01-19-2017, 09:23 AM
Usually, focus checker charts are set up in 25...50×FL which means the target is somewhere distant in between 15 and 30 meters from a 600mm lens.
Most birds are shot at closer ranges.
One of the upcoming problems to solve in a test is stabilize the whole unit enough and avoid mirror/shutter slap. Next will be, get a big enough target. And keep it safe an clean. And light it up evenly enough. Do that in a room without atmospherical distortion. Dust, wind, humidity will lead to worse results.
After that you can look a t systematic problems. I know that my Nikon 300/4 E will getting me blurred images in bright daylight at shutter speeds between 1/180 and 1/500 when I forgot to switch off Image stabillsation. Next, if AF is slow , not reliable or unpredictable, even an otherwise great lense loose value.
Usability, ergonomics, weight, weather and meanchical resistance also come into equation, but cannot be rated. A phsysically trained person can hold a 3 kg lens longer without too much of shake than another. Stabilisation is great but we tned to forget the limits. In-lens stabilisation is constantly changing the optical axis as far as I understood. Comes bad to worse, the corners will suffer more.
Also, at the end of the day experience counts a lot. 15% more sharpness of one lens under test conditions? Forget it. Using it not careful enough, I loose quickly 30...70% of that advantage - and I'm only talking about static objects. Birds in flight benefit a lot more from experience than from IQ of a certain lens.
Most birds are shot at closer ranges.
One of the upcoming problems to solve in a test is stabilize the whole unit enough and avoid mirror/shutter slap. Next will be, get a big enough target. And keep it safe an clean. And light it up evenly enough. Do that in a room without atmospherical distortion. Dust, wind, humidity will lead to worse results.
After that you can look a t systematic problems. I know that my Nikon 300/4 E will getting me blurred images in bright daylight at shutter speeds between 1/180 and 1/500 when I forgot to switch off Image stabillsation. Next, if AF is slow , not reliable or unpredictable, even an otherwise great lense loose value.
Usability, ergonomics, weight, weather and meanchical resistance also come into equation, but cannot be rated. A phsysically trained person can hold a 3 kg lens longer without too much of shake than another. Stabilisation is great but we tned to forget the limits. In-lens stabilisation is constantly changing the optical axis as far as I understood. Comes bad to worse, the corners will suffer more.
Also, at the end of the day experience counts a lot. 15% more sharpness of one lens under test conditions? Forget it. Using it not careful enough, I loose quickly 30...70% of that advantage - and I'm only talking about static objects. Birds in flight benefit a lot more from experience than from IQ of a certain lens.