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Re: Offlist -- [OM] lens comparisons : apologies to Doris!

Subject: Re: Offlist -- [OM] lens comparisons : apologies to Doris!
From: george <george@xxxxxxxxxxxxxxxxxx>
Date: Thu, 27 Jan 2000 22:04:25 -0800
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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