Re: bellows extension

Gee, Wayne . . . I'm sorry you don't understand me; but I don't understand
you too, neither.

I guess the proportion of four to one, devided by two and then halved is one
click to me, but directions lost to youse. I dunno? Maybe it's the lab.
We use different labs.

S.
----- Original Message -----
From: "Wayne D" <wdewitt@snip.net>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Friday, December 02, 2005 1:48 PM
Subject: Re: bellows extension

>
> ----- Original Message -----
> From: "SteveS" <sgshiya@redshift.com>
> To: <alt-photo-process-l@sask.usask.ca>
> Sent: Friday, December 02, 2005 1:19 PM
> Subject: Re: bellows extension
>
>
>>
>> ----- Original Message -----
>> From: "Shannon Stoney" <sstoney@pdq.net>
>> Subject: Re: bellows extension
>>
>>
>> >
>> > The 90mm lens I am using now (thanks, Clay!) is 3.5". So if it's
>> > racked
>> > out to 7", that's two stops I guess. Somewhere in between would be
>> > about
> 5
>> > 1/4", which would be one stop. I guess you could mark all these places
> on
>> > your camera.
>> >
>> > --shannon
>>
>> No. That would be one stop. One click on the diopter ring, actually . .
> .
>> the ratio is 4=one stop or two times the distance equals one click, which
> is
>> actually a half of a stop.
>>
> Don't know what you're trying to say here (what's a "diopter ring"?) but a
> lens with an infinity backfocus distance of 3.5", when extended to 7" from
> the film plane, will project an image that will cover 4x the area of the
> image that is projected when focused at infinity. That requires a 2 stop
> adjustment.
>
> Wayne
>
>
>
>
Received on Sat Dec 3 15:55:06 2005