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Digital Infrared Photography Explored: Part III
Third installment in a series on specialty cameras for infrared photography.


Sigma's digital SLR cameras SD14 and SD10 allow infrared photography with high shutter speeds but without expensive modifications.
The internal IR blocking filter of the Sigma SD14 also functions as a dust shield and can simply be removed without tools.
Without internal IR-blocker, the Sigma SD14 records a false color image consisting of UV, IR and daylight combined.
Because its fast shutter speed counteracts blurring, the SD14 can also be used for subjects in motion.

Sigma SD14--Infrared Photography Out of the Box

There is an SLR camera which allows both regular daylight photography as well as infrared photography without the need for expensive modifications: Sigma's SD14. This camera's internal IR blocker doubles as a dust shield and can easily be removed in case the sensor needs cleaning. On the SD14, this can be accomplished without any tools, but on the camera's predecessor, a tiny screw has to be loosened. The process is described in the camera's manual. When this filter is removed from the camera, the photographer can make use of the entire light spectrum from ultraviolet to near infrared. Once the filter is placed back in the camera, there is no infrared sensitivity at all.

One word of caution: if the camera is used without a filter, lens changes should be done in a dust-free environment to prevent airborne dust and debris from settling on the sensor.

As with other SLR cameras, the viewfinder will darken once an infrared filter is attached. Again, this means that the picture has to be set up before the filter is applied. In most cases this means that a tripod will be necessary, even though the shutter speeds will be only slightly slower than what we might expect in daylight photography. Under sunny conditions, we could expect exposure times of 1/500 seconds or even less, using an aperture of 8. It is best to select aperture and shutter speed manually, and to make the exposure rather low in order to avoid overexposure. Hand-held shots become possible with a little practice. This involves holding the infrared filter against the front lens after first setting up in visible light. Fortunately, the autofocus works well for this technique.

Among the SD14's downsides is that it is impossible to adjust the white balance with an IR filter attached. This necessitates a use of the RAW-format and the successive conversion into black and white images, by using either the included converter software or any software that can perform this function. This method achieves much greater image quality and is therefore not necessarily a disadvantage.

Using an appropriate filter (such as the RG715), the camera can also produce colored infrared pictures. However, labor-intensive conversion in a RAW converter or in other image editing software becomes necessary. The reason is that without the internal IR-blocker, the camera records a false color image. From this, interesting images can be produced by swapping out color channels and by performing other manipulations. Once the IR-blocker is inserted back into the camera, it is again fully capable of shooting regular daylight pictures.

Links to the first and second installments of our completed series are below:

www.imaginginfo.com/web/online/Online-Exclusives/Digital-Infrared-Photography-Explored--Part-I/49$4258

www.imaginginfo.com/web/online/Online-Exclusives/Digital-Infrared-Photography-Explored--Part-II-/49$429

Excerpted from the new book release Digital Infrared Photography by Cyrill Harnischmacher and published by Rocky Nook. For more information visit http://www.rockynook.com.


   







PTN Dailes HERE