers :roll:

PostPosted: Fri Jul 01, 2005 10:43 am
by wile_E
Hi Chazman, I'm sure you're going to get a more educated answer than the one I'm about to provide...

From my understanding a 10x lens (on a P&S) is basically stating the zoom factor of a lens. So it could mean a lens of 12-120mm or a 30-300mm lens.

I'm pretty sure thats the explaination...

PostPosted: Fri Jul 01, 2005 11:25 am
by Glen
Chazman, Wile E is correct, plus a little more. First of all this X times stuff is all marketing crap, means very little unless in context. There are two ways of using the X crap:

1)As Wile E said as a multiplication factor of the widest the zoom is capable of to get to the longest a zoom is capable of. As can be seen in Wile E example they are both 10X zooms, but if you wish to look at items far away, only one is useful. You can see the zoom factor means nothing, you cant tell anything from it in this example.

2)In film cameras a 50mm lens was considered normal view, so sometimes a 500mm lens was described as 10 X. This is not often used these days.

As can be seen above, these numbers mean little, just get the real number in mm, eg 300mm, 600mm.

I can see you are interested in long lenses, just for your reference they are expensive and the average person finds it hard to afford over 400mm in a quality lens. A Nikon 80-400 retails at about $3k, a second hand manual 500mm lens is about $2.5K, a new auto focus 500mm is about $11k, new af 600mm is $14k. These are quality Nikon lenses and often you get what you pay for. The 500-1200mm zooms on ebay for $300 may not deliver the same quality as the above lenses :wink:

PostPosted: Fri Jul 01, 2005 11:36 am
by Glen
ps Chazman, if you after long lenses, do bit of a search around here, things such as the 500mm mirror lens are cheaper and may suit. Feel free to ask an opinion before you purchase, most are friendly here and better to find out before rather than after if something is crap