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 Olympus -mini IR-Diva IR-sensitivity

Camera: Olympus -mini IR-Diva 
ISO64
Filter: Heliopan RG715
white balance exposure time aperture EV
auto - without IR Filter 1/500 s f3.5 13.3
tungsten 1/200 s f10 15
flourescent 1/250 s f10 15.3
 setting:
time: around 10:00 o clock MET
date: 10 May
weather: clear sky, some wind
LIGHT LOSS: ~+1.7 EV

The Olympus -mini IR-Diva is a IR-modded version of the original Olympus -mini. The filter glass in front of the sensor has been replaced by a piece of normal glass.
The scratches in the middle of the images from the modified camera are damages on the CCD matrix caused by a laser in the lab before modification

Focus works very good but the exposure metering failures. Normally you will need from -1.3 to -2 EV exposure compensation, it depends somewhat on the white balance and the daytime. In some circumstances you will have to use spot metering for preventing overexposure.

The exposure time with IR-Filter is very short, you can do handheld work even in the evening hours. Shooting without tripod gives you a lot of flexibility. Also smearing caused by wind is no problem anymore.

 Colors:
without filter from original -mini (WB: daylight/Fine weather):

-mini IR-Diva without filter (WB: auto):

with RG715 (WB tungsten), -2 EV compensation:

with RG715 (WB Fluorescent), -2 EV compensation:

 comment: So far, so nice. Doing the following post precession we get this picture:
- copy the blue channel into the green one (= deleting green channel)
- swap the red and the blue channel
- applying a negative S tone curve to the new blue channel

Looks not that bad. For comparison an IR picture from the unmodified -mini taken last year:

In terms of colour the unmodified -mini is more vibrant with a weaker wood effect. So the sensitivity boost of the modification takes it toll.

 Sharpness:
Sharpness is very good across the frame.
The following pictures are 1:1 crops of the original images. Saved in Photoshop with quality level '10'.
The first crop is taken from the centre of the image:

(ignore the little scratch, the CCD was damaged by a laser)

The second is from the left down corner:

The third from the right border of the image:

It's better than the unmodified version.

The -mini seems to be a very good base for IR-modding. The lens isn't fast and has little zoom (35 - 70 mm). On the other side it consists of only 5 elements in 3 groups, so you have only 6 surfaces and therefore little scattered light and a good contrast. The good control of chromatic aberrations in visible light is a hint for good sharpness beyond the visible spectrum.

You should be able to print a nice little poster from that shot.

 Noise
You can use nearly every time the ISO64 setting of the camera but with tungsten or fluorescent white balance. So you get some more noise in the blue channel than expected at the first sight.
How visible it's getting in the print depends on your way of post processing the image. If it's getting critical for your application, I recommend using NeatImage for cleaning up the colour noise.

1:1 crop with NeatImage

 For some own tries I've provided a original IR file out of the camera:
 [P5100155.JPG]

[go back to sensitivity list]                    May 2008