DIGITIZING FILM NEGATIVES WITHOUT SCANNER
Mirror image of the front element of the Nikkor 105mm f/2.8 G with the camera directed towards the the enlarger with a mirror placed in the negative plane instead of a film.
There is a lot of interest in converting B/W 35mm film negatives to digital positives. In this respect, the option of a 1:1 magnification offered by the Micro Nikkor 105mm f/2.8 G VR ED in combination with a full frame camera is appealing.
I use the Vivitar VI enlarger, setting the condenser to the position for medium format to have a more even light distribution. Mounting the camera on a sturdy tripod or any other solid support (see below) and shooting vertically upward into the enlarger with the camera lens mounted and the enlarger lens removed. To align the sensor plane parallel to the film plane I place a mirror in the plane of the negative holder of the enlarger and align the camera such that the mirror image of the lens seen by the camera is centered (image on the left). This is facilitated by a grid which could be overlaid the image by the tethering software. Thereafter, one can align the frame and focus by moving the enlarger and/or the focus ring of the camera lens. For the moment I use the tethering software qDslrDashbord (digiCamControl made my PC freeze) and the D800 connected to the PC to collect the images. Live view allows for a very comfortable focusing if the image is covering slightly less than the full sensor (the camera must have some range to search for the focus). The negatives reproduced can easily be converted to positives using the tone curve of whatever software used and post-processed thereafter.
Santorini 2005. Reproduced with D800 and Micro Nikkor 55mm f/2.8 AI-S plus extension ring PK13 set to aperture f/8. The original photo was taken with the Nikon F3 and probably the Nikkor 105mm f/2.5 AI-S.
Center: 105mm at f/11.
Tests using the Micro Nikkor 55mm f/2.8 AI-S, which can only magnify up to 1:2, raised high expectations. But the results obtained with the 105mm Micro Nikkor where somewhat disillusioning. As detailed below the sharpness of the 105mm at 1:1 magnification is o.k. The sharpness is quite even across the whole image including the corners (at the optimum aperture). But but the grain is not really sharp at 100% view of the raw file and the fine structure of the images is a bit soft. In comparison to that, the 55mm combined with the PK13 extension tube (allowing for 1:1 as well) is sharper in the center. The corners are siginificantly weaker than the center, but they are still slightly better that what the 105mm can deliver. A good source of information on these and other macro lenses is coinimaging.com or the web page of Bjørn Rørslett.
On the left and below some details are shown. For each lens a series of images was made changing the aperture. After each change of the setup it was given time to allow for any oscillations to decay. Then the shutter was released with 3s mirror pre-release. For the 105mm, VR was switched off, of course. Shown are cropped images for those apertures which yielded the best visual results. On this web page they are shown slightly smaller (re-scaled). The visually best results seem to have been obtained using f/11 for the 105mm (center and corner) with f/8 being close. For the 55mm the center was visually best at f/5.6 and the corners at f/8 or f/11.
In conclusion, the 55mm 1:2.8 AI-S with PK13 yields better image quality using the above technique than the 105mm 1:2.8 G VR ED. Unfortunately, focus has to be set manually for the 55mm (wide open with 100% live view magnification). But once aligned properly, a series of negatives can easily be reproduced. Using a conversion preset in the software probably makes this technique much faster than any other scanning procedure.
Center: 55mm + PK13 at f/5.6.
Corner: 105mm at f/11.
Corner: 55mm + PK13 at f/11.
The image on the left shows the current setup. The camera (D800) is mounted on a MDF plate via a solid ball head. The camera has a permanent power supply. It is operated in live view and connected to a PC. For convenience I use the Nikkor 105mm f/2.8 G, sacrificing some sharpness (see above), because it allows a one-click refocus through qDslrDashboard, whenever the film strip is moved to the next negative. Since the light intensity from the Vivitar VI color head is quite high, the setup can be operated even in normal daylight. Typical exposure times using f/8 range from 1/250 s to 1/1000 s. The D800 is well capable of catching the normal dynamic range of film negatives. For correctly exposed and developed negatives I have never run into the need of exposure bracketing.