Panasonic 100-300 vs. Olympus 75-300 II lens test

Started Apr 4, 2013 | Discussions thread
Anders W
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Re: Panasonic 100-300 vs. Olympus 75-300 II lens test
In reply to Adjuster, Apr 5, 2013

Adjuster wrote:

tt321 wrote:

Anders W wrote:

Adjuster wrote:

Anders W wrote:

Adjuster wrote:

Thanks for the test. But I am not so sure about the conclusion. Note that a) the new 75-300 is optically identical to the old save for new (and hopefully better) antireflective coatings and b) the two lenses were not focused identically in your test images (focus placed closer to the camera with the Pany 100-300).

I was concerned about those issues as well. I wanted to give Olympus the benefit of the doubt in case the older one was a bad copy.

The old may have been a bad copy. Hard to tell at this point. But there is no real reason to expect any optical difference between the new and the old lens design, except possibly with respect to flare.

That is why I wanted to test it.

I tested the lenses repeatedly with the OM-D and the results were always the same. So if the focusing was off, it was off consistently. The "Do Not Enter Sign" was consistently sharper with the Olympus lens. Hard to see in the photos, but the horizontal white line was sharper with the Olympus.

Focus may well have been different consistently. In the shots you show, neither lens is focused perfectly on the "Do not enter" sign. As far as I can tell, focus for the Oly is on the middle section of the leftmost trunk and for the Pany on the topmost section of the same trunk. It follows that the sign is more out of focus with the Pany than the Oly, which probably explains the difference you are seeing.

The focus rectangle was located directly over the sign.

For whatever reason, the focus is nevertheless not on the sign in either image.

Focusing through a window, esp. if it is double-glazed, could have funny results.

It was only a single pane window, sort of like a filter. Evidently, no one on the forum puts a filter on their lenses.:-)

Yes, I do. And if it's a bad filter, it can have weird effects, particularly at longer FLs.

A while ago, I was experimenting with some close-up lenses for my 100-300. The lenses were high-quality (two-element achromats) but pretty old, probably with less than perfect coatings. When I tried to AF, I noticed, to my surprise, that the focus was systematically, not just randomly, a little off.

Now that shouldn't happen with a CDAF system, right? As we all know, there is no such thing as systematic back- or front-focus due to less than perfect calibration as is the case with PDAF. So I was pretty mystified.

I then noticed that in the perfectly focused state, there was something like a flare zone (halo) around bright edges and that this phenomenon was reduced when the lens was very slightly out of focus. So in all likelihood, the system did what it should, i.e., maximize contrast. It was just that maximum contrast did not, in this particular case, correspond to what we would say is perfect focus.

I later tried the same experiment with a more up-to-date close-up lens of the same strength and everything worked just as it should.

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