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Re: [OM] just another Intro

Subject: Re: [OM] just another Intro
From: dreammoose <dreammoose@xxxxxxxxx>
Date: Wed, 12 Dec 2001 21:52:58 -0800
Hi, I'm Moose and new to this list, courtesy of a a short e-mail conversation with Tom Scales. I saw my first OM-1 soon after they came out and immediately got rid of my Nikon Ftn and bought a chrome, pre MD OM-1, so I'm approaching my 30th Oly anniversary. Shortly after the OM-2n came out, I bought a black one and the OM-1 became my backup. With the 50/1.8, 35-70/f3.6, 100/2.8, Tokina RMC 80-200 f4.0, Vivitar 28mm f2.5 and a T-32, I was a happy photograhper for many years. Then I found I had more time and money than when I was younger and wanted to get back to photography as fun and creative art. Then I discovered eBay and the rest is (sordid?) history. What I really need is a 12 step program, but I'm here instead. I don't think I'm in Tom's league, but.... I do have many OM bodies from the OM-1 that started it all through a 4Ti. And lenses!! Do I have lenses?! They run from 18mm to 1000mm, with way too many stops and duplicates in between. Maybe I'll let you know more when we know each other better - and I've taken an inventory and start selling off the excess.

In the meantime, I'd like to reply at way too much length to:
---------------------------

Please don't tell me there is a 2/90 OM for sale on ebay, please.... ;)


There is a 50/2 macro, first in a long while. Sell those investments. Mortgage that Cello.

tOM

---------------------------

Actually, there are 2 50/2s on eBay at the moment. What I don't get is why it's such a big deal. For a collector, ok, but for a picture taker??? Back in the archive, someone suggested a 135/2.8 was better for distance than a 135/4.5 macro... and somebody else said the equivalent of "Plueeeeze!!". I'm not immune to the "Newer, faster, more expensive is better." syndrome. However, there is more than that to this subject. In the current state of lens making, it is not possible to make a single lens of a given focal length and speed that is BOTH as good focused at infinity as a lens optimized for infinity AND is as good at 1:1 as a lens optimized for 1:1. In the case of Zuiko, they have a set of 'pure' macros optimized for close-up work with a bellows. They also have the two 50mm and the 90mm 'macros' with helicoid mounts that focus to infinity. These are obviously compromises somewhere between 'pure' macro and conventional lenses. I have a couple of the 50/f3.5s and a Tamron SP 90mm macro. (By the way, I've heard that the later version of this lens is optimized for a greater focal distance than the earlier one; either to cater to it's most common use or to get better ratings in magazine tests run at long focal distances.) Used on a copy stand, they do a superb job of preparing slides for college lectures. The questions are: Should I use a 50/3.5 for regular photography instead of a 50/1.4 or even 50/1.8. Should I buy a 50/2.0, for macro work? ..for regular photography?

I already know the answers from many years of photography and designing equipment for highly specialized copy and projection work years ago, but I think it's also easy to show.

First of all, for actual close-up work, no matter how much fast a lens may be wide open, it has the same depth of field at any f-stop and focal distance as any other lens. As a practical matter, all close up work tends to require small f-stops. This is obvious for small 3-D objects. Everyone who walks up to a flower and tries to get a good close-up quickly finds that a small f-stop is needed. However, it is also true to an important extent for copy work of flat objects. I know that we all think our cameras are perfect and the distance from the lens to the focusing screen is exactly the same as the distance to the film.. and the film is perfectly flat... and our lenses have no curvature of field... and our camera is absolutely square to the copy... and our our can see focus perfectly after hours of work. The truth is that good copy work is also done at smaller apertures. So a faster lens per se dosen't have any advantage for macro and copy work.

For work at greater focal distances, there is an enormous amount of good information on Gary Reese's lens test page. His tests of a flat subject at a 1:40 magnification ratio are excellent for judging quality for everyday photography. So lets look at some 50mm lenses. I've converted Gary's comments on contrast and vignetting into columns:

50mm f/2.0 Zuiko Macro (multi-coated) 50mm f/3.5 Zuiko (multi-coated) 50mm f/1.8 Zuiko ("Made in Japan" variant) 50mm f/1.4 Zuiko >1,100,000 OM-2000 with mirror and aperture prefire. OM-4 with mirror and aperture prefire OM-2S with mirror and diaphragm prefire OM-2000 with mirror and diaphram prefire. Distortion = none Distortion = very slight pincushion Distortion = slight barrel Distortion = none Aper. Cent. Cor. Cont. Vign. Aper. Cent. Cor. Cont. Vign. Aper. Cent. Cor. Cont. Vign. Aper. Cent. Cor. Ctr. Cont. Cor. Cont. Vign. f/1.4 B B M ML D f/2 B- B- M B f/1.8 B C H C- f/2 A- B H H B f/2.8 B- B M ? f/2.8 A- B+ H A- f/2.8 A A- H H A- f/4 A- A- M ? f/3.5 B- C MH A- f/4 A+ A VH A f/4 A A H H A f/5.6 A- A M ? f/5.6 A A MH A f/5.6 A A- VH A f/5.6 A A- H H A f/8 A+ A+ MH ? f/8 A+ A H A f/8 A A- VH A f/8 A- A- H H A f/11 A A- MH ? f/11 A A MH A f/11 A- B+ H A f/11 A- A- H H A f/16 A- B+ M ? f/16 A- A- MH A f/16 B+ B H A f/16 B+ B+ H M A f/22 B+ B+ MH A It's easier to see the forest when the trees are lined up like this. I know these comparisons aren't really valid at the 1/3 grade level, but just for fun... I converted all the resolution grades to numbers, A+=9, C-=1 and the contrast grades to numbers, VH=5, ML=1. I then added up the two resolution scores for each f-stop for each lens and selected a winner based on high score. I then added the contrast scores to the totals. Since I use only one contrast score and the contrast numbers are lower, this total is still heavily resolution rated.

Here are the winners based on the exercise:
f-stop  Resol.    R & C
f/1.4    f1.4         f1.4
f/2       f1.4         f1.4
f/2.8    f1.4         f1.4
f/4       f1.8         f1.8  (scores of  all lenses basically a tie)
f/5.6    f3.5         f1.8
f/8       f2.0         f2.0+f3.5
f/11     f3.5         f3.5
f/16     f3.5         f3.5
f/22     f3.5         f3.5

Now, some of the scores are too close to be meaningful, but I think you see the point, the f1.4 is the best general use lens. The question of best for close-up lens is not quite as clear, but based on the above discussion of the practical needs and especially the availability of f/22 for additional depth of field, I think the f3.5 is the best choice. Add in the large cost and availablity difference and it's no contest!

Cheers,
  Moose





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