Different results with different lenses...?

[shellb]

Why does a picture with an f5.6 look so different with my 55-200 than with my 18-50 lens...or is it just me?

[esther_a]

How are they different? Obviously the 55-200 zooms in closer, but I assume you're seeing other differences?

[audrey77]

Isn't the 18-50 lens a wide angle lens? What's the stats on the photos?

[LauraBean]

Zoom affects depth of field, so you'll have much less depth of field at 200mm than at 18 at the same f stop: Is that the kind of thing you're seeing?

[katrinak]

show us your examples Michele and we can help even more. Those are very different focal lengths so your field of view is going to change substantially.

[shellb]

I'm sorry guys... I was pretty vague. It's the depth of field like Laura described. I took a picture of my sister with my zoom lens and it was just amazing. She was crisp and everything else was blurry. When I use my 18-55 the center or clarity is so much smaller. Which makes me have to move up to f8 which means I need more light.

Taken at 180mm f5.6 (55-200)


Taken at 18mm f7.1 (18-55 lens)


The picture of Mr.Wiggles (the cat) has a really blurry forefront but it's at a higher f which goes against everything I've been studying? The focus was on his face.

Can anyone explain this or have a link to a description. I think it might be the key to what's holding me back with my technical understanding of my camera. Hopefully...
Thanks!

[katrinak]

This makes sense in my head, let's see if I can describe it. With your cat photo you have a foreground, mid and background present so you are going to blur the foreground given your focal point.

With your sister's photo you have no foreground since you are standing directly in front of her. Her entire body is in the same plane so it is all in focus. The cat, floor and background are all on different planes so you get a different focus with each.

Does that make sense?

[SAHMom]

To add to Laura & Katrina's explanations, your distance to your subject also effects DOF.

[shellb]

Thanks...that's really helpful. Thinking about it in terms of planes and distance from the subject makes a lot of sense. There is SO much to think about while taking a picture. It's crazy. At least I'm another step closer to understanding the big picture.

Thanks!

[Starlite9711]

This was informative thanks for asking Michele!!! And perfect explanation K.

[Debbyo]

I sure appreciate this question too, Thanks Katrina for such a clear explanation.