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Using Magic Lantern => General Help Q&A => Topic started by: mapompei on September 16, 2012, 07:06:25 PM

Title: 5D mk2 Rack Focus Help
Post by: mapompei on September 16, 2012, 07:06:25 PM
5D mk2 and 24-70 mm. f 2.8 L:
I fixed end and start points and I get the correct footage: all is ok but I have some questions:
1) How can i control the focus movement SPEED?
2) How can I AVOID the recording TO STOP soon after the end point is reached?
3) With the 24-70 lens i get a "soft limit reached" when I try to set a far away start point (after the "here" end point):
with this lens, can I work in the full range from macro position to infinite or not?
Title: Re: 5D mk2 Rack Focus Help
Post by: ScarySquirrel on November 09, 2012, 10:29:27 AM
Hi mapompei,

Did you ever find an answer to these questions as I have exactly the same questions, same camera and lens as well.

Thanks
Title: Re: 5D mk2 Rack Focus Help
Post by: a1ex on November 09, 2012, 12:28:35 PM
1) adjust step size and step delay
2) first start recording, then start rack focus (not viceversa)
3) probably the lens has poor mechanical condition.
Title: Re: 5D mk2 Rack Focus Help
Post by: oterpoter on November 26, 2012, 04:46:53 PM
I have the same lens, same issues.
Probably NOT a lens issue.. Pretty expensive piece of glass....
My lousy tamron macro lens works...
Title: Re: 5D mk2 Rack Focus Help
Post by: Francis on November 26, 2012, 07:33:04 PM
Quote from: oterpoter on November 26, 2012, 04:46:53 PM
I have the same lens, same issues.
Probably NOT a lens issue.. Pretty expensive piece of glass....
My lousy tamron macro lens works...

Expensive glass does not necessarily mean an AF drive system that takes commands for small precise steps very well.

Depends on the travel of the focus ring as well it seems as well as the lens design. The same speedy AF motor that gets moves that big heavy element from one focal distance to another extreme very quickly is probably not as efficient at moving that big heavy element a very small amount. And if that Canon 24-70 2.8 is anything like my Sigma 24-70 2.8, there is some big heavy glass in there.