I'm Dr. Florida today since I well understand gators and moccasins but
haven't a clue about DOF and magnification with tilted lenses. I've
never thought about it before but the wedge shaped DOF (illustrated in
your link) makes perfect sense to me. But my head already hurts from a
further read of that link. I think I'll go out back and check if there
are any gators in Frog Creek today. Maybe if I had a tiltable lens I
could take a close-up, end-on shot with nostrils and tail tip both in
focus. Ooops. No tiltable lens available. I'll have to skip that part
today. :-)
Dr. Florida
usher99@xxxxxxx wrote:
> Hmm,
> A Dr. Florida now---I bet he as as astute as the renowned but
> reclusive Dr. Focus and the
> esteemed list treasure, Dr. Flash.
>
> I suppose focal length will effect magnification on the same extension
> but I was trying to assess the effect of magnification per se
> on the ability of tilt to move the plane of focus. Most of the
> calculators I have seen assume thin lens approximations and
> fall apart with higher magnification. Longer FL seems to reduce the
> effect of tilt on moving the near and far plane of acceptable focus.
> My first attempts with the Mirex with landscapes was plagued by
> over-tilting as I did realize how little was required. I now have an
> excel
> spreadsheet with FL and tripod height. I think only 2 deg is required
> for a 45mm lens at my eye level tripod height.
>
> http://www.cambridgeincolour.com/tutorials/tilt-shift-lenses2.htm
>
> I really have no clue if magnification per se----( i.e. shortest
> extension using the 38macro on the autotube with 8 deg tilt vs
> longest extension)
> has on the ability of tilt to shift the plane of focus. Perhaps very
> little though total dof and ?angular dof will decrease.
>
> Mike
>
>
>
>
> How do you distinguish between "longer focal length" and
> "magnification". To me they go hand in hand... or didn't I understand
> your point.
>
> Dr. Florida
>
>
> usher99@xxxxxxx wrote:
>> Thank you Ed and Don for your comments. Longer focal length
>> diminishes the effect of tilt on shifting the plane of focus. I
>> have no clue if magnification has any effect on this though the
> total
>> angular dof I suspect may diminish. Wonder if Dr. Focus is in
> Fla.
>> It would be nice to see this effect in the VF, but if the subject
> is
>> not properly focused, all is lost anyway. The 1-12 is weird--
> largely
>> clear but doesn't alter metering.
>> Sometimes wish I could swap screens with a dial.
>> Mike
--
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