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 Night to day bramping with 0.9 ND filter. 
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Joined: Mon Oct 18, 2010 9:13 pm
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Location: Toronto, Canada
Post Night to day bramping with 0.9 ND filter.
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No probs, Edmond. Almost right, but think of the ISO and ND adjustments as 2 separate operations. Here's a typical day->night example:

1. Start bramp with 3-stop ND attached.
2. Proceed until you feel it is time to take off the filter.
3. Adjust the B-step to read 3.1.
4. After start of the current exposure apply the ND reciprocity by hitting the D key. This will decrement the bulb value by 3.1 stops.
5. In the gap between frames take off the filter.
6. Continue bramping as the light fades.
7. When the bulb starts to encrouch on the interval, prepare for your first ISO adjustment.
8. Adjust the B-step to read 1.0.
9. After start of the current exposure apply the ISO reciprocity by hitting the D key. This will decrement the bulb value by 1.0 stop.
10. In the gap between frames increase the ISO by 1 stop.
11. Repeat until you're done.


Does anyone here know the procedure for bramping from night to day with a 0.9 ND filter attached? Sorry I should have asked this question right after the day to night bramping discussion from above. Thank you.

Edmond.


Thu Jun 02, 2011 8:31 am
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Post Re: Night to day bramping with 0.9 ND filter.
Isn't the .9 a 3 stop filter ?

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Wed Jun 29, 2011 12:09 am
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Post Re: Night to day bramping with 0.9 ND filter.
Yup, some companies use 0.3, 0.6, 0.9 for 1, 2 & 3 stop filters. Other companies call them ND2, ND4, ND8 for the fraction of light they let through (1 stop = 1/2, 2 stops = 1/4, 3 stops = 1/8).

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Wed Jun 29, 2011 12:32 am
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Post Re: Night to day bramping with 0.9 ND filter.
I believe I have made all the appropriate adjustments to the instruction needed to do a night to day transition. I would probably prefer to do the ISO stepping first. that way you eliminate the noise sooner that Higher ISOs introduce.


1. Start bramp with-out a 3-stop ND attached.
2. Proceed until you feel it is time to install the filter.
3. Adjust the B-step to read 3.1.
4. After start of the current exposure apply the ND reciprocity by hitting the C key. This will increase the bulb value by 3.1 stops.
5. In the gap between frames install the filter.
6. Continue bramping as the light increases.
7. Prepare for your first ISO adjustment.
8. Adjust the B-step to read 1.0.
9. After start of the current exposure apply the ISO reciprocity by hitting the C key. This will increase the bulb value by 1.0 stop.
10. In the gap between frames decrease the ISO by 1 stop.
11. Repeat until you're done.


Wed Jun 29, 2011 4:40 am
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Post Re: Night to day bramping with 0.9 ND filter.
Also you will want to calibrate the bramper to your ND filter. It might not be exactly 3.1 B-step.


Wed Jun 29, 2011 4:41 am
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Post Re: Night to day bramping with 0.9 ND filter.
Sorry I didn't see this thread earlier.

Zigmo is right.

1. Start bramp using high ISO (e.g. 3200), long exposure time and without a 3-stop ND attached. Maximum light-collecting setup. Load Preset B (hold the key and press Reset on LB) - this is a suitable starting point.

**** ISO stepping ****

2. Continue bramping (downwards) as the light increases.
3. Prepare for your ISO adjustment, (e.g. when Bulb drops below 200ms.)
4. Adjust the B-step to read 1.0.
5. After start of the current exposure apply the ISO reciprocity by hitting the C key. This will [b]increase
the bulb value by 1.0 stop.
6. In the gap between frames decrease the ISO by 1 stop.
7. Repeat until you've run out of ISO values (i.e. 3200 -> 1600 -> 800 -> 400 -> 200 -> 100). Proceed to step 8.

**** ND filter ****

8. Proceed until you feel it is time to install the filter.
9. Adjust the B-step to read 3.0.
10. After start of the current exposure apply the ND reciprocity by hitting the C key. This will increase the bulb value by 3.0 stops.
11. In the gap between frames install the filter.

**** comments ****

A. Remember that ISO stepping and ND filters all serve the same purpose: to win you back more room to bramp. In the night -> day scenario the danger is that Bulb gets too small (I recommend avoiding Bulb times less than 100ms), so all the actions above serve to increase the bulb time.

B. Make sure you understand what you're about to do before you try doing it (rather than blindly following a list of steps). I've carelessly started Night to day sequences with the ND filter attached (a mistake), primarily because I'm more used to doing Day->night.

C. As Zigmo stated you can calibrate a ND filter using LB. Take a bulb exposure of about 1s - this is the reference exposure. Then set Bstep to 3.0 (if it's a 3 stop filter), attach filter, compensate by pressing C key (increases Bulb by Bstep), take another image and compare with reference image. Adjust Bstep until images are comparable. The success of this method relies on the ND filter being very neutral.

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Wed Jun 29, 2011 5:44 am
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Post Re: Night to day bramping with 0.9 ND filter.
Thank you for replying Zigmo, and Tom. Looks like I have my work cut out for me. Seems a lot of steps to do just a normal transition from dark to light or vice versa. I've already calibrated my 0.9 ND filter using the LB. I'll be doing more experimenting before I start shooting.

Edmond.


Fri Jul 01, 2011 7:50 pm
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Post Re: Night to day bramping with 0.9 ND filter.
Once you truly understand why you are doing each step it becomes second nature. It does take a few test runs to get the hang of it.


Wed Jul 06, 2011 7:23 am
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Post Re: Night to day bramping with 0.9 ND filter.
Just did a sunset bramping with the ND filter. Now I see what happens with each step. But I did notice a slight colour shift when I applied the ND reciprocity by hitting the D key to decrement the B-step by 3.2. The colour seemed cooler, maybe I should try 3.1? Or higher? Could it be the ND filter? It's a High Tech 100 filter. Not sure if it's truly neutral. Any true ND filters you can recommend? I was thinking of the Tiffen or Schneider water white glass filters are they truly neutral? Thank you.

Edmond.


Wed Jul 06, 2011 8:11 am
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Post Re: Night to day bramping with 0.9 ND filter.
hi edmond

it is in the nature of filters that they are not really neutral - if you are shooting in RAW it is easy to correct the color-shift later in post - if you are shooting jpgs it is not that difficult as well wit a 3 stop ND-filter [a 10-stop filter is much harder to correct ;)], i used hitech filters as well and was not totally happy due to the described color-shift-problem - lee filters are a little more neutral - but you can't expect that they are 100% neutral as well - they are not and a little bit of adjustment is always necessary

that is another reason for me to always shoot in RAW if possible

just my experience...


Thu Jul 07, 2011 2:22 pm
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Post Re: Night to day bramping with 0.9 ND filter.
deep_dark_blue wrote:
it is in the nature of filters that they are not really neutral

Well, they are but they're not. It's more the nature of current digital sensors that's caused old ND filters to not be as neutral as they once were. They are neutral in the visible spectrum, but DSLR sensors are still somewhat sensitive to near-infrared, which gets through the ND filters in greater quantities than the visible light - never an issue with film that wasn't sensitive to infrared - which leads to most ND filters giving a slightly magenta tint to longer exposures.

Tiffen (got to play with 'em at the Broadcast Video Expo in February) and other companies have released new versions of ND filters that compensate and block more infrared - I believe the Tiffen are available all the way from 1-7 stops (2 different kits, 1-4 stop and 5-7 stop filters). They're a bit more pricey though.

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Thu Jul 07, 2011 3:57 pm
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Joined: Mon Oct 18, 2010 9:13 pm
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Location: Toronto, Canada
Post Re: Night to day bramping with 0.9 ND filter.
Thanks a lot for the advice guys. Looks like I'll be spending more time during post then, cause I sure can't afford those Tiffen or Schneider filters plus there's not guarantee that they won't cause the same problems too.

Cheers,
Edmond.


Thu Jul 07, 2011 7:13 pm
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