What explains the vast differences in perceived sharpness when comparing GX7 and E-M5?

Started May 7, 2014 | Discussions thread
MOD Tom Caldwell Forum Pro • Posts: 34,155
Re: It's the AA filter

Anders W wrote:

Tom Caldwell wrote:

Anders W wrote:

knickerhawk wrote:

thornhale wrote:

I was trying to get a sense of how well different lenses perform when I noticed by chance that there is a huge difference between p-sharpness scores and others when comparing even just the Panasonic kit lens between the E-M5 and Panasonic GX7.


For the Panasonic kit lense, we are looking at 4 Mpixels (on Gx7) and 7 Mpixels (on E-M5). Similar observations can be made when looking at the Olympus 17mm 1.8, or Panasonic 20mm 1.7.

These numbers create the impression that the E-M5 or perhaps E-M10 are vastly superior to the GX7, but am I missing something here?

I'll just throw this question in the room: What explains these not small but vast differences?

Use the Imaging Resource "comparometer" to compare the resolution chart shots for the GX7 and EM5. They used the same lens (an Oly 50mm macro) on both cameras, so that variable is eliminated. What you will clearly notice:

  • The contrast and resolution limits are visibly better on the EM5
  • The amount of moire is visibly greater on the EM5

Obvious conclusion: the GX7 has a stronger AA filter relative to the EM5.

Hi Knicker,

While you are probably right that the GX7 has a stronger AA filter than the E-M5, the differences between the two cameras in DxO's result is far too large for that to be the only explanation. The GX7 results are worse than for early cameras with only 12 MP sensors and probably at least as strong an AA filter as the GX7, e.g., the G1.

I had thought that taking out the AA filter completely actually improved resolution but made moire worse.

You are perfectly right about that. But neither knickerhawk nor I said anything to the contrary. So I am not sure I understand your point.

I am sorry if I seemed out of order, I have seemed to have misinterpreted the order of the dialogue. The GX7 does apparently have a stronger AA filter. My apologies.

But then I am no expert and not getting my knickers in a twist. I don't read laboratory tests as they only make me weep.

Best to stick to watching old silent movie melodramas that the argument of this thread derives its plot from

.... or might it be chicken little and the sky is falling in - best dump your GX7 before the price goes through the floor?

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Tom Caldwell

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