For all those who think the 5D2's AF sucks in low light...

Took this picture in Beijing, China a couple of days ago...almost no light at all...(the EXIF speaks for itself...still underexposed at ISO 25,600, f2.8, 1/20s)

I took several test shots (yes, using the centre point only) and each time it locked on without hesitation...because of the high ISO/low shutter speed/fast aperture it appears to be bright, but I'm sure most of you can tell by those numbers that there was virtually no light there...I was thoroughly impressed (yes, the contrast between the black letters and the shiny background helped, but still...I <3 my 5D2):

IMAGE LINK: http://www.flickr.com …/56150019@N07/8​049805068/

If you look at most complaints against the 5D / 5D2 AF systems in the past you will note that the bulk of the issues revolve around the usability of the outer AF points. Most people are underwhelmed with the spread of the points and the low level of accuracy / locking on from those points.

Looking at this shot, I would guess you used the center point. Most people would agree that the center point of the 5D2 is competent, on par with most contemporary Canon bodies.

Cameras need contrast, not gobs of light, to focus. A Rebel could lock onto the black letters set into the reflective silver plaque.

This is like saying your camera is so awesome it can focus on your stereo in pitch black...of course it can when you're aiming for the lit LEDs.

JeffreyG wrote in post #15073587
If you look at most complaints against the 5D / 5D2 AF systems in the past you will note that the bulk of the issues revolve around the usability of the outer AF points. Most people are underwhelmed with the spread of the points and the low level of accuracy / locking on from those points.

Looking at this shot, I would guess you used the center point. Most people would agree that the center point of the 5D2 is competent, on par with most contemporary Canon bodies.

No need to guess, my friend...I stated clearly that I used the centre (and thus superior) focus point.

cdifoto wrote in post #15073593
Cameras need contrast, not gobs of light, to focus. A Rebel could lock onto the black letters set into the reflective silver plaque.

This is like saying your camera is so awesome it can focus on your stereo in pitch black...of course it can when you're aiming for the lit LEDs.

Actually, contrast and amount of light go hand-in-hand...there was precious little light here.

I know all that and stated as much in my write-up (do people even READ the post before replying?). However, if you looked at the settings/picture, you'd realize that even with the subject being what it is, there was a ridiculously small amount of light available.

LowriderS10 wrote in post #15073507
Took this picture in Beijing, China a couple of days ago...almost no light at all...(the EXIF speaks for itself...still underexposed at ISO 25,600, f2.8, 1/20s)

I took several test shots (yes, using the centre point only) and each time it locked on without hesitation...because of the high ISO/low shutter speed/fast aperture it appears to be bright, but I'm sure most of you can tell by those numbers that there was virtually no light there...I was thoroughly impressed (yes, the contrast between the black letters and the shiny background helped, but still...I <3 my 5D2):

IMAGE LINK: http://www.flickr.com …/56150019@N07/8​049805068/
IMG_5264small by canonzenit, on Flickr

Nothing new here. It is recognized that the center point is excellent in low light. Try that with any other point. That is the biggest issue with the 5d2 AF system, it basically becomes a 1 point system in minimal, not even low, light.

Hogloff wrote in post #15073685
Nothing new here. It is recognized that the center point is excellent in low light. Try that with any other point. That is the biggest issue with the 5d2 AF system, it basically becomes a 1 point system in minimal, not even low, light.

I am another satisfied user of the 5DII. If the centre AF point does the business, I see no good reason to use any of the others in poor light.

Only once did my lens hunt and that was a recent studio situation when by mistake I had set it to all AF points, ot just the central one. So user error.

I never thought my 5D2 sucked. Very good centre point. Just never used the outer points very much and I wish I could have.

LowriderS10 wrote in post #15073671
No need to guess, my friend...I stated clearly that I used the centre (and thus superior) focus point.

Actually, contrast and amount of light go hand-in-hand...there was precious little light here.

I know all that and stated as much in my write-up (do people even READ the post before replying?). However, if you looked at the settings/picture, you'd realize that even with the subject being what it is, there was a ridiculously small amount of light available.

Yes I do wonder if some people read posts before replying here. As I stated with the stereo example, amount of contrast and amount of exposure-affecting light are not directly related. Another example: the AF-assist beam of Speedlites. Its not a flashlight.

Again, you don't need light, you need contrast.

Edit to add: Quite frankly I don't really demand too much of any AF anymore. I'll let my Speedlite assist with the tough stuff since I'm adding my own light at that point anyway. When people are at f/1.2, ISO25600, 1/50th and expecting autofocus I have to stop and ask "why?"

cdifoto wrote in post #15073821
Yes I do wonder if some people read posts before replying here. As I stated with the stereo example, amount of contrast and amount of exposure-affecting light are not directly related. Another example: the AF-assist beam of Speedlites. Its not a flashlight.

Again, you don't need light, you need contrast.

Edit to add: Quite frankly I don't really demand too much of any AF anymore. I'll let my Speedlite assist with the tough stuff since I'm adding my own light at that point anyway. When people are at f/1.2, ISO25600, 1/50th and expecting autofocus I have to stop and ask "why?"

Agree with you entirely, and was about to post why AF was able to lock on, but you already stated it.

Now something to add to your comment, the speedlite is of no use when in AI Servo though. So if you have a situation where AF won't lock on at all, you have to flip it to One Shot, and you might lock focus, and also use a flash AF assist if you have it mounted.

Lowrider, if you had a pitch black room and just one lit led on a stereo, as CDI points out, you could get AF. It is not so much how much light, but rather how defined a line or point the AF can make out.

cdifoto wrote in post #15073821
Yes I do wonder if some people read posts before replying here. As I stated with the stereo example, amount of contrast and amount of exposure-affecting light are not directly related. Another example: the AF-assist beam of Speedlites. Its not a flashlight.

Again, you don't need light, you need contrast.

Edit to add: Quite frankly I don't really demand too much of any AF anymore. I'll let my Speedlite assist with the tough stuff since I'm adding my own light at that point anyway. When people are at f/1.2, ISO25600, 1/50th and expecting autofocus I have to stop and ask "why?"

Because not all of us carry around Speedlites

I like to travel as light/small as possible, and I prefer ambient light...

TeamSpeed wrote in post #15073912
Agree with you entirely, and was about to post why AF was able to lock on, but you already stated it.

Now something to add to your comment, the speedlite is of no use when in AI Servo though. So if you have a situation where AF won't lock on at all, you have to flip it to One Shot, and you might lock focus, and also use a flash AF assist if you have it mounted.

Lowrider, if you had a pitch black room and just one lit led on a stereo, as CDI points out, you could get AF. It is not so much how much light, but rather how defined a line or point the AF can make out.

I realize that...still, as I've pointed out numerous times, there wasn't much contrast to work with either, as the entire scene was incredibly scarcely lit.

Sheesh...try to make a positive thread and BOOM! everyone wants to take turns pissing on my parade I just wanted to share my satisfaction with my camera

TeamSpeed wrote in post #15073912
Now something to add to your comment, the speedlite is of no use when in AI Servo though. So if you have a situation where AF won't lock on at all, you have to flip it to One Shot, and you might lock focus, and also use a flash AF assist if you have it mounted.

Indeed. I sort of wonder what the point of tracking would be though if you're only eeking out 1/50th anyway. Tracking and adding your own light, sure, but the only thing I can think of wanting to track in the dark is bats in flight. Anything else needs its own light to see where it's going...and then you have enough for AI Servo.

I'm open to being corrected though if someone has a scenario that's ISO25600, 1/50th, f/1.2, and needs Servo. That's pretty bloody dark.

5D2 AF doesn't suck... can be a little challenging at times, but once you know its strengths and weaknesses, its very manageable

I also use a small flashlight, at low setting, with a red filter on it to assist in focusing.... even at weddings!

cdifoto wrote in post #15073935
I'm open to being corrected though if someone has a scenario that's ISO25600, 1/50th, f/1.2, and needs Servo. That's pretty bloody dark.

Middle of the night... on a beach... 2 turtles are racing in the sand...

LowriderS10 wrote in post #15073930
I realize that...still, as I've pointed out numerous times, there wasn't much contrast to work with either, as the entire scene was incredibly scarcely lit.

Sheesh...try to make a positive thread and BOOM! everyone wants to take turns pissing on my parade I just wanted to share my satisfaction with my camera

Don't take it personal as this is a typical reaction from a post of this type. I don't know what it is with POTN and positive threads, but folks are just possessed to try and turn it into a negative.

That's why we don't see many posts like this, and its too bad because I wish people would share more experiences.