needmorethan24

Hello everyone. This is my first question on the forum.

I'm preparing to photograph the 8-21-17 solar eclipse. I came across this formula for time to open the shutter from Fred Espanak's website (mreclipse):

t = f^2/(I x 2^Q) where Q represents levels of brightness ranging from 11 to -3 during various phases of the eclipse. Is anyone familiar with how to recognize these levels? I'll be in the Charleston area to do this. Any suggestions would be appreciated.

Nikonman44

another great query.

A fuller explanation of the formula would be helpful.

Tet68survivor Loc: Pomfret Center CT

Not sure about formula, but I can tell you about photographing Solar Escipes on a budget. Go to your local welding supply company and purchase two or three #14 (2-1/2" dia approx) then play with the lens starting with 2 or 3 to get the idea of how it works, My final set up was 1 lens all the way through the eclipse! I am trying to recover my photos from a dead hd. If I can recover them before the show I will post on this site! The welding lens are about $6 each! To mount the lens I used a 3" through the firewall rubber geometry from a truck repair shop or junk yard! Pretty inexpensive filter for a once in a life time photo shoot! The other alternative is a telescope solar filter for a lot more money!

SS319

Someone has to say it - DO NOT LOOK THRU THE VIEWFINDER AT THE SUN. Of course, you will only do it once.

If you go to an astronomy site, you can find a source for a bader film filter for your camera or instructions on how to make one. I have made Bader Film filters for my old 500 mm cat lens as well as my 8 inch and 10 inch telescopes. I think from there, I would meter on the sky away from the sun (next to the moon) and bracket +/- 2 stops. You may want to look into a Hydrogen-alpha filter as well - a 62 mm one is about $100, but they give a great image of the sun and will enhance the flares or CMEs of our sun.

were it me, I would put a piece of black tape over the viewfinder and use the live view screen - even with a filter. But, then, I am rather fond of my eyes....

krl48 Loc: NY, PA now SC

Does this table from Fred Espanek (Mr. Eclipse) help answer the question?

www.mreclipse.com/SEphoto/image/SE-Exposure1w.GIF

jerryc41 Loc: Catskill Mts of NY

Forget that formula! There's probably an expensive piece of electronics that could tell you the brightness.

If these links don't give you the information you need, that formula certainly isn't going to help.

Filters -
http://www.thousandoaksoptical.com/solar.html

Technique -
http://www.mreclipse.com/SEphoto/SEphoto.html
http://www.eclipse2017.org/2017/photographing.HTM
http://www.nikonusa.com/en/learn-and-explore/article/h20zakgu/how-to-photograph-a-solar-eclipse.html
https://photographylife.com/how-to-photograph-a-solar-eclipse

StanRP Loc: Ontario Canada

DO NOT LOOK THRU THE VIEWFINDER AT THE SUN:

A wise decision - also using the live view screen can help get correct focus. Focus point on a lens changes with colour ( Changes of wavelength - the cause of aberration). On a DSLR, the image is normally focussed by separate sensor that works with the mirror. The light from the Sun has a very high Infra-Red 'long wave' content and it will focus on that. When the camera is in live-view mode it is focussed using the same sensor as the image and will aways be in focus.

kvanhook Loc: Oriental, NC

Can you just focus manually at infinity? Seems like the sun would be as close to infinity as we can get. Then the in camera auto focus won't be used at all. Will that work?

MtnMan Loc: ID

There will be plenty of images of the sun better than I could do. I'm thinking of setting up the camera to take a sequence showing the darkening and lighting and making a movie of it. We live close to the path of totality over Idaho. There is a good chance of clear skies here.

We have our eclipse glasses already.

Ringer

At what point might it be safe to point the camera sunward without a filter? Ever? I'm not talking about my eyes -- just the safety of the camera. And, a related question that is really the same: We are going to Norway soon and will experience the midnight sun. Sometimes the sun will be right at the horizon and might be safe to photograph -- or not?

sjb3

Well, as I understand it from visiting the Great American Eclipse site, the one and only time anybody can safely look at (or look thru a viewfinder / eyepiece at) the unfiltered sun is during the period of totality and that applies only if you are within that 68-70 miles-wide path of totality. For me, that means I can take off my cardboard-frame eclipse glasses, and twist my DIY-made solar filter off the camera for a total of 2 minutes & 20 seconds before having to cover up again. I live in Clarksville, Tennessee and am well within the path.

Also, regarding filters, I bought a 4"x4" piece of Black Polymer filter material from Thousand Oaks (as referred to by jerryc41) and after cutting it to size sandwiched it between a Skylight 1A filter and a twist-on-off filter adapter made for my Fuji camera. The sheet cost ten dollars, ordered thru Amazon.

I had plenty left over to rig up a little filter to protect my GoPro hero 5. After making some test shots, though, I'll probably stick to my original plan of pointing the GoPro in a wide-angle view of the Northwest, making a series of exposures at 1-second intervals starting about 15 minutes before the Moon completes transit-on to the Sun, then the full period of totality, followed by the first 12 minutes or so of transit-off; a half-hour total of the high-point of the eclipse, showing the steadily darkening sky and gradual return to normal afternoon daylight. I also hope to get a good view of the Moon's shadow, or Umbra, which will as the Moon passes come streaking out of the Northwest at about 1,400 mph. Since it won't be pointed at the Sun, no filter will be needed. I'll process the resulting 1800 or so photos into a 60-second timelapse video.

Sorry for going on so long; I'll attach a test shot made with the filter attached to the Fuji camera. And here is a link to a short (1:12) video of the same test, along with an unfiltered Moon shot. The video was distilled down from about 20 minutes total of video footage, over 2 separate shooting sessions.
www.youtube.com/watch?v=3-fglsCI7Qo

View of Sun thru solar filter

(Download)

jerryc41 Loc: Catskill Mts of NY

Nice shot.

wdross Loc: Castle Rock, Colorado

Before and after totality one must use a filter if using an optical viewfinder. Even the thinnest slice of sun will burn one's eye permanently. But once totality occurs, no filters of any kind are needed. Just be careful when the sun comes back out from behind the moon.

Also, even when the sun is low on the horizon, it still produces UV which will burn your if using an optical viewfinder.

PhotoKurtz Loc: Carterville, IL

http://www.airgas.com/product/Safety-Products/Head%2C-Eye-%26-Face-Protection/Welding-Lens/Welding-Lens---Passive/p/RAD64005028

Here's a 4 1/2" x 5 1/2" lens for $3.25 at your local welding store. I'll pick one up tomorrow and see how I can duct tape it to my lens hood.

DougS Loc: Central Arkansas

B&H Photo still has some inexpensive solar lens covers, as well as "glasses".