Thanks! My eyes are sore!
george
ALEXSCIFI@xxxxxxx wrote:
>
> Very good analysis, George!
>
> Alex
>
> In a message dated 2000-01-27 9:57:28 PM Eastern Standard Time,
> geanders@xxxxxxxxx writes:
>
> << Folks;
>
> OK, I'm pickin up the gauntlet and I'm gonna try to defend our beloved
> Zuikos against this numerical assault. I'm going to place the photodo test
> results for our 3 lenses along with results for their competitors, under
> the *Totally Unbiased* "Anderscope". I'll be looking for factors that
> perhaps are overlooked when photodo comes up with it's big overall rating.
> We'll see about this numbers game.
>
> ********************************************
>
> First, the lens that Dirk left out, the 35-80/2.8:
>
> I ran advanced search, only zooms, only mtf above 3.5 on Nikon D AF mount.
> Had 9 hits. Of those, only 2 are focal range competitors:
> Overall wide open
> ave mtf@40lpmm
> Zuiko 35-80/2.8 3.6 (77.5) 71.0
> .49
> Nikon 'AF D' 35-70/2.8 3.8 (79.3) 63.3
> .51
> Nikon 28-70/2.8 ED-IF 3.7 (78.4) 69.3
> .51
>
> First off, the Zuiko has the widest focal range, so it's the more
> challenging lens design, and the more useful lens, eh? Next, the way
> photodo comes up with the rating is based *solely*on the average weighted
> mtf. And the weighted mtf has the following weights: F/4 = 40%, F/8 = 60% .
> They say that they assume that fast lenses 'suck' (paraphrasing) when tested
> wide open, that's why they use F/4. And that after F/8 diffraction becomes
> a bigger issue than lens quality. They **totally ignore** wide open
> performance.
>
> Now, based on this, our baby is 3.6 But wait, the Anderscope has noted that
> our ave mtf is 78. **And so is that for the Nikon 28-70. Yet it received a
> 3.7 !! ** Hmmm. (We note for the record that Nikon advertises on this site
> ...) What explains the same mtf # giving 2 different test ratings if it's
> only based on that number? Hmmm? Well, the Anderscope crunched the numbers
> and found that the Nikon was 78.46 while the Zuiko was 77.53 Maybe this
> explains it? They round off when posting the mtf #, but not when deciding
> overall rating?
>
> As for the NNow consider the Nikon 35-70. A nice lens, but *where's the
> extra 10mm of range? It has a 3.8 rating based on ave mtf of 79.3, but we
> notice under the scope that photodo was very *right* in their poor wide open
> performance assumption for this lens. But it was very *wrong* about the
> Zuiko. Under the Anderscope, our baby is *far* better than the Nikon at
> F/2.8 But photodo ignores that data altogether. If that was factored in we
> would kick this lenses' butt and been virtually identical to the 28-70.
>
> One other spec that's quite important to me is the mtf @ 40 lpmm, because
> higher numbers here indicate better ability to make large prints, which is
> my forte. Unfortunately, the Nikons both edge out the Zuiko here.
>
> All in all, I feel the Zuiko is under-rated at 3.6 especially since it's a
> big winner wide-open. Nice, sharp photos with great wide-open bokeh! ahhhh.
>
> BTW, I also looked at the rating for the much-ballyhooed Nikon 24-120
> F/3.4-5.6 IF - it got a 2.3
>
> Other than Nikon:
> Canon EF 28-70/2.8 L USM (3.9) Looks a bit better. But one data point is
> missing. Did they make it up?
> Minolta 28-70/2.8 G (3.7) Just slightly better,even under the scope.
>
> That's it. Of all zooms in this range, only 3 are in the ballpark. Even
> Leica and Contax fail to hit this mark.
>
> *********************************************************
>
>
> >
> >OM 100/2 - (3.9)
> >Canon 100/2 (4.2) - Anderscope says "Zuiko better wide open, but overall
> :>("
> >Minolta 100/2 - (4.4) - Anderscope says "Er, sorry fellas, this is better."
> >Nikon 105/2.5 (4.2) - Anderscope says "Too slow"
> >Leica Summicron-M 90/2 (4.3) Anderscope says "Zuiko better wide open, but
> overall :>("
> >
>
> OK, so of *all* F/2 lenses in 90-110 range, only 3 are comparable or better.
>
>
> ****************************************************
> >OM 90/2M - 4.2
> >Leica Summicron-M 90/2 - 4.3
> >Tokina AT-X 90/2.5 - 4.6
> >Tamron SP 90/2.5 - 4.2
> >Contax G Sonnar 90/2.8 - 4.4
>
> Forget the above chart, see text.
>
> OK, last, the venerable Zuiko 90/2 macro. FLASH: If we insist on F/2
> aperture, ***there is NO competition***. So, we have to make it easy on the
> other guys.
>
> First, the lenses are tested at infinity. The 90 is best in the macro
> range, obviously. So Dirks comparisons above are moot. So I did a search
> on Nikon 'AF D' lenses, 80-100 mm, macro lens only, rating >= 4.0 I got
> *only* one hit. Surprisingly?, it's a Tamron 90/2.8 macro.
>
> So, how does it compare to our favorite under the unbiased Anderscope?
> Well, the Tamron's a stop slower - hey, gimme back my bright lens! As
> before, I did the math and Zuiko = 83.2, Tamron = 83.6 Virtually identical.
> mtf @ 40 lpmm? Here, the Zuiko blows the Tamron away .63 to .57 I'll take
> the Zuiko for my big prints.
>
> If I open up the search to macro lenses from 60 to 105, I get 2 more hits. A
> Sigma!! and a Nikon. (I have to search specifically on Adaptall to find the
> 90/2.5 SP) Again, all are slower than the home team. And the Zuiko beats
> them all numerically. The overall numbers below show the Nikon up by 0.2,
> but don't be fooled! Under the Anderscope, we see the Zuiko has better mtf
> at F/2 and F/2.8 than the Nikon at f/2.8 Again, if wide open performance
> were included - Z beats the Nikon hands down. I'll take the Zuiko for speed
> and wide open performance. And the Nikon really should be compared to the
> 50/2 anyway.
>
> It's quite astounding to me that the Tamron and Sigma lenses are actually
> more competition for the hometown favorite than the Nikons.
>
> Overall
> mtf@40lpmm mtf @ wide open
> Zuiko 90/2 macro 4.2(83.2) .63
> 0.76 (f/2) 0.78(f/2.8)
> Tamron 90/2.8 macro 4.3(83.6) .57
> 0.79(f/2.8)
> Tamron SP 90/2.5macro 4.2(83.4) .60
> 0.68(f/2.5)
> Sigma 105/2.8 macro 4.1 (82.2) .60
> 0.77(f/2.8)
> Nikon 60/2.8 micro 4.2 (83.4) .61
> 0.71(f/2.8)
>
> Just for grins:
> Nikon 105/2.8 micro 3.9 0.52
> 0.75
>
> Also, I did 80 to 135mm macro >4.0 mtf searches on:
>
> Contax got 0 hits
> Canon EF got 5 hits. Only the Canon 100/2.8(@4.4) was actually
> 'better' -but only very slightly under the Andersope and again, the Zuiko
> has the speed advantage .
> Leica M got 0 hits
> Leica R got 1 hit. The APO-macro-Elmarit-R 100/2.8 at 4.5. Again, the
> Zuiko is faster, but the Leica is much better wide open (0.87) and slightly
> better mtf@40lpmm (0.65)
> Minolta AF: got 4 hits, only 1 the Minolta 100/2.8, was 'better'. It was
> actually darn good at 4.5 and is a 1:1 macro to boot.
> Pentax K AF: got 4 hits, Pentax 100/2.8 was a virtual draw at 4.3 after
> several Anderscope adjustments.
>
>
> So, in summary, of all competitive lenses, only the Leica 100/2.8 and
> Minolta 100/2.8 were noticably better than our boy. But did I mention, ours
> is a stop faster? :>)
>
>
> george
>
> >>
>
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