Max ND

[Annie M.]

I need to photograph an entire daylight ocean storm on one negative. Although it will not be one continuous exposure (I will be chopping out the slop) I will still be laying down about 2-3 hours of light on the neg. Any ideas on what I can use for a ND filter... safelight glass? welders glass? ... and how can I figure out the filter factor of very low transmission materials.

Cheers... Annie

[eric black]

Yikes- sounds like you need to invest in the types of filters that are used to photograph the sun- B + W makes a ND3.0, 4.0 and 6.0 filters for this which gives you a filter factor of 1000, 10,000 and 1,000,000 respectively. This way you would have an idea of how to time out the exposure. You might have to custom order it from B + W or the filter connection which has a typical turn around time of about 2-3 months. You could also check dealers of telescopes as well.

[Bob Salomon - HP Marketing]

Why not use a ND filter? Heliopan makes them up to 3.0 density. That is a filter factor of 1000. Some companies make them up to at least 6.0 density. That would be a factor of 1,000,000.

3.0 requires 10 stops of correction. 6.0 requires 20 stops. How many stops of correction do you need? You can always double them up.

Welders glass and other non-photographic materials may not be optically flat so they could materially effect the final result. ND filters are optically flat.

[Annie M.]

Thanks!!... 20 stops should get me a few hours of exposure time.

The layer cake thing could get me days.... the possibilities are wonderful!

With a big stack I might be able to shoot my cedar grove through an entire season... I hope the bear hibernates there again then I can photograph him and his long dreaming...

Thanks again you made my day!!

[Ron Marshall]

Thanks!!... 20 stops should get me a few hours of exposure time.

The layer cake thing could get me days.... the possibilities are wonderful!

With a big stack I might be able to shoot my cedar grove through an entire season... I hope the bear hibernates there again then I can photograph him and his long dreaming...

Thanks again you made my day!!

Don't forget to take reciprocity failure into consideration when calculating your exposure.

[David_Chanter]

Don't forget to take reciprocity failure into consideration when calculating your exposure.

So , being the studio guy I was and having in some studio's doing multiple pops on the strobe to get the depth of field we needed , How do you figure reciprocity failure in the field and the color shifts that surely will follow? We just did the shot and sent the film to the developer and adjusted ... Not so easy to do in the field ? Of course I really liked the one studio that had an Ascor Sun Gun , no worries about reciprocity.... Just curious....

[Annie M.]

Reciprocity... yippee!

With a big stack of NDs & reciprocity I might be able to make that one sheet last the rest of my life... no more worries about the demise of film... I will certainly have enough chemistry... as I near the end of my days I will have a showing at the MOMA... it is not as if my life's work of one print would take up much wall space...

[Bill L.]

Just remember to post the results here - I gotta see a couple of hour exposure of a storm!

Cheers!
Bill

[rippo]

so...how will you keep your camera steady? tripod might be a bit too wobbly over a couple of hours. bolt it to a rock perhaps? vibration from the surf might be a problem....

[jetcode]

I need to photograph an entire daylight ocean storm on one negative. Although it will not be one continuous exposure (I will be chopping out the slop) I will still be laying down about 2-3 hours of light on the neg. Any ideas on what I can use for a ND filter... safelight glass? welders glass? ... and how can I figure out the filter factor of very low transmission materials.

Cheers... Annie

I have a variable ND from Singh Ray that varies from 2 stops to 8 stops. You could stack a couple of them and likely expose a negative all day long.

Joe