Calibration - Why, How and When?

Mr_T

Mr_T

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I'm probably a little paranoid about my gear but I can't help thinking that at least one lens and perhaps my camera body needs calibration. Very recently my camera along with 70-200 VR took a trip into the floor from the top of my PC (I still don't know how it happened). Over the years looking back at it the body has probably taken quite a battering since I had it new in 2006.

Is there any sure fire method to test if there is a focusing problem with either the body or a lens? It seems to me by looking at the threads here than no matter how flawless a lens is it will come out badly on these tests. I have tried to work out what front and back focusing are but to be honest I don't what I'm looking for.

If a lens is at fault is it worth sending both the lens and the body to the manufacturer or just the lens? I would imagine that if I send anything in for calibration it's going to cost me rather a lot (I don't mind about the time so much so long as I see an improvement) but as someone has never done this before I wonder if it's really worth it.

If even a fraction of my annoying questions could be answered I would really appreciate it.
 
To be honest I would have thought any damage would be obvious in the shots but if you have a Jacobs near you take it in and get them to service the body but take your lens along too.
Once you explain it to them you should find they would be able to give you help on this matter.

At the end of the day no matter how good a tog you are the tech part of your gear should be left to the pro's.

I get my gear serviced around ever 12-18months just as a rule.

I know its not a great answer but its a direction! :lol:

Phil
 
Quite simply if you focus on an object and it appears out of focus yet something in front of the object is sharp then that is front focusing. If the background is sharp and your subject is out then that is back focusing. Simple test is to line up three objects in varying heights (smallest at the front largest at the rear) and take a few test shots. I would also test the edges too just incase. For further peace of mind send your lens in for service stating its had a knock but ask for an estimate first should it require a repair. You could include the body too asking for them to be calibrated.
 
After reading about it a little bit I decided to give one of these test sheets a go. I set the camera up so that it was sturdy on a tripod, used a remote release and shutter delay to make sure camera shake didn't affect the result. I had the camera itself angled as close as I could get it to 45 degrees but the horizontal alignment isn't great.

The result can be found here (clicky for bigger):



I think this means I have a slight back focusing problem but from this I can't honestly tell the severity of it.
 
I think this means I have a slight back focusing problem but from this I can't honestly tell the severity of it.
Click to expand...

You mean front focussing?

It certainly looks ~10mm out.

Have you got another lens to perform an identical test with?

That might give you a clues at to if it's the lens or the body.
 
Thanks for the replies everyone, I just did another test with my 50mm 1.8 under the same conditions (wide open, on a tripod, shutter delay and remote release).



I seem to be having the same problem with this lens. I thought this was back focusing since the focus is behind the focus line instead of in front of it then again (as you can tell from this thread) I'm completely useless at this jargon :(.
 
That looks a similar amount in the same direction as the other lens.

Though it seems to be sharper on the left than on the right as well..
 
All of these were done with single AF mode. Does this mean it's more likely for there to be a problem with the body rather than the lenses? I guess I could do another one of these test sheets with another prime or zoom to make it a fairer test.
 
OK, I've just done the test once again with my 60mm macro lens. The results can be found here:



It looks like it's the same issue (perhaps illustrated a bit clearer in this example). Where would I go from here?
 
Well if those three samples are representative, it suggest you're camera is at fault, rather than the lens(es).

Having said that I'd do a number of tests if you haven't already to be sure, then send the camera off to the servicing centre with details of the focussing problem.
 
The reason I was a little suspicious is that I have found the focus to be off when using auto focus on a few recent trips. Generally over the last several months my shots haven't been as consistently sharp as I would like them to be. Previously I was thinking it was the fault of either me or a particular lens. I decided to put everything to the test today and also to get opinions from people that know better.

It looks like a trip to the Nikon Service Centre for my D200. This reminds me slightly of a thread I saw not too long ago clicky with this in mind do I need to send one of my lenses along too?
 
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