200-600mm lens coatings

[Paradox.db.3]

I have two lenses, both with slightly different coatings, as it appears. What does this indicate? I seem to get similar image quality from both, but haven't done a real world side by side test. 

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[FunWithCameras]

I have to admit that I've never owned two copies of the same lens, so I've never had the chance to do this comparison.

At a guess, I'd suspect they may have been coated on different machines? I'd expect them them be as good as each other - this is a G lens, after all.

If you noticed one deteriorating, send it into Sony, but I wouldn't worry about it until them.

[Paradox.db.3]

6 hours ago, FunWithCameras said:

I have to admit that I've never owned two copies of the same lens, so I've never had the chance to do this comparison.

At a guess, I'd suspect they may have been coated on different machines? I'd expect them them be as good as each other - this is a G lens, after all.

If you noticed one deteriorating, send it into Sony, but I wouldn't worry about it until them.

There's a part of the story I didn't share, but in short, I ordered a second copy of the lens with the intent of either returning it if it had the same "defect" as my original copy, or keeping it and selling my original. As it turns out, I'll be returning the new lens. Looks like the lens was not meant for taking Moon photos in my climate.

At 600mm, the lens will not focus to infinity in colder than freezing weather. I noticed the strange behaviour in my original lens a couple of Winters ago, but didn't do anything about it at the time. After all, I don't like to shoot often in -35°C weather. But the lens also exhibits the same behaviour even at -10°C. Last night, I took both lenses out side by side in -10° weather and they both, at the same rate, began to lose the ability to manually focus on the Moon. The focus went as far as it could, and stopped just short of getting the Moon in sharp focus. I'm going to test one more lens, just to be sure, but I'm thinking this lens wasn't designed to be used in sub zero weather. At least not for astrophotography.

[FunWithCameras]

Wow - that's interesting to hear. I have had troubles of my own attempting to "shoot the Moon", but I was never attempting to do it in sub-zero temperatures. I think last time was a bit over 20C.

Shame the lens doesn't do what you were hoping it would.