Wednesday, 23 November 2016

Infra Red with Nikon FE Electric Film

Swap the IR Filter with Clear Glass

Well this has been a fun adventure. The IR/Lens filter I have fitted to a frame, which mounts up behind the Nikon mirror, is quickly replaced with a clear glass filter enabling the Nikon to photograph onto the bare sensor of the Nex. The clear glass is from a microscope slide and it protects the sensor from some dust that could come from the lens side of the shutter. Dust is my enemy now as I suspect that a sensor with the filter removed is more susceptible to dust than normal as the electric field is on the face of the sensor. Where as at manufacture the IR filter is fitted on a small frame 1.5mm from the sensor face and seals off the space between, which maybe reduces the static dust attraction at the outer glass face (another theory). 

What has been interesting is the extra amount of light that now hits the sensor which makes the Nikon light meter out by about 2 stops. The photo exposures seem more sensitive to aperture adjustment. I was using a Leitz Elmarit 28 lens which has 1/2 stop adjustments and the variance shows significantly as compared to normal photos with the IR filter in place. Thinking about the light meter issue I concluded that the Sony engineers have to make the IR/Lens filters to a particular density so that the sensor calibrates exactly to the Calibration Standards for light meters (basically the sensor is the same as film). Which is why when I fit the 2012 CMOS sensor (with filter) to a 1980 Nikon, the sensor absorbs the correct illumination to match the Nikon light meter readings. When I remove the IR filter, the Nikon light meter is giving a reading as bounced off the mirror, which is now not matching the extra illumination the bare sensor receives during an exposure. Reading Wikipedia this same situation occurs when infra red film is used and the film camera's light meter has to be recalibrated to suit that specific IR film.

As I'm using a rather unique camera, I came up with a simple solution to fix the light meter calibration. I set the Nikon to 1600 ASA and the Nex to 400 ISO effectively 2 stops difference. This worked a treat and gave good images with the speed and aperture needles in alignment. I could then make fine tuning adjustments as normal with the Nikon's exposure compensation dial. The other benefit was I need to keep the speed over 125 as I shake and a 1600 ASA on the Nikon is a real help for this.

The photographs that can be produced with the IR Filter removed can make for some interesting black & white results. I don't have photoshop, just Preview and Photos on an iMac. Photos Edit has some B&W Filters that change the infra red photo to Mono or Tonal or Noir which give some great variations to a B&W image. Ming Thein did a lot of work with a Sony Nex with filter removed and there are some great shots on his album Multispectral . There is no reason that images to this level of excellence could not be produced with a SLR/Nex modification that I am working with here - provided that is you are a better photographer than me.

Below is a collection of some shots I quickly took to give you some idea of what a bad photographer with the shakes can produce from this camera. Click image to expand. Recently excerpts of this blog appeared in the Flipboard app resulting in a quick jump to over 5,000 views and 1,000 YouTube. It is pleasing to see so many take an interest. But when is someone else going to build one of these fantastic cameras? All the info you need is on the links in the top right of this page. Enjoy. RG.

Infra Red B&W Mono

Standard colour result in Infra Red
Infra Red B&W Noir
Infra Red B&W Noir

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