Shooting SOLAR ECLIPSE in Stockholm - WHICH ND FILTER

[Michele Baggio]

Hi REDusers.
I'm setting up my Red Epic to film the solar eclipse tomorrow in Stockholm.
I'm traveling super light so I have only a Canon 70-200mm 2.8 + Extender 1.4x + Vari-ND (8 stops max).
Should I use a Solid IR ND to get a more consistent density?
3.0 is enough?


If someone of you is from Stockholm, which is the best spot to go?
Thanks so much for your help.
Best
Michele

 

[Randall Weatherington]

As an amateur astronomer, we do the following:
Use a mylar solar filter over the outside of the front element of the lens, at least 4.0 ND.
Under no circumstances do you want direct solar light or heat to be able to penetrate even the first lens element. It could fry anything and everything.
The first to go would be lens coatings.
ND filters absorb sunlight and heat. You want to reflect sunlight and heat away from the equipment.
The ND filters used alone might heat up and crack, then you have direct sunlight to the sensor. At that point, you can plan on replacing the sensor.
It would also be good to add a large card around the perimeter of the lens to stop any additional sunlight from heating up the outside of the equipment.
I have the same lens, and even with a 2x Canon extender, you will still have a relatively small sun image.

 

[Brice Ansel]

As an amateur astronomer, we do the following:
Use a mylar solar filter over the outside of the front element of the lens, at least 4.0 ND.
Under no circumstances do you want direct solar light or heat to be able to penetrate even the first lens element. It could fry anything and everything.
The first to go would be lens coatings.
ND filters absorb sunlight and heat. You want to reflect sunlight and heat away from the equipment.
The ND filters used alone might heat up and crack, then you have direct sunlight to the sensor. At that point, you can plan on replacing the sensor.
It would also be good to add a large card around the perimeter of the lens to stop any additional sunlight from heating up the outside of the equipment.
I have the same lens, and even with a 2x Canon extender, you will still have a relatively small sun image.

Hi Randall,
I'm not looking for an astronomer shot, but more buldings shot under this special light by pointing the sun
Is it risky for the lens coating and sensor with short takes and a composition like this?
Cheers

 

[Christoffer Glans]

I'm sorry to say, but the weather in Stockholm doesn't look good. Cloudy and rain :001_unsure:

 

[Todd T]

This type of shot would be no different than any other outdoor shot. you only need to adjust your exposure to account for the reduced amount of visible light.

The amount of UV radiation does not change during a solar eclipse, is the same as a normal sunny day, actually a smidgen less.

The danger warnings that have been drilled into our brains about horrible UV damage during a solar eclipse is because our iris response is not properly triggered by UV light, the reduced amount of visible light that make it easier to damage your retina when looking directly at the eclipse. Cameras and sensors are much more durable than our eyes, but If you are really worried about it, a simple UV/Daylight filter will protect your sensor.

Hi Randall,

I'm not looking for an astronomer shot, but more buildings shot under this special light by pointing the sun
Is it risky for the lens coating and sensor with short takes and a composition like this?
Cheers

 

[Michael J Brennan]

As an amateur astronomer, we do the following:
Use a mylar solar filter over the outside of the front element of the lens, at least 4.0 ND.
Under no circumstances do you want direct solar light or heat to be able to penetrate even the first lens element. It could fry anything and everything.
The first to go would be lens coatings.
ND filters absorb sunlight and heat. You want to reflect sunlight and heat away from the equipment.
The ND filters used alone might heat up and crack, then you have direct sunlight to the sensor. At that point, you can plan on replacing the sensor.
It would also be good to add a large card around the perimeter of the lens to stop any additional sunlight from heating up the outside of the equipment.
I have the same lens, and even with a 2x Canon extender, you will still have a relatively small sun image.

Randal, over the years I've shot full frame sun using rear of lens NDs and electronic shutters to adjust exposure on 3 chip ccd cameras without damage to the lenses which I owned.
This included locked off wideshots of 30 minutes or so.
How long before lens coatings are damaged?
Are cmos sensors more prone to damage?
Also I have a 2000mm mirror lens that has survived shooting the sun.
I'm of the view that a wide angle lens has far more potential to do more damage than a telephoto because in wide shots the sun is projected on relatively few number of pixels and the exposure is for the foreground so sun is enormously over exposed.


Mike Brennan

 

[Michele Baggio]

Hi!
Thanks Randall for your great advices. Really appreciated.
Sadly, as Christoffer said, the weather in Stockholm was really cloudy.
But for the next one, I'll be more than ready.
Thanks again
Best
Michele

 

[Christoffer Glans]

Actually, the clouds made it visible without protective glass :smile:
Taken with my phone

 

[Randall Weatherington]

Checking back in after the fact.
General scenic shots - yes, shoot like you normally would.
An interesting phenomenon that you might have noticed, weather permitting, was multiple crescent sun images in the shadows of tree leaves.
Glad somebody was able to get something.

The more heat that gets into the lenses and cameras, such as from direct sunlight, the more damage is likely to occur.
Case in point: The Cinerama Dome in Hollywood had Panavision make a special pair of anamorphic projection lenses in the 70s so that the image would be sharp all across the curved screen.
The labs would make a print that was 1/2 stop lighter specifically for that theater just so that the Xenon lamp houses could run a little less intense so as not to burn the lenses.
Granted these lenses were in use all day long. Shooting the sun is a different story, but can be way more intense.

The Griffith Observatory has a 26" reflector telescope that they bring out during their star parties. This is a telescope that was originally destined to be launched into space. By the way, 26" is the diameter of the mirror, not the focal length.
At one time, they pointed the scope at the sun without an eyepiece. When they held up a piece of paper to the draw tube where the eyepiece goes, they instantly burned a 2" hole in the paper, the same diameter as the draw tube.
Had there been a camera sitting there, it probably would have melted through the back of the camera.

I have never liked rear mounted filters. First because they change the back focus.
For solar work, they are much more susceptible to heating and cracking because the sun is so much more concentrated at that point. Remember burning holes in leaves with a magnifier lens when you were a kid?

Once again, when shooting the sun directly in an astronomical fashion, the safest way is to cover the outside of the lens, telescope, etc. with the solar mylar film or even a solar filter. That will go a long way to protecting everything.

 

[Ben Roper]

I was under the impression that the only potential for damage was with the sensor... An optical lens allows almost all energy to pass through, no?

...Unless we are talking about mirror lenses or something more bizarre?

 

[Manuel Wenger]

Here in Munich we had blue sky, and from my balcony i could follow the event. I didn´t shoot the event since i didn´t have my camera here but i did measure the exposure change during the event with my Sekonic. I think i read about a coverage in our area of 68% and when i used my light meter, set to 25fps/100 ISO i had a drop vom 16.8 down to 11.6 , so about a stop and a quarter which would match the aprox. the coverd area ratio.
I had my ND filters for my Canon lenses here, and i stuck them all together to see it with my bare eyes, so the ashtray i was looking through stopped the light down 18(!) stops.