Photo rumblings and whispers – Page 4 – Techniques, equipment, approaches, commentaries and more

Pinholes in NIR and UVA

Pedro J. Aphalo 2018-04-28 2018-06-18Equipment, Photography, Techniques 0

Using the E-M1 converted to full spectrum with the Pinhole Pro objectives is possible. Using a 58 mm NIR filter (Hoya R72) attached to the front of the 11 mm Pinhole Pro S11 worked fine, with no increase in vignetting. Using the StraightEdgeU 52 mm or Baader U-filter 2″ with a step-down ring blocked the corners of the image completely. The original 26 mm Pinhole Pro suffers a lot less from vignetting and can be used with these filters of smaller diameter than the front thread of the lens without problem.

Pinhole objectives arrived today

Pedro J. Aphalo 2018-04-26 2018-06-18Equipment, Photography 0

Introduction Pinholes need to be very small to provide a useful image. Consequently the corresponding f-values are small, in most cases f:100 or smaller. This results in either very long exposures, or requires the use of very high ISO values. As we will see in the example images this is less of a problem than what could be expected because as the resolution of the pinhole is low, the images tolerate very strong noise reduction processing without losing there character or mood.

Camera objectives for UV photography

Pedro J. Aphalo 2018-04-23 2021-11-25Equipment, Mehods, Photography 0

I have been testing some objectives for their UV transmission using LEDs as sources of radiation. I developed a protocol for such tests. Although used in this example to measure the spectral sensitivity of a camera sensor, the protocol can be easily adapted for the measurements of biological action spectra.

MIDOPT filters

Pedro J. Aphalo 2017-12-30 2018-06-18Equipment, Photography 0

For those interested in photography “beyond the visible”, some of the filters available from Midwest Optical Technologies Inc. under the MIDOPT brand name should be very interesting. They are distributed in European countries by Stemmer AG. Both companies are specialised in the supply of machine vision equipment. What adds additional interest is that filters are supplied in very many different sizes (from M13.25 all the way to M105, mounted and unmounted, and even with mounts suitable for installation at the back of objectives with C-mount).

Timelapse in the “dark”

Pedro J. Aphalo 2017-12-12 2018-06-18Photography 0

Here are three examples of time lapse videos captured in the absence of visible light. Two videos were captured under ultraviolet-A (UVA) illumination and one under infra-red (IR) illumination.

Black anodised aluminium in IR

Pedro J. Aphalo 2017-12-12 2018-08-05Equipment, Photography 1

Many cheap extension tubes, lens adapters and lens hoods are made of aluminium and have a black anodised finish: are they always better than plastic ones? As it was revealed by the macro extension tubes comparison internal reflections can be a problem in visible light and lead to glare and low contrast. These problems are caused by a relatively small amount of visible light reflected by anodised aluminium, specially if the surface is smooth. The ribbed surface frequently used avoids specular reflections, so controlling “stars” and similar artefacts but not so much the loss of contrast due to diffuse reflection.

Depth of Field (DOF)

Pedro J. Aphalo 2017-12-11 2019-02-13Photography 0

Depth of field is the depth region that looks in focus in a photograph of a three-dimensional object or arrangement of objects. Consequently, we discuss here how and why DOF is not absolute.

Pinhole Pro and Pro S

Pedro J. Aphalo 2017-12-03 2018-06-18Equipment, Photography 0

An on-going Kickstarter campaign offers sophisticated pinholes for digital cameras in an assortment of different lens mounts.