About the new lens reviews ...

Started Nov 2, 2012 | Discussions thread
wfektar
Contributing MemberPosts: 689
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Re: About the new lens reviews ...
In reply to Pedagydusz, Nov 5, 2012

Pedagydusz wrote:

I may be wrong, but AFAIK they set the lens and the target at a distance such as the image of the target fills the frame, in every case. So, magnification (which is a parameter which I see rarely used, if ever) is the same for all.

Actually that's one of the first things that goes into a lens design. And it used to be reported in older tests -- it's always reported in technical data.

That is the same way the user sets up the camera: so that the scene fills the frame.

That would be strange then, because different lenses have different intended magnifications. Wideangles are designed for low ratios, telephotos usually for significantly higher ones. But even here there's a range, with portrait lenses optimized for higher magnifications than wildlife superteles. At the extreme end, astronomical telescopes are optimized for extremely low magnifications but are not so good at higher.

Filling the scene doesn't mean much if you don't know how far away it is.

In the big picture this is not a big deal, anymore than whether a lens resolves 917 whatevers per whatnot or has a t-stop of 3.1 instead of 2.8 or what contrast ratio we use in the MTF. But if you're going to make a big effort to do a test, it would be nice to know the test conditions.

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