15mm 1.7 is much sharper than the 17mm 1.8!

Started Jun 15, 2014 | Discussions thread
javayoda Regular Member • Posts: 371
Re: 15mm 1.7 is much sharper than the 17mm 1.8!

micksh6 wrote:

javayoda wrote:

micksh6 wrote:

It is true. 15mm beats 17mm at F2.8 and slower apertures and it should be better for landscapes. Wide open it's a different story.

I have both lenses and I find that hard to believe.

I made two statements. Which one of them, or both, do you find hard to believe?

I agree that 15 beats the 17 at 2.8 and slower. Useful apertures, I've found. I'm not on board with the notion that the 17 is sharper at the wide end. My cursory tests suggest otherwise.  I suppose I may have a bad 17 and a good 15...or DxO has the opposite problem.

I definitely don't believe DXOMark when it comes to lens sharpness on the GX7.

GX7 is an exception. Everyone can have exceptions, you just need to understand why and how exceptions happen.

DxO had shutter shock issues with two GX7 bodies they tested, and they just reported what they measured. Later, when testing GM1 they switched to electronic shutter. That resulted lower DR than GX7 despite both using the same sensor.

So, it's easy to interpret DxO results correctly if you know how they got some particular results (I got this info from their forum). Regarding GX7 - if you are not affected by shutter shock, or you can deal with it - use sharpness results of GM1. And if you only use mechanical shutter on GM1 - use DR and high ISO results from GX7 measurements.

It's very easy to find explanation, really. DxO has a public forum and they are constantly being scrutinized by community. They don't have many other exceptions like that, otherwise they would have been buried in complaints.

Are you saying DxO had shutter shock issues on every lens they tested on the GX7? I find that dubious. I hope you aren't suggesting they take a single result and extrapolate across all lenses. In any case, the responsible thing for them to do is correct their misleading review(s).

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