Northern Bob
Well-Known Member
“I attended the DJI Photo Academy.
The instructors both agreed filters are:
1) Not needed if you know what you are doing and
2) Just a gimmick to make money”
Unless they were just trolling students with those statements, I’m shocked by their ignorance.
As a professional photography teacher for 35+ years I know better.
Polarizer: I regularly test 1st year students on its use. Go shoot pairs of images (with/without filter) of four different scenes.
Scene 1 - 100% cloud cover. Scene includes 1/2 sky and 1/2 landscape which contains significant amounts of plants/trees.
Scene 2 - as above with 40-70% cloud cover.
Scene 3 - 0-40% cloud cover. Scene is framed to include sky and water.
Scene 4 - 0-40% cloud cover. City scene capturing glass/metal surfaces with reflections.
Afterward, they are to compare and write up their conclusions. Most importantly they are to take the images shot without polarizer and using either LightRoom or Photoshop try to match the look of the polarizer shot of the same scene.
Can’t be done. Except perhaps in the case of 100% cloud cover - since there is so little polarized light to filter out.
Neutral Density filters: Others have mentioned that on bright days they cut the light down so we can set shutter speed at about twice the frame rate (30fps=1/60th shutter) to bring in a slight blur to movement-much like film stock.
Another reason would be to open up the lens F-stop to about 2-3 stops from wide open. All lenses give the sharpest imaging at that setting. Any F-stop near wide open or fully closed down will project a softer image. Of course the Spark’s aperture is fixed but higher end drones have variable apertures.
Sorry to be so long winded but it’s hard not to slip into teacher mode.
Northern Bob
The instructors both agreed filters are:
1) Not needed if you know what you are doing and
2) Just a gimmick to make money”
Unless they were just trolling students with those statements, I’m shocked by their ignorance.
As a professional photography teacher for 35+ years I know better.
Polarizer: I regularly test 1st year students on its use. Go shoot pairs of images (with/without filter) of four different scenes.
Scene 1 - 100% cloud cover. Scene includes 1/2 sky and 1/2 landscape which contains significant amounts of plants/trees.
Scene 2 - as above with 40-70% cloud cover.
Scene 3 - 0-40% cloud cover. Scene is framed to include sky and water.
Scene 4 - 0-40% cloud cover. City scene capturing glass/metal surfaces with reflections.
Afterward, they are to compare and write up their conclusions. Most importantly they are to take the images shot without polarizer and using either LightRoom or Photoshop try to match the look of the polarizer shot of the same scene.
Can’t be done. Except perhaps in the case of 100% cloud cover - since there is so little polarized light to filter out.
Neutral Density filters: Others have mentioned that on bright days they cut the light down so we can set shutter speed at about twice the frame rate (30fps=1/60th shutter) to bring in a slight blur to movement-much like film stock.
Another reason would be to open up the lens F-stop to about 2-3 stops from wide open. All lenses give the sharpest imaging at that setting. Any F-stop near wide open or fully closed down will project a softer image. Of course the Spark’s aperture is fixed but higher end drones have variable apertures.
Sorry to be so long winded but it’s hard not to slip into teacher mode.
Northern Bob