How to increase the ISO sensitivity of your digital camera beyond the manufacturer’s limit. logo

The Fuji FinePix® E900 comes with a wide range of ‘digital film speeds’. The slowest is a very fine [low noise] ISO 80. The fastest speed that may be set on the camera is ISO 800. In practice the ISO 800 setting produces very nice prints up to size 18″ x 12″. There will however be times when you’re faced with taking photographs in conditions where there is very little light, without flash, and the camera is indicating that your pictures will be underexposed.

There are various solutions to the problem but all except using flash will involve some depletion in the overall picture quality of the final image. For this reason it may, after all, be best to use the E900’s built in flash.

Use Flash As A Fill

Low power flash adds highlights to this
atmospheric picture of a mother and child relaxing.

The first and most obvious solution is to use the E900’s built in flash. This isn’t really up-rating the camera’s sensitivity but if managed carefully it can still enable you to take an atmospheric photograph. Rather than attempting to illuminate the picture solely with the flash you might try using the Night Scene Mode, which fires the flash and also opens the shutter for a longer period in an attempt to capture a dark background. The E900 works well in this mode but if you wish you can achieve the more control by using the flash with manual exposure settings.

Correcting The Exposure In Adobe Photoshop®, Paintshop Pro®, ACDSee® etc.

Two other solutions are possible. These don’t require you to use flash but instead rely on digital manipulation on your computer.

The first method involves using Adobe Photoshop, or similar software such as
Paintshop Pro, ACDsee Pro, or The GIMP. The GIMP is a free program, which may provide a solution if you’re on a tight budget.

Load your .jpg image into Photoshop and go to Image – Adjustments – Auto Levels. Click and your picture will probably become brighter. If the result is too bright you can bring it down by selecting ‘Edit’ – ‘Fade.’

Exposure corrected using Adobe Photoshop® auto levels

Sometimes Auto Levels doesn’t bring up the picture brightness. When this happens you must use a different tool from the Image – Adjustments Menu. The most professional tool is called ‘Curves’.

Curves are great fun, especially when you’ve got time to experiment. For our purposes today however we’re going to use the eye dropper tool which is located to the right of the curve itself.

The eye dropper tool is located
at the bottom right of the curves pallete

Firstly, select the middle eyedropper and click on any area in the picture that is grey. In the example I clicked on the back of the mirror, which Amazon is holding. The image went slightly darker, but don’t worry about this as the setting just helps the software to find the right colour balance.

Secondly, select the eyedropper to the right and click on any area that you want to appear as black as coal. I clicked on one of the corners of the image. This picture became slightly brighter, but yours may become darker. It doesn’t really matter.

Thirdly, select the eyedropper to the left of the panel and click on any area that you want to be pure white. Voila, your picture will become brighter and contain a complete tonal range. When you click on ‘OK’ your setting will be saved to the image. you can reduce the effect, if you wish, by going to Edit – ‘Fade Curves’

Correcting the exposure via the curves tool has
helped preserve the original colour balance.

The Power Retouche Exposure Filter

My favourite way of boosting the ISO sensitivity in Photoshop® is to use the Power Retouche Exposure Plug-In. This utility also stands alone, and will work with the other digital editors such as Paintshop Pro®.

It’s very simple to use and preserves the colour balance of the original photograph whilst boosting the exposure setting.

After you have installed the Power Retouche Filter(s) in Adobe Photoshop®, (or your preferred editor), click on Filter – Power Retouche- Exposure. The Power Retouche exposure control panel, [and editing screen not illustrated here], will load.

The Power Retouche exposure control panel

Make sure that the Power Retouche Exposure Correction Box is checked. Then move the slider next to it to the right. The image on the preview screen becomes lighter. When you have obtained the result you want simply click ‘Apply’. The corrected image will appear in Photoshop.

Exposure correction using Power Retouche is easy.
It preserves the qualities of the original whilst
boosting exposure by several stops

Adjusting A RAW Image

A RAW image consists of the information the camera sensor ‘sees’ before it is converted into a .jpg by the camera. Images taken in the RAW format must therefore be converted in your computer using RAW editing software.

A RAW image may be saved on the Fuji FinePix® E900 by going to the Camera Menu, selecting Settings – Page 2 – RAW and toggling the tab to ‘ON’

You cannot make adjustments to RAW images using the Finepix® Viewer, which comes bundled with the FinePix E900 digital camera. Instead I recommend you to use S7raw, which is a free utility developed for the Fuji Finepix® digital camera range. s7RAW provides a full range of editing options including exposure compensation.

If you own a different brand of digital camera you may like to try UFRAW which is another free editor that will translate a wide range of RAW formats from many different manufacturers. It is however slightly more difficult to install on your computer so please read the instructions carefully.

Increasing the exposure is the same for both s7RAW and UFRAW.

Firstly, load the RAW file into the editor.

The image of the flower is slightly dark

Secondly, select the ‘Sensitisation’ slider and move it toward the right. The picture will become brighter in the preview screen.

Half a stop gain has been added in S7Raw

An increase in exposure is achieved in a RAW editor by increasing the gain of the CCD, (or equivalent), sensor. This will result the file becoming noisier and you may wish to apply one of the various methods of noise reduction available before printing your images.

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