Rought cost of fixing a backfocusing pro zoom lens?

[Garbz]

Has anyone here ever sent a backfocusing zoom lens into repair and can give me a rough indication of what the repair costs?

I have a Nikkor AF-S 28-70mm f/2.8 that backfocuses quite consistently to about -12mm on the D70 focus test chart, but only at the 28mm mark. It's down to about -9mm when zoomed to 35mm, and pretty much nails the focus at 50mm and 70mm.

I'm going to take it into get fixed but I'd like to go in with a cost expectation.

No longer under warranty.

 

[Derrel]

Are you serious? How do you know the issue isn't with the particular camera body? And seriously, a 12 millimeter focusing error at the 28mm focal length, and a nine millimeter focusing error at 35mm focal length? Really? That little tiny bit of focusing error is enough to make you want to send the lens into Nikon for repair?

 

[Garbz]

12 mm at closest focus using the focusing chart (bogus number really because it means nothing without info of how close I was to the chart). I wouldn't even have considered using a chart if I didn't actually have focus problems with this lens in the field. I've actually stopped using it favouring my kit lens for now because of the issue.

As for the body, I have 9 lenses, and this is the only lens that exhibits this problem. I'm inclined to think there is something wrong with the lens.

 

[table1349]

Don't know if this will be much help or not, but I can't imagine that Canon and Nikon can be that far apart. My 24-70 f2.8 need repair out of warranty for a broken focus motor ring. $175.00 later they fixed the focus issue, cleaned and calibrated the lens to the body that I sent in.

 

[ghache]

Don't know if this will be much help or not, but I can't imagine that Canon and Nikon can be that far apart. My 24-70 f2.8 need repair out of warranty for a broken focus motor ring. $175.00 later they fixed the focus issue, cleaned and calibrated the lens to the body that I sent in.

thats not bad at all

 

[mikehaugen]

Don't know if this will be much help or not, but I can't imagine that Canon and Nikon can be that far apart. My 24-70 f2.8 need repair out of warranty for a broken focus motor ring. $175.00 later they fixed the focus issue, cleaned and calibrated the lens to the body that I sent in.

Is it really the best idea to get the lens calibrated to a body? Isn't there like a "universal" calibration standard so that it would work with all bodies. I have an eos3 with which the focus is way off with all of my lenses, but they also all work fine with my 20d. I would have to assume that it is an issue with the body.

 

[Garbz]

The issue is there's a standard point for lenses and a standard point for cameras, both have room for error. I remember reading an article once with someone who had issues with focus every time he bought a new lens and it often took him a couple of returns to the store to get a new lens that will focus to his liking on his camera. Fast forward a few years later and now he couldn't find a camera to work with all of his existing lenses. Mind you this kind of thing is usually overly pedantic.

While I ran all of my lenses through this focus testing chart they did bounce around a bit in sharpness, but usually on the chart the focus was +/-2 on it's scale. And each did it consistently. But you are right there should be a standard focus point to calibrate to.



The only reason I'm considering repair at all is because this lens has the issue only at wide angle, which means even if I had a D300 or newer body with built in lens compensation I wouldn't be able to calibrate the error out, since it only provides one absolute bias to all focusing on the lens it detects on the body.

Actually one thing that warrants testing is if this issue happens on all focusing points. Will report back

 

[djacobox372]

It would probably be better to just upgrade to a body that allows you to adjust focus for each lens.

 

[subscuck]

It would probably be better to just upgrade to a body that allows you to adjust focus for each lens.

The problem is it doesn't really work for zooms. You have to adjust it for only one fl on your zoom. Then there's no telling what it does at other fl's. I have all my lenses ma'd except my zooms.

 

[Garbz]

You should be able to characterise zooms and find an optimum adjustment level. For the most part I tried a few of my lenses on the focus chart and every other zoom was consistent across focal length. Only this one varied to any significant degree.