12 Jun
2010
12 Jun
'10
12:34 p.m.
On Sat, 12 Jun 2010, Philip Pemberton wrote:
Of course. This applies to any camera, digital or not. For many SLR
camera systems there are 'extension tubes' which fit between the lens
unit and the camera body, for close-up work.
> I once saw a digital camera wit ha
2-position focus control (normal and
> close-up). it dit appear to move the lens on a focussing mount. There was
> no autofocus, or anything like that.
Anything that increases the lens to sensor distance will decrease the
distance between camera and subject. Short focal length lenses need less
movement, and have a wider range of "acceptable" focus. > I wonder
if you could use front-of-lence closeup lenses? The resolution
> of the sensor in such a caerma is not going to be great, so I doubt you'd
> notice any loss of qaulity.
Yes. With on the front of the lens "close-up" of "portra" lenses, it
will
focus on a closer distance. With some loss of lens sharpness. Probably. The macro mode on most decent digicams
should do it as well.
The "slose-up" lenses will work on the INdecent ones even without a
"macro" (close-focussing) mode.
If you need good quality pictures of paperwork or circuitboards, get
something that will focus close, preferably with a "flat-field" lens (such
as a cheap enlarger lens)
The other trick, if you can do it is to fit the lens back-to-front. Most
camera lenses are designed to work with a larger object than image
distance. Byu turning it round you reverse this, which is a help for the
short object distances in close-ups.
A few cameras (the Rollei SL66 being the obvious one) were designed to
work like this.
The problem is that you genrally loose all automatic coupling to the
lens, which means it's not a lot of use with modern
electronically-controlled cmaeras. The Praktica PLC/VLC series had a
special pair of afapater rings to maintain full aperture metering even
when the lens was fitted backwards, but I've not seen this for anything
remotely modern.
-tony