Panasonic old and new versions of lenses

Panasonic 14mm. F-2.5 and Panasonic 20mm. F-1.7 - old and new versions.

What are the differences between the older and new version?

Which is better, if at all.

Samples to compare?

Ron Zamir wrote:

Panasonic 14mm. F-2.5 and Panasonic 20mm. F-1.7 - old and new versions.

What are the differences between the older and new version?

Which is better, if at all.

Samples to compare?

Here's the DXO test results for the 20mm.
The older lens appears to do better by just a whisker.

RedDog Steve wrote:

Ron Zamir wrote:

Panasonic 14mm. F-2.5 and Panasonic 20mm. F-1.7 - old and new versions.

What are the differences between the older and new version?

Which is better, if at all.

Samples to compare?

Here's the DXO test results for the 20mm.
The older lens appears to do better by just a whisker.

That tells you something about the manufacturing tolerances and the measuring tolerances. Unless they tested a dozen lenses or so, you really shouldn't interpret these results so that the old model is better than the new model.

Which brings up an interesting point, has someone done a comparative study that is sensitive and large enough to have an idea about manufacturing variation?

It may be the way the wind blew on that day .  I have read that the new lens is sharper...I own both and see no difference.

I have both the 20mm and the 14mm, so I tend to read any thread (e.g. here in this forum) about either, and I've never seen any evidence that the mark-i and mark-ii have any IQ difference. Someone once claimed that the 20mm mark-ii was somehow faster than the mark-i, but there was no evidence provided, and the innards of the old and new versions appear to be identical from what I've seen, and other users claimed no difference in speed.

ThePalindrome wrote:

Which brings up an interesting point, has someone done a comparative study that is sensitive and large enough to have an idea about manufacturing variation?

Roger Cicala from LensRentals did a few tests on lens variance last year (link 1, link 2). He tested 10 copies of many different models, but only goes into 24mm and 50mm models in the above links.

About number of copies to test, he says:

Ten copies of each lens is the most we have the resources to do right now. That’s not enough to do rigid statistical analysis, but it does give us a reasonable idea. In testing 10 copies of nearly 50 different lenses so far, the variation number changes very little between 5 and 10 copies and really doesn’t change much at all after 10 copies.