Intermittent sharpness issues with AF 35-70mm f2.8

[xypher]

This lens was unused for a very long time and I just took some shots with it today. On my D90, some shots turn out quite soft. There appears to be no clouding of the elements when I look at the lens from the back.

Here are some examples..
http://www.flickr.com/photos/26216013@N00/5579463300/sizes/l/in/photostream/
http://www.flickr.com/photos/26216013@N00/5579462912/sizes/l/in/photostream/

Does anyone think that the lens has poor image quality? I'm still new to SLR and lenses so I am unable to determine the exact cause. Most samples of this lens found online are sharper than what I manage to take .

Thanks.

 

[cutecdo]

EXIF data pls. First photo looks ok. Second photo is a little bit soft.

 

[xypher]

1st pic: shot at 35mm(53mm on DX), 1/2000sec, f3.2, aperture priority. for some reason the ISO number used wasnt registered.

2nd pic: shot at 70mm(105mm on DX), 1/4000sec, f4, ISO 400, shot using aperture priority

 

[cutecdo]

The settings seems to be ok. Does this happen with other lens you have? If yes, are the focusing points used the same?

 

[wdEvA]

its common for zoom lenses to have slight difference in sharpness throughout the whole focal length.
but your test isn't far anyway, the subjects are different.

try doing the test again, on a tripod + shutter release or timer, and shoot the same scene, keep the aperture and iso consistent between the 2 shots as well

 

[Benji77]

I'm an ex-user of the 35-70/2.8. Its super sharp. You'd need to do the following so as to eliminate factors -

1. Remove any filters
2. Use a tripod
3. Set to your lowest ISO (200)
4. Test from 2.8 - 8 with individual shots
5. Set to JPEG / Colour settings Normal (No sharpening)
6. Do auto focus & manual focus. Remember to ensure your diopter is accurately set for yourself
7. Ensure your focus controls are 'S' & 'M' when using Auto Focus / Manual

 

[fatigue]

Try to check the lens on a bright light and look for signs of haze.
For that lens, usually it's on the 2nd group. ( 2nd from the front where the filter is mounted)