Author Archives: Kirk Martinez

Ashmolean dome test

Published / by Kirk Martinez

good to see the first seal test with dome15 – looking at the bubbles and damage on our seal replica:

with Nikon Z6 and 105mm macro lens
and a 200mm test on two coins
and a seal detail using the 200mm lens
an extreme crop shows the slim depth of field at F10 and the wierd structure of the replica

Using the Nikon Z6

Published / by Kirk Martinez

The newer mirror-less cameras have a few features which make them ideal for use in RTI imaging. Apart from the lack of mirror-flip for each frame (and possible vibration) they tend to have faster memory cards (CF express) so the system needs to wait less for images to be flushed to the card. Live preview with zoom also makes it easy to focus. I used a F to Z converter for a 105mm macro, which is manual only and the converter acts as the mount point for the whole camera.

Settings I used were saved in U3: Manual socus and exposure, fixed 100 ASA, stabilisation OFF, Silent ON, fixed white balance (use grey card), Picture Control normal (all zero) and auto-playback off. I left auto-distortion correction on as the cameras tend to know the characteristics of each lens.

Testing Glasgow’s Dome12

Published / by Kirk Martinez

My usual test is a cuneiform replica or a fossil. Today this dome had a full test with the tablet and my Nikon D650 (100ASA, 1/10s F10, jpg, no white balance calibration).

with the virtual light slightly off to the top-right, PTM viewed in RTIviewer
snapshot in rtiviewer – at 100% scale
in specular reflection mode
Normals visualisation mode

This replica is very useful and is of the Sumerian period (2600 BCE). It is 8cm x 7.5cm and came from the Sumerian city of Shuruppak. It describes the sale of a house and names two witnesses. The original is in the Louvre Museum