Intro: Solar Filter for You and Your DSLR
Sun and moon are amazing! So when take picture, or just observing, if not during a solar eclipse ? But there is a problem: sun is incredibly powerful and it's light can easily blind spot or even completely blind you FOREVER. That would be very unpleasant. How to protect your eyes and also your camera sensor from all this light?
########### WARNING! ###########
You won't burn out your retina if for an instant you look directly to the sun but Sunlight is VERY dangerous, so pay attention while looking at it! I'm not an expert so I can't guarantee that you can sit all day looking at the sun, but I think it's safer than many others DIY method. I used it and I can still see perfectly, I'll take no responsibility, do it at your own risk! For no-risk-at-all method see the end of this instructables!
This Instructables is meant to give you the tools and the knowledge to protect you from sunlight and take awesome pictures, you can modify it to fit your needing.
Step 1: The Idea and Credits
It was the March 19th (2015) evening, I was comfortably lying down on my sofa watching TV when I realized it: the following day there would have been a Solar Eclipse and I was completely unprepared! I had prepared no filter and had no idea about what to use for it. I started looking around on the web and I found that in photography is used what is called the Mylar filter. Looking for DIY project I found that the best are
https://www.instructables.com/id/DIY-Solar-Filter-f... , that is good if you can't get your hands on the material,
Let's move on, Materials!
Step 2: Filter Material
For this instructables the main material you need to go to a mountain equipment store and find an emergency emergency blanket, is a small package about the size of a smartphone. The blanket is a large and thin silver sheet, very lightweight, it's used in case of emergency for example if you have to wait rescue. It's very cheap, about 5$, and it will last forever, it's huge! This actually is a Mylar filter. Other material you may need are: black cardboard, scotch tape, glue, scissors, cutter, stapler.
These are just two random images taken from internet to show how the blanket looks like, for more just google "emergency blanket" and you'll find images and online-sellers.
Step 3: Test Your Filter
Before start loosing time building a frame for our filter is a good idea to try it, making sure it will do the trick.
To test it I suggest to find a common halogen bulb and look at it with the filter. Doing this I found that just one layer of my blanket wasn't enough, two was good and three was almost completely dark, so (in my case, verify with your!) 2 layers were good.
Step 4: Mount Filter on Your DSLR
To mount the filter on your DSLR I suggest to use the lens hood, it provides more space to work with and allows perfect access to focus and zoom ring with the filter on. If you don't have one you can buy it (seriously?) or make it!
The original design was much more complicated but I simplified it.
Take some black cardboard and trace the outer circumference of your lens hood, than cut a bigger square with the circle in his center.
Start folding the 4 corners on the lens hood, to make it fit you have to do 8 cuts: two for each bend that will form in the middle of the square edge, one on it's left and one on it's right.
Fold all together and tape it down, you should have something like the picture. It's firm in place with no tape between the cardboard and the lens hood.
Turn it around and trace lines to find a point near the center, then draw a square and cut it with a cutter. You have to leave enough space to tape the filter down and keep it somehow under tension. After the first square draw another 4 corners (like another square but 45°) and cut them also.
Now just get some filter and tape it over the hole, one or as many layer you need.
Step 5: Taking Pictures
To take pictures I strongly suggest you a tripod, makes your life easier a lot. The taller the tripod, the better. If you can stand and look up into your camera is perfect, if not I recommend a chair ;)
Set up your camera, filters and you are ready to go! A common mistake is manual focus to infinity: wrong! The autofocus don't focus correctly so you have to manually do that. Even if the sun is 150 million km away it is not infinity. Switch your lens to MF and go to infinity, you are pretty close but not exactly on focus, you have to slightly move back until you find the perfect point. There you are. The difference can be seen in the photos, the one with the moon My setup was Canon 7D with Tamron 70-300mm on a tripod, 2-layers filter; the camera was on manual and I shoot between f/10 and f/16 with shutter speed between 1/2500 and 1/4000, ISO around 1000. I shoot RAW 5184x3456 and also a sun-spot the size of earth was visible!
Step 6: Filter to Observe: Mod Your Sun Glasses!
(Help me find a cool name!)
I was looking for a practical way to filter sun's light for my eyes, and I made a rectangular cardboard frame with 2 layers of Mylar filter, but I still needed to hold it with one hand... then the magic idea, use sun glasses! Obviously a simple sunglass is not enough, so just cut few filter pieces (approx) the shape of your glass lens and tape them! Now you have super-cool Sun Glasses! In normal light condition you can't see, but when you point up your nose, ta-daan! With naked eye two layer were good but still a tiny bit too shiny, I found that with sunglasses lens it was absolutely perfect, if it's too much you can try remove the lens and use just the frame. Make Real Sun Glasses for the whole family, if you want you can let the kids do their own glass, scissors and tape is all what they need.
Since you are going to tape the filter to sunglasses or remove the lens I would recommend doing it with cheap ones, maybe the tape can damage your lens treatment or leave traces ;) You can easily find them on eBay or Amazon for 10$.
Step 7: Super-Safe Method: Pinhole & Camera Obscura
If you are worried that your kids can forget their filter and start burning out their retinas, didn't find suitable filters, have no time, etc. or just wanna see something very cool, the Pinhole is just what you need!
As the name the Pinhole is just... a hole, a small hole. I'm not going to explain how and why a Pinhole works, on the internet you can find tons of tutorials, explanations and so on, also Pinhole cameras exists, they are very fascinating and cool. A pinhole made with the finger is also a trick if you have bad sight, but this is another story. What happens with the pinhole is that the sunlight pass through the hole and project a circle with the moon shadow. It's super-safe because you are not looking at the sun but just at reflected light, the same you look at every day.
##### WARNING #####
The pinhole has no magic or special powers, it isn't a filter, just a hole, so don't look directly at the sun through it!
You can use a colander that will project many small eclipses, the spaces between the leaf of a tree, your fist, you can cross your fingers, use crackers... anything has a hole!
A cool solution is the camera obscura, but even cooler is a camera obscura with zoom! A camera obscura is just an empty dark light-proof chamber, with a pinhole.
Just take two cardboard tubes, one a bit smaller that fits into the bigger one: by sliding them you will "zoom" the eclipse. Now we need to close the ends: one is for the pinhole, one is for the projecting surface. The pinhole cork must be made of something you can easily hole and that will keep it's shape. You can use some cardboard and a needle, or you can cut a small window on the cardboard and tape on it aluminum foil and then hole it. Or even some thin metal or plastic sheet and a drill or a hot-something. For the projecting surface you should use some light and thin paper, try different ones! Point it at the sun and zoom in and out the eclipse on the bottom of the tube. If you have a tripod everything will be easier.
Step 8: Bonus - Apply Filter to Bigger Lens and Telescope
Ok, a small bonus! :)
My grandad was a photographer and he has some very interesting lens around his house, like a russian MTO-120: a double mirror lens with about 1000mm of focal length. Unfortunately I've only found this little image of a MTO-11CA but it's the same, it's very big and bright. Also he built a Dobson telescope with a 320mm f/5 parabolic mirror, it's beautiful but also huge! So, how to apply a filter to these big instruments? On the MTO you might use the same method as in the DSLR but with such a big telescope it's better to make a light-proof cover, for example thick cardboard or light wood, cut a round hole not in center and apply the filter here. I didn't make one for my telescope but on google there are good pictures. Remember to put the filter on the finder too!
(As soon as I have time for that I'll upload some photos of my telescope)
Step 9: Have Fun and Save Your Retinas
Next Solar Eclipse can be found here:
Thank you for reading this Instructable, I hope I can help you look safely at the sun and enjoy eclipses or other event like Transit of Venus . Please avoid doing stupid things, retina does not have any pain sensor so, if you are burning your cones and sticks you wont feel it, you will just realize it when it's too late!
I've written this Instructable also to enter the Photography contest and the Remix Contest, I would really appreciate if you step there and vote me! Thanks a lot!