Focus Test Charts

[ricktas]

For those members who have a need to do focus testing with their gear, I have attached some focus test charts that you can download and use.

http://www.ausphotography.net.au/staff/Rick/Focus-Test-Chart.pdf

http://www.ausphotography.net.au/staff/Rick/Siemens-Star-Focus-Chart.pdf

http://www.ausphotography.net.au/staff/Rick/FocusChart.pdf - one with instructions to create your own 45 degree chart

http://www.ausphotography.net.au/staff/Rick/ISO_12233-reschart.pdf

[Ventureoverland]

If I need to ask it probably means I dont need to know... but I'll ask anyway, how does one use the charts?

If its a long answer tell me to Google it! If its a quick and simple answer, please humour me:)

Thx
Jon

[ameerat42]

Ta 4 these, Rick. Am.

[Kym]

These 45 degree charts work well... http://pentaxdslrs.blogspot.com.au/2012/01/front-or-back-focusing-problems-free.html

[ricktas]

To use most of these, you place them on a table etc, then set your camera up at a 45 degree angle to the printed chart. Use a tripod. You then focus on a central part of the chart using the largest aperture (smallest f stop number), the centre focus point on your viewfinder and take a photo. Then look at that photo on your computer and see where the result is sharpest.

If sharpness is closer to the camera than where you focused, then your camera/lens combo is 'front focusing'
If sharpness is further away than where you focused, then your camera/lens combo is 'back focusing'

You can also test other focus points by selecting them. This will let you see if there are variations across your focus points.

When printing your charts do not use Gloss photo paper. Matt paper should be used for more accurate results.

[Ventureoverland]

Thanks very much. Now I see the validity in the sentence in your initial post, "for those that need / use them", or words to that affect.

Thx
Jon

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[ricktas]

And if you want to spend some money, you could go for the ultimate home test : http://michaeltapesdesign.com/lensalign.html

[sinequanon]

Thanks for the charts Rick and Kym.

I've used a few charts through the years with varying degrees of disappointment. My main problem is that at the recommended 25X to 50X focal length, the resultant images are too often too small for me to decipher any useful difference in focus. This is especially true of lenses under 100mm. Or have I got it all wrong somehow?

[Miss Jane]

Thanks for these. I was wondering how to test your focus.