CPL + ND

[arild]

Yo

I´ve got an 8.5 stop ND, and a CPL. I´m going to Båtsfjord next weekend, which is pretty much as far north as you can get on the Eurasian mainland.

I want to use those two in combination, but I haven´t really figured out if the CPL should be the furthest out. I think it should be like that, but I have no idea.

[mtcham]

I'll use 1 or 2 ND's first and then the CPL. Check your combination for vignetting on wide angle lenses, sometimes it's good to use a step-up ring and larger sized filters.

[Tippster]

CPL on the outside.

[Lonnie]

CPL on the outside.

This. If you have it on the inside, it will interact with the light coming off the ND. The tough thing about using it with a 8 stop, is making sure that the polarizer is aligned correctly to eliminate glare, given the opacity of the ND8.

[summit]

What tip and lonnie said

[arild]

Thank you all!

I figure I´ll just find the correct alignment straight on the lens first, then take it off again, put on the ND and get the cpl on again. My camera can´t meter for shits worth with the ND on, so I´ll calculate on the go.

[Lonnie]

Also, when using 6+stop ND's it's best to manually focus first, then put the filters on.

When stacking filters, their light blocking properties are additive. So if you stack your 8.5 stop ND on top of your 2 stop Cir pol, that adds up to 10.5 stops of reduction in the light hitting your sensor.

So your shutter speed can be calculated by the following formula where;

Shutter speed = E*(2^S)

E = exposure time of the original TTL metering
S = the total number of stops your filters are reducing the light by

If your ND filter and Cir polarizer reduce the light by a total of 10.5 stops and your original shutter speed was 1/25 sec then your final exposure will be 362 seconds (just over 6 mins).

What I do so I don't have to figure these on the fly is on the filter case for my 9 stop, I have written down all the conversions for my most common shutter speeds. All I have to do is look at my original metering and then look at my case and break out my stopwatch.

Given how much light these filters block, the light that seeps through the back of the view finder can cause some significant flaring in the final image. It's useful to block off the viewfinder so that no light leaks back in from that path. (My Sony has a lever that closes the viewfinder, so that's how I work it. I've seen others use a ball cap, or a piece of electrical tape).

[hitek79]

Given how much light these filters block, the light that seeps through the back of the view finder can cause some significant flaring in the final image. It's useful to block off the viewfinder so that no light leaks back in from that path. (My Sony has a lever that closes the viewfinder, so that's how I work it. I've seen others use a ball cap, or a piece of electrical tape).

Little known and great advice. On a bright day covering the eye piece will also significantly help with the camera's ability to meter properly as well if you aren't able to set it manually.

[outabounds]

That's funny Lonnie, I never have viewfinder light leakage problems on my D90 during exposures. Maybe you should be shooting Nikon.

[arild]

Haha. ^^

Turned out my fix with something resembling JB-weld for the tripod socket on my camera wasn´t such a good solution as I thought initially. Had to stress test it a bit (L-plate practically glued to the camera) and it snapped after the second tug. No long exposures for me this weekend. Managed a few 0,5 sec ones that turned out reasonably sharp, might post some tomorrow.

As for how you manage to fuck up a tripod socket; screw on an L-plate while moving in sort of a rush. I´m seeing the actual part that needs replacement costing about $200 usd, and I don´t want to bite that bullet just yet.

[Chainsaw_Willie]

That's funny Lonnie, I never have viewfinder light leakage problems on my D90 during exposures. Maybe you should be shooting Nikon.

LOL! Zinnnggg!

It does mention this as a potential issue in my D7000's manual... I've never done any real long exposures in daylight so don't know whether it really is or not.

[arild]

^^ Uninspired shot, but at least it was shot at 0,5 sec handheld!



^^ Sunset in an abandoned fishing village, Syltefjord, near Båtsfjord.

We were taken on a sightseeing by a local, drove us around for nearly four hours. Didn´t want gas money or any thanks for it, he just wanted to show us his paradise. Beautiful landscape/scenery. Figured I shouldn´t steal more of his time by shooting an extra hour, but this last one, I´m pretty satisfied with none the less.

[arild]

Those are edited on the laptop, and colors might be off by a hair or two. Looking forward to work with these on a larger screen!

[Lonnie]

That's funny Lonnie, I never have viewfinder light leakage problems on my D90 during exposures. Maybe you should be shooting Nikon.