That's a very fine image, Ralf - I might try that myself. My *ist-D has been sitting on the shelf for most of the last seven years, it will be nice to fire it up again.
John in Brisbane -----Original Message----- From: Ralf R Radermacher <fotor...@gmx.de> Sent: Thursday, July 13, 2023 6:13 PM To: pdml@pdml.net Subject: Re: IR Photography Am 13.07.23 um 01:59 schrieb Larry Colen: > You'll need to focus based on the live view, which is what the sensor sees, > either that or manually focus based ton the distance scale and the little red > dot that shows the IR focus point. Maybe even a little beyond the red dot which is calibrated for an IR wavelength of around 750 nm corresponding to the usual near-infrared film stock like Ilford SFX200 or Konica 750. The infrared sensitivity of a DSLR sensor extends way beyond that, well into the 800's, shifting the focus point even more. And don't try to step down beyond f8 to gain more DOF. Aperture diffraction at IR sets in a lot sooner than with visible light. I've been using a #87 gelatine filter on my unmodified *istDS. This filter is almost completely impervious to visible light. Here's an example: https://www.fotocommunity.com/photo/la-bistade-fotoralfbe/32223101 Ralf -- Ralf R. Radermacher - Köln/Cologne, Germany Blog : http://the-real-fotoralf.blogspot.com Audio : http://aporee.org/maps/projects/fotoralf Fotos : https://www.fotocommunity.de/user_photos/770012 -- %(real_name)s Pentax-Discuss Mail List To unsubscribe send an email to pdml-le...@pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions. -- %(real_name)s Pentax-Discuss Mail List To unsubscribe send an email to pdml-le...@pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
