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Hi all

Just thinking . . .

Why would somebody buy say, a 50mm lens when an 18-70 lens will cover that size lens?

I mean my next lens will probably be an 80-400 VR (the ever amazing Birddog let me have a play with his!) but I always thought that a lens with a range would be more versatile.

I figure that there is obviously a reason that I have no doubt I am about to find out.

thanks
Glenn

Any number of reasons.

The prime may be faster, sharper, lighter, smaller ....

And more expensive in comparison with zoom in the same range

G'day,

I'm certainly not very knowledgeable when it somes to photographic equipment, I still consider myself a newbie in that stuff, but for example...

I assume a prime (ie; non-zooming 50mm) can be built to specialise for its intended use, whereas I assume a zoom needs to be a compromise over it's zoom range... The 50mm F1.8 for example can be bought for less than $200, the F1.4 less than $400, but try to get a zoom over the 50mm range at that aperture range for that. The "kit lens" appears to be a very good example for a zoom lens but it starts at F3.5 (at 18mm) and goes to F5.6 (I think) at 70mm. The F-stop making the lens very "fast", good in low light, also very light etc...

Dunno if that helps, other more experienced guys will chip in...

Cheers,
Mudder

Hehe, Gary said in 4 words what I was going to say in 4 paragraphs

I'm still very much in newbie status, but to expand on what Gary said:

Faster: It's all about aperture,aperture and aperture. I just checked with my kit lens and it won't go below f4.5 at 50mm. Buying a prime lens (50mm,85mm, etc) allows you to let 3-4 times as much light in for a given shutter speed. This has two benefits, either you can shoot in much lower light without a flash or you can use that wide aperture to create a pretty out of focus background that portrait photographers get all moist and excited about

Sharper: Because the lens is set up for only one focal length, there are no comprimises made to allow for bits of glass moving about such as occurs in a zoom lens.

Lighter and Smaller: See above. That is, no need to allow for moving bits of glass and the different physical focal lengths they require.