What does a graduated ND filter do?
It darkens one part of the frame and leaves the rest alone. Point a camera at a bright sky above darker land and the scene holds more range than the sensor does, so you lose the cloud detail or you lose the foreground. A graduated ND takes 3 stops out of the bright part before the light reaches the sensor, so both ends of the picture land inside the range the camera can record.
Medium or Soft, which one should I buy?
It is decided by how far your subject climbs up the frame. Medium uses a 1/2 graduation and suits skylines, treelines and low ridges that break the horizon but stay close to it. Soft uses a 1/3 graduation, so only the upper third carries the full effect and the long blend passes over peaks, trees and tall buildings that reach well up the frame without clipping an edge across them. If you shoot both, most people start with the Medium.
How many stops is GND8 (0.9)?
3 stops, a density of 0.9, in the graduated area. The clear part of the glass is unaffected, so the exposure you set for the foreground stays where you set it.
Can I move the transition up or down the frame?
No. The blend is built into round glass and its position is fixed, which is why the choice between Medium and Soft matters so much. If you need to slide a graduation up or down a composition, that is what a square graduated filter in the 100mm JetMag Pro holder is for.
Do I need an adapter ring?
Yes. The filter mounts magnetically to a JetMag Pro adapter ring, and the ring is the only lens specific part. 82MAG rings come in 82mm, 77mm, 72mm, 67mm and 62mm; 95MAG rings come in 95mm, 86mm, 82mm, 77mm and 72mm. One ring per lens, and the filter moves between them.
Will it vignette on a wide lens?
The frame is an ultra slim aluminium one built to stay out of the picture. We see no vignetting as wide as 16mm on full frame for the 82MAG filters, and as wide as 15mm on full frame for the 95MAG filters.
Can I stack it with another JetMag Pro filter?
Yes. It stacks with the rest of the JetMag Pro range in the same size, including the True Color CPL, the FS ND and the mist and diffusion filters, and each filter locks to the one beneath it rather than just sitting on the magnets.
Will it change the colour of my photos?
That is what the FS in the name is for. Full Spectrum means the density is held evenly across the visible spectrum, so the darkened part of the frame comes back with the same colour as the clear part and there is nothing to correct in post.
82MAG or 95MAG, which size?
Buy for your largest lens thread and step up from there. 82MAG covers the majority of full frame zooms and takes rings down to 62mm; 95MAG is for the big front elements and takes rings down to 72mm. The filter is the part worth buying once, and the rings are the cheap part.
Can I leave it on the lens in my bag?
Yes. The JetMag Pro magnetic front cap in the same size clips onto the filter, so the whole assembly stays on the lens and goes into the bag as it is. Cap kits are in JetMag Pro Adaptors.
How should I clean it?
Blow the dust off first, then wipe with a clean microfiber cloth and an alcohol-free lens cleaning fluid. Never put anything containing alcohol on the coating. The NiSi Nano optical cleaning kit has the right fluid and cloths.