how to imagine zoom lengths

Hi, I'm in between selecting the ES-F 18-85 Canon or the 18-200 DC Sigma.

But not sure if I need so much zoom , especially as I dont have a tripod.

Does anyone have some zoom comparison?

Simon

One thing to remember about zoom quality. All else being equal, the greater the zoom ratio (max focal length divided by shortest focal length), the worse the image quality.

The reason is that so many compromises in design need to be incorporated to get the greater zoom ratios.

If you look at all the "pro" quality zooms, they seldom have a zoom ratio greater than 3:1. For example: 16-35, 24-70, 70-200, etc.

There are a few lenses that seem to be decent and still have longer zoom ratios. One example that I read about but have not tried is the Sigma 50-500. I would doubt that many zooms with a 10:1 ratio are very good when compared to the pro level zooms or fixed focal length lenses ("primes").

When choosing an array of lenses, I usually avoid a lot of overlap in the focal lengths. For example, you already have the 18-85. Look at a 70-200 to go longer. You'll likely get better quality in choosing that way.

I don't know if this helps or not....

There is a very convenient way to experiment with different focal lengths!
Just get some cardboard or whatever and cut a 23x15mm rectangle out of it (this is the size of the camera sensor)
Now hold it in front of one eye and move it forward and back until it gives you the framing you want.The distance from your eye is the focal length you need.Easy huh?!

Actually one doesn't need the cardboard -one can even use fingers held to about the right shape
Just be a little carefull when judging shorter focal lengths as they are easier to get wrong.