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26th October 2004
Project: make your own digital camera resolution test chart
by Ian Burley
1263: Project: make your own digital camera resolution test chart

Results and Conclusion

Results and Conclusions


The first thing that's noticeable about the respective (Westin and Edmunds Optical) targets is that the text size used in the scales are different – Westin's are smaller. There are some other minor detail differences, but apart from that the two targets are essentially the same design, as you would expect from two accurate interpretations of the same ISO specification.

We have reproduced cropped selections of the results below to minimize download delay. PNG lossless image format has been used to avoid the limitations of GIF and JPEG that would compromise detail image quality. The colour differences are down to the different tungsten light balance presets in each camera.

Olympus Mju:300

Horizontal resolution
A.

Olympus-Mju310-Z55-realISOa

B.

Olympus-Mju310-Z55-replicaISOb

Can you tell which target is which? Sample B, with the smaller scale legend, is the Westin target. The three megapixel Olympus doesn't stretch the target. Both samples show that the test lines merge between 10 and 11 on the scale (1000 to 1100 lines per target height).

Casio Exilim Zoom EX-Z55

Horizontal resolution
A (Edmunds Optics)

Casio-Z55- realISOb

B (Westin)

Casio-Z55-replicaISOb

With the higher resolution Casio Z55, differences between the two targets stand out a little more, but the result is still pretty good for the Westin target. Both indicate a measurement of around 1500 lines, though the Westin target looks a bit less refined, with a harder moiré pattern towards the resolution limit.

Vertical resolution

res-vertical


Again with the Casio Z55, the Edmund Optics target is on the left and the Westin on the right. Much the same conclusion for the horizontal results applies here, though the Westin target, if anything, shows a slightly increased resolution result.

Conclusion
I doubt that an optics expert would be totally satisfied with our testing methodology or the absolute quality of the results we obtained with our 'version' of the Westin target. But we're not suggesting those that require high quality, professional level, test data replicate our method. If you want a professional result, the best advice is to buy a professionally produced target like the Edmunds Optics one.

However, we hope we have demonstrated how you can get close to professional results using an ordinary printer, that you get a feeling for the limitations of printed resolution and maybe have a bit of fun and learn a few things on the way.


 
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