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Archive 2008 · Adapter matching?

Cableaddict
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p.1 #1 · Adapter matching?

Today I was doing some research on medium-WA lenses, because I'm not happy with my Zuikos.

In a 2006 thread, Mark Hubsand wrote:

"The Olympus 24/2.8 used on 16:9 required some internal modification to compensate for the adaptor. Before the mod, wide aperture performance was particularly compromised. Unless the adaptor matches perfectly, you won't see what the Oly 24/2.8 is capable of. "

I have the Zuiko 24/2.8 and 28/3.5. I got them because everyone here raves about them. I even got TWO of the 24's, and all three are super-late serial numbers. I am severely underwhelmed by all three:

The resolution at distance kind of stinks, (they are fine at close distances) and distortion is higher than any other lens I own. I'm wondering about the adapters.

-But how does one know if they are "perfectly matched" ? It doesn't sound like Husband is talking only of infinity-adjust.(or is he?)

Can anyone elaborate or illuminate?
What problems was Husband alluding to?
What mod was done? (to the lens, not the adapter)

Dec 02, 2008 at 12:50 PM

Ed Sawyer
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p.1 #2 · Adapter matching?

Did you email him yet? He's a member here...

The only 2 dimensions I can imagine mattering w.r.t. adapters would be the flange distance (film to flange, e.g. registration) and the flatness of the adapter. Both are fairly easy to check.

I hear a lot of talk about Kindai adapaters, but don't see them on ebay or elsewhere. Whats' the story with those? (v.s. say the $20 ones on ebay from China)

-Ed

Dec 02, 2008 at 02:38 PM

JimBuchanan
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p.1 #3 · Adapter matching?

It was probably adapter issues that gave me a bad first impression of Oly lenses in general, as I don't usually here about lateral CA in their wides. I had a 28/2.0 and 28/3.5 and the 2.0 had color fringing and the 3.5 didn't, using the same adapter. Can't understand why, unless the lens sat at an angle off axis. I also didn't like the aperture going in the wrong direction.

I find the Minolta wides relatively free of this.

Dec 02, 2008 at 03:18 PM

pdmphoto
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p.1 #4 · Adapter matching?

The Oly 28/2 is a floating element design, so it requires precise adapter spacing to get the best result.

JimBuchanan wrote:
It was probably adapter issues that gave me a bad first impression of Oly lenses in general, as I don't usually here about lateral CA in their wides. I had a 28/2.0 and 28/3.5 and the 2.0 had color fringing and the 3.5 didn't, using the same adapter. Can't understand why, unless the lens sat at an angle off axis. I also didn't like the aperture going in the wrong direction.

I find the Minolta wides relatively free of this.

Dec 02, 2008 at 03:28 PM

Cableaddict
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p.1 #5 · Adapter matching?

So...

What have we learned today?

(still hopin' for some illumination.)

Dec 03, 2008 at 04:36 AM

mawz
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p.1 #6 · Adapter matching?

Cableaddict wrote:
So...

What have we learned today?

(still hopin' for some illumination.)

Floating element designs don't have the easily tunable infinity focus and rely on precise registration for best performance and thus are FAR more sensitive to adaptor precision than non-floating designs.

Dec 03, 2008 at 04:45 AM

Cableaddict
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p.1 #7 · Adapter matching?

Thanks, Mawz.

That raises another question, maybe kinda' noob, but: How does one tell if a lens is floating element, assuming you can't find that specific information online?

Does it have to do with whether or not the front element moves when you focus?

Dec 03, 2008 at 01:59 PM

Ed Sawyer
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p.1 #8 · Adapter matching?

mawz wrote:
Cableaddict wrote:

Floating element designs don't have the easily tunable infinity focus and rely on precise registration for best performance and thus are FAR more sensitive to adaptor precision than non-floating designs.

Mmm.... I don't really agree. Floating/non-floating really has nothing to do with adapters. the lens will focus at a certain point, regardless of what camera or adapter it's on.

By definition, Floating = elements that move relative to one another, or a single fixed rear element with the rest of the lens moving as a group. (This is Canon's version of Floating, among others). There's no reason that should be problematic w.r.t. adapters. All zooms have some sort of floating design, according to the definition - they simply have to. And you don't hear tons of stories about Zooms being finicky about adapters. So I don't buy the 'floating = more trouble to adapt' story.

-Ed

Dec 03, 2008 at 02:23 PM

Ed Sawyer
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p.1 #9 · Adapter matching?

cableaddict - the only way to tell is look at or read about the design. Front element moving or not is irrelevant. Sometimes you can tell by watching the internal elements move while slowly racking through the focus range. But, it takes knowing what to look for.

Dec 03, 2008 at 02:24 PM

JimBuchanan
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p.1 #10 · Adapter matching?

Cableaddict wrote:
How does one tell if a lens is floating element, assuming you can't find that specific information online?

Yes, it is a challenge. Ed is right, finding a reference is the best way.

One thing I have noticed, besides the absence of infinity adjeustment screws, is a secondary cam arrangement, in addition to the regular helicoid attached to the focus ring. This is what moves that front lens group differently. The extra cam mechanism puts extra resistance on the whole system and it can be felt in the turning of the ring.

Dec 03, 2008 at 05:32 PM


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