conurus Forum Index conurus
smart adapters and lens mount conversions
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

50/1.4 focus speed/attributes on 5D2

 
Post new topic   Reply to topic    conurus Forum Index -> Contax N to Canon EF Mount Conversion
View previous topic :: View next topic  
Author Message
AX-fan



Joined: 12 Dec 2006
Posts: 21
Location: Vancouver, Canada

PostPosted: Thu Apr 18, 2013 7:27 am    Post subject: 50/1.4 focus speed/attributes on 5D2 Reply with quote

Conurus,

In comparison to the other Contax primes and zooms, how 'fast' and 'accurate' would conurus consider the 50/1.4 when it come to focussing speed on a 5D2? I know we have talked about this in the past and it was explained to me that the lenses are not calibrated on a 5D2 but another FF Canon camera.

Problem:

I'm having a great deal of difficulty getting the camera (5D2) to focus quickly and accurately when in AI Servo or AI Focus mode when focussing through the view finder.

When I'm doing 'Live View' and getting the camera to do contrast focussing (not using the 5D2's viewfinder AF circuits), it tends to zoom through and past the focus point and only with difficulty can I get it to make a clean auto-focus attempt. Usually I end up switching to MF at that pointů which does defeat the purpose of AF if you can't use itů perhaps because the 50/1.4 depth of field when focussing at 1.4 is so narrow?

What solutions can Conurus suggest? None of these problems are noted with any other lenses I've tried, be it 85, 24-105 etc. This is only specific with the 50/1.4.
Back to top
View user's profile Send private message
chmod



Joined: 16 May 2013
Posts: 7
Location: San Francisco Bay Area

PostPosted: Sat May 18, 2013 6:00 pm    Post subject: late reply Reply with quote

Hello. I recently bought a copy of the N50, and use it on Canon full frame bodies. So, I just now say your post.

Did you get this sorted?

regards,
chmod
Back to top
View user's profile Send private message
conurus
Site Admin


Joined: 15 Aug 2006
Posts: 795
Location: Vancouver, Canada

PostPosted: Sat May 18, 2013 7:14 pm    Post subject: Reply with quote

As noted in our FAQ section, contrast detect AF is not supported.

In my experience the 50/1.4 is harder to lock onto focus near closest focusing distance, but should be fine at medium distances and infinity.

In terms of AF speed, yes the VS24-85 and P85 are both faster then P50, which means P50 would be harder to do continuous AF in AI Servo. We are already doing better than the original Contax N1 camera body, but I could see how that is still grossly inadequate for moving subjects. We have however already tried our best to do what we could do.
Back to top
View user's profile Send private message Visit poster's website
Leon Liew



Joined: 13 Dec 2010
Posts: 34

PostPosted: Sun May 19, 2013 4:36 am    Post subject: Reply with quote

conurus wrote:
As noted in our FAQ section, contrast detect AF is not supported.

In my experience the 50/1.4 is harder to lock onto focus near closest focusing distance, but should be fine at medium distances and infinity.

In terms of AF speed, yes the VS24-85 and P85 are both faster then P50, which means P50 would be harder to do continuous AF in AI Servo. We are already doing better than the original Contax N1 camera body, but I could see how that is still grossly inadequate for moving subjects. We have however already tried our best to do what we could do.


I concur absolutely but still it manage to capture what I wanted
so no seriuos issues
Back to top
View user's profile Send private message
AX-fan



Joined: 12 Dec 2006
Posts: 21
Location: Vancouver, Canada

PostPosted: Mon May 20, 2013 8:03 am    Post subject: Reply with quote

Out of curiousity then, what is it about either the conversion or the lenses that prevent live view contrast detection working as a focus mechanism with a converted Contax lens?
Back to top
View user's profile Send private message
conurus
Site Admin


Joined: 15 Aug 2006
Posts: 795
Location: Vancouver, Canada

PostPosted: Mon May 20, 2013 6:30 pm    Post subject: Reply with quote

We don't know yet.
Back to top
View user's profile Send private message Visit poster's website
AX-fan



Joined: 12 Dec 2006
Posts: 21
Location: Vancouver, Canada

PostPosted: Tue May 21, 2013 4:47 am    Post subject: Reply with quote

I would, taking a wild guess, wonder if it has anything to do with the inherent 'slowness' of the ultrasonic AF motors compared to the Canon breed.

I have no idea exactly how Canon's lenses work, but it would make sense to have circuitry calibrated to the 'speed' of a focusing effort resulting in a 'change' to higher or lower contrast, hence why it often seems that the lens focuses through/past the focus point before backing up and trying to readjust.

Is it electrically/firmware possible to replace the ultrasonic motors with something faster? I haven't disassembled a lens before so I have no clue if this is or isn't even within the realm of possibility.
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    conurus Forum Index -> Contax N to Canon EF Mount Conversion All times are GMT
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum

RSS Atom

Powered by phpBB © 2001, 2005 phpBB Group

phpBB SEO