PDA

View Full Version : Digital LF lenses, not the best choice for film?



Vick Ko
27-May-2012, 06:05
So are digital LF lenses, not the best choice for film?

Try to read between the lines on the advertising, I "sense" that they have fewer aperture stops and are optimized for smaller sensors.

Am I reading the ads correctly?

If I only intend to shoot film, is it best to stay with "analog" lenses?

Vick

vinny
27-May-2012, 06:49
many of them don't cover 4x5 film area.

polyglot
27-May-2012, 18:29
What do you mean by a "digital" lens? It's still glass and still forms an image; if it covers your format it should be fine. Did you have any particular model in mind?

The only technical distinction (i.e. a real design difference, not just "we put a new label on it") that I've seen on "designed for digital" lenses is the use of better anti-reflection coatings on the rear elements in order to avoid a central hot-spot in the image from inter-reflections between CCD and lens. There are no real drawbacks there.

Leigh
27-May-2012, 19:55
The current crop of "digital" LF lenses typically have a different rear cell and
a much smaller image circle than the non-digital version of the same lens.

Not a good choice for film use.

- Leigh

Oren Grad
27-May-2012, 21:36
Those "digital" lenses that have a large enough image circle to cover the film format you want to use should generally be first-rate. I have the 90mm Apo-Sironar-Digital (now relabeled as the HR Digraron-W), which covers 6x9cm comfortably. It's an excellent lens, my favorite among all the medium format lenses I've ever tried.

The one complication that comes to mind is that some "digital" lenses (e.g., Rodenstock HR Digaron-S series) have optical designs that take into account the cover glass of a digital sensor. Rodenstock offers a matching "corrector plate" for those lenses if you want to use them with film.

Oren Grad
27-May-2012, 22:03
...and a much smaller image circle than the non-digital version of the same lens.

For those first-generation digital lenses that are close cousins of existing analog designs, the smaller image circles are largely an artifact of their being re-specified for relatively large working apertures (typically f/5.6 to f/8 or f/11) and with a more stringent MTF criterion. Slice the MTF of an Apo-Sironar-S or an Apo-Symmar L the same way and the difference between those and their digital counterparts won't seem so large.