Digital BW, The Print

Carl,

Good work - but so surprise here.

We should remember that placing a matrix of 3 columm x 6 rows APS 
sized sensors (your ~80 MPix) is not the same as placing the entire 
80 MPix into a single APS (or even full frame 35  mm film) sized 
sensor.  No doubt that modern DSLR sensors(>6 MPix) capture detail 
close to (or by some people's opinion, even better than) modern high 
res film of the SAME APS SIZE.  Your comparison is actually very good 
at showing that a small format lens has a great deal more resolution 
than LF lenses.  As I read somewhere else recently, "there ain't no 
substitute for real estate".  Your test shows that an 80 MPix sensor 
approximately 1/2 the physical size of 5x4 film will beat 5x4 film 
scanned on an Epson 3200.  To beat a high end drum scan may take 200 
MPix onto a 5x4 sensor.

Shilesh

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, Carl Schofield 
<scho@m...> wrote:
> Just to follow up on my previous post about stitching, I took some 
> comparison shots yesterday at a local waterfall with a 4x5 and a 
Canon 
> 10D.  Here is a side by side comparison of a stitched composite 
image 
> (18 frames (landscape orientation) in a 3 column by 6 row matrix) 
made 
> with the Canon 10D and 135mm f/2 L lens and a scanned (Epson 3200 
set 
> to produce a 16x2016 bit grayscale at 360 ppi) image from a 
Polaroid 
> type 55 4x5 negative, shot with a Tachihara 4x5 field camera and 
> Fujinon A 240mm f/9 lens.  Exposure for the 4x5 was 2 seconds at 
f/32 
> (EI 25) and for the 10D images 1/6 sec f/16 (EI 100).  The 
comparison 
> images are side by side screen grabs in Photoshop at 8, 25, 50 and 
100% 
> of image size.  The 4x5 image is 83.6 MB and the stitched 10D image 
is 
> 80.1 MB and both are 16 bit gray. The 25% image is approximately 
the 
> appearance when the images are printed at 16x20 inches.  The 
stitched 
> 10D image compares quite favorably to the 4x5, although the 
stitching 
> is very tedious and time consuming.  You would need a 40 MP digital 
> camera to get single shot images comparable to the size and quality 
of 
> either the 4x5 or stitched 10D images.
> 
> http://homepage.mac.com/scho/forweb/index.htm