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 p.5 #20 · p.5 #20 · Is it worth buying a Nikon d850 for wildlife in 2022? | |
Why AFFT our lenses with cameras? Because all cameras and lenses coming out of factories have tolerance due to component selections for cost vs volume, profit vs performance, test equipment tolerance, stack-up tolerance and human error.
Nikon set their AFFT limits to +/- 20 but many a times we found that our lenses with respect to our cameras are very close to its limits or are actually out of range.
For a tolerance of +/- 20 Nikon would have to set their internal tolerance to no more than +/-10, preferably at +/-5 for both their cameras and lenses. But after testing many of Nikon’s cameras and lenses I found that they are actually setting it at +/-10.
With this limits there are lots of opportunities for their products to be at the border or out of specs due to stack-up tolerance, test equipment tolerance and poor QC judgement.
Let’s take an example of a lens with +/-10 and a camera also at +/-10.
If the lens is at -10 and the camera is also at -10, then it will be at the border. Test equipment also has its own tolerance, if it is also towards the negative side than the AFFT will be out.
On the other hand if the lens is at -10 and the camera is at +10, then it will cancel out and ends up dead center. Even with some test equipment tolerance, it will still be within the tuning range.
AFFT actually involves both the camera and lens and not just the camera or the lens as some would have believed as in one of the recent post where people are sending in just their lens or camera to be calibrated for $98 or more to Nikon USA. Even by sending both the camera and lens, the calibration will only work with that combination. Using the calibrated lens on another camera will have very different outcome. Not only that there are times that you will never be able to calibrate it to another camera because the performance curve has been skew to one side. What is worst is that there is no way to reset it to its original settings because it has been set by Nikon, not like we can reset the AFFT to zero if we are doing ourselves. So users with multiple cameras be warned.
What are the possible adjustments that Nikon do to the camera and lens? The adjustment of the tilt angles of the primary and secondary mirrors, inspection of the AF module on the camera, and the stepper control of the motor in the lens. So now you see why the calibration only works for the calibrated pair and not across the board.
I had noticed that some people like Trenchmonkey/William, Steve Perry and many others are doing it the right way and are getting positive results, but many did not and complains about it.
There is no sure fix, each has its advantages and disadvantages.
Take William’s way of using a ruler set at 45º at the distant where he will be shooting, this is definitely going to work 100%, but will have to perform the AFFT every time he shoot at a different location. Since he already get so used to it, it works for him but might not to others who are new.
Then there is Steve’s method of performing multiple sampling and then dropping the highest & lowest values and then taking the average value. This I will said works 90% of the time with some margin of errors.
Then there are industrial and commercial software that some are using, myself included. It will perform a very comprehensive test that will take into consideration lots of variables like across aperture range, resolutions, sharpness, MTF, vignetting, chromatic aberration, astigmatism, color, focus shift and lots more. Many are proprietary, expensive extremely time consuming, while the commercial ones are still fill with errors. One has to have some related technical knowledge to interpret the multiple charts and curves to come to a conclusion.
Here the industrial ones are at 95% - 99% performance while the commercial one are at around 90% same as the one used by Steve but with a lot less information about the lens.
Note: I intentionally not to name those commercial products because they are still fill with errors, and I don’t want anyone to blame me for them spending lots of money and not getting results.
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Regarding heat though, the D5 should be able to cool itself better than either of the smaller bodies. We see this in the Z9 as well, and to a much higher degree as it can shoot 4K/120 and 8K/60 internally which generate a lot of heat. They can use the extra body size to turn the camera into a giant heat sink basically.
