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Re: [ARSCLIST] LP sized scanner
Hi, Tom,
The classic approach is two floods at 45-degree angle. You can use
lower-power lamps and with the digicam you don't need to use a filter
like you used to with auto white balance, but beware, you may end up
with more blue channel noise in the digicam image without the filter than with.
If I were doing a bunch of these, I'd probably set up a tripod with
lights (I don't like the elCheapo copy stand I bought) and put them
on the floor and use my D200 and the 60 mm micro-Nikkor.
If I had a real large bunch to do, I'd probably figure out a
horizontal arrangement with the album cover vertical to avoid the
aching back syndrome. A vacuum stand might just work. The noise of
the vacuum (cleaner) would bother me, but a piece of plywood with
some small tubing in it brought out to multiple "Y"s with a pressure
relief (so you don't burn out the vacuum cleaner) should do it.
As to the zoom vs. the macro lens, I would go with the macro lens as
the linear distortions (barrel/pincushion) of the zoom would be
worse, but I have the lens already so it's a no-brainer. In fact,
almost all of the studio shots on my blog are done with a D100 and
that 60 mm macro lens. It lives in the studio. Edge falloff is much
less of a problem with the DX-sized sensor with Nikon DigiCams as
most lenses are designed for film, but the linear distortions would
still be there.
If you are lighting the stuff at 45 degrees look at the edges for
reflections where the cover material wraps around. You can do crossed
polarizers on lights and camera, but the lights will burn most
polarizing material.
If you are happy with the colour balance, you can use Chroma 50
fluorescent tubes and that will provide a more even and cooler light.
Again 45 degrees on two sides, but now there are no round hotspots,
as you've got 2' line fixtures which are larger than your target. You
may still see some gradient across between the two tubes, adjusting
them should balance that out. If you get utility reflectors that's
probably better than bare bulbs as it provides more of an option for
evening out the light.
I don't know how many you're doing, but if you're doing 100, it makes
sense I think to get the fluroescents and give them a try. Finding
2-foot Chroma 50 lamps may be a bit of a challenge, but a good
hardware store or photo store ought to be able to order them for you.
I'll bet B&H stocks them.
Nothing is perfect, of course, and even the chroma 50s are a
discontinuous line spectrum, but incandescent lamps create so much
heat and unless you use four, are subject to hotspotting on albums
and can't easily be fitted with polarizing sheets (as they melt).
Lower wattage incandescent lamps (like 75 W or 65 W reflector floods)
tend to have rougher patterns than true photo lamps, and also a lower
yet colour temperature (maybe 2900 instead of 3200 for true, hot
photo lamps). The lower the colour temperature, the more relative
noise in the blue channel as you boost the colour balance in the
camera -- that can be overcome by an 80A filter.
Cheers,
Richard
At 02:44 PM 2008-02-29, Tom Fine wrote:
Copy stand is probably best affordable option. I was thinking using
the regular D70 zoom, which is 18-70mm in digital mm's, so there's
some conversion factor to traditional mm's as you know. Anyway, my
thinking was to bring the camera out to about 18" and not zoom too
far in but use high-rez setting and crop in photoshop, in other
words keep the LP cover centered with leeway on the side that just
gets cropped out later -- I think this is needed anyway due to LPs
being square and aspect ratio of lens being rectangular. That should
eliminate edge distortions created by the lens bothering the LP
cover image but lighting is what I'm wondering about. Maybe use a
photo light and diffuser stood off and above? Or just use both
floodlights with a dimmer? I would think you need less light for a
digi-cam than an 1960's close-circuit black and white video cam, no?
I have to retrieve the stand from where it is now and experiment.
I'll report back eventually ...
Richard L. Hess email: richard@xxxxxxxxxxxxxxx
Aurora, Ontario, Canada (905) 713 6733 1-877-TAPE-FIX
Detailed contact information: http://www.richardhess.com/tape/contact.htm
Quality tape transfers -- even from hard-to-play tapes.