The day before a big game coverage like the Chick-fil-A Kickoff, I am getting my gear ready. Charging all the batteries and being sure I have all the gear packed before the next day.
One of the things we are now more aware of with digital cameras is front or back focusing of a camera. When the camera and lenses ship they have some tolerance which gives you reasonably acceptable images, but if you want to get the sharpest images, then you need to calibrate. This is from Nikon's website showing you the concept of calibrating that I am doing.
In the Nikon D4 menu you go to the wrench and then Fine Tune. You will adjust the settings here:
Watch this video on how you adjust your lens using Fine Tune on the camera. Sometimes it is easier to adjust the camera just +/- 10 or 20 points which might be all you need to do than to go and adjust 16 different focus points. Another point is you may have gone +/- 20 points and still need more adjustment and this is where the combination of the two can give you more range for calibrating.
I am calibrating the new Sigma 120-300mm ƒ/2.8 DG OS HSM | S lens today before the big day tomorrow.
I am using the Sigma Optimization Pro software coupled with the Sigma USB docking station to calibrate the lens in addition to using the Fine Focus on the Nikon D4 as well.
To check the focus point I am using the LensAlign Pro system.
I set the Camera and LensAlign Pro at the distance I will need to focus and then parallel to each other. The LensAlign direction help you set that up.
Then I take a shot at one of the four zoom positions with this lens: 120mm, 150mm, 200mm or 300mm. Then there are four different focus positions to also choose for each focal length you choose. When you have done all the possible combinations you will have 16 different customizable calibrations to get the sharpest image possible with your camera.
Here I am set for the closest focusing point for 120mm |
I would do a test shot that might look like this and then I needed to zoom in on the photo to see the detail of where the focus point was for the photo.
Here you can see the focus point is actually slighting in front of the 0 where I wanted to be.
I open the Sigma Optimization software and put the USB dock on the lens replacing the camera. This is why you need a tripod to do this, you need to lock everything down make the change and then reshoot to see if the custom change worked.
In the screen grab here you see I moved the focus point +4 further from the lens. They give you pictures to see what you are doing, which really helps.
After doing this a few times you can see where I ended up with focusing. Now you repeat this 15 more times with 120mm, 150mm, 200mm and 300mm at four different focusing points: Closest, Furthest and two in between.
Stay tuned for my results from the Chick-fil-A Kickoff with the new Sigma 120-300mm ƒ/2.8 DG OS HSM | S lens.
4 comments:
Legend mate. Very well put and makes it easy to calibrate. Awesome
Thanks for an interesting article. I am keen to see how this lens works particulary after a friend of mine had considerable trouble calibrating his lens.
He found the autofocus repeatability was very poor during the calibration. One minute it was perfect and then when he moved it out of focus it would front focus then back focus. He has had to send it bacck to Sigma. Did your lens show consitent auto focus during the calibration process.?
Tom
It was consistent. I believe often some people's problems are more about their camera.
Tom
My performance review is here http://blog.stanleyleary.com/2013/09/sigma-120-300mm-28-dg-os-hsm-s-lens.html
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