makeshift tilt/shift plungercam?

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Paul Furman - 17 Mar 2006 01:22 GMT

I should be able to use a full frame lens on an aps sensor & wobble it
around like a 'plungercam' right? I just tried with my sigma 12-24 & it
seemed to work. I taped the aperture open, still it seems there was a
big light loss even pointing straight on.

I'm not sure how messed up infinity focus gets, I didn't want to play
for long with the sensor exposed, a better solution would be some sort
of bellows or flexible rubber plunger gasket.

I also assume this is not really the same thing as true tilt shift
lenses? aren't there some additional changes between lenses inside with
those versus just tilting relative to the image plane?

The Sigma 12-24 is slow at 4.5-5.6 so it's hard to ever get anything out
of focus therefore maybe not noticeable change in focus plane except
with closeups since it's already got an 'extension tube' macro thing
going. Also there's the straightening effect on buildings so it could be
interesting for that.

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Stacey - 17 Mar 2006 07:27 GMT

> I also assume this is not really the same thing as true tilt shift
> lenses? aren't there some additional changes between lenses inside with
> those versus just tilting relative to the image plane?

Nope, that's all there is to it. Go look at a view camera.

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Stacey

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Paul Furman - 17 Mar 2006 17:55 GMT

>>I also assume this is not really the same thing as true tilt shift
>>lenses? aren't there some additional changes between lenses inside with
>>those versus just tilting relative to the image plane?
>
> Nope, that's all there is to it. Go look at a view camera.

OK well it seems to work pretty well taking advantage of the crop frame
on a dSLR. Of course there's going to be some quality problems with all
sorts of abberations too but...

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Paul Furman - 17 Mar 2006 21:56 GMT

>>> I also assume this is not really the same thing as true tilt shift
>>> lenses? aren't there some additional changes between lenses inside with
[quoted text clipped - 5 lines]
> on a dSLR. Of course there's going to be some quality problems with all
> sorts of abberations too but...

Here's samples with a few different lenses:
http://www.edgehill.net/1/?SC=go.php&DIR=Misc/photography/tilt
If any kind of plunger is used it needs to be extremely tight fitting. I
can only get it to work if I set the bare lens mount in at an angle, any
connector just increases the extension distance, reducing infinity
focus, making it more of a macro lens. To get normal focusing distances
you'd need a specially designed lens I guess. Longer lenses are more
useable at a longer distance, wide angles are only useable with the lens
jammed against the subject.

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Paul Furman - 17 Mar 2006 08:46 GMT

> I should be able to use a full frame lens on an aps sensor & wobble it
> around like a 'plungercam' right? I just tried with my sigma 12-24 & it
[quoted text clipped - 14 lines]
> going. Also there's the straightening effect on buildings so it could be
> interesting for that.

So yes it works, I tried the 45mm 2.8 prime (easier to handle) & it
becomes more close focusing (probably losing infinity) and the shifting
works on DOF even stopped all the way down so no need to tape the
aperture lever.

Taking a couple sample shots at the computer monitor vantage point at an
angle from the right side, the lens keeps the same angle to the screen,
if I tilt the camera to the left so it's pointing more toward the
screen, it has very shallow DOF across the text on the screen, if I tilt
the camera to the right so it's pointing at more of an angle to the
screen, it gains DOF and light. It is backward because the image is
reversed. Kind of like backing up a car with a trailer.

The trick seems to be getting a flexible bellows that is still as close
as possible to the original mount. A body cap would have to be ground
away to bare bones then a rubber hose section the right size to slip
over the lens or even better if some kind of tight fit ball joint.

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