Archived from groups: rec.photo.digital (More info?)
"jess" <jgates@erols.com> wrote in message
news:1127598136.442095.138800@f14g2000cwb.googlegroups.com...
> Nominally it's about 1000mm f11, but I have read that the effective
> aperture is more like f12.5 (as Ray Fisher suggests below). I'd
> believe you about the exposure, but I read ISO 1600, 1/1800 from the
> EXIF data and if anything the image looks underexposed.
>
1/1800 @ 1600 ISO
= 1/900 @ 800 ISO
=1/450 @ 400 ISO
=1/225 @ 200 ISO
=1/112 @ 100 ISO
from my figures of 1/250 @ f8 using 100 ISO
your f number = approx f 16, so 12.5 sounds about right.
try setting 100 or 200 ISO for better quality.
and use the mirror lock facility in the camera.
Cheers
"jess" <jgates@erols.com> wrote in message
news:1127598136.442095.138800@f14g2000cwb.googlegroups.com...
> Nominally it's about 1000mm f11, but I have read that the effective
> aperture is more like f12.5 (as Ray Fisher suggests below). I'd
> believe you about the exposure, but I read ISO 1600, 1/1800 from the
> EXIF data and if anything the image looks underexposed.
>
1/1800 @ 1600 ISO
= 1/900 @ 800 ISO
=1/450 @ 400 ISO
=1/225 @ 200 ISO
=1/112 @ 100 ISO
from my figures of 1/250 @ f8 using 100 ISO
your f number = approx f 16, so 12.5 sounds about right.
try setting 100 or 200 ISO for better quality.
and use the mirror lock facility in the camera.
Cheers