As I'm re-reading my own note I noticed that the best possible
explanation for the sharpest focusing occurring at f/8 is that I
probably forgot to open up again to shoot at f/2 after focusing. The
shot was most likely taken at f/8 with lots of DOF.
Oh, well. Not very good science here.
Chuck Norcutt
Chuck Norcutt wrote:
> I did some tests today which only left me confused. I used the 85/2
> manually focused at f/2, 2.8, 4, 5.6 and 8 but all shot at f/2. Was the
> best shot focused at f/2. No, the best one was focused at f/8. The f/4
> shot was grossly out of focus and the others were pretty close to being
> in focus as judged by using the Tokina 28-80 at 2.8 in autofocus mode.
> But I didn't feel really bad since even one of the autofocus shots was
> as bad as my worst. Not sure what happened there.
>
> All of this caused me to question my shooting without glasses. I use
> only the built-in dioptric adjustment which does not correct for my
> astigmatism which is maybe worse than I realize. So I tried another
> test using the Tokina in both auto and manual focus modes but this time
> I changed the dioptric adjustment so that all was correct using my
> reading specs. Then I was able to take the sharpest shot of the day by
> focusing the Tokina (using the DOF preview) at f/5.6 and (without
> thinking) shooting at f/5.6 instead of wide open at 2.8. Focus or DOF.
> I don't know. I'm tired of testing and going to quit for the day.
> Anyhow, I don't really believe the Ee-s screen is an impediment to
> manually focusing above f/2.8.
>
> Chuck Norcutt
>
>
> Chuck Norcutt wrote:
>> For those not in the know, the Canyon Ee-s focusing screen is designed
>> to assist manual focus for lenses of f/2.8 or larger apertures. If I
>> get a chance today I'll try a comparison test with the standard and Ee-s
>> screens with the Zuiko 135/3.5. I did try a couple shots with it
>> yesterday which seem to be fine but I didn't compare. I did notice that
>> metering was quite accurate at f/8. The Ee-s screen works fine with the
>> Tokina 80-200/2.8 on auto but, with my eyes, I haven't even tried
>> manual. That lens has a minimum focusing distance of 1.8 meters and I
>> don't have a Canyon mount extension tube so it doesn't get used with
>> anything even approaching macro which is where I'd probably choose
>> manual focus.
>>
>> Chuck Norcutt
>>
>
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