New resolution test chart for black and six colours

Started Jan 20, 2013 | Discussions thread
J C Brown
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Re: New resolution test chart - Small colour and B&W versions
In reply to J C Brown, Jan 21, 2013

J C Brown wrote:

Resolution test chart for black and six colours

The test chart shown above was designed for printing on A4/Letter size paper. When printed actual size the length of the 400 pixel vertical scale line should have a length of 100 mm. To avoid excessively long chart to camera distances when using it with very long focus lenses and with TCs it should be printed half size at which the length of the 400 pixel vertical scale line should be 50mm.

Jimmy

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J C Brown



Resolution test chart - small colour version

The small colour version above is a revised version of the chart which I developed for assessing the resolution of my FZ50 and Nikon TCs as described in my November 2009 thread,

Resolution in Black and Six Colours – FZ50:  http://forums.dpreview.com/forums/post/37031036

This small version of the chart which uses only single letters of each size and colour is available for download from my gallery. It is intended for use on its own or at the centre, edges and corners of the frame as described in the thread referenced above.

A composite test board with the new test chart at the centre and copies of the small version at the edges and corners is ideal for assessing the resolution at the centre, edges and corners and their variation with aperture, ISO value and light level at various focal lengths.

It is also useful for assessing geometrical distortion and the extent of any CA associated with the camera lens on its own and with a conversion lens attached. In addition the 50 pixel spacing between the individual letters in the large version allows the extent of any colour spreading to be assessed.

The large and small versions of the colour test chart were designed to allow assessment of the variation of resolution with colour. The smaller "Black" version below was designed for assessing only the B&W resolution. As with the large colour version a full size copy of the black version may be downloaded for private use by clicking on View:original size, clicking on the resulting image to magnify it, then right clicking on that image, selecting "Save as" and choosing a suitable name and location for the downloaded 2.54 MB file.

Resolution test chart - Black

As with both the colour versions the resolution of the black chart is 4 pixels per mm. Thus when printed at actual size the length of the 300 and 500 pixel scale lines will be 75 mm and 125 mm.

While copies of that size are suitable for use with most focal lengths to avoid excessively long chart to camera distance with very long focal lengths and TCs it is advisable to print them at half size.

As with the test chart used by DPReview for camera resolution tests, in order to obtain acceptably accurate measurements when using any of these three test charts it is necessary to ensure that the chart to camera distance is sufficiently accurate and that both the camera and the chart are  levelled with sufficient accuracy. When I have some free time I intend to provide more detailed  information about the use of these charts and the interpretation of the resulting images in a separate post.

Jimmy

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J C Brown

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