7D Mark II - Focus Discussions

The presentation even looks good

Pondrader wrote in post #17826895
Yes but we left it open until today, both 7DII's that I have readily available shoot very well, I know my camera was super, why would another not be..... but I will do everything in my power to never let it out of my site. I don't care what falls off of it.

Jeff,
I might pile on a road trip from Chicago if AL makes the trek.
Alternatively, some were mentioning Eagle season in January around the Quad Cities (Moline Illinois, Davenport Iowa etc)

You mention you have two 7diis currently, one is the loaner, which is the second if yours is still at Canon.?

Have they given an update regarding the CPS tech visiting to help work on your camera?

John,
This should not be the case. You should get very high consistency. My suggestion it to try it in a controlled setting but on a tripod to rule out technique and also rule out the possibility that the AF point might have grabbed a higher contrast adjacent object. If you are next in the field before you get a chance to test, Give Spot AF a try to reduce stray focuses.

TeamSpeed wrote in post #17827504
Angled subject material like that doesn't work well, especially trying to focus on one out of several marks. You need a vertical subject with the measuring "device" off to the side a bit to show you where focus lies. I don't like the bill on the wall method, because it takes too long. You can see how little the AF actually moves from 0 to +19 in my sample below.

Here is my test, long hallway with hardwood floor, using my 500mm. I use spot AF, and the subject just fits around that AF point. LED lighting... Within 4 tries or so I can narrow down exactly where I want it. If you click my signature on the focus genie, I think that sale post has a link to a thread where you can download my DIY focus chart that is a free alternative to what I sell.

Hosted photo: posted by TeamSpeed in
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Hosted photo: posted by TeamSpeed in
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These photos are a great example that demonstrates the fact that the full dof is 16mfa units (not 8 as many claim). You shift of 19 moves the target from the very back of dof to just in front of it.

TeamSpeed wrote in post #17827508
All CFLs and LEDs flicker, due to the AC cycling, correct? Also, I am not sure that it is the flicker necessarily that causes focus shifts? I am pretty sure it is the color temperatures can cause issues with the different wavelengths.

TS is correct, it is the wavelengths that impact Af.
However, LEDs are DC devices, and when plugged into a/c, it gets rectified to DC and thus do not flicker. The exception is when pulse width modulation is used for dimming the LED.

gschlact wrote in post #17827952
TS is correct, it is the wavelengths that impact Af.
However, LEDs are DC devices, and when plugged into a/c, it gets rectified to DC and thus do not flicker. The exception is when pulse width modulation is used for dimming the LED.

My first step was to find daylight balanced incandescents at the hardware store but it was not easy. Everything has gone LED.

Focal warns about LED/fluorescent and about flicker. We have seen results of shots taken in a gym with flicker prone lighting. I thought about the 7D2's anti flicker option so I figured it must effect it somehow after reading FoCa's warning. We know that gym lighting causes exposure shifts but don't recall reading about any focus issues. I must admit I don't have a great understanding when it comes to this at a molecular level so I thought I'd be safe and cover both aspects. This is pretty interesting.

Now that I think about it flicker many only effect that specific software in some way as opposed to a non software method. The few times I did MFA using Dot Tune was last summer, outdoors in daylight.

Flicker from lights, fluoros in particular, will be of different colour casts and so different predominant wavelengths throughout the AC cycle

gschlact wrote in post #17827952
TS is correct, it is the wavelengths that impact Af.
However, LEDs are DC devices, and when plugged into a/c, it gets rectified to DC and thus do not flicker. The exception is when pulse width modulation is used for dimming the LED.

My 11 W LEDs (60 W equiv) do flicker, but I doubt it would cause any issues doing MFA with the dot-tune method.

No biggie in any case. If the MFA was not the best, just do it again. It doesn't take long, and can be done on the fly in the field if you want.

Since canon themselves state that one mark of MFA is 1/8 the dof wide open, I would tend to believe them and instead believe that when I did this test, when I autofocused each time, the focus simply shifted a tiny bit, not allowing us to fully see the effect.

Canon themselves have confused us a bit, because we throw around DOF, which is really depth of field. Canon, in their technical whitepaper, specificially calls out what MFA covers, and that it is 1/8 the single side of depth of focus. However later, Chuck and others mistakenly change the meaning and tell us it is 1/8 the DOF (which we translate to depth of field), which is incorrect.

This indeed means that each mark is very tiny, and is probably closer to the 1/16 you mention than 1/8, once you take all this in. This means that you can shift the depth of field (DOF) around 2-3 in total, not 5 total as others may believe, if you were to use the entire -20 to +20 range.


Some references:

How to do the adjustment? This is from an email by Chuck Westfall:
https://photography-on-the.net …/showthread.php​?p=4522704

TeamSpeed wrote in post #17828107
Since canon themselves state that one mark of MFA is 1/8 the dof wide open, I would tend to believe them and instead believe that when I did this test, when I autofocused each time, the focus simply shifted a tiny bit, not allowing us to fully see the effect.

Canon themselves have confused us a bit, because we throw around DOF, which is really depth of field. Canon, in their technical whitepaper, specificially calls out what MFA covers, and that it is 1/8 the single side of depth of focus. However later, Chuck and others mistakenly change the meaning and tell us it is 1/8 the DOF (which we translate to depth of field), which is incorrect.

This indeed means that each mark is very tiny, and is probably closer to the 1/16 you mention than 1/8, once you take all this in. This means that you can shift the depth of field (DOF) around 2-3 in total, not 5 total as others may believe, if you were to use the entire -20 to +20 range.

Some references:

How to do the adjustment? This is from an email by Chuck Westfall:
https://photography-on-the.net …/showthread.php​?p=4522704

TS,
FWIW,
8 units in front and 8 units in back of the field of focus at the sensor are each respectively directly proportionate to the front and back dof. So if dof is 50/50 they will be 16 equal units, or if dof is such that it is 33/66, the units won't be equal, but still 8 units in front and 8 units in back.

I have gotten email from Chuck this year with explicit clarification on this issue. He also looped in Rudy Winston to create consistent messaging.

gschlact wrote in post #17827859
Jeff,
I might pile on a road trip from Chicago if AL makes the trek.
Alternatively, some were mentioning Eagle season in January around the Quad Cities (Moline Illinois, Davenport Iowa etc)

You mention you have two 7diis currently, one is the loaner, which is the second if yours is still at Canon.?

Have they given an update regarding the CPS tech visiting to help work on your camera?

Hey Guy, Yes I have friend's with 7DII's. Through out the year we camp and most of Ontario shooter's hang out and have fun together. So at that time you get to use and shot with many camera's test them against one another standing around camp, test them in real life shooting not indoors or under lights, Because thats where you find wildlife outdoors. and there are some that come out on top always. The great thing is some guys I hang with have most of the Canon line and big gun safes built into there motor homes to store them. lol I have one friend that buys two of every camera that canon makes so he can evaluate and keep the one that works the way he likes. Having access to there knowledge and gear is something thats invaluable. This loaner is as patrol50 has stated just another 7DII, Im sure canon has more than one can count. And the people I'm dealing with now are very good at what they do, they have the power to make things happen and the expertise to get it done right. They just don't have there hands tide. There is no double talk or trying to out talk you they ask simple questions and get the answers there after to make decisions. I have pushed for nothing only taken what they offer. This for me is coming to an and I'll go back to shooting and posting the good stuff people like to see. I know what my camera was like in the field and how it performed. And I'm sure my next camera will be the same. On the topic of my old camera ...I don't think we will ever know just what they found or didn't find. I asked and the answer was short and empty.

To me AF is only part of the image, IQ and a fast accurate camera that seemingly knowing what it is that you are doing it priceless when shooting fast birds in the best overcast conditions. I will miss that camera, it was a well put together peace of equipment.

Pondrader wrote in post #17828328
Hey Guy, Yes I have friend's with 7DII's. Through out the year we camp and most of Ontario shooter's hang out and have fun together. So at that time you get to use and shot with many camera's test them against one another standing around camp, test them in real life shooting not indoors or under lights, Because thats where you find wildlife outdoors. and there are some that come out on top always. The great thing is some guys I hang with have most of the Canon line and big gun safes built into there motor homes to store them. lol I have one friend that buys two of every camera that canon makes so he can evaluate and keep the one that works the way he likes. Having access to there knowledge and gear is something thats invaluable. This loaner is as patrol50 has stated just another 7DII, Im sure canon has more than one can count. And the people I'm dealing with now are very good at what they do, they have the power to make things happen and the expertise to get it done right. They just don't have there hands tide. There is no double talk or trying to out talk you they ask simple questions and get the answers there after to make decisions. I have pushed for nothing only taken what they offer. This for me is coming to an and I'll go back to shooting and posting the good stuff people like to see. I know what my camera was like in the field and how it performed. And I'm sure my next camera will be the same. On the topic of my old camera ...I don't think we will ever know just what they found or didn't find. I asked and the answer was short and empty.

To me AF is only part of the image, IQ and a fast accurate camera that seemingly knowing what it is that you are doing it priceless when shooting fast birds in the best overcast conditions. I will miss that camera, it was a well put together peace of equipment.

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Are they sending back the repaired camera for evaluation? Can you request some test shots first to try to gage whether they actually fixed something?

Regarding using LED lights for AFMA... I have high-end lights ($80 and up) that I used once. AFMA turned out to be incorrect. I now use only sunlight, or a 4700k Solux lamp.

For something to do 6 months ago I tried to figure out if DO field and distance to target effected MFA results. I started a thread on this. By the numbers below you can see ⅛ DO field will be different.

400mm, 5.6 at 20 ft. Total DOF = .15 ft

400mm, 5.6 at 50 ft. Total DOF = 1 ft

People came and told that that was wrong because it is actually DO Focus even though Canon clearly call it DO Field. They said it was just a reference so people had a visual idea. Personally I can't see how one can't effect the other but I'm not an optics engineer. I got to the I really don't care point anymore point but since this has come up again . I spent a lot of time looking around and found interesting articles. This paragraph is from the digital picture.