NX200 test shots - lenses, focus, and ISO 400

Started Nov 9, 2011 | Discussions thread
sensibill
sensibill Veteran Member • Posts: 5,401
Re: NX200 test shots - lenses, focus, and ISO 400

Thank you for going into great detail with these samples and retaking them with the NX 60mm.

Andy Westlake wrote:

From 2) it was assumed the lens was front focused, causing the images to be soft. This was incorrect - the lens was correctly focused, but DOF extended further forward.

I guess what I don't understand is how those shots (and indeed the new ones) had more DOF in front of the intended focal plane and far less behind it. And now even more pronounced with the 60mm. Is that really the case, that two very different lenses are exhibiting similar dropoff in clarity, and that it's such a stark difference to most other cameras tested?

Most of what people considered to be incorrect focus was simply the result of high ISO noise reduction (noone was ever able to demonstrate an obvious problem with the ISO 100 shot).

To be fair, while most of us did acknowledge there was heavy NR being performed by the NX200, there were questions of focus, aperture and/or depth of focus/background or edge clarity and very subtle CA issues with the 50mm., even at base ISO.

With the new round of shots taken with the NX 60mm macro, we're confident the aperture setting is now correct (F8), and shutter speeds consequently match other cameras to within 1/3 stop at any given ISO. However the longer focal length and larger aperture inevitably combine to reduce DOF compared to the previous set. Most obviously, the Queen of Hearts and corner checkerboards are now just beyond the depth of field, and look slightly soft as a result. There's little we can do about this given the 3D-nature of our test scene.

Again, I am surprised to see a lens that has more DOF in front of the target than behind, as was shown (less so) with the 50mm.

It's not just theory, either; we've seen essentially the same effect previously with the Olympus E-PL3 and E-PM1.

The E-PL1 had it but I can't remember if it was fixed by using IBIS. Also, some people seemed to experience it more than others, with the wobbly lens segments being named as the fault, at least initially.

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