Calibration... what do they actually do?

Hi,

I'm soon going to be taking my 7D in for calibration as I've a nagging feeling it could be sharper and the AF quicker - all that aside though does anyone know what they actually do?

I don;t mind having it done professionally, its not much £60 and its relatively close so I'll get it done in a day anyway, I'm just curious.

Does no one know what they do?

They probably can put a meter on certain test points to make sure the mili-voltages meet spec and no doubt they have "golden sample" lenses with which they can test the electro-mechanical aspects. Don't know what else they can really do in a "body only" situation.

Don't know if they automatically include a cleaning but I would think they will do it.

Cant help with what they do but that seems cheap. I sent my 100-400mm lens to Canon and was relieved of £160 for the privilege. BUT the resulting images I had with it was totally worth it. No point in a quality lens/camera, if it isnt functioning to its best.....
Hope it resolves your issues, I love my 7d

Thank you, mines off to H. Lehmann Ltd but the £60 is for body only, I'm not sure how much extra for a lens too.

I best find out!

Remember products are only made within manufacture tolerances, so if your camera (or lens) sent in alone conforms with the overall tolerance charts there is nothing the tech people can do to "fix" any possible slight softness etc.. That is because any softness of a camera and lens setup is a product of both the camera and the lens (assuming user error and lighting are not factors of course).

Thus in order to get a system properly calibrated you've got to send the camera and the lens in. Of course if you use more than one lens/camera then you've also got to send them in as well (if adjustments are made to the body and lenses it might well throw them out of sync with the other gear you use).

IT sounds like a lot, but if you want to go down the route of having your system fully calibrated then you've got to do it with all of it. Note I think for lenses you can have a note sent in for calibration changes to be made only to the lens and not the body ( considering how repair shops work I'd make sure this was stated in a cover letter taped to the box as well as included inside the box+packaging - to help ensure that the message does get to the tech staff).

I'm an avid person for sending gear in for adjustments. I recently sent in my T2i for adjustment along with my 50mm 1.4, kit lens and got them back. I now have some seriously great stuff going here....

I'm now getting great images at 1.4 with the 50 and the kit lens also was adjust which has been giving me much better results. Until I sent everything in to be fixed/aligned I never knew how little of an f/ you really needed in order to get everything in focus. It's insane the complete turn around that I've now gotten in my gear. Though I sent my gear into canon directly to be fixed.

They wanted 250 US if it wasn't under warranty but after getting it back I would have happily paid for the adjustments if I had to, thankfully I was still under warranty though.

Fore the body they can adjust several things from what I have been reading. They have abilities to micro adjust the distance that the sensor is from the mounting point if that is off as well as if the built in metering system for range to subject and light metering are off as well. This was pretty much the problem with my T2i body. They did some stuff to the sensor and also re-calibrated the auto-focusing system to be accurate.

the lenses they replaced a board in the 50mm and adjusted the focus on the lens, the kit lens they had to adjust it so that it wasn't rear focusing anymore.

After these adjustments I rarely even bother to go over f/4 unless like the kit lens it makes me... lol. I really need to replace the kit lens with a 2.8.....

An excellent description of the AF process used by Canon can be found here It's from a few years ago but still "current" . One paragraph is relevant for this "calibration" topic

Each lens has a stepper motor that tells the camera its position (from min to max on the focus ring's range) by providing a "number". Each lens will have a series of numbers (addresses) from its min focus to its max focus distance and once the AF has calculated the necessary movement, camera is supposed to tell the lens to go to # xyz. The lenses should come from the factory with those addresses "well calibrated" to the real distances they correspond to (but it may be "off" a bit and can be reset). How well these settings correspond with the distances ( +/- some number of counts or inches or whatever) is a manufacturing variable. It is these addresses that are reset in the calibration procedure. When you do micro AF it adds or subtracts from these addresses, as you adjust the scale on the display, until you find it's right. This number tells the camera the distance now corresponds exactly.
The AF sensor also has "tolerances" in how it measures and sends its commands and these can be off slightly in a "manufacturing tolerance" range. The combination of these two tolerances is what can result in pairings that are quite "off" and also make a lens work fine on one camera but not so well on another. I think the "body" side of things is under better manufacturing control than each lens so micro AF will usually do the trick!