Re: paleonet Digital photography again

At 16:47 -0700 2001-10-24, Jonathan Adrain wrote:
>For many purposes, including probably most purposes of people on 
>this list, this is likely true.  For specimen photography, it 
>depends. For relatively large specimens, stuff you'd shoot with a 
>standard macro lens with or without regular bellows, digital cameras 
>are probably now the way to go.  Perhaps I'm biased by my own needs, 
>but for photography of small specimens - a few mm to perhaps 2 cm in 
>dimension, really on the boundary between micro/macro (e.g., most 
>trilobite sclerites), it's not so simple.  You ideally need quite 
>specialized lenses (many of the people currently publishing 
>high-quality photographs of trilobites, e.g., Harry Whittington, 
>Derek Siveter, still use a Leitz Aristophot system made in the 1950s 
>and 1960s [fixed camera with bellows/extension tubes to 20-35 cm, 
>focussing manually using universal stage], and Milar and Summar 
>lenses [which close down to f48 or f96] or else the Multiphot copy 
>made by Nikon in the 1970s and 1980s).  As far as I know there is no 
>way to use these with a digital camera (I would love to be educated 
>if it's possible!).  Photography down the barrel of standard 
>microscopes generally yields lower quality images, with sharpness of 
>optics and depth of field the main problems (I do have a Pixera 
>digital camera hooked up to a Leica MZ75 trinoc, but only use it for 
>morphometrics; years ago I shot quite a lot with a Wild 
>Photomicroscope setup, but always got better results with Zeiss 
>Luminar micro/macro lenses, another alternative to Summars/Milars).

But all this is about lenses and microscopes, not about the way the 
images are captured. There is no question that you can take great 
pictures on film - or on CCD chips. I've been using the same Micro 
Nikkor macro lens on a 35-mm camera and on a digital camera 
(MicroLumina): the digital images are generally better, as they have 
not been filtered through the grain of the film and the subsequent 
scanner.

The SLR-type digital cameras (though more expensive than the ca $1000 
lot we have been discussing; the Fuji S1 Pro camera body sells for 
about $3000) can be fitted to macrolenses or microscopes  - but you 
may have to search for a proper adapter.

Granted, people will often swear by the lens they have been using for 
decades, and then tragedy ensues when it doesn't fit any of the new 
digital cameras. Yet my experience with the Minolta Dimâge for 
moderate macro suggests that that lens is not in any way inferior to 
earlier favourites of mine. I don't know how the Coolpix (which 
supposedly has a more extreme macro) fares in that respect, and 
certainly for beasts of millimeter size the Dimâge would not do. For 
that I use a microscope setup.

>  And, for people in this boat, resolution continues to be an issue. 
>With 4000 dpi negative scanning, you get 5512x3675 pixel resolution 
>of a 35 mm frame.

But again, do you need that resolution? Accepting the 300 dpi 
resolution as standard for good print, you could blow up your hi-res 
35 mm negative to more than 18" width, nearly half a meter. At that 
size, the inadequacies of the camera lens and the 35 mm media will 
start to show, and yet you still won't see any pixels. And your image 
file (assuming 8-bit TIFF in colour) will be a crippling (unless you 
use a supercomputer) 60 MB ...

>Don't get me wrong - the sooner everything is totally digital the 
>better, for the many reasons you list.  But for some of us, I'm not 
>sure we're quite there yet.

I don't think we see things too differently. We all want to pass the 
divide and only disagree on whether or not we've already done so.

Stefan
-- 
Stefan Bengtson
Senior Curator (invertebrate fossils)
Swedish Museum of Natural History
Department of Palaeozoology
Box 50007
SE-104 05 Stockholm
Sweden

tel. +46-8 5195 4220
      +46-8 732 5218 (home)
fax  +46-8 5195 4184
e-mail Stefan.Bengtson@nrm.se