FS7: onboard ND not enough in bright sun

C

Cornmedia

New member
Hi all,

filming with the FS7 with Sigma 1835 in bright sunlight. Wanted a shallow DOF for a talking head but there's no way I could open the lens up enough without over exposing. Thinking in future I'll just use a vari-ND I have when I'm in this situation again and leave the onboard ND set to off. I've been filming in bright sunlight at 3200EI but dropped it down to 800 EI and greater risk of over exposing. Not enough to open up the lens.

Thoughts or suggestions?

Jamie
 
The confusingly labelled 1/64 ND is an ND1.8 or a 6-stop ND filter. In bright sunlight shooting 25fps at 2000ISO you're generally going to be looking at around f/64-f/90 for exposure. Take 6-stops off that exposure and you're still up at f/8-f/11. So realistically, for proper control of your exposure (and aperture) you want a set of NDs including 0.3, 0.6, 0.9 and 1.2 so that you can fine tune things to where you need them.

With an ND1.2 in addition to the 6-stop ND you have onboard, that gives you 10(!) stops of total exposure reduction, which will bring you back down to an f/2.8 or so even under the brightest sunlight conditions.

I've found the Tiffen 'water white' NDs to be superbly neutral both alone and combined with Sony's internal NDs. A set of four is a bit of an investment, but it's an absolutely essential investment in my opinion. Because if you can't control your aperture and the depth of field you have for each shot - you're violently compromised your ability to control your imagery.
 
Cornmedia said:
Hi all,

filming with the FS7 with Sigma 1835 in bright sunlight. Wanted a shallow DOF for a talking head but there's no way I could open the lens up enough without over exposing. Thinking in future I'll just use a vari-ND I have when I'm in this situation again and leave the onboard ND set to off. I've been filming in bright sunlight at 3200EI but dropped it down to 800 EI and greater risk of over exposing. Not enough to open up the lens.

Thoughts or suggestions?

Jamie
Click to expand...

External NDs are a long term solution. Getting an entire set is one approach, for a low cost approach, consider getting a single thread-in ND1.8(or 2.1) fitting the size of your preferred lens. You would only use it when the brightness exceeds the capabilities of the internal ND filters, and could still use the internals to provide extra ND beyond 1.8 or 2.1

Mind you, if I were caught in the field with no ND in sight, the on the spot solution is to reduce your shutter angle, and add motion blur in post if needed. One further step is to go negative on gain, at the cost of dynamic range, but that only helps if you're not overexposing the sensor.
 
Cornmedia said:
Hi all,

filming with the FS7 with Sigma 1835 in bright sunlight. Wanted a shallow DOF for a talking head but there's no way I could open the lens up enough without over exposing. Thinking in future I'll just use a vari-ND I have when I'm in this situation again and leave the onboard ND set to off. I've been filming in bright sunlight at 3200EI but dropped it down to 800 EI and greater risk of over exposing. Not enough to open up the lens.

Thoughts or suggestions?

Jamie
Click to expand...

Please do not consider a vari-nd filter, they're basically two polarizers and take all the glow out of skin. As Grug mentioned buy yourself a few quality Tiffen water white ND's to use in conjunction with the camera's built in and you'll be all set. Always defer to the strongest internal ND first before going heavy with a glass one. The stronger they get the more chance of green or other color shift.
 
Cornmedia said:
Hi all,

filming with the FS7 with Sigma 1835 in bright sunlight. Wanted a shallow DOF for a talking head but there's no way I could open the lens up enough without over exposing. Thinking in future I'll just use a vari-ND I have when I'm in this situation again and leave the onboard ND set to off. I've been filming in bright sunlight at 3200EI but dropped it down to 800 EI and greater risk of over exposing. Not enough to open up the lens.

Thoughts or suggestions?

Jamie
Click to expand...

If I was in that situation (and I have been before with my FS700) I will use all the inboard ND I can.
Then, for a 'talking head' I will up the shutter speed a little. Normally I don't like doing this as it
changes motion blur, but I've found in interviews, it's pretty hard to tell as long as you don't have
to go crazy with it. Mainly because there isn't much movement during a talking head for the faster
shutter speed to screw up. And if you double your shutter speed to 1/96 instead of 1/48 you lose another
couple stops. I've even pushed it up to 1/200 and you can't tell much of a difference at all in an interview.
Maybe if you went up to 1/1500 you would be able too, but most interviews are fairly static shots and not a
lot of movement so you can cheat this way a little bit.
 
Thanks for the feedback. I don't usually mess with shutter speed much & didn't consider it TBH. I'll check out the water White ND's
 
I also found that out the hard way the other day. I thought great the FS7 will be the perfect fit for this run and gun job. Ooops, nope. Have to put on my rails and matte box and stack ND filters. Then the lighting changed quite drastically because of clouds and here was I taking off and putting back in NDs. The wheel wasn't quite enough to nail the exposure. This was the day after I had shot with an Alexa and got me wishing I had the AC with me. Wasn't any easier to shoot with the FS7. Can't wait to try the new Varicam with the dual ISO thing.
 
I like the idea of a 1.8 or 2.1 ND filter, but at that kind of light reduction, I would be worried about IR creeping in. Therefore, I am planning to buy an IRND filter. More expensive, but worth it.
 
Jim Ritscher said:
I like the idea of a 1.8 or 2.1 ND filter, but at that kind of light reduction, I would be worried about IR creeping in. Therefore, I am planning to buy an IRND filter. More expensive, but worth it.
Click to expand...

Better to use the camera's built in NDs, then just add the minimum amount of ND in front of the lens to bring you to the correct exposure. Even under the strength of the Australian sun, I find I never need more than an ND1.2 in front of the lens (in addition to the ND1.8 that my F5 has built-in). I've never run into IR contamination issues either that way.
 
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