Longshadow Loc: Audubon, PA, United States

[quote=rwww80a]

Didn't read the thread, it is a polarizer.

bnsf

I have an ND 8 and a Circular Polarizer Filter. Would you use both of these back to back on a digital camera or which on would you mainly use as your main filter? Polarizer when you want to take display photos of items through windows?

Longshadow Loc: Audubon, PA, United States

Neither as a "main filter".
I would use the ND when I want silky water<falls, ocean> or a small depth of field (wider aperture) and the polarizer when I want to eliminate reflections or water glare. Neither would be on my camera all the time.
My main filter, the only filter that lives on my lens, is just to protect the front element of the lens, and is either a UV, skylight, or clear. No other filters unless I want a certain effect.

SuperflyTNT Loc: Manassas VA

I would use both if the situation called for it. Most of the time I would use neither. Here’s a short blog post explaining the difference.

https://www.kentfaith.com/blog/what-s-the-differences-between-nd-filter-and-cpl

burkphoto Loc: High Point, NC

In general, every additional optical surface added to a complex multi-element lens adds additional potential for flare, distortion, diffraction, and other optical artifacts. Most of the time this is a non-issue, but when bright, specular, or point sources of light strike the filter at an oblique angle, you may see artifacts you don't like. The cheaper the filter, the worse this can be.

Astrophotography (photographing stars) is one instance where filters are definite no-nos. Light bounces off the lens front element, onto the rear surface of the filter, and back into the lens. This creates flare, halos, double images, blurriness... none of which you'll get with no filter on the lens.

I quit using filters unless absolutely necessary. I have a box in the closet with over 75 of different sizes that I once used with film. But I carry only ND8, ND64, ND1000, and CPL. I have some cheesy special effects filters I use once in a blue moon, but with all the post-processing power of Photoshop and Lightroom, I only use what software can't do better.

My ND filters are used primarily for video and portraiture outdoors. Cinematic video at 24 frames per second requires a shutter speed of 1/48 second, which I get by setting my camera to SHUTTER ANGLE instead of TIME. At 180°, the shutter angle setting calculates a shutter speed twice whatever the frame rate is. That's great, but the Lumix GH4 base ISO is 200. So in bright sun, that means an aperture of f/32! The ND64 reduces that to a nice f/4, which is the ideal aperture on all my f/2.8 Micro 4/3 lenses.

For portraiture, I like to use a 35-100mm f/2.8 zoom wide open. That's where the ND8 comes in. In bright sun, 1/800 at ISO 200 with ND3 gives me f/2.8.

The CPL is primarily used to darken skies at right angles to the sun, and to cut glare from water, artwork, and glass I'm trying to see through.

In those rare instances when I'm at the beach in salt spray and wind-blown sand, or a desert, or a dirt track race, or a welding party (!), the clear glass protectors go on.

In all cases except macro, I use a lens shade. THAT protects somewhat against drops, fingerprints, and side-swipes.

I pull out the UV filter only in the mountains of the West. I don't need UV filters anywhere in the Eastern Time Zone of the USA.

repleo Loc: Boston

Why do have an ND on unless you are trying to reduce light for a long exposure or wide aperture in bright light? Only use the filters you need to get the effect you are looking for. More filters mean less light and more diffraction etc.

Architect1776 Loc: In my mind

You perhaps will get best results using one filter at a time without stacking.
Use the UV for protection, but when using a different filter remove the UV and use the different one.
Stack if necessary when you want to say, use a ND and cross screen together for a specific reason.
When complete return the UV by itself again.
Have fun!!!!!!!!!!!!!!!