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Digital Long Exposure Tips?

gurtch

Well-known member
I have long admired here the seascapes made with long exposures to get the blurred moving water effect. I specialize in seascapes, but have never tried this. I bought a very "cheapy" 77mm multi coated ND Fader filter on ebay. It is cool, as it has marked increments from almost clear (probably one stop) to almost opaque. I assume shutter speeds around 5 to 10 seconds will be needed. I will be using a Pentax 645D, & mirror lock up. In my film days I did some long night exposures, and compensated for film reciprocity failue, but have never made digital exposures longer than around 1 second. Is there anything I need to know (noise, reciprocity, etc)? Any special processing from RAW? I will be using ISO 100 and f16 to 22 (I am willing to accept difraction lens issues).
Thanks in advance. If I get something worth keeping, I will post here.
Dave G
 

Shashin

Well-known member
No reciprocity with digital, but an increase in noise. The Pentax will use dark frame subtraction after a long exposure which takes the same time as the exposure. I don't mind the wait, but I know some that make their own dark frames and apply them later. But noise is well controlled in the Pentax--I have made 200 second exposures at 1600 ISO with very good results.

I have done one experiment with a 13 stop ND filter. WB was the only thing off, but I shot RAW and so is not a big deal. The nice thing is you get to preview after the shot.

I Pentax IR remote is really good to have.
 

darr

Well-known member
Dave,
I shoot a P45 with various tech cameras usually @ 50 ASA. Sometimes I leave the shutter open for up to 45 seconds with ambient light, long-bellows + macro work, and see no reciprocity like we had with film. It is a different world these days with digital--I welcome it! :)

Kind regards,
Darr

PS: How's the Jersey Shore season coming along?
 

Jeffg53

Member
You will probably see some magenta getting in there particularly with a cheapy filter. I expose up to 256 seconds with an H4D. You will get the same intensfified colour as film over the longer exposure, and will certainly need shorter exposures than with film without reciprocity which is good if you have dark frame time to add in.

You can find loads of digital long exposures on my website.
 

gurtch

Well-known member
Darr & Jeff: Thanks much. Jeff...yes your work is what I am trying to do. Darr: Fourth of July weekend here on a barrier island (read shore resort) is a zoo. When our visitors leave is when I do most of my serious stuff. I will keep you informed of any success (or failures) I have. Darr: I am using my new killer Puget Systems PC....thanks for the advice some months ago.
Dave
 
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