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Re: [OM] Comparing 50 mm lenses

Subject: Re: [OM] Comparing 50 mm lenses
From: Moose <olymoose@xxxxxxxxx>
Date: Sun, 20 Nov 2011 02:43:48 -0800
On 11/19/2011 4:33 PM, WayneS wrote:
> If the Oly was exposed to match the Zeiss, I'd go for it, as it seems sharper.

C'mon guys, these are web images downsized without any resharpening. I don't 
think you can tell anything meaningful 
about sharpness from them.

> Zeiss seems a bit soft, could just be a focus issue?

I did what I could to focus all the same. Sure, I might have missed, or an old 
four element lens may be less sharp than 
a newer 6 element one, or it might be DOF. or:

> Really need to have 100% blowups to really compare sharpness.

I don't think this is the right subject for sharpness, unless perhaps one only 
looks at the center. The subject isn't 
flat. So how does one know what part of sharpness is field curvature and/or 
DOF? If you shoot something convex with a 
lens that has field curvature in the same direction, it will appear sharper 
than with a lens with flat field or opposite 
field curvature. The reverse is true as well.

These three lenses have wildly different optical designs. Complex lens designs 
don't necessarily have the same DOF as 
calculated from the thin lens formula. It is often asymmetric, front vs back. 
The only 'fair' way to compare sharpness 
for general use is with a flat subject.

> And exposure seems to be the biggest difference to my eye.

As I said in a prior post, that's on me, not the lenses. They do differ, but 
differently than displayed

> I also have the Canan 50mm. I find critical focus the biggest challenge
> with that lens, when AF is used, it has some variation.

Wouldn't have affected this comparison, as I used MF on live view. My simple 
test of it with a flat target showed it to 
be quite sharp.

> Thanks for sharing the experiment. I still give thumbs up to late vintage Oly 
> mij.

Thanks for commenting.

Moose
-- 
What if the Hokey Pokey *IS* what it's all about?
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