Does FF body focus better than APS-H

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rollee
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p.1 #1 · Does FF body focus better than APS-H

I use 4 1-series bodies. 1Ds mark II, 1Ds mark III and 1D mark III and 1D mark IV.
I noticed that the focus accuracy on FF are more stable than the APSH cameras.

Using the same group of multiple lenses in the field, I find the images on FF bodies are sharper than the ones from APSH bodies.
Is there any explanation to this?

I read that FF sensors being larger in size, captures more light. Might this affect the focus accuracy for FF being more consistent?

Aug 22, 2012 at 02:49 AM

jcolwell
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p.1 #2 · Does FF body focus better than APS-H

I can't say that I've noticed the 1DsIII has more consistent AF lock than the 1DIV and 1DIII. I generally get equally good results from my 1DsIII and 1DIV. I previously also used the 1DIII and 1DII.

Do you tend to use One-Shot AF on the FF and AI Servo AF on the APS-H bodies?

Aug 22, 2012 at 03:21 AM

RobDickinson
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p.1 #3 · Does FF body focus better than APS-H

I doubt the larger sensor comes into it from a focus point of view, the lens lets in the same amount of light to the same focus system which is totally independent of the sensor.

A crop sensor though is usually higher pixel density so your effectively placing the image under higher magnification

Aug 22, 2012 at 03:24 AM

rollee
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p.1 #4 · Does FF body focus better than APS-H

I use one shot most the time, ai-servo scares me cause I am addicted to focus lock recomposing.

RobDickinson wrote:
I doubt the larger sensor comes into it from a focus point of view, the lens lets in the same amount of light to the same focus system which is totally independent of the sensor.

A crop sensor though is usually higher pixel density so your effectively placing the image under higher magnification

+1 I think this makes sense.
I find overall image sharpness is more consistent on FF, more magnification on APSH increases tendency of image shift due to 'vibration' perhaps?

My work consists of a large variety in different scenarios, and I rotate over 10 L lenses mostly primes.
If I have to count on a shot to be sharp (right on) in a sudden instant, its the FF camera I will pickup with 'any' lens attached.

Aug 22, 2012 at 03:41 AM

EB-1
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p.1 #5 · Does FF body focus better than APS-H

The APS-H mechanisms are all full flame. Only the focusing screen/viewfinder are masked to the dimensions of the sensor. The spring rates for the mirro and submirro may be a bit different as may be the damping. Theoretically a lower FPS camera, such as a 1Ds series, will have an advantage in that the mirror is down (viewing=AF) more of the time than a high FPS body.

EBH

Aug 22, 2012 at 03:44 AM

Lars Johnsson
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p.1 #6 · Does FF body focus better than APS-H

My 1Ds3 does not focus better than my 1D3 or 1D4

Aug 22, 2012 at 05:16 AM

mttran
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p.1 #7 · Does FF body focus better than APS-H

rollee wrote:
I noticed that the focus accuracy on FF are more stable than the APSH cameras.

I feel the same way between 1d2 and 1ds2 while shooting fast lenses...can't explain since i really don't know what exactly the differences between f/w and h/w configuration of these two. My 1ds2 seems to handle back lit better than 1d2. Any way, i have more keeper with full frame...i tried to figure out one time then gave up since 1d2 was no longer with me

it could be my 1d2 having some calibration issue...

Aug 22, 2012 at 05:51 AM

jerbear00
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p.1 #8 · Does FF body focus better than APS-H

The ansr to OP question is no

Aug 24, 2012 at 05:44 AM

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