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Camera / Lens Calibration
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Dec 7, 2016, 22:18
So yesterday I spent 6 hours calibrating 7 lenses to two bodies. I downloaded a calibration target that is cut apart and assembled on foam core to create a three-dimensional calibration target.
A few lenses needed next to no adjustment, while others were quite a bit off.
So I was just wondering, does anyone else calibrate their lenses to their bodies?
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I wouldn't know how. Never read anything about it or heard anyone talk about it, before now.
Ask yourself, "What's most important for the final image?".
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Interesting to hear if you see any visible/tangible differences. I was not aware this was possible. No mention instruction wise about this, although I have a fairly basic Sony. Ed.
To each his own!
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I always calibrate my lenses to my bodies. For those who would like to know how, see here:
https://photographylife.com/how-to-calibrate-lenses
A calibration target does not have to cost the earth - I bought mine from Amazon but this one works just as well:
http://petapixel.com/2013/03/12/ghettoca...led-dslrs/
Here's the Amazon version - the pack comes with two targets:
https://www.amazon.co.uk/DSLRKIT-Focus-C...ation+tool
You will be surprised at the difference it makes!
GrahamS
Take my advice. I'm not using it.
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Thanks for that information. As I have never had a camera that had the facility to calibrate for lenses, that may explain my ignorance of the procedure.
Ask yourself, "What's most important for the final image?".
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Special equipment is not really needed, except that it's best to mount the camera on a tripod. Lay a 30cm ruler (one with mm markings) on the table in line with the axis of the lens, then tilt the camera and lens down at roughly 45 degrees, and at about 50cm away from the ruler. Set the lens to a wide aperture, and adjust the position of the ruler so that the 15 cm mark is in the centre of the field of view. Set the camera to use the centre focus point, and use the camera's self-timer to eliminate camera shake when taking the shot. In the image, the "15" and its line mark should be sharp, with blur increasing towards 14 and 16. If not, adjust the focus calibration in the camera, and repeat as necessary.
Cheers.
Philip
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My Sony inst make no reference to this, was not aware this was possible, so does not apply.Would like to see some before and after conventional pics.
Surprised the manufacturers could not get it right! Ed.
To each his own!
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(Dec 9, 2016, 10:30)EdMak Wrote: Surprised the manufacturers could not get it right! Ed.
Perfection would most probably only be attained at a ridiculously high price point, Ed, and so it is astonishing how close they often are.
To make cameras affordable, their components are manufactured within a range of tolerances rather than to perfect accuracy. Many DSLRs use a separate autofocus sensor, whereas the image is created at the camera's image sensor. So it should not be a surprise that even extremely microscopic differences in distances between lenses and sensors (although within the tolerance ranges) might combine to cause slight errors in focusing, particularly for close subjects, and/or large apertures, when depth of field is already very small.
Cheers.
Philip
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Years ago I had a Zorki 4K which produced the sharpest, snappiest negatives/transparencies of any camera I have ever owned. Foolishly, I sold it, then years later bought another. What a disappointment. The second one was mediocre, to say the least.
The first camera was obviously "centre of spec", whereas the second was just "in spec". When building performance engines, for bikes or cars, there is a term "Blueprinting", which means picking all the components which are spot on in middle of spec. This gives superior performance without using any performance parts. The same goes for cameras, Hi-Fi, etc.
Ask yourself, "What's most important for the final image?".
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That's the target I used Graham, the petapixel one.
Have only shot a few pics with the 5dIII and 24-70 since calibration, and they do seem a little sharper.. or I should say a higher percentage are satisfying me.
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I had the same experience, Craig. Especially when I went to a higher resolution camera
GrahamS
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(Dec 8, 2016, 06:46)Jocko Wrote: Thanks for that information. As I have never had a camera that had the facility to calibrate for lenses, that may explain my ignorance of the procedure.
The first camera I had that was able to be calibrated was my Canon 50D, that had a screen for adjustment.
Now both my 5DIII and 7DII have the ability to have an adjustment made at both the wide end, and zoomed end of the lenses range. This is much better as a lens that needs say -7 adjustment wide open, may only need -2 when zoomed all the way in.
In both cases, the adjustment is less important when you have the lens closed down as the DoF is obviously greater.
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Well after a Christmas trip and only taking 2 lenses and 1 body to travel light, I can say I do see a marked improvement on focus with the 5dIII and my Sigma 24-70 f2.8. The most noticeable change was in lower light, the images were noticeably sharper. Seems that the focus was much closer to the target focal plane. I was already happy with the daylight performance.
Had far fewer missed focus shots though, I feel it was a day well spent. (of course, this could all of been blind luck and the placebo effect!)
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