Cryptopixel wrote:
>>
>
> There seems to be a presumption here that having a F2.8 lens you will
> use the wide aperture for taking photographs. That goes to show me,
> none of you have a long, fast lens.
I don't own anthing longer than 80mm at 2.8, but I do have
ready access to long fast glass, and wide open is most
definately used for taking photographs.
> A telephoto lens with F2.8 gives
> you brighter images in the viewfinder and more precise auto focus.
yep.
>At
> 200 mm FL the depth of field is minuscule and unless you have a reason
> for wanting a face out of focus either side of the point of focus, it
> has little practical use.
The DOF is also dependent upon the distance to the subject.
With a 200mm lens on a crop sensor body, the subject
distance for a ****trait is such that at 2.8 you have
adequate DOF.
For typical s****ting shot distances, 2.8 gives more than
enough DOF.
>
> The edge of one of the insect's shells is the point of focus. There
> is more DOF past the focus point than there is in front of it. About 5
> mm range before the OOF starts to be obvious. Certainly not enough to
> photograph a person's face side on and have usable images.
I've never done side-on face ****traits at macro
magnifications. I guess if you want a shot of just the nose,
then 2.8 won't be enough DOF.
The Sigma,
> 120 - 300 F2.8 I sold before Christmas never took a shot in
> seriousness at F/2.8 for that very reason.
But what were you using it for? Take it to the footy at
night, and I can guarantee you'd use it wide open more often
than not.
>
> The camera used was a Canon 10D belonging to the buyer of the lens and
> some other Canon stuff I had left over from the change to Nikon. She
> wanted to satisfy herself that the lens was indeed a viable rival for
> Canon's own 70 - 200, F2.8. She used her partner's Canon lens to
> compare shots with on my computer. My comments were aimed at those
> people seeking decent glass and not having the means to shell out a
> few grand to get it.
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