Up A Bit, Down A Bit, Repeat, Repeat
When you see the award-winning portrait photographs in the magazines and books, do you look at the eyes? I do, and as well as looking for the expression, I am also checking for the sharpness. Most of them - indeed all of them - are superbly sharp. Modern lenses can do that.
So why do my modern lenses sometimes fail? Is it me? Is it the camera? Is it the lens?
Our Senior Technician, Ernest, explained it this way; every component of the camera and lens chain has certain manufacturing tolerances - most of the components fall within their own specifications. But sometimes the lens that is at one end of its spec is coupled to a camera that is at the other end of its own measurements. Both good, but the combo means that auto focus is not really going to be dead on.
Some camera manufacturers recognize this and provide an electronic adjustment inside the AF section that can be set to compensate for these different tolerances - in effect to fine-tune the camera and lens combination so that it will deliver focus on the spot that the camera specifies..
My Nikon D300 is one such camera. There is a section of the AF that allows me to nominate a lens, then move the electronic response to it forward or back by small increments. I discover how far by taking a series of photos and looking at the LCD screen to see when I am spot-on. What do I see?
I see a Datacolor LensCal target. We have them in stock now and they are perfect for this sort of calibration. I screw the target onto a light stand or tripod, level it, and set up my test camera looking directly at the center of the target. One shot of the sliding scale tells me if I am front or back focussing, and I can then move that electronic command to correct it. The Nikon D300 will let me do this for 12 lenses and then remember what is needed for each lens when I mount it.
Result is a much better rate of AF success. I can recalibrate the lens/camera interface if things change and check periodically to see that I am still on target - it is quick and simple. Come into the shop now and we can show you the LensCal. It might make all the difference for your precise portraits.
So why do my modern lenses sometimes fail? Is it me? Is it the camera? Is it the lens?
Our Senior Technician, Ernest, explained it this way; every component of the camera and lens chain has certain manufacturing tolerances - most of the components fall within their own specifications. But sometimes the lens that is at one end of its spec is coupled to a camera that is at the other end of its own measurements. Both good, but the combo means that auto focus is not really going to be dead on.
Some camera manufacturers recognize this and provide an electronic adjustment inside the AF section that can be set to compensate for these different tolerances - in effect to fine-tune the camera and lens combination so that it will deliver focus on the spot that the camera specifies..
My Nikon D300 is one such camera. There is a section of the AF that allows me to nominate a lens, then move the electronic response to it forward or back by small increments. I discover how far by taking a series of photos and looking at the LCD screen to see when I am spot-on. What do I see?
I see a Datacolor LensCal target. We have them in stock now and they are perfect for this sort of calibration. I screw the target onto a light stand or tripod, level it, and set up my test camera looking directly at the center of the target. One shot of the sliding scale tells me if I am front or back focussing, and I can then move that electronic command to correct it. The Nikon D300 will let me do this for 12 lenses and then remember what is needed for each lens when I mount it.
Labels: Datacolor
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10:18 AM
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