1DX - Ai Servo Issue - Low light focus failure! Final Update 05/09/12

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Sycotek

EOS 90D
Mar 26, 2012
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Re: 1DX - Ai Servo Issue - Low light focus failure! UPDATE 31/07

Peter Dawson said:
Last night I finally got a chance to test the AF in low light. I shot a little tennis action with very poor flood lights. 70-200mm 1/1000s, F2.8, ISO12800. IMO this is pretty poor lighting and the AF was incredible. I did not notice any difference when using 12FPS or < 10FPS (I also tried the zone AF, which I never trusted much on the 7D, and it was amazing how the points danced around the players torsos - I was grinning ear to ear). So in a nut shell, I'm very stoked with the AF performance.

I then decided to try and reproduce the H speed AI AF issue, and sure as nuts, in lower lighting situations the 12FPS AI AF just racked the lens back and forth. Switch to 10FPS and locks first time. I got home and tried the 5D II and it also locks first time. This was by no means an extensive test and I did not try and find that exact lighting point where the 12FPS falls apart, but as a reference 70-200, F2.8, 1/80, ISO25800.

So thats +1 with a low light AF gremlin :( (not that I'll ever shoot in these conditions in AI AF, but still . . . .)

Any thoughts about the metering being 0-20ev and the af being -2ev-20ev ? I can' recall where I read the dx constantly meters the scene in servo which could be a reason?
 
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Peter Dawson

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Re: 1DX - Ai Servo Issue - Low light focus failure! UPDATE 31/07

I had actually not realized the metering range differed to the AF range until reading it this morning. I never did quite understand why the 7D's frame rate dropped to 4FPS when the lighting was poor, even when in MF. Maybe this is a similar scenario? Along similar lines then, if you disable iTR, use a WB mode other than AWB and manual exposure mode, then are you essentially negating the need metering, in which case eliminating the metering range from the scenario? Maybe worth a test when i get home from work this afternoon.

as an aside, do you know if there was ever an explanation for the 7D frame rate drop in low light?
 

Skulker

PP is no vice and as shot is no virtue
Aug 1, 2012
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Re: 1DX - Ai Servo Issue - Low light focus failure! UPDATE 31/07

I've noticed the 7D was slower in dark situations. But as some one said above you don't drive a fast car flat out in the rain, or the dark come to that. Is it really reasonable to expect world beating good conditions in poor conditions? I don't think so.

FWIW I never realzised how much of an step up the 1Dx would be compared to the 7D. Not only will it focus better. It produces pictures that can be cropped harder so I don't miss the 1.6 crop on the sensor. It also drives the lenses much faster. I used to turn off the search for focus if AF is not posible feature, there is no need to do this with the 1Dx because it drives the lens so fast its quicker to wait the second or so it takes to run the lens from stop to stop, rather than the 3 seconds the 7D took. All this on top of the breathtaking low light IQ.

BTW Dont think I don't like the 7D. Its a great camera. To go back to the car senario, I like my Volvo and its been great for me, but its not a super car.

Spelling edited 11:30
 
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Peter Dawson

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Re: 1DX - Ai Servo Issue - Low light focus failure! UPDATE 31/07

I Quite agree Skuller.

I also upgraded from a 7D and the difference is incredible. The 7D slow FPS caused lots of noise when the camera was released. I dont think there was ever an explanation, nor a fix, but because noone shot in those conditions, the issue went on the back burner.

Just for the record, I have yet to experience the Err 80 issue with my camera. I have never used the orientation linked AF points function and that menu item is still set to the default "same for both orientations" option.

Quick question. Do you normally turn the camera off prior to changing lenses or just change them. I never turn the camera off before changing lenses. Is this wrong?
 
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Sh1n1ng Forc3

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Re: 1DX - Ai Servo Issue - Low light focus failure! UPDATE 31/07

Peter Dawson said:
I had actually not realized the metering range differed to the AF range until reading it this morning. I never did quite understand why the 7D's frame rate dropped to 4FPS when the lighting was poor, even when in MF. Maybe this is a similar scenario? Along similar lines then, if you disable iTR, use a WB mode other than AWB and manual exposure mode, then are you essentially negating the need metering, in which case eliminating the metering range from the scenario? Maybe worth a test when i get home from work this afternoon.

as an aside, do you know if there was ever an explanation for the 7D frame rate drop in low light?

This is great thinking. I will test this out as well. I will do all the metering manually (manual WB, disable iTR full manual mode) and let the camera just worry about AF and see what happens.
 

neuroanatomist

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Re: 1DX - Ai Servo Issue - Low light focus failure! UPDATE 31/07

Sh1n1ng Forc3 said:
This is great thinking. I will test this out as well. I will do all the metering manually (manual WB, disable iTR full manual mode) and let the camera just worry about AF and see what happens.

I predict no difference. I don't believe there's a way to actually turn off metering. Setting everything to manual means the camera won't actually do anything with the metering information, but it's still going to collect it, and I would bet that if that's the cause of the problem then setting everything to manual will be irrelevant. Worth a try though…
 
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Richard Lane

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Re: 1DX - Ai Servo Issue - Low light focus failure! UPDATE 31/07

When I did my low light, low contrast tests, I used single point with 4 expansion points.

I would like to reiterate that I don't think this is a low light issue. It is more of a "low contrast" issue. When I did my tests I used a low contrast solid color gray towel, in AI Servo @ ISO 25,600 and the 1DMKIV and 1DX had a difficult time locking focus onto the center of the towel. Then when I focused on the edge of the gray towel, there was no problem focusing at all, even though the light hadn't changed and it was still considered very low light @ 25,600.

Then yesterday I tried a coloroful "high contrast" striped beach towel also @ 25,600 in low light, and the 1DX focus locked on the center of the towel with no problem at all. Then I tried the gray towel again as a control and the 1DX wouldn't lock onto the center of the low contrast gray towel. Please note that the light source hadn't changed at all. So, the issue was more with a "low contrast target" and "not a low light target."

However, even in low light @25,600 ISO plus low contrast, it was still very easy to overcome any deficiencies by simply aiming for the "edge" of the gray towel whereas there was no focusing issue at all, even in AI Servo at 12fps.

Just for completeness, as soon as any reasonable amount of light was introduced into the scene, the 1DX locked right onto the center of the low contrast gray towel. Also from the other day, One Shot Mode had no problem focusing on the center of the low contrast gray towel even in low light.

I didn't use the All 61 Focus point mode, which would make it nearly impossible to focus on the edge or corner of the low contrast gray towel since the camera doesn't know what I want it to do.

I hope that helps!

As far as changing lenses with the camera on or off, it is probably a good idea to try and change the lens with the camera off, since it has been said that when the camera is on the charged sensor may attract more dust. So my practice has been, when I'm not in a rush I shut the camera off, and if I'm in the middle of shooting something and I need to change lenses quickly, then I leave the camera on.

Rich

Edited: I don't think this is a metering issue either. If it were a metering issue or low light issue then why was I able to focus on the "EDGE" of the low contrast gray towel in low light, and why was I able to focus on the "center" of the higher contrast srtiped towel in the same low light? In my opinion, I wouldn't call any of these test results an issue at all.
 

Viggo

EOS R5
Dec 13, 2010
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Re: 1DX - Ai Servo Issue - Low light focus failure! UPDATE 31/07

Just a question here, so how is the 1d X af?

How many keepers do you have of a runner, a car speeding towards you, kids running around, birds leaving a branch , simple tasks compared to what Canon says it can..

I remember the D4 gave of 100% tacksharps and honestly would like to hear if it's as good as that... i found the mk4 pretty average for a simple test of a speeding biker, i had to chose the few focused one's and not the right moment. Is it perfect under good light and simple movements?
 

Sycotek

EOS 90D
Mar 26, 2012
111
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Re: 1DX - Ai Servo Issue - Low light focus failure! UPDATE 31/07

Viggo said:
Just a question here, so how is the 1d X af?

How many keepers do you have of a runner, a car speeding towards you, kids running around, birds leaving a branch , simple tasks compared to what Canon says it can..

I remember the D4 gave of 100% tacksharps and honestly would like to hear if it's as good as that... i found the mk4 pretty average for a simple test of a speeding biker, i had to chose the few focused one's and not the right moment. Is it perfect under good light and simple movements?

Hi Mate - in good light, tack sharp nothing dropped, in low light (where i normally shoot and hence the problem) it does drop probably in the realm of 8% and not all images are tack sharp - it is a bit like the lottery in low light at 12 fps.

However at 10fps or lower I haven't seen a frame dropped in similar conditions.
 

Viggo

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Dec 13, 2010
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Re: 1DX - Ai Servo Issue - Low light focus failure! UPDATE 31/07

Sycotek said:
Viggo said:
Just a question here, so how is the 1d X af?

How many keepers do you have of a runner, a car speeding towards you, kids running around, birds leaving a branch , simple tasks compared to what Canon says it can..

I remember the D4 gave of 100% tacksharps and honestly would like to hear if it's as good as that... i found the mk4 pretty average for a simple test of a speeding biker, i had to chose the few focused one's and not the right moment. Is it perfect under good light and simple movements?



Hi Mate - in good light, tack sharp nothing dropped, in low light (where i normally shoot and hence the problem) it does drop probably in the realm of 8% and not all images are tack sharp - it is a bit like the lottery in low light at 12 fps.

However at 10fps or lower I haven't seen a frame dropped in similar conditions.

Wow, that's awesome to hear, since I'm aware of the 12fps lowlight problem, and counting on a fix from Canon, and i can easily live with 10 fps in lowlight.

Thanks! Seems the 1d X can makes use of the 12 fps, something the mk4 never could at 10...
 

Viggo

EOS R5
Dec 13, 2010
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Re: 1DX - Ai Servo Issue - Low light focus failure! UPDATE 31/07

Any new updates here?

I tried with my 1d X, and where the One Shot still locks, both the 12 fps (H) and the 3-10 fps (L) I tried stops working. That isn't a problem, and fully understandable.

Where the 3 fps lovked, the 12 fps locked. It seemed very much like it to me that the framerate didn't make a difference and that Ai Servo gave up no matter the framerate, but the One Shot kept going.

Ai Servo locked with very little light and contrast at f1,4, 1/60s at iso 16k.

*update* Tried on my grey couch and at 12 fps (H) it locks, at 8 fps (L) it doesn't ???

*UDPATE 2* I just realized my battery was at 31% (still two dots) and Canon states:

"EOS-1D X maximum continuous shooting speed is restricted to 10 fps when the battery charge is less than 50%, or when the ISO speed is above 32,000. If the camera's internal temperature is low and ISO speed above 20,000, maximum continuous shooting speed is restricted to 10 fps"

So I guess my tests tonight isn't useable, I'll charge up and try again.
 

Viggo

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Dec 13, 2010
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Re: 1DX - Ai Servo Issue - Low light focus failure! UPDATE 31/07

Charged the battery and tried again with the 35 L and the results; exactly the same as before. 12 fps H and 8 fps L locked at exactly the same thing equally quick and they both lost their ability to lock at the same amount contrast and light. One shot still worked until too dark to see and beyond.

In 12 fps H mode it locked on the black zipper of my black Induro tripod bag with f1,4 @ 1/60s 6400 iso. I think that's pretty crazy... Shot with center point, no expansion.

My serial number is: 053011xxxxxx
 

Sycotek

EOS 90D
Mar 26, 2012
111
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Re: 1DX - Ai Servo Issue - Low light focus failure! UPDATE 31/07

Viggo said:
Charged the battery and tried again with the 35 L and the results; exactly the same as before. 12 fps H and 8 fps L locked at exactly the same thing equally quick and they both lost their ability to lock at the same amount contrast and light. One shot still worked until too dark to see and beyond.

In 12 fps H mode it locked on the black zipper of my black Induro tripod bag with f1,4 @ 1/60s 6400 iso. I think that's pretty crazy... Shot with center point, no expansion.

My serial number is: 053011xxxxxx

Remembering that my main issue wasn't even in remotely low light - it is a strange issue with seems to effect a fair few bodies. I can make it fail in daylight - i can just about predict where it will fail at 12 fps.

However:

I spat the dummy with mine - I have had it die on my twice in one wedding shooting in broad daylight - two days ago, one shot - 70-200 f2.8 II with 600ex rt on board (fill flash) - iso 100 1/600 at f4 - lens locks up and refuses to rack, had to turn it off and on again to start working.

Canon are replacing it tomorrow when I get back to Australia from overseas, however after not hearing back from them for 4 weeks I had to threaten to dump my Canon gear to get their attention.

The most annoying thing is even the head of Canon Australian and CPS Australia won't comment on the findings. They are basically ignoring the issue... it's disheartening.

I'm not sure if you have noticed there was a report of olympic shooters having issues during the games where canon reported 5-6 months to fix the af issues...

---

On a side note - we were in a reception with 5D2, 5D3, 1D4, 1Ds3, 1DX and 7D. The 5D3 and 1DX consistently had issues locking onto dark skin (not so good if you are working in asia). 5D2 actually had very little issues. on the 1DX I had to actually manual focus to get any shots which to me is rather stupid.

Using the 600EX for af assist did help (and didn't lock up when using at EF 50 f1.4)

---

I will have to redo all my tests with the new body tomorrow.
 

neuroanatomist

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Re: 1DX - Ai Servo Issue - Low light focus failure! UPDATE 31/07

Sycotek said:
The 5D3 and 1DX consistently had issues locking onto dark skin...
I haven't noticed this with the 1D X, neither on One Shot nor in AI Servo with iTR enabled.


EOS 1D X, EF 70-200mm f/2.8L IS II USM @ 200mm, 1/250 s, f/2.8, ISO 4000


EOS 1D X, EF 70-200mm f/2.8L IS II USM @ 200mm, 1/320 s, f/2.8, ISO 4000
 

Sycotek

EOS 90D
Mar 26, 2012
111
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Re: 1DX - Ai Servo Issue - Low light focus failure! UPDATE 31/07

neuroanatomist said:
Sycotek said:
The 5D3 and 1DX consistently had issues locking onto dark skin...
I haven't noticed this with the 1D X, neither on One Shot nor in AI Servo with iTR enabled.

You light is excellent there f2.8 1/320 iso4K - The conditions we were in need flash if we could lock on - it was iso 25K territory f2.0 1/125.

Still noted :)
 

Sycotek

EOS 90D
Mar 26, 2012
111
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Re: 1DX - Ai Servo Issue - Low light focus failure! UPDATE 21/08

Picked up the new body and ran a simple test: finding's added to initial post.
 

Sycotek

EOS 90D
Mar 26, 2012
111
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Re: 1DX - Ai Servo Issue - Low light focus failure! Last Update September 2012

Final update on main post :)

Finally
 

neuroanatomist

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Sycotek said:
Anyway - since I hadn't heard from Canon, chasing it up every day I actually switched over to a D4 setup...

Just curious...what lenses are you routinely using with the D4, and are you pleased with the Nikon counterparts to the Canon lenses you used previously? Or by D4 did you mean 1D Mark IV?
 

Sycotek

EOS 90D
Mar 26, 2012
111
0
neuroanatomist said:
Sycotek said:
Anyway - since I hadn't heard from Canon, chasing it up every day I actually switched over to a D4 setup...

Just curious...what lenses are you routinely using with the D4, and are you pleased with the Nikon counterparts to the Canon lenses you used previously? Or by D4 did you mean 1D Mark IV?

Nikon D4 - I have only replaced my core lenses: 24-70 f2.8, 70-200 f2.8 VR II and the 50 1.4G (which frankly is superb). Build wise the nikkor glass on the face value seems to be built better and nice little touches such as the front element on the workhorse glass has a visible rubber gasket. The tripod collar on the 70-200 on a probody acts as a stand in landscape mode. All lenses I have purchased so far have come with bags/pouches and hoods.

Majority of their lenses are sealed and have rear rubber gaskets (G's anyway) including the 50mm 1.4.

IS to me seems better then VR II however that may just be because VR II is quieter and *feels* like it isnt doing much - no more then 1/3 stop at best if anything.

70-200 2.8 II vs 70-200 VR II - I'd probably give it to canon in terms of wide open sharpness (let's face it, it's a killer lens) 24-70 Nikkor hands down (the two ef 24-70's I owned were horrible) and the 50 easily the nikkor - fast quiet accurate - and doesnt hunt. Actual drive speed of the lenses on a probody feels to be as quick as the L grade ef ultrasonics, if not a little quicker (again that could be the fact they are quieter and the af on the d4 (in my experience) is just quicker overall)
 
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