7DMKII Focus keeper rate ideas?

[Loswr]

I was afraid I'd get asked that
Tonight I'm scrutinising a jar of garlic with the camera sitting on the table... 8)
Oh and the 2mm difference (at a guess) isn't every shot... 8 are fine, 2 are off... with miniscule differences between the great ones.

That's a lot of garlic!

Reasonable target, though. I expect the variation you're seeing is normal. But it likely wouldn't hurt to call Canon and ask.

 

[Bundu]

i don't think you need to have your af settings that high. i use -2,0,0 for bif and it is plenty fast enough for birds flying straight at me. i experimented with some higher settings and found it to be inconsistent as if the af was overreacting.
[/quote]

@candc Thank you, will definitely try those settings. There is just so much that you can change/fine tune......
A LOT to learn yet

 

[Mt Spokane Photography]

AF systems in cameras are variable, and some lenses are more variable than others. The 50mm f/1.8 has a lot of variability, for example.


http://www.reikan.co.uk/focalweb/index.php/online-tools/lenscamera-information/

 

[Sella174]

Shocking. Just simply shocking. Plus unbelievable.

Care to elaborate?

I'm not 100% satisfied, and rather than send the body in for fruitless repairs I'm just wondering if I have anything to worry about...

With current technology, for the 7DII to exhibit any form of AF problems is in my opinion totally unacceptable. This is a professional-grade camera and to expect any professional (where time equals money) to first calibrate the lens and camera combination is just plain wrong. What will happen if such a professional photographer rents (or borrows) a lens at the last moment, but must now spend an hour first to calibrate the combination? That is if he actually has his calibration tools with him!

Any professional-grade equipment must work 100% perfectly straight out of the box.

 

[sanj]

Shocking. Just simply shocking. Plus unbelievable.

Care to elaborate?

I'm not 100% satisfied, and rather than send the body in for fruitless repairs I'm just wondering if I have anything to worry about...

With current technology, for the 7DII to exhibit any form of AF problems is in my opinion totally unacceptable. This is a professional-grade camera and to expect any professional (where time equals money) to first calibrate the lens and camera combination is just plain wrong. What will happen if such a professional photographer rents (or borrows) a lens at the last moment, but must now spend an hour first to calibrate the combination? That is if he actually has his calibration tools with him!

Any professional-grade equipment must work 100% perfectly straight out of the box.

In my experience (just Canon) it works almost always right out of the box. But I see your point. Is this just how cameras are or there is a QC issue? Is this not same with other brands of cameras?

 

[Sella174]

In my experience (just Canon) it works almost always right out of the box. But I see your point. Is this just how cameras are or there is a QC issue? Is this not same with other brands of cameras?

I think it is more of a lowering-production-cost-through-lowering-quality-control situation. I never had any problems when using old Canon lenses on my old Canon cameras (film and digital). Only when I started purchasing/borrowing new lenses did I encounter focusing issues - all of which could have been corrected using AFMA, which my old cameras did not possess.

 

[Valvebounce]

Hi Sella.
I read posts like this and realise you either have bottomless pockets stuffed with money or lack a clear understanding of manufacturing tolerances.
To have to calibrate a lens to a body is in my opinion not only acceptable but necessary. Each body and each lens are made to a plus or minus tolerance, measured in 0.01 or 0.001mm or even smaller! If both lens and body are middle limit, or out in complementary directions, ie the tolerances cancel all will be fine, if they are out in the other direction the tolerances are additive, I suspect each lens and each body is allowed + or - 10 AFMA POINTS and given this, a worst case scenario could see you needing all 20 AFMA points. (I don't know how many bits of a mm = 1 AFMA point)
To halve the tolerance range could add a significant percentage (I don't know how much so I won't quantify it) to the cost through extra manufacturing time and component scrapage! And then what you still have a tolerance, yes smaller, and still need to calibrate! So halve the tolerance again, can you see where this is going? Except the next reduction will cost more than the first reduction!
Personally I'd sooner be able to afford a camera and lenses and calibrate than dream about equipment that is perfect, + or - 0.0000000mm and doesn't need calibration.
14 yrs toolmaking working to tenths of a thousandth of an inch so I know a bit about increase of time with lower limits and scrapage rates. Conversely I don't know how much they would cost Canon as I don't work there!

Cheers, Graham.

With current technology, for the 7DII to exhibit any form of AF problems is in my opinion totally unacceptable. This is a professional-grade camera and to expect any professional (where time equals money) to first calibrate the lens and camera combination is just plain wrong. What will happen if such a professional photographer rents (or borrows) a lens at the last moment, but must now spend an hour first to calibrate the combination? That is if he actually has his calibration tools with him!

Any professional-grade equipment must work 100% perfectly straight out of the box.

 

[DominoDude]

To answer the question about how much is 1 unit on the AFMA scale: It is 1/8th of the current lens DoF at its widest aperture.

Edit: Adding source to the above. Rudy W @ Canon, as described in this article -> http://www.learn.usa.canon.com/resources/articles/2011/af_microadjustment_article.shtml

 

[Sella174]

Hi Sella.

Howdy.

I read posts like this and realise you either have bottomless pockets stuffed with money or lack a clear understanding of manufacturing tolerances.

The bolded statement I do not understand, giving what you explain later on in the same post (quoted below).

To have to calibrate a lens to a body is in my opinion not only acceptable but necessary. Each body and each lens are made to a plus or minus tolerance, measured in 0.01 or 0.001mm or even smaller! If both lens and body are middle limit, or out in complementary directions, ie the tolerances cancel all will be fine, if they are out in the other direction the tolerances are additive, I suspect each lens and each body is allowed + or - 10 AFMA POINTS and given this, a worst case scenario could see you needing all 20 AFMA points. (I don't know how many bits of a mm = 1 AFMA point)
To halve the tolerance range could add a significant percentage (I don't know how much so I won't quantify it) to the cost through extra manufacturing time and component scrapage! And then what you still have a tolerance, yes smaller, and still need to calibrate! So halve the tolerance again, can you see where this is going? Except the next reduction will cost more than the first reduction!
[..]14 yrs toolmaking working to tenths of a thousandth of an inch so I know a bit about increase of time with lower limits and scrapage rates.[..]

True. Now apply it in reverse: Double the tolerance and you reduce the production cost by a significant percentage (unknown, as you stated) due to a lower scrapping rate.

Personally I'd sooner be able to afford a camera and lenses and calibrate than dream about equipment that is perfect, + or - 0.0000000mm and doesn't need calibration.

I partly agree. Canon, as an example, could use a larger tolerance criterion for the "Rebel" to reduce cost, but must then offer AFMA in those models. In "professional"-grade gear (both cameras and lenses), although also offering AFMA, it should not be necessary because of the more accurate machining of the mechanical/physical parts.

But that's just my opinion. I like good stuff that work 100% out of the box and don't mind paying extra for that convenience.

 

[DominoDude]

I just showed this thread to a psychologist who's used to working with obstinate and "damaged" children; she almost wet herself and asked to borrow the bathroom. I don't know if it was from laughter, or if she got a glimpse of future revenues...

 

[Marsu42]

I just showed this thread to a psychologist who's used to working with obstinate and "damaged" children; she almost wet herself and asked to borrow the bathroom. I don't know if it was from laughter, or if she got a glimpse of future revenues...

 

[Loswr]

I read posts like this and realise you either have bottomless pockets stuffed with money or lack a clear understanding of manufacturing tolerances.

+1 on the latter. The former wouldn't impact Canon's choices for manufacturing tolerances in general.

Any professional-grade equipment must work 100% perfectly straight out of the box.

That's a nice pipe dream. Cinematographers spend substantial time calibrating new lenses costing tens of thousands of dollars.

I think it is more of a lowering-production-cost-through-lowering-quality-control situation. I never had any problems when using old Canon lenses on my old Canon cameras (film and digital). Only when I started purchasing/borrowing new lenses did I encounter focusing issues - all of which could have been corrected using AFMA, which my old cameras did not possess.

It's more of a your-old-gear-lacked-sufficient-resolution-to-make-the-problems-evident situation.

 

[Sella174]

I just showed this thread to a psychologist who's used to working with obstinate and "damaged" children; she almost wet herself and asked to borrow the bathroom. I don't know if it was from laughter, or if she got a glimpse of future revenues...

The trouble with "rules" on forums are that they only prohibit the ridicule of an individual, and not that of several (unnamed) individuals as a group.

That said, if your psychologist had that reaction from this thread, then she's obviously not ready for the real world.

 

[Sella174]

Any professional-grade equipment must work 100% perfectly straight out of the box.

That's a nice pipe dream. Cinematographers spend substantial time calibrating new lenses costing tens of thousands of dollars.

Are you a cinematographer that spends valuable time calibrating new lenses because the manufacturer didn't do it (properly)? Are you even a cinematographer? Unless you can answer yes to both questions, then what you wrote is hearsay and of absolutely no value whatsoever.

I think it is more of a lowering-production-cost-through-lowering-quality-control situation. I never had any problems when using old Canon lenses on my old Canon cameras (film and digital). Only when I started purchasing/borrowing new lenses did I encounter focusing issues - all of which could have been corrected using AFMA, which my old cameras did not possess.

It's more of a your-old-gear-lacked-sufficient-resolution-to-make-the-problems-evident situation.

A yes, the old standard put-down. Give it rest, it's getting really old ... and totally redundant, because I do own new photographic gear ... just not Canon.

 

[Valvebounce]

Hi Sella.
I give a plus one on that! But then I don't think I need help from someone with ologist in their title, I could be wrong?

Cheers, Graham.

That said, if your psychologist had that reaction from this thread, then she's obviously not ready for the real world.

 

[Valvebounce]

Hi Domino Dude.
I was aware of that, what I was referring to was how many 0.001mm manufacturing errors cause 1 AFMA unit of correction to be needed.

Cheers, Graham.

To answer the question about how much is 1 unit on the AFMA scale: It is 1/8th of the current lens DoF at its widest aperture.

Edit: Adding source to the above. Rudy W @ Canon, as described in this article -> http://www.learn.usa.canon.com/resources/articles/2011/af_microadjustment_article.shtml

 

[Loswr]

I think it is more of a lowering-production-cost-through-lowering-quality-control situation. I never had any problems when using old Canon lenses on my old Canon cameras (film and digital). Only when I started purchasing/borrowing new lenses did I encounter focusing issues - all of which could have been corrected using AFMA, which my old cameras did not possess.

It's more of a your-old-gear-lacked-sufficient-resolution-to-make-the-problems-evident situation.

A yes, the old standard put-down. Give it rest, it's getting really old ... and totally redundant, because I do own new photographic gear ... just not Canon.

Interesting that you interpret it as a put down, when it's a simple fact. With 35mm film and lower resolution dSLRs, subtle focus errors aren't as obvious. When the 7D came out, upgraders from the 40D claimed it was soft. In fact, the nearly double resolution of the sensor meant focus errors were much more evident (camera shake, too). The same is true with slower lenses. An 18 MP xxxD user may not notice slight backfocus with their f/3.5-5.6 zoom, but could with a 50/1.8.

 

[Loswr]

To answer the question about how much is 1 unit on the AFMA scale: It is 1/8th of the current lens DoF at its widest aperture.

Edit: Adding source to the above. Rudy W @ Canon, as described in this article -> http://www.learn.usa.canon.com/resources/articles/2011/af_microadjustment_article.shtml

Actually, Rudy Winston is incorrect. It's not 1/8th the depth of field, but 1/8th the depth of focus. The latter is the sensor-side equivalent of DoF, measured in microns. DoF changes with subject distance, depth of focus is relatively unaffected by subject distance. That distinction means the magnitude of the DoF shift for a given AFMA value changes with subject distance, which is the basis for the recommendation to calibrate at 25-50x the focal length unless you're consistently using the lens at a closer distance.

 

[Marsu42]

Actually, Rudy Winston is incorrect. It's not 1/8th the depth of field, but 1/8th the depth of focus. The latter is the sensor-side equivalent of DoF, measured in microns. DoF changes with subject distance, depth of focus is relatively unaffected by subject distance.

Thanks for pointing this out, I was wondering about this very thing when I read the article.

Personally, I find the text to be a bit too much on the marketing talk side for my taste - and it's funny that the 2011 text points out that afma is totally fantastic and then they removed it from the 60d right after :->

 

[Khnnielsen]

Any professional-grade equipment must work 100% perfectly straight out of the box.

That's a nice pipe dream. Cinematographers spend substantial time calibrating new lenses costing tens of thousands of dollars.

Are you a cinematographer that spends valuable time calibrating new lenses because the manufacturer didn't do it (properly)? Are you even a cinematographer? Unless you can answer yes to both questions, then what you wrote is hearsay and of absolutely no value whatsoever.

I am not a cinematographer, but I can confirm that statement. When we buy gear at at the news station I used to work for, we also spend some time to calibrate the gear.

For example: We bought a $30,000 lens to go with our new $30,000 camera. Afterwards we had to spend some time adjusting backfocus in order to make sure, that the focus is constant throughout the zoom range.

And that is perfectly fine.