The way to read MTF (actually the contrast is MTF at 30lp/mm) is to analysis
both resolution and contrast, at F2 they both have similar resolution,
different only 1lp/mm, but the ontrast of 100/2 is much higher, that
means for lower contrast objects, the resolution of 100/2 will be much
higher. At F2.8 100/2 has obvious higher resolution and ontrast. Actually
I wanted to say "wider" aperture not only the largest aperture.
100/2
Resolution (lines/mm) at 1:49x
Center: Ex 55 Ex 62 VG 62 Ex 69 Ex 69 Ex 62 VG 55 VG 55
Corner: Ex 49 Ex 55 Ex 55 Ex 62 Ex 62 Ex 55 Ex 49 Ex 49
Contrast(%) at 30 lines/mm
Center: Hi 54 Hi 62 Hi 62 Hi 65 Hi 68 Hi 60 Hi 50 Hi 47
Corner: Hi 42 Hi 50 Hi 54 Hi 56 Hi 58 Hi 49 Hi 41 Hi 39
90/2
Resolution (lines/mm) at 1:50x
Center: Ex 56 Ex 56 Ex 63 Ex 70 Ex 70 Ex 63 Ex 56 VG 50
Corner: Ex 50 Ex 50 Ex 50 Ex 56 Ex 63 Ex 56 Ex 50 Ex 45
Contrast (%) at 30 lines/mm
Center: Low 30 Med 47 Hi 69 Hi 68 Hi 60 Hi 54 Hi 48 Low 33
Corner: Low 25 Med 30 Med 43 Hi 45 Hi 50 Hi 42 Hi 40 Low 27
C.H.Ling
----- Original Message -----
From: "Alan" <atk@xxxxxxxxxx>
> C.H.Ling wrote:
>
> You can check Modern Photography test report at:
>
> http://brashear.phys.appstate.edu/lhawkins/photo/mp-zuiko-tests.txt
>
> which shown 100/2 is better at wide aperture, I'm not interested on
> photodo's report, the 28/2 owner will tell how they love the lens, but
> check the result in photodo, it is almost the poorest fixed lens.
>
> ---
>
> Huh -- the link you pointed me towards indicate both lens have about the
> same resolution wide open (slight favor for the 90). The 100 has (much)
> higher contrast according to those tests.
>
> Can't comment on the 28f2 - never owned/used it but yea photodo results
look
> pretty bad for that lens - maybe it was a bad sample. Their results for
the
> 90/100 look pretty close to what modern has (cept you would predict
contrast
> to be closer at f2). I've never been an mtf fan since most of my shots are
> not taken at infinity. Oh well.
>
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