Advice sought on lens calibration...

Hi,

I have the 17-55 f/2.8 IS USM and the 70-200 f/4L IS USM lenses (on my 40D).

With the 70-200 my focus is always spot on so I think my technique is fine (also I have shot with film cameras since I was little so one would hope my technique would not be too bad)...

But with my 17-55 sometimes focus is good but sometimes focus is definitely front focused. I can easily tell because the focus point was on the person's eye yet their face is out of focus but for example their knees (sitting down, thus knees are a lot further forward than the head/body) or their forward outstretched arms are in perfect focus.

The shallower the depth of field is, the more pronounced is the effect / the more often do I see the focus missing like this. But as I said sometimes it works perfectly although it has to be said that I have started focusing on things just behind the person and then getting the person's head in focus so at least some of my successes are thanks to me cheating the autofocus...

My lenses and camera are all still under warranty.

My questions are:

- Should I send the 17-55 to get serviced/calibrated?

- Assuming yes, should I send the camera at the same time? I would prefer not to given it works perfectly with the 70-200, I don't want them messing with the camera and causing that combination to stop working properly!

- Given everything is under warranty, will it cost me anything to get the lens calibrated? And if so can anyone give me an idea of how much this is likely to cost (I am in the UK)?

- Finally, where in the UK should I send it to be calibrated? Looking around I have found two places: Canon themselves and Lehmanns Direct. Have any of you used either - what was your experience like in terms of cost/turnaround time/etc? Or have you used any other place?

Thanks a lot in advance!

Best regards,

Anton

If you can be without you camera for a bit, it would be best to send them in together. They can then calibrate the lens to your camera, assuming it is only a calibration issue. Since everything is under warranty, it should only cost you shipping to get everything done, at least that is how it is in the US.

I'd question my technique long before sending in a lens. How many AF points are you using?

Hi Derek, thanks for the advice. I will just have to hope they don't do anything to the camera that may throw off my 70-200...

gasrocks, I normally use the centre focus point (as it is higher sensitivity on the 40D with my 17-55 f/2.8 lens) but if the subject is not centred I tend to switch to a focus point which covers one of the eyes of the subject and if that is not possible I either move the camera such that it becomes possible and then crop in PP or I focus lock and recompose. But the images I am seeing the problems with are not recomposed, the focus point is dead-on where it should be and I always wait for the autofocus to click in an the IS to stabilise before pressing the shutter fully. Also with my 70-200 I have never had front focused photos and given that is a longer focal length it should be harder to use, not easier so I would be surprised if it is my technique...

Best regards,

Anton

Anton,

It won't cost you anything to get it calibrated under warranty, apart from the cost of sending it to them.

I sent my 17-40mm in recently that was absolutely appalling (haven't tried it yet, but it was tighter on the camera when it came back, so they've had it apart at least! ). Actually I must remember to have a rant about this in the 17-40mm soft lens thread.

I sent mine to Canon's service centre at Borehamwood, Hertfordshire. You'll need to send a letter (obviously!) telling them what's up, plus a copy of the sales receipt. Don't send it in its original box or you'll lose the box (they return in their own packaging)! Just pack very well in plain packaging and it will be okay. I paid £6.40 to send mine by Special Delivery, insured up to £500.

Communications were great. I got e-mails telling me when they received it, a tracking number for progress at Canon, e-mails to let me know when it was ready to despatch, when it was despatched AND two text messages to my mobile phone letting me know the same thing. Also a tracking number for the return parcel. I was really impressed with that! The whole process took eight days for mine, which was quicker than I was expecting.

As with you, my other two lenses (70-200mm f/4 L and 400mm f/5.6L) are bang-on wide-open with my camera body, so there's no way I would get that messed with in case it messed up the calibration for the other lenses.

Mike

After struggling to figure out if my Tamron 28-75 had a problem....front focussing...

For weeks now, I've shot hundreds of shots to find out what/where the problem is and have driven my wife crazy.... sweety, don't move...click.....

It does have one problem... at 75mm/2.8 with extremely high contrast edges... an element is decentered. White on black letterig, the lettering will exhibit a slight "ghost" on the right edge. It is biting sharp at all apertures all focal lenghts, edge to edge, with very good contrast and color, imo. I expected good IQ from the reviews such as at Photozone but not this good. It is excellent. I've been shooting for over 20 years, with a 10 year break along the way, and regularly print 11 x 17's.

Now that I have gone off on a tangent... there is a purpose to this monologue....

what I thought was a front focus problem, most often seen at short distances (less than 10 feet), 75mm, f2.8 is just a need to be very deliberate in your focussing. If I stop down to f4, the lens looks like it focusses fine. Of course it doesn't but the slight extra DOF masks any slight focus errors.

The lens shows no focussing problem with the "battery" test.

This brings me to why I thought it was a lens problem. I don't have that problem with my 70-200 f4 IS,.... BUT it is an f4...

If I never used the Tamron at < f4, I would never have noticed a "problem" but I bought it for it's 2.8..... I still have to send it in for the decentered element but other than that, any focussing error is me not providing a focus area with sufficient contrast for this lens.

There is still one other possibility... a slight loose element causing it to sometimes focus right on, other times to be slightly off. That I will determine in the next day or 2.

So, make sure you give your lens a really good target to focus on.... does it still FF/BF ?

If your other lenses are slower lenses, the fact that they may seem like being bang on, they might not be... the problem may just be masked by the greater DOF in those lenses.

Oops, forgot, the body is a 40D.

That's interesting. Apart from being soft, mine occasionally did the ghosting thing, but not all the time and it would sometimes throw a seriously out-of-focus shot into a series of others taken at the same setting - with manual focus as well. I wondered if it could have been something loose inside the lens.

It got to the stage where I was wondering if it was messing things up as the lens stopped down when the photograph was taken. I had eliminated all other possibilities as far as I could see. I'm not talking about hand-holding wide open either; this was tripod, mirror lock-up, remote release, f/8, manual focus and the damned thing was still all over the place.

Mike

Then you have a problem.... with the "give the AF a good target to focus on"... proviso.

My eyes aren't what they used to be..... manual focussing has not been successful for me, so I don't

I consider myself very logical and technically proficient. I am surprised that it took me so long to actually figure out what the lens is doing, and when. It has certainly been a learning experience, especially concerning small changes in aperture masking camera/lens focussing errors and poor focusiing targets.

It's been back to Canon and I've got it back now, so I'm hoping it will be okay. Haven't been out with it yet though.

I think I took all possible steps to eliminate user stupidity, which I am not immune from with most things!

Mike

Hi Mike,

Thank you for the detailed reply! Much appreciated! I will be sending my 17-55 to Canon in Borehamwood without the camera or original packaging (will use lots of bubble wrap instead) next week. Let's hope it comes back performing like my 70-200!

Once you try out your 17-40 I would be curious to know whether it is now fixed... I will post an update once mine has come back, too.

Best regards,

Anton

Anton

You're welcome. As others have done, I didn't contact Canon first, I just sent it straight to them. Don't forget to put the copy of the sales receipt in there because they will want that before they do any warranty work. A detailed letter wouldn't be a bad thing either. Just in case they don't check something unless asked specifically, along with detailing the problems and speculating about the cause I asked them to check focus, alignment, lubrication and aperture mechanism. As mentioned before, they must have had the thing apart because it is now tighter on the camera mount, which may or may not be a good thing!

I did have trouble finding the address on the Canon site, but it is posted various places around the internet:

Unit 130
Centennial Park
Centennial Avenue
Borehamwood
Hertfordshire
WD6 9AW

I wasn't sure quite what department to address it to, so I just began the address with 'Canon UK Ltd', then 'Lens Warranty Service' on the second line. That did the trick!

I'll post back when I have tried out my lens, which should be after the weekend.

Mike

Hi,

Just to let everyone know my experience with sending off my lens in case it is useful to anyone in the future...

First of all, I chickened out and phoned Canon's UK support line before sending it and they gave me a case reference number and the exact address to send it to and noted what was wrong with it. - I did in fact write a letter describing it anyway and sent it with the lens, wrapped in bubble wrap and in a small box via special delivery insured up to new lens value to Canon UK. I of course included a photocopy of my receipt as well (do not send the original as it does not come back!).

Next day I got an email to tell me it has arrived at Canon and details of how to check the progress of the repair online.

About a week later I was told by email the lens repair was complete and the lens was dispatched by courier and I was given the tracking information - it was with UPS.

The day after I received the lens, again wrapped in bubble wrap and a small box (not the box I sent it in though - not that it matters as I knew to not send it in original Canon lens packaging).

I promptly put the lens on my 40D and took about 30 shots of our littlest one and various objects around the house to see how it did.

Downloaded the photos into Lightroom and WOW! I know this is not a big sample but all 30 shots are PERFECTLY in focus. Just like using my 70-200 f/4L IS lens!

And the lens resolution is much better - resolving individual hairs on my son's face easily when looking at 100% crop of a photo taken at 55mm and close up - and he is only 20 months old so they are very little thin hairs... Before I sent the lens off I would basically never get shots that were that well in focus...

I knew I had a front focussing problem but I always assumed this was in part the non-L nature of the lens just being not as good as an L lens but now I am truly impressed with the 17-55. It really is no worse than the 70-200 f/4L IS at all.

And on top of that I now have 6 months warranty on the 17-55 which given it only had less than two months left on its warranty means I get an extra 4 months warranty as well as a perfectly working lens.

btw. The repair sheet that came back with the lens said the following:

"Comments: Lens examined and tested, Front focus corrected. Lens cleaned.
Repair work: General cleaning, Adjustment: Lens system"

So in summary I am very happy indeed that I sent my lens to Canon!

The only thing I regret a little is having waited for so long before sending it. I have literally thousands of photos that are sufficiently out of focus to be useless for printing collected over the last 10 months... I will know next time to trust my abilities more and send a misbehaving lens in sooner!

Best regards,

Anton

Thanks for the update. I still haven't sent my lens in but soon.

Glad to hear that you got it sorted out, Anton.

I still haven't tried my 17-40mm as I have recently got a 24mm TS-E, which has captured my imagination!

On my repair paperwork it had 'Adjusted resolution and set to std' in the comments section, then 'Adjustment: Lens system' and 'Checking: Focus' in the Repair Work section.

Mike

Thanks for the update, glad it all worked out.