What's acceptable sample variation?

[kaiserkudo]

I recently had to send my Z180-600 to get the VR motor replaced under warranty. While it was there it had a full clean, calibration.
While it was away I was lent a loaner 180-600 which I used for a few weeks. The loaner lens worked great and to my eye was a bit sharper than my own.

When it came time to pick up my serviced lens, I was able to take a few comparison shots with the loaner lens to see if everything was in order.

I took some shots with each lens at the same subject, same settings. C-AF single point, burst mode, SS 1/640, f/6.3 ISO 2000. Throughout the series of images it was clear that my lens was significantly softer than the lens I had on loan.

My question is, my lens is now 9 months old, so out of any free returns period - but now that Ive been able to compare mine to another sample and found it to be significantly softer - where do I stand?

My lens has just been calibrated so i assume its already at its best?

Ive attached two equally cropped example below. My lens on the left , the loan lens on the right.

 

[aolander]

Send it back and show them the images.

 

[bleirer]

That is dramatic, the one on the left seems out of focus rather than soft.

 

[DRwyoming]

The shutter speed seems awfully low for sharpness tests on a long lens. How was the camera supported during testing?

 

[JAJohnson]

I recently had to send my Z180-600 to get the VR motor replaced under warranty. While it was there it had a full clean, calibration.
While it was away I was lent a loaner 180-600 which I used for a few weeks. The loaner lens worked great and to my eye was a bit sharper than my own.

When it came time to pick up my serviced lens, I was able to take a few comparison shots with the loaner lens to see if everything was in order.

I took some shots with each lens at the same subject, same settings. C-AF single point, burst mode, SS 1/40 f/6.3 ISO 2000. Throughout the series of images it was clear that my lens was significantly softer than the lens I had on loan.

My question is, my lens is now 9 months old, so out of any free returns period - but now that Ive been able to compare mine to another sample and found it to be significantly softer - where do I stand?

My lens has just been calibrated so i assume its already at its best?

Ive attached two equally cropped example below. My lens on the left , the loan lens on the right.

Just to be clear, is the focus point identical in each comparison? You can check that in NX Studio.

 

[kaiserkudo]

Yes the focus point was the same in each shot. All shots handheld - but seems odd that nearly all of the burst images from the loan lens were sharp and all of the the ones from my lens were not. To clarify I took several bursts, refocusing each time on the cropped area.

 

[kaiserkudo]

The shutter speed seems awfully low for sharpness tests on a long lens. How was the camera supported during testing?

Sorry I should clarify that was a typo, shutter speed was 1/640s not 1/40. Faster would be better I agree, but all shots in the burst series were consistently bad on my lens and a lot sharper on the loan lens.

I'll see if I can get back to the store to try on tripod. My primary intention at the time was testing the VR which had been replaced.