Sun Time Lapse

[Stephen Williams]

If you normally shoot 24fps with a 4 stop ND, when you slow down to 1 frame every 30 seconds, your exposure goes up by about 1000 times, which is about 10 stops. Thus, 10+4=14 stops ND.

I always use 10 stops ND when shooting with 50 ISO film so 14 stops seems like a good idea to me.

 

[Tom Lowe]

Most likely, like you will not be able to shoot directly into the sun with the Epic. You will get the red-dot flares -- which I believe is the low-pass filter reflecting onto the back of the lens, then back into the sensor. Once the sun is about 10 degrees above the horizon, I usually cannot continue shooting directly into the sun, no matter what filters I use.

This is a deadly serious flaw in the Epic that needs to be addressed immediately, IMHO.

 

[Lauri Kettunen]

If I'm not mistaken, the low-pass filter is not next to the sensor as is the case in Canon EOS bodies. (If so) The good thing is, dust etc. does not appear that easily in the images. The other side of the coin are the reflections you mentioned. My guess is that the reflections are between the sensor the the low-pass filter. Occasionally have got interesting light rays in my images due to the reflections. But somebody from RED could explain what's really going on within the camera.

 

[James Brundige]

I used 5D II, but I don't think it is any different than the Epic as far as IR is concearned. I use a special ND filter that does not contaminate the image with IR as much as most other ND filters do. It is hard to find a heavy ND filter with reasonably flat transmission across the spectrum. Most dyes are transparent to IR.

Also, it helps if your lens can focus IR on the same plane as the visible spectrum - most lenses don't.

Who makes that filter? I've been using a Tiffen 2.1, but the colors are suffering.

 

[Jeff Kilgroe]

Also, it helps if your lens can focus IR on the same plane as the visible spectrum - most lenses don't.

This is what I've been trying to tell people for years here when there was all the hubbub over IR contamination on the RED One... Not all lenses transmit IR to the same degree, and not all lenses focus the IR end of the spectrum the same, so you get visible CA in IR. My Cooke 18-100 zoom was a great example of this. It arguably didn't need IR filtration, it just didn't transmit much IR with that big heavy glass and all those elements. I had to be shooting some seriously IR-entensive shit with some seriously heavy ND to see any color shift at all due to IR. OTOH, high-intensity IR subjects would often show visible halos. Usually white to slight purple, looked like CA, but it was all around the object and not necessarily shifted to either side of focus as CA color separation typically is.

Most likely, like you will not be able to shoot directly into the sun with the Epic. You will get the red-dot flares -- which I believe is the low-pass filter reflecting onto the back of the lens, then back into the sensor. Once the sun is about 10 degrees above the horizon, I usually cannot continue shooting directly into the sun, no matter what filters I use.

This is a deadly serious flaw in the Epic that needs to be addressed immediately, IMHO.

I wouldn't say it's a flaw with the EPIC... I can produce the exact same "OLPF flare", or internal reflection of the photosites / micro-lenses, on *ANY* CMOS camera with an OLPF. It even looks almost the same on various cameras. RED One M, MX, EPIC, ALEXA, various DSLR's. It seems to be worse on the cameras where the OLPF system sits further in front of the CMOS surface, rather than right up against it. Some camera makers (like RED, ARRI and SONY) tend to do this as part of the design to further soften the OLPF ringing and/or to reduce moire. ...Yeah, I mentioned SONY. A couple of their Alpha DSLRs do this and so does the F35. Anyhoo... Didn't want to hijack the thread. But yeah, I agree, this flare is a problem. It's funny that it's been there since the beginning. It was one of the first "issues" I encountered with the RED One back in late '07 at Gibby's LART test and only on one camera -- the one "X" camera present for the test. The one with the new OLPF that sat further in front of the sensor, which is what all RED Ones and subsequent Mysterium sensor configurations became.

It's funny though, you see it all the time in samples posted on here by people and no one complains. Yet we get a little gate-flare from the EPIC and it's like the sky is falling.. WTF? IMO, the OLPF Flare is more problematic and much harder to avoid or control than any gate flare... But whatever... People will bitch about whatever they want. Sony Alpha DSLR forums are riddled with the same thing. Had a hell of a time with the OLPF flare on my last ALEXA shoot. It was a commercial, shooting pretty much into the sun. Meh...

Who makes that filter? I've been using a Tiffen 2.1, but the colors are suffering.

I'm having the best luck with IR+ND filters with Formatt. I can stack an IR+ND 1.5 with one of their regular ND .9 filters behind it (2.4 or 8 stops ND with IR cut) and I hardly experience any color shift at all. EPIC handles IR much better, but at that extreme amount of ND, it can still rear its head. As good as the Formatt hot-mirror coating is, it's still not quite powerful enough at ND 1.8 and up if you have a high-IR scene. The IR effect is more visible on the RED One vs. the EPIC, but it's still there. That said, the color cast is minimal and typically a proper white-balance will clear it up. If the IR is really bad, I might still see some hint of pink when at ND 1.8 or stronger in some reflective surfaces that are very hot or can bounce a lot of IR -- chrome car bumpers or shiny tools left in the sun, some reflections off water or sand, that sort of thing...

Tried the Pancro filters as well. Their iR coating wasn't bad, but the color casting was a problem at ND 1.2 and up. They don't sandwich their coating in the glass like Formatt and others do. I shot a timelapse with sun in frame with the Pancro filters, IR+ND 1.2 up front and after about 4 hours or so of that each day for 4 or 5 days in a row, the coating actually started to look scorched. Not that it's unusual for that to happen. I melted several drop-in ND 0.9 and 1.2 filters in my Cooke 18-100, especially gels. Not like physically melted them out of the holder, but some of the gels showed physical warping or distortion and "scorching" or fading around the center where the projected image circle passes thru... And that wasn't from shooting time-lapse. ...Melted a mirror shutter on a Nikon D2Xs a few years back. Should've ND'd up and lengthened my exposure time.... Live and learn. Hehe.

 

[Julio Quintana]

Most likely, like you will not be able to shoot directly into the sun with the Epic. You will get the red-dot flares -- which I believe is the low-pass filter reflecting onto the back of the lens, then back into the sensor. Once the sun is about 10 degrees above the horizon, I usually cannot continue shooting directly into the sun, no matter what filters I use.

This is a deadly serious flaw in the Epic that needs to be addressed immediately, IMHO.

I 100% agree with you, Tom. The red OLPF dots have totally boned me on several occasions, most notably on a specific high-profile project with a director who really likes back-lighting

 

[Lauri Kettunen]

OLPF dots

... sometimes not only dots but rays instead. Still, in this case they made the image more interesting, I guess.