Optical Density vs. "Filter Factor" number
BigBen08 wrote:
Karl_Guttag wrote:
SigZero wrote:
This year I've decided to visit AirPower airshow in Zeltweg Austria.
All taken with my R5 with RF 100-500, some with 1.4x converter.
As for parameters: all on electronic shutter, Tracking AF (all area) with subject set to "none", Av with Auto ISO (with manual modifications for some propeller photos)
I'm curious why you chose to use Av with Auto ISO. My go-to for air shows is Manual with Auto-ISO. I typically leave the RF100-500 at f11 and then adjust the shutter speed based on the motion blur I want to achieve (vs. the better hit rate at higher shutter speeds). I typically use an ND4 with prop planes to keep the ISO above 100 at slower shutter speeds.
I also have the RF 100-500mm. What density ND filter do you recommend. They are usually available in 0.6 to 1.5 density. When I shot propeller planes at slow shutter speeds (no ND filter used), it resulted in f number between f10 to f19.
One more thing to buy
Thanks.
I understand your confusion.
There are TWO ways, both preceded by ND, for specifying the light blocking of the filter. You are using the (more common with brand names) Optical Density method, which is base 10 logarithmic, whereas everything else in photography is binary logarithmic (as in stops = EVs).
I gave the filter factor number (more common with some newer photographic product companies and sometimes called NDX by older companies), which is simply the amount of light blocked linearly. I like this way of specifying as if I put an ND4 filter on the camera, it changes the shutter speed or ISO by 4x or two stops.
It turns out that 0.6 by the OD method is equal to 2 stops or ND4 using the filter factor method. I find the For a complete table, scroll down in the link below:
https://www.bhphotovideo.com/explora/photography/hands-review/guide-neutral-density-filters.
I don't use variable ND filters as they can cause some issues with color and sun direction as they are based on polarization. So I use a straight-up, simple (and less expensive) ND filter. The ones I bought for the RF100-500 are:
https://www.amazon.com/gp/product/B08V1DPQ69
I don't recommend using the belt-loop case. the Loop is velcro, and it silently gave way, and the rest of the filters were lost.