Photographers who aim for high-end picture quality cannot simply “hang” a digital back onto the familiar old film camera. What can be tolerated with roll- or large-format film is often quite unacceptable when much smaller digital sensors are involved. This means that hitherto treasured large-format lenses need to be critically scrutinized as regards their digital compatibility. It is obvious that the widely used digital sensors with an area of around 1,800 to 2,200 sq.mm make entirely different demands to that of the more than 11,000 sq.mm of a 4x5 inch sheet film. If used correctly, the advantages in picture quality that a digital back can bring to many photographic fields cannot be doubted – but only if used correctly. What does that mean? Here a few hints:

• Only high-end components should be used. Quality in photography is the result of a chain of properly connected and properly functioning components. The weakest link of the chain determines the highest achievable quality. The best lens of the world can be reduced to a humdrum level if other components in the chain fail to measure up. Any straying from the possible optimum at once extracts a price in the form of reduced quality.

• Nothing has changed since the analog era concerning the rule "the shorter the focal length of a lens and the larger the f-stop available resp. used, the more important the mechanical precision of a camera".

• The capabilities of the lenses used must fit the requirements of the digital sensors used.
  A resolution of 25 to 40 line pairs per mm (lp/mm) for example may be sufficient for medium- and large-format film, but digital backs require at least 60 lp/mm, with the latest backs (featuring 36x56mm resp. 40x54mm sensor chips [56 resp. 65 MP] and 6.0 micron pixels) requiring more than 80 lp/mm. Moreover, digital backs are highly sensitive to lateral color shift, a phenomenon that is insignificant in analog photography.

• Generally speaking and corresponding to the present state of technology, digital backs resp. most lenses should be used with apertures between f 8 and f 11. New developments are, of course, possible at any time. A few new lenses allow the be used at apertures of f 4.0, f 4.5 or f 5.6 and even these often produce somewhat better results if slightly stopped down. We do not recommend the use of f 16 or higher. Reason: diffraction.

• Generally, when using digital backs, the lowest possible sensitivity should be used. Recommended settings are: ISO/ASA 50, 100 and 200. ISO/ASA 400 and higher settings should be avoided. Reason: noise.

• The longest possible exposure time with most digital backs is limited at around half a minute. Some backs offer a special modus that allows exposure time of up to an hour or even more - please consult the respective technical documentation of the digital back manufacturers). Besides the limitations mentioned, the new possibilities in exposure technology that digital photography can offer must also be mentioned. For example, HDR (High Dynamic Range) is a method where a multiple picture is taken from a tripod, with each shot at a different exposure. The many pictures are later digitally merged together, resulting in a range of contrasts that has not been thought possible before.

• All back manufacturers offer special tools to correct or avoid "color cast" and/or "center fold".

• Limits in movement: do not use shift, tilt and swing with digital backs that have been marked by the manufacturer as unsuitable for it. Please consult the respective technical documentation of the digital back manufacturers.