DOF problems

a5i736 · Mar 19, 2007

idk try backing up and zooming in more.

rebecca the curious · Mar 19, 2007

can the f/2.8 lenses also function as good "walk around" lenses like the 18-200 f/3.5-6.3? the reason i'm asking is because i really like taking portraits using telephoto zoom, but i'd also like a lens that is useful for other purposes like scenery, action, etc. thanks.

Big Mike · Mar 19, 2007

An F2.8 lenses can do anything that an F3.5-6.3 lens can do...and do it better. Those are just the maximum apertures...the faster (F2.8) lens just gives you the option of using a larger aperture if you want or need it. It's like the difference between a Honda and a Porsche, they can both get you from A to B...but the Porsche can get you there faster, if you want it to. Given the choice, we would always choose the faster lens...but we have to consider cost and weight as well.

As for the type of shooting you will be doing, you also have to consider the focal length (the amount of zoom). The 18-200 has a wide range of focal length but an F2.8 zoom will not have as much range. It should be noted that usually the more range a lens has, the worse the image quality is.

xfloggingkylex · Mar 19, 2007

Big Mike said:
An F2.8 lenses can do anything that an F3.5-6.3 lens can do...and do it better. Those are just the maximum apertures...the faster (F2.8) lens just gives you the option of using a larger aperture if you want or need it. It's like the difference between a Honda and a Porsche, they can both get you from A to B...but the Porsche can get you there faster, if you want it to. Given the choice, we would always choose the faster lens...but we have to consider cost and weight as well.

As for the type of shooting you will be doing, you also have to consider the focal length (the amount of zoom). The 18-200 has a wide range of focal length but an F2.8 zoom will not have as much range. It should be noted that usually the more range a lens has, the worse the image quality is.

and even if you do choose to go the same speed as the "honda", the "porsche" is always going to LOOK nicer