1D Mark IV: Are there focus problems?

Started Mar 27, 2010 | Discussions thread
PhotoKhan
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Re: I have a love/hate thing with my 1DIV
In reply to xerojay, Jun 24, 2011

xerojay wrote:

PhotoKhan wrote:

xerojay wrote:

Put simply, in decent light, the 1DIV is the fastest, most accurate AF I can think of.

In even moderately low light situations, the AF is completely sub-par. Complete garbage, even with the flash assist beam.

Just last night while shooting a wedding, I found myself saying "I can't use this camera" after the grand entrance, and first dance. I had the 580II AF assist on, and was only about 15ft from the b&g, but the camera took at least 4 or 5 seconds to focus, and even then almost never accurately. Sometimes it just wouldn't move at all...like it was giving up without trying, which is particularly dumb because the AF beam was triggering!

I thought the 5DII was bad in low light, but it runs circles around the 1DIV...and the 1DIII trumps the 5DII...

Whatever they did from the 1DIII to the 1DIV, it has completely killed the low-light AF of the camera.

Not to mention, even in lamp light, there's no point in selecting a specific AF point; the camera will just pick the tiniest little reflection way in the background, and completely miss whatever you're trying to focus on, even if it's nowhere even remotely close to the AF point!
Canon, can't you just get it right?!?!

In your experience, does it happen consistently?

...Because, in my case, I've had the camera behaving like that in a few instances and then, for the most of the time, it will focus-lock with pinpoint precision in ridiculously dim lighted subjects.

Some months ago, I was decided to go to Canon about this but gave up precisely because I could not consistently make the camera behave like that, for demonstration purposes (...and I know, from personal experience, it is a waste of time sending the camera in if it does not show whatever I am complaining from consistently. It will just be sent back with a "nothing found" notice).

From that time onwards, it never "misbehaved" again, in low-light...it is quite strange...

PK

It happens consistently. Cameras don't change; conditions do. I did some comparative testing a while back to determine how the low light AF fared against the 5DII and even my old 20D. I discovered that the ambient color temp has everything to do with how the AF responds in low light. I think my findings were something like; with warm (tungsten) light it would slow down to a crawl, with almost no accuracy at about 4EV to 5EV. In tungsten or warmer lamp color light, it refused to focus at all by around 2EV, with the 5DII running circles around it, and even the 20D besting it. When I switched the light source to cooler daylight color, it had about a 4EV improvement all-round, and would actually focus at -1EV (albeit, slowly). The other two cameras (5DII & 20D) weren't noticeably affected by the color of light.

The problem with this is that most low-light situations are very warm indoor lighting scenarios. Also, I believe that the red AF assist beam is actually a poor color for the camera.
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http://www.jamiesondean.com/blog

Thanks for the reply.

Cross-referenced, as this might interest you:

http://forums.dpreview.com/forums/read.asp?forum=1032&message=38721084

PK

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