MFA tweak...How much is acceptable?

Got an MFA question. How far off is too far? My brand new 85 f1.8 was simply not hitting the focus point. Last night at an awards ceremony I had to switch to the 135L and stand in the back of the room. The images from the 85 weren't even looking sharp on the LCD, so I knew they'd be crap on the laptop. Today I set up a jerry-rigged MFA session in our hotel room and managed to dial in the 85 to what seems to be a sharp focus. But it's an adjustment of -6. Is that acceptable (assuming it really is now hitting focus)? Or should I send it in to Canon for calibration?

You have 14 more places before you get to -20. I don't think -6 is so bad. If it is brand new like you say, return it and get another.

Read this, it's very informative. An MFA of -6 on your camera might be a +2 or 0 on mine. There are certain tolerances, and being able to adjust the focus via MFA was meant to address the variation in those tolerances. If it works at -6, keep it and use it at -6.

I did send back a third-party lens (two copies, in fact) because of focus issues, though. In that case, the lens required a [rather extreme] MFA with relatively close subjects, and a completely different MFA with farther away subjects. There was no way to reconcile the two, and I decided it wasn't worth the hassle.

Recently, though, I dialed in a -4 MFA on a lens I purchased used off of Ebay and it works absolutely perfectly for me. I couldn't be happier. This particular 28-70 f/2.8 L may be 10 years old, but I wouldn't trade it for anything, MFA and all.

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Originally Posted by M_Six

Or should I send it in to Canon for calibration?

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I have older models that do not have MFA. Anyone have an idea of cost to send canon a body and lens for calibration?

Great results with -6 mfa....I wouldn't hesitate to keep the lens.

Thanks, All. I'll run a proper MFA drill this weekend. I might even buy Reikan Focal and give that shot. My 50mm f1.4 could use some tweaking as well.

FoCal is wonderful - equivalent results to what I get with the LensAligh Pro, not all that much faster...but the automation (which I think requires above the base version, I have the Pro) means I can walk away and let the work be done for me...

A 6-unit adjustment is no biggie...I'd be concerned if a new lens needed >15 units, and would likely exchange it.

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Originally Posted by clemmb

I have older models that do not have MFA. Anyone have an idea of cost to send canon a body and lens for calibration?

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So, anyone have an idea on cost for Canon to calibrate my lens and camera? 24-105 and 1DmkIIN

Last I heard, you'll spend close to two hundred dollars. If you buy the $100 CPN package, you'll save 30% and get a couple cleanings out of the deal... Or you can buy a 5d3 and not worry about it. Come on. You know you want to:)

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Originally Posted by andnowimbroke

Or you can buy a 5d3 and not worry about it. Come on. You know you want to:)

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No, actually I love my 1DmkIIN. I really want the 1DmkIV but now that it has been removed the used prices will probably go up:(
I would really like the 1DX but $6,799, OUCH:eek:

I keep staring at the markIV in the refurb store and hoping I could hit the 20% off day AND have money to pull the trigger. Always sumthung:)

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Originally Posted by andnowimbroke

I keep staring at the markIV in the refurb store and hoping I could hit the 20% off day AND have money to pull the trigger. Always sumthung:)

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Same thing with the 5D MkII for me. Last time it was $1495 delivered, but I had just bought the 7D and couldn't swing it. Didn't see any MkIIs this time around.