Robert Alatalo (03.30.13, 9:10 PM): ok, I finally found the reason for the dismal performance of the non-center points... http://www.usa.canon.com/cusa/consumer/products/cameras/slr_cameras/eos_6d#Specifications ... ... AF Working Range Center AF Point: EV -3 to 18 (at 73°F/23°C, ISO 100) Other AF points: EV +0.5 to 18 (at 73°F/23°C, ISO 100) ... ... And I suspect all of the Nikon points are rated at -1 So you get 2 Stops better center for almost 2 stops worse on everything else

Michael Andrew (03.18.13, 4:31 PM): Ive done tests with the non-center focus squares, and can tell you that they are no good in low light. It is only the center square.

Robert Alatalo (03.18.13, 1:33 PM): I wonder how the non-center focus points compare with the D600 for low light. I am curious because I am really tempted to move from my Nikon D80 to the canon 6d for the extra 2 stops ISO over the D600 but I wonder at what light level the non-center ones start to fail.

joema (12.31.12, 10:48 AM): I shoot weddings with a 5D3; AF struggles in extreme low light conditions. Your test properly reflects that. Of course most cameras do, but the 5D3 and 6D can get decent shots (exposure wise) at ISO 25,600. IOW in extreme low light the 5D3 runs out of AF capability before running out of exposure capability. Speedlite AF assist doesn't always help if you're shooting a small subject. E.g, across a dark room at 200 f/2.8. The projected AF-assist grid pattern doesn't zoom with the lens and is too coarse. In normal (even dim) interior lighting the 5D3 AF does fine, it's only in extremely dim lighting this becomes a factor.

Torben Christiansen (12.16.12, 2:49 PM): Nice to see the different cameras against each other in low light

Michael Andrew (12.13.12, 5:10 PM): @ Brake Systems- You clearly haven't read the test carefully. I have tested it both with and without the assist light, which the other cameras do not have. Depending on what type of photographer you are, this may not be an option. If a photographer cannot use it in many cases, why would that be an unfair test? Dont take it so personally.

Brake System (12.13.12, 3:45 PM): The engineers work for auto magazines must disable the anti-lock brakes of some vehicles to order to compare to others that don't have it, and provide a "fair" review for the "native ability" of the brake systems. Very funny.

Michael Andrew (12.13.12, 2:31 AM): Hi Jon Rista- How would changing the measurement of light in these conditions change the performance of the cameras? What are you shooting with? Who is dying? (Isnt "gravely" a bit harsh?)

Jon Rista (12.12.12, 10:06 PM): After the analysis of your review on CanonRumors, I'd have figured you would have updated this review by now. I hate to say it, but you are gravely misleading your readers as to the capabilities of the 6D. I really think you should re-do this test with a proper incident light meter, and base your EV0 on the official spec.

Joe (12.08.12, 9:05 PM): Michael, would you mind listing the D600 performance with AF-Assist on and off respectively and let photographers decide how they should use it? I think a fair comparison is to use the best facilities a camera provides. Anyway, there will be no argument if all of the results are listed.

Tim (12.08.12, 6:53 AM): We have 2 5dii bodies and 1 7D bodies, and notice this same effect on the 7D. Using only the center focus point, the 7D seems more responsive than the 5D. How would the 7D do with your test?

Dyun (12.08.12, 3:12 AM): I think it's an interesting test and seems pretty fair. I don't expect to shoot my D600 in pitch black. The dimmest I usually go is Target 2. If I'm shooting a show in some small venue with bad lighting, I still have adequate light to focus. AF-Assist light is a no, no in those situations, so people need to stop whining about it not being used during the test. Yes, Nikon does have that advantage in pitch black, but it depends where you're shooting. Some places won't let you use it. I commend Canon for giving the 6D this ability to lock in near darkness.

Henrik (12.07.12, 11:18 PM): Sorry, I didn't realize linebreaks didn't work.

Henrik (12.07.12, 10:53 PM): Yeah, I know they are. But that was the reason for contributing with my own calculations. In other words – I believe the their are wrong. Here is how I reasoned: EV 0: 1/1, 1.0, ISO100 -> 1/60, 1.0, ISO6400 EV 1: 1/60, 1.0, ISO3200 EV 2 1/60, 1.0, ISO1600 EV 3 1/60, 1.0, ISO800 EV 4 1/60, 1.0, ISO400 EV 5 1/60, 1.4, ISO400 EV 6 1/60, 2.0, ISO400 EV 7 1/60, 2.8, ISO400 Correct me if I'm wrong.

annoy (12.07.12, 6:13 PM): biased test with D600 focus light disabled

MIchael Andrew (12.07.12, 2:15 AM): AC- The D600 actually does fine with the AF light turned on, but there are real -world cases where this isnt always ok to turn on. The other cameras dont have such a light.

Michael Andrew (12.07.12, 2:12 AM): Hi Henrick- How did you come to these calculations, they are a bit different than what I am hearing from other readers.

Michael Andrew (12.07.12, 2:11 AM): Surprised at the number of people who are choosing to ignore the heart of matter here over semantics, but do as you like- I love haters. The hard part is getting all 4 of these cameras together, if you dont like what I did, please make a constructive criticism. Re-doing the test would be simple. I turned the AF assist light off on the D600 simply because the other cameras dont have one.

Henrik (12.06.12, 9:01 PM): Based on the fact that 0 EV is defined as correct exposure with 1 s, f.1 and ISO 100, the light level called "0 EV" in the test, according to my calculations, corresponds to 7 EV. Thus, the light level called "-3 EV" corresponds to 4 EV and "-7 EV" to 0 EV. This indicates that the 6D starts getting the advantage already on 0 EV and that it should be able to handle three full stops lower. I myself rarely go below EV 3 or EV 2 so perhaps the 6D will not give me a properly noticeable advantage compared to my old 5D mkII. Of course also depending on the 6D:s actual accuracy. Thanks again for your kind testing.

Joe Wiegman (12.06.12, 2:23 PM): The reason Michael didn't use the Nikon's focus assist light is probably because in event/low light work you can't always use the focus assist lamp or the subject is too far away to be effective (e.g. night landscape).

Camera Lover (12.06.12, 12:49 PM): I found your article in canonrumors.com. It was an interesting test. However, you mentioned in canonrumors.com that your Nikon D600 test was based on disabling the AF illuminator but you did not specify here. I believe AF-assist illuminator exists in Nikon but not Canon, and most people with Nikon leave it on. Why would you disable this great function for your tests? The results were misleading.

Teemu (12.06.12, 9:44 AM): Thank you for the comparison. Some further test case proposals: - Repeat some tests by using only horizontal / vertical tape - Use rightmost crosstype point instead of rightmost point for 5D mark III. Distance from center is nearly same but performance could be much better in horizontal / vertical tape only test case

ac (12.06.12, 7:40 AM): Interesting test, but the results are quite expected given the AF specs of all of them. If anything it looks like Nikon understates a little bit the AF capabilities of the D600. For the sake of completeness, can you make a quick and dirty test of the D600 with the AF assist lamp turned on using the same methodology to have an idea of the absolute low light AF capability potential of all these bodies?

Sam (12.06.12, 7:24 AM): nice, thanks for taking the time to test. Like Henrik, I'd like to see the precision of the 6D's AF, but spefically the 6D's outermost point vs. the 5DII's outermost point. Using say the 50/1.2. But realise that's a big ask! :)

sebastian (12.06.12, 7:12 AM): The "beep confirming focus lock" does not say anything about the focus accuracy acheived.

Henrik (12.06.12, 3:36 AM): Thank you very much for your exceptional test! It would be very interesting to see whether the precision matches the locking performance on the 6D. Did you perhaps get any impressions on the matter? Did the test shots on -7 eV seem sharp on the 6D, at a first glance? Thanks again.

Ofir (12.06.12, 3:15 AM): Well performed test. I highly appreciate it!