Long exposure photography: I'm going to try some long exposure images. Should I get a 3 or 6 stop neutral density filter? I think the 9 stop would be too dark. B&H has B&W neutral...

terpfan Loc: central coast, California

I'm going to try some long exposure images. Should I get a 3 or 6 stop neutral density filter? I think the 9 stop would be too dark. B&H has B&W neutral density filters single coated and multiple coated. Is the extra cost justified for the multi coated filters? Can the neutral density filters be used in combination with a CP filter. I have a 5D IV, will the auto focus still work? Thanks in advance for your replies.

CHG_CANON Loc: the Windy City

You can stack ND filters, although 1 is better simply because the more glass you stack together, the more likely of a loss of sharpness. Although you can stack an ND with a CPL, the need to do this is unlikely. The 'highly reflective' surface will likely be lost in the blur of a long exposure, assuming movement of that surface during the exposure.

Multiple coating are superior for cleaning the surface of the glass without damage to the glass. They're worth expense.

If the filter and light is too dark for the AF to operate, focus the lens without the filter. Flip the lens to manual focus, add the filter and shoot. Alternatively, set the camera to BBF and focus without the filter. Just don't re-engage the Back-Button-Focus after installing the filter.

RWR Loc: La Mesa, CA

terpfan wrote:

I'm going to try some long exposure images. Should I get a 3 or 6 stop neutral density filter? I think the 9 stop would be too dark. B&H has B&W neutral density filters single coated and multiple coated. Is the extra cost justified for the multi coated filters? Can the neutral density filters be used in combination with a CP filter. I have a 5D IV, will the auto focus still work? Thanks in advance for your replies.

You might want to post this in the Long Exposure Photography Forum:
https://www.uglyhedgehog.com/s-108-1.html

jeep_daddy Loc: Prescott AZ

CHG_CANON wrote:

You can stack ND filters, although 1 is better sim... (show quote)

I used to stack them like this but now I have a 10 stop filter by Lee Filter System that I use most of the time. Chg is correct in simply focus first then turn of AF at the lens or use BBF. I like to turn off the AF at the lens because my thumb goes straight to the BBF button and I'm bound to do that with the filter on an then have to start all over.

I do have a 2 and 3 stop ND as well as a 3 stop grad ND for images that need just a little light cut from them....

Grahame Loc: Fiji

terpfan wrote:

I'm going to try some long exposure images. Should I get a 3 or 6 stop neutral density filter? I think the 9 stop would be too dark.

Have you considered the lighting conditions you are likely to want to be shooting in?

If you want to shoot in the bright midday sun and do 20 second exposures what you need can be calculated.

rgrenaderphoto Loc: Hollywood, CA

terpfan wrote:

I'm going to try some long exposure images. Should I get a 3 or 6 stop neutral density filter? I think the 9 stop would be too dark. B&H has B&W neutral density filters single coated and multiple coated. Is the extra cost justified for the multi coated filters? Can the neutral density filters be used in combination with a CP filter. I have a 5D IV, will the auto focus still work? Thanks in advance for your replies.

I combine CPL with ND and ND Grad filters all the time. Set the CP to where you want, hold with finger, straighten the fliter holder, insert the filters.

To get best use out of a ND filter, download the Lee Stopper smartphone app; set your exposure without the filter in place, focus on your subject then insert ND 6x and see with the Lee app the recommended exposure is. Example, 1/250th of a sec = ¼ sec with 6X ND or 4 sec with a 10x.

I only use 100mm square or rectangular filters. Screw on filters cannot be reliably combined as the rims can add vignetting to images.

I've combined Lee 6x and 10x for really interesting effects on 2 or 4 minute exposures.

Dikdik Loc: Winnipeg, Canada

I've not done any long term exposures, and am ignorant about doing so.

Why would you use a 6 or 10 stop neutral density filter to reduce the light coming in?

thanks, Dik

Grahame Loc: Fiji

Dikdik wrote:

I've not done any long term exposures, and am ignorant about doing so.

Why would you use a 6 or 10 stop neutral density filter to reduce the light coming in?

thanks, Dik

To obtain a long exposure when the light conditions are bright to allow the 'smoothing' of such elements as flowing water, moving clouds etc.

larryepage Loc: North Texas area

Grahame wrote:

To obtain a long exposure when the light conditions are bright to allow the 'smoothing' of such elements as flowing water, moving clouds etc.

Or eliminate people...

Grahame Loc: Fiji

larryepage wrote:

Or eliminate people...

Dikdik Loc: Winnipeg, Canada

Thanks very much, gentlemen/ladies.

Dik

repleo Loc: Boston

terpfan wrote:

I'm going to try some long exposure images. Should I get a 3 or 6 stop neutral density filter? I think the 9 stop would be too dark. B&H has B&W neutral density filters single coated and multiple coated. Is the extra cost justified for the multi coated filters? Can the neutral density filters be used in combination with a CP filter. I have a 5D IV, will the auto focus still work? Thanks in advance for your replies.

Breakthrough Photography has a good, free, 52 page guide to Long Exposure Photography here;
https://theartofphotography.lpages.co/52-page-long-exposure-guide/.
They make excellent filters. I have switched from B&W to BT for any new filters I buy.
They also have a good guide to ND filters on their website.

Dikdik Loc: Winnipeg, Canada

repleo wrote:

Breakthrough Photography;

https://theartofphotography.lpages.co/52-page-long-exposure-guide/.

They also have a good guide to ND filters on their website.

Thanks for the info.

Dik

billnikon Loc: Pennsylvania/Ohio/Florida/Maui/Oregon/Vermont

terpfan wrote:

I'm going to try some long exposure images. Should I get a 3 or 6 stop neutral density filter? I think the 9 stop would be too dark. B&H has B&W neutral density filters single coated and multiple coated. Is the extra cost justified for the multi coated filters? Can the neutral density filters be used in combination with a CP filter. I have a 5D IV, will the auto focus still work? Thanks in advance for your replies.

First of all, for long exposures, you must first focus without the filters on, then, turn the auto focus off and put on the filters. If you do not turn off the auto focus, the camera will try to focus during you long exposure, resulting in an undesirable result.
Also remember to cover the eyepiece as it can let in stray light and ruin your shot.

mizzee Loc: Boston,Ma

I use a 6 or a 10. I don’t stack them. I had a bad experience with a variable ND where moisture got between the elements.