New 50-140 not sharp at 2.8

[screenbyte]

Hi all.

I've just taken delivery of a 50-140 2.8

The problem is it's not sharp at all at 2.8 at any focal length.

Even with manual focus, it's not good.

I can only compare it to the lenses I have already, the 90mm f2 and 16mm plus the kit lens.

Is it possible I have a bad copy or is it that I'm expecting too much?

[milandro]

please publish examples. 

 

Without that what can we possibly talk about?

 

 

 

I am assuming that you are NOT evaluating sharpness on raw image (as someone else turned out he was doing) since a raw image is only shown in a low resolution embedded jpeg.

 

A raw image should be fully processed and sharpened to be judging sharpness.

 

Having said this.

 

are you using a tripod to shoot the test images? Is the shutter speed sufficiently fast? 

 

It is certainly possible that you have been given a bad copy but first you need to eliminate human error.

[screenbyte]

I'm comparing sharpness to the other lenses I have been using in the 2 weeks I have had the X-T2

I can get tack sharp images with the 90mm at F2 without any OIS. I can do the same with the 16mm at 1.4

With the zoom, nothing is sharp at 2.8 with or without OIS, tripod or not

I'm just not sure If I'm expecting too much from the zoom

 

I've had a Nikon 70-200 VR2 on a D810 in the past and that was fine.

 

I'm pretty sure my copy isn't any good. I've requested a replacement.

Edited July 22, 2017 by screenbyte

[drandyperry]

My copy is perfect and pin sharp at f/2.8. Please post some examples and we'll have a look for you.

 

Sent from my ONEPLUS A3003 using Tapatalk

[Tikcus]

without examples i'm assuming you are focussing on a flat object at fixed distance to compare?

 

As Shooting wide open on a telephoto zoom lens will give you a shallow depth of field with potentially only a few cm of sharp focus

 

at F/2.8 @ 140mm on APSC sensor with a focus distance of 5 meters

 

 

Nearest Acceptable Sharpness: 4.93 meters

Furthest Acceptable Sharpness: 5.07 meters

Total Depth of Field: 0.15 meters (15 cm)

 

Where as on a wide angle lens

at F/1.4 @ 16mm on APSC sensor with a focus distance of 5 meters

 

Nearest Acceptable Sharpness: 3.18 meters

Furthest Acceptable Sharpness: 11.75 meters

 

you have a total Depth of field of 8.57 meters

 

So without examples can only post the physics

[BobJ]

My copy is certainly very sharp at f2.8. So either you are doing something wrong or the lens is faulty.

[screenbyte]

Thanks for all the replies.

It does indeed turn out my copy was faulty. I got the replacement today and everything is fine 

Very sharp at f2.8 just as I hoped it would be.

 

I was worried that because I had only used the primes up to now, IE the magical 90mm f2 and the equally amazing 16mm 1.4

The zoom wouldn't be up to the same standard that has drawn me the Fuji system, but thankfully things are looking very good.

Edited July 25, 2017 by screenbyte