What do they actually do when they calibrate a camera?

JohnN

JohnN

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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'm happy to have it done professionally, its not much £60 and for the peace of mind worth it in my eyes and its relatively close so I'll get it done in a day anyway, I'm just curious.
 
The normal phase-detect AF system uses sensors in the base of the camera which are in a simulated focal plane position. If it's not dead right, the AF will be out. Calibration makes sure it is. It's not user-adjustable.

Then in turn, the lens must be calibrated to the camera so when it is instructed to move to the estimated sharp focus position, it moves the right amount. That's what AF micro adjustment does. If they do make changes to your camera, the lenses must all be recalibrated to the new setting.

Contract-detect AF in live view is different. It's independent of either the camera or lens as it reads directly off the image sensor, and so if it gets a good lock on a well-lit contrasty target, it's extremely accurate. It's a good way of checking if the normal AF is out, by comparing the two on the same subject. Use a tripod ;)
 
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HoppyUK said:
The normal phase-detect AF system uses sensors in the base of the camera which are in a simulated focal plane position. If it's not dead right, the AF will be out. Calibration makes sure it is. It's not user-adjustable.

Then in turn, the lens must be calibrated to the camera so when it is instructed to move to the estimated sharp focus position, it moves the right amount. That's what AF micro adjustment does. If they do make changes to your camera, the lenses must all be recalibrated to the new setting.

Contract-detect AF in live view is different. It's independent of either the camera or lens as it reads directly off the image sensor, and so if it gets a good lock on a well-lit contrasty target, it's extremely accurate. It's a good way of checking if the normal AF is out, by comparing the two on the same subject. Use a tripod ;)
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I didn't realise that....Surprising what you pick up from other peoles posts
Thank you
 
I didn't know that either cheers Richard.

When I get mine done they want to do the body only first, but I may take a lens or two anyway.

Cheers again.
 
When i inquired about this, this is what fixation said

I believe you are talking about us matching your lenses precisely to your camera body to over ride the tolerance that sometimes allows slight differences to exist between camera bodies and lenses.

In this case we would ask you to send your camera body and lenses to us. We would first recalibrate the AF sensor on the camera body which costs £160.00 Plus VAT. Your lenses would then be checked with your camera body, and if the focus results are still inacurate the cost will then be £80.00 Plus VAT per lens thereafter.
 
Euan said:
When i inquired about this, this is what fixation said

I believe you are talking about us matching your lenses precisely to your camera body to over ride the tolerance that sometimes allows slight differences to exist between camera bodies and lenses.

In this case we would ask you to send your camera body and lenses to us. We would first recalibrate the AF sensor on the camera body which costs £160.00 Plus VAT. Your lenses would then be checked with your camera body, and if the focus results are still inacurate the cost will then be £80.00 Plus VAT per lens thereafter.
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Expensive business.

While it's nice to have everything zeroed up exactly, if you have AF microadjust on all your camera bodies then, within reason, it doesn't matter.

Use AF microadjust, and calibrate all lenses on all bodies. It's possible that they will be factionally different, and the same lenses will be different on each body, but the custom microadjust sorts that out.

I'm pretty sure that is the case, but since I don't have two bodies with AF microadjust to hand, I can't check it. In other words, while AF microadjust is used to calibrate different lenses, what it actually does is tweak the software in the body, which knows which lens is fitted, and tells the lens to move to a fractionally different position to achieve best sharpness. The lens itself is unchanged, and just does what it's told by whatever camera it is fitted on. Maybe someone could confirm this.
 
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HoppyUK said:
Contract-detect AF ...
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:eek: I really hope this mode doesn't become mainstream -- this stuff already costs me far too much.

Hmmm... coin-op AF cameras... :lol:
 
^^^
Sometimes it isn't an issue with AF, sometimes the high pass filter needs adjustment, like my 50D did.

@ Op

Lehmann's offer a pretty good service...
 
acs said:
:eek: I really hope this mode doesn't become mainstream -- this stuff already costs me far too much.

Hmmm... coin-op AF cameras... :lol:
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What do you mean you hope contrast-detect doesn't become mainstream? It already is. All compacts use it, all the compact MILC system cameras use it, and when they can get it to work a bit better, we'll all be using it.

Contrast-detect has several fundamental advantages - accuracy, can read from anywhere in the frame (and track things as they move around it), and cost. Right now though it's a bit slow, and needs better light than normal phase-detect.
 
acs said:
Hmmm... coin-op AF cameras... :lol:
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If you have Wi-Fi transmitter on the camera...

"Your licence for Firmware v1.2.5 has expired. Please enter your credit card details to continue using this camera with full functionality or press 'Demo' to continue in Demo Mode (Program mode with JPEG output only, no autofocus)"
 
Thanks goodness I can't mess around with calibrating my lowly Nikon's - have to say though, never had the problem on anything I've had.
 
aye, that seems to be the thing with the newer models such as the 7D, its almost like now you can fix it you need to!
 
JohnN said:
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'm happy to have it done professionally, its not much £60 and for the peace of mind worth it in my eyes and its relatively close so I'll get it done in a day anyway, I'm just curious.
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Where are you taking it in? £60 seems relatively cheap for calibration
 
H Lehmann, with any luck today - its £60 plus VAT, but thats not a massive difference.
 
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hehe, scrap that - not going today they're too busy :(

Oh by the way the way H Lehmann do it confirmed as they test a body with a "golden lens" and vice-versa, so they don;t actually calibrate the specific lens to a specific body, in my opinion a better way of doing it anyway.
 
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