306 THE HASSELBLAD MANUAL
Figure 16-10 Sharpness within the depth-of-fi eld range. Depth-of-fi eld is not a range of critical
sharpness (in the example, from 8 to 50 feet) with an abrupt falloff to blur. Instead, it is a
gradual decrease in sharpness on both sides of the set distance (15 feet in the example) even
within the depth-of-fi eld range.
such evaluation. This sharpness difference may be more obvious with very sharp lenses, but
again do not blame the lens. Blame the incredibly sharp fi lm available or the fabulous sharp-
ness created in a digital image by the large Hasselblad sensors. These are the elements that
make these differences in the sharpness range more obvious. You can also blame the age of
the depth-of-fi eld scales and tables which were calculated years ago when fi lm was not very
sharp. Although the scales are still usable for general work, you may want to make your own
adjustments for critical work, either by not using the entire depth-of-fi eld range shown on
the charts or lenses or by closing the aperture one or two stops more than necessary for the
desired depth-of-fi eld range. Whenever a specifi c subject is to be critically sharp, focus the
lens on that subject. Do not rely on depth-of-fi eld.
Depth-of-Field on the Focusing Screen of SLR Cameras
The ability to see depth-of-fi eld on the focusing screen of SLR cameras made for digital
imaging or fi lm photography such as all Hasselblad models except the Superwide, is often
described as a main benefi t of working with such cameras for serious photography. In prin-
ciple this is true since you view the image through the lens and you can stop down the
aperture manually to see the image as it will be recorded in the camera at the set aperture.
Unfortunately this is incorrect. The focusing screen on SLR cameras, or the Preview screen on
digital sensor units even on Hasselblad cameras made for larger fi lm and sensor sizes, is sim-
ply too small to see where the sharpness is acceptable or where the sharpness starts falling
below the acceptable limit when the image is enlarged. Furthermore the image on a focusing
screen, even the Acute Matte types, cannot show a razor sharp image to see how depth-of-
fi eld changes when closing down the lens aperture. The problem is increased when you try
to evaluate the dark image at smaller lens apertures.
The focusing screens on SLR cameras, especially the large screens on Hasselblads, are
wonderful for focusing and evaluating the image to see what is really sharp and how much
blur you have in background and foreground areas.
For determining depth-of-fi eld or to determine the minimum and maximum distances
where images are acceptably sharp, use the charts or scales on the lenses.
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