When you reverse a lens the focus point is very close to the rear
element. With your setup the focus point is somewhere inside the lens
if not inside the bellows, (yes I know that's not technically true but
the hyperbole expresses the problem), use a longer lens and don't
reverse it if you want to use that setup. If it were me I'd just use
the 12mm extension and the bellows, with the 100mm the focus point will
be just a few millimeters from the front of the lens.
On 7/6/2012 10:52 PM, John Celio wrote:
So I have this setup for shooting seriously close-up macro:
https://picasaweb.google.com/lh/photo/CIUtr5fsiR0rzShfFjE08NMTjNZETYmyPJy0liipFm0?feat=directlink
That is: Camera / helicoid tube at 49mm / bellows at 137mm (approx)/
12mm tube / 20mm tube / 36mm tube / generic reverse mount ring / D-FA
100mm macro at 1:1
I've been meaning to share this for a while, because the last time I
tried using it in this configuration (sans rear cap on the lens, of
course), I was unable to focus on anything. I had a little flower
practically pressed against the glass at the end there but had to pull
the lens' focus back about halfway before I could actually focus on
it.
So I'm hoping you guys can help me figure a couple things out:
1. Is it possible to have a lens so far away from the sensor plane
that focus can't be achieved?
2. What's the macro ratio of this setup as it is in the picture?
3. Does it make a difference if I have the lens reverse-mounted like
this rather than mounted normally on the last extension tube?
4. Would it be ridiculous or just silly to attempt to add more
extension in the future?
John
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