Help! 35-70mm F2.8 lens not sharp

[windflower]

Hi all

This is my first post in the forum although I have been reading it for quite a while.

I recently bought a second-hand Nikkor 35-70mm f2.8 lens for my D700, having done lots of research and based my decision on its price and the excellent reviews I've read about this lens, especially about how sharp it is. So I'm very surprised to find that the photos I take with this lens are not at all sharp. In fact I am quite disappointed? I've never had a push-pull zoom before so I'm wondering if there's something I'm not doing right? I can't really see what it can be though to be honest.

I have of course tried shooting the same shot with different lenses and the 35-70mm is just not measuring up to my expectation.

What reasons could there be for a lens that's generally accepted as being sharp to be not sharp?

Thanks and I hope I can get to the bottom of this.

Regards

 

[John Mc]

Could be a faulty lens? where did you purchase it from?

 

[windflower]

Hi John

I bought it on eBay from a reputable person with 100% feedback. I haven't asked him about the problem yet because I want to make sure it's not something I'm doing, and also feel that if there is something wrong with the lens he probably won't admit it.

 

[Robin Usagani]

post some pics and post the EXIF data as well.

 

[ann]

i have that lens on that body, and it is very sharp what focal points are you using?

 

[traylorc]

Hi John

I bought it on eBay from a reputable person with 100% feedback. I haven't asked him about the problem yet because I want to make sure it's not something I'm doing, and also feel that if there is something wrong with the lens he probably won't admit it.

One of the challenges of purchasing a lens off of e-bay is that the person selling the lens may not be as knowledgeable as you are regarding how a lens should perform. From the perspective of the former owner, the lens produced great pictures. That same lens in the hands of an experienced vet may yield a different opinion.

Hopefully the seller did not knowingly sell you a bad lens.

 

[windflower]

Thanks for all the replies.

Ann, glad to know that you have the lens on the same body and it's sharp. Your comment about focal points led me to do some experiments.

If I place my point of interest, say an eye, in the middle of the frame, and focus using the central focal point, then all is good.

If I place the off centre, to say nearer the right edge, and focus using a focal point near the edge of the focusing area, then the eye is not sharp. If I now focus using the central focal point and re-compose, again the eye is not sharp.

You can see the effect here:
album3 :: temp.jpg picture by snowmoon0522 - Photobucket

Hover over top left corner of the image and zoom in to see more clearly. The left image was focused on the central focal point. The right one using a focal point on the edge.

I photograph models a lot. They tend not to be in the middle of the frame and I tend to move to focal point to where an eye is. This would explain why I have sharpness issues.

Would a servicing help in this situation?

Thanks a lot.

 

[ann]

have you consider using the back af button for focusing so when you use the shutter it will no longer engage the fousing feature? This is the button marked AF not the AE-L/AF-L one

 

[Sw1tchFX]

considering that lens, those look ok to me and close to what i experienced when i had it.

Have you tried AF fine tune?
Or using live view and manually focusing to compare?

 

[djacobox372]

Those lenses are known to often suffer from hazing of the internal elements. This would affect sharpness and contrast--most noticeably in bright light.

If you can, return the lens and buy another one. The 35-70 is quality glass, but lenses can become degraded if they're dropped or stored improperly.