Author Topic: Solar filter for camcorder  (Read 721 times)

Offline Ranb

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Solar filter for camcorder
« on: July 14, 2017, 06:31:12 PM »
I plan on viewing the solar eclipse in August near Salem Oregon.  I'll have an SLR camera with a 600 mm zoom and a Sony Handycam both equipped with solar filters for recording during the partial eclipse.  I'll take them off during totality. 

I made a filter from cardboard and Baader film based on what i saw on the internet.  The results were poor to say the least.  I need help.

https://www.youtube.com/watch?v=YnSoU5s696E

Not sure why results were worse after I painted it.  It is possible I damaged the film when I spray painted the film holder even though I covered it prior to spraying.  I think the camcorder might be trying to focus on the filer instead of anything farther away when it has an unobstructed view of the sun.  The camcorder works fine when performing the usual recording without the filter in place.

I'm going to obtain two 37 mm filers to contain a piece of Baader film and attach it directly to the camcorder lens next.

Ranb
« Last Edit: July 14, 2017, 07:00:12 PM by Ranb »

Offline smartcooky

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Re: Solar filter for camcorder
« Reply #1 on: July 15, 2017, 01:07:10 AM »
Mylar.

http://www.instructables.com/id/3-Camera-usable-Solar-Filter/

But make sure it is VERY, VERY secure, If it comes off, your CCD is toast!
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Offline Ranb

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Re: Solar filter for camcorder
« Reply #2 on: July 15, 2017, 02:30:54 AM »
My second test.  I taped the filter backwards onto the lens.  Going to buy 2 $6 37mm filters to sandwich the solar film between to make a durable filter that will not leak light or fall off.

https://www.youtube.com/watch?v=IxObe6ZbtWk

Offline molesworth

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Re: Solar filter for camcorder
« Reply #3 on: July 15, 2017, 10:16:11 AM »
My second test.  I taped the filter backwards onto the lens.  Going to buy 2 $6 37mm filters to sandwich the solar film between to make a durable filter that will not leak light or fall off.

https://www.youtube.com/watch?v=IxObe6ZbtWk
That's not too bad, and zoomed in it seems to be focussing on the sun correctly.  If there's a way to switch to manual focus on that camera, it would be worth doing that.

Note also that "extended zoom" is simply cropping frame (and possibly some interpolation of pixels) so you'll end up with reduced resolution across the view.  Best to stick to optical zoom only.
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Offline Zakalwe

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Re: Solar filter for camcorder
« Reply #4 on: July 15, 2017, 10:23:32 AM »
Your camera is focusing on the interior of the filter.  Can you set it to manual and focus on infinity? Of take the filter off, focus on a distant terrestrial object, lock the focus and then pit the filter back on?

I wouldn't sandwich the solarfilm between two other filters either- absolutely no need for that.

Also, can you manually adjust the exposure? A bright object in a sea of black will throw the camera's auto exposure unless you can manually adjust it or use a spot exposure setting.
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Offline sandopan

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Re: Solar filter for camcorder
« Reply #5 on: July 17, 2017, 01:19:39 AM »
Are we looking at DIY filters because the store-bought ones are very expensive, or because they don't exist?
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Offline Zakalwe

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Re: Solar filter for camcorder
« Reply #6 on: July 17, 2017, 08:18:35 AM »
Are we looking at DIY filters because the store-bought ones are very expensive, or because they don't exist?

DIY, but using the correct Baader solarfilm.
The problem is with the focusing of the camera, not the filter.
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Offline Ranb

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Re: Solar filter for camcorder
« Reply #7 on: July 17, 2017, 04:59:44 PM »
The Sony CX160 has no manual focus capability when recording video.

I was told that using solar film by itself would introduce less distortion compared to one of the lower end glass filters.  Considering the fact that I'm a amateur using basic equipment, price, not minor distortion is the major concern.  That said, I'll be spending more on gas to get to the eclipse area than on anything else.

Offline Ranb

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Re: Solar filter for camcorder
« Reply #8 on: July 17, 2017, 10:34:39 PM »
$12 for two 37mm filters and $25 for solar safety film.  The results are better than with my cardboard holder.  I only get acceptable video with it zoomed in to at least 30x, but this is where I'm going to operate anyway.

https://www.youtube.com/watch?v=os6JgbJn4Zk

I made a filter for my Nikon D3400; using a 70-300 zoom with a doubler attached.  The sun fills up about 35% of the vertical portion of the frame. 

Offline Zakalwe

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Re: Solar filter for camcorder
« Reply #9 on: July 20, 2017, 03:56:11 AM »
I was told that using solar film by itself would introduce less distortion compared to one of the lower end glass filters. 

That's correct. Most glass filters are made with ordinary float plate glass and are nowhere near optically flat.
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Offline Kiwi

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Re: Solar filter for camcorder
« Reply #10 on: July 20, 2017, 11:43:59 AM »
Back in the 1980s I easily and cheaply made an excellent solar filter that was much thicker and more rigid than mylar. A square of it could just be taped over the front end of binoculars without needing a filter ring.

All I did was, under ordinary room light, crack open a roll of 120 (6 x 6 cm frame, same as used on the moon) black-and-white SILVER-based medium-speed film (Ilford FP4) and wave the blank film around so it was evenly and fully exposed to the light, then develop, fix and wash it in the usual manner, without needing to be in a dark room.

Being silver-based film, the fully-exposed and developed silver grains are dense enough to provide safe viewing of the sun through binoculars or a telephoto lens. So dense and dark that it was quite hard to get the sun in view. It gave me my first ever live 3D view of the sun, complete with sun spots. I still have most of that same film just in case a need for it arises again.

In posts above are mentioned the two things that bug me most about modern auto-everything cameras. It can be difficult or impossible to focus them on infinity and get a suitably long exposure for astronomical photos. Give me full manual control for most photos except those where there is little or no time to make manual adjustments.

I'm sure that auto-focusing is responsible for many "UFO" photos that are of fuzzy lights that change colour and shape. It's a result of the lens struggling to focus and make sense of a small, bright light in dark sky. There was a case in the 1980s where a "UFO sighting" was actually the result of a movie camera focusing on its own parts inside the lens, and the light was a street light on top of a hill.
« Last Edit: July 20, 2017, 11:53:39 AM by Kiwi »
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Offline Zakalwe

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Re: Solar filter for camcorder
« Reply #11 on: July 20, 2017, 01:30:23 PM »
For anyone interested in basic "white-light" solar astronomy then I'd recommend NOT trying to make a solar filter out of anything but the Baader solar film. The film is dirt cheap, so it's just not worth messing your eyes up. Some substitutes might cut down the visible light but you just do not know how much UV or infra-red light is coming through. Infra-red light is particularly pernicious as it takes a while for the damage to appear. I've seen examples of people messing with Mylar, DVDs, those terrible eyepiece filters...all sorts.

Solar astronomy is great fun, but it really is one of the very few ways that you can do life-changing and irreparable damage to yourself in this hobby.
This is what happens to a DSLR when the solar filter comes off a telescope. A camera can be replaced, an eye cannot.


http://www.camerarepair.org/2012/05/solar-eclipse-burned-camera/

[youtube]http://youtu.be/fjshhNbSlCs[/youtube]
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Offline Ranb

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Re: Solar filter for camcorder
« Reply #12 on: August 21, 2017, 11:42:33 PM »
I went to Stayton Oregon with my wife and mom.  I had a Nikon D3400 with a 600mm lens and a Sony Handycam CX160 both with solar filters on tripods.  Fiddling with the tripod adjustment every few minutes to keep the sun in frame was a pain, but it didn't interfere with watching the eclipse.  My primitive photos and video don't do the scene we experienced any justice at all.

Right after totality when I had to look away and reattach the solar filters to the camera, the park got much brighter very quickly.  I did a quick pan of the park with the camcorder to show how dark it got, but within thirty seconds past totality it was no longer dark and the moment was gone.

I almost settled for a 93% eclipse in the Bremerton area where I live but my wife kept an eye on the traffic cams which showed very little traffic on I-5.  We were told to expect a very long commute if we didn't go the day before.  Instead we left at midnight and got there in 3.5 hours driving the speed limit the entire way.  Then we tried to sleep in the truck for several hours prior to the 0908 eclipse start. 

The party atmosphere at Santiam Station Park was very nice; not too many people, free coffee and snacks.  There were other people present with basic camera and camcorders to record the event.  One guy had solar film on his binoculars; I wish I had thought of that.  It made for far better viewing of the eclipse than just using glasses. 

The return trip was about eight hours in much stop and go traffic.  The 2014 eclipse will pass over my daughter's house in Texas; we'll be visiting her then.  :)

A few minutes of my video and photos.  https://www.youtube.com/watch?v=zX9F1zr3W0M

Offline bknight

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Re: Solar filter for camcorder
« Reply #13 on: August 22, 2017, 07:11:09 AM »
Nice video, an awesome site in person no doubt.
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Offline LunarOrbit

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Re: Solar filter for camcorder
« Reply #14 on: August 22, 2017, 07:27:13 AM »


A few minutes of my video and photos.  https://www.youtube.com/watch?v=zX9F1zr3W0M

Thanks for the video. I only got a partial eclipse (about 70% coverage) but it was still fun to watch.

The 2024 eclipse should pass right over me, so I'm looking forward to that. I'll probably get a solar filter for my telescope.

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