Sounds good to me. From which seller did you buy this adapter?
The center focusing point on a 5D is a "cross-type" point. Unlike the
other 8 focusing points the center point is sensitive to both vertical
and horizontal lines although twice as sensitive to vertical lines. The
other points are sensitive to either horizontal or vertical but not
both. The center point is the only one guaranteed to work down to f/5.6
brightness and nothing is guaranteed at smaller apertures. Canon
guarantees that the autofocus is accurate to 1/3 the "depth of focus"
which is a term that was used here recently in another context. For an
explanatory paper on the subject see:
<http://doug.kerr.home.att.net/pumpkin/AF_accuracy.pdf>
Yes, DP Review says the 5D sensitivity at ISO 100 is really 125 and
that's something I try to keep in mind when using my Sekonic L358. My
Minolta A1 is also more sensitive than the ISO setting indicates and
that needs a 2/3 stop correction.
Chuck Norcutt
jking@xxxxxxxxxxxxxx wrote:
> I have a focus confirmation adapter purchased form a Hong Kong seller on
> ebay.
>
>
> I also have a Canon right angle finder and if I focus using it and then
> press the shutter halfway the focus confirmation inevitably agrees and
> visa versa. I found the centre square to be moer sensitive then the other
> squares around it and have actually set the focus mode to the centre
> square only. I focus wide open and then stop down. If you stop down and
> then focus simple tests seem to indicate that it works up f5.6 and
> sometimes when stopped down to f8 so I doubt if it would work for a 500/8
> mirror or slower.
>
> Focus confirmation works fine with all the lenses I have tried:
> tamron 80-200/2.8
> tamron 90mm (hot spotting in centre at f22 and 32 - NOT the fault of the
> adapter)
> olympus 50/1.8
> 35/2
> 28/2
> 24/2
> 21/3.5
>
> not tried it with bellows or shift lenses.
>
> As far as metering modes go again I meter wide open in manual adjust to
> the recommended shutter speed then decide what app I want to shoot at and
> clculate the corresponding shutter speed and adjust the camera's shutter
> speed to match. I don't meter stopped down or use app or shutter speed
> priority.
>
> Its slow and clumbersome for street photography but for landscapes and
> static subjects I find it no slower than using my Bronica. I also have a
> sekonic L558 and I have found that the Cannon 5d seems about 2.3rds of a
> stop more sensitive than the Bronica with fuji slide film. I am guessing
> that the fuji film is about 1.3 of a stop less sensitive than it should be
> and I have read reports of the canon being 1.3 of a stop more
> sensitive....
>
> Overall I am happy with the focus confirmation adapter and feel no desire
> to replace my tamron 90/2.5 or 80-200/2.8 with a modern autofocus version.
> I don't feel any of the olympus wides are as sharp as these telephotos.
> But I never felt any of the bronica wides where as sharp as the 75mm
> standard lens either. I guess that if you want razor sharp wides its a
> Mamiya 7 and a lots of money... :-(
>
> James
>
>
>
>
>
>
>
> ==============================================
> List usage info: http://www.zuikoholic.com
> List nannies: olympusadmin@xxxxxxxxxx
> ==============================================
>
>
>
==============================================
List usage info: http://www.zuikoholic.com
List nannies: olympusadmin@xxxxxxxxxx
==============================================
|