Question Preparing for Solar Eclipse

[raphaelr]

Apologies in advance for the newbie questions.  I have a relatively new (for me) Canon Rebel T5i with a Canon 18-200mm lens.  I have a few questions regarding the August solar eclipse.  I will be using a tripod and remote shutter control.

1.  Can I use my current lens to take a decent photo of the solar eclipse without  damaging the lens or camera?  Or, is another lens recommended?

2.  Do I need a special filter to protect the lens and camera?  If so, what would you recommend.

3. I have started birding and am considering getting the Canon 100-400mm lens.  I saw something posted by Canon that suggests this is a better lens for getting pictures of the solar eclipse.  Can this lens be safely used and does it need a special filter?

Thanks,

EMT RR

[kvbarkley]

You *ALWAYS* need a special filter except in 2 rare circumstances:

1. It is close to sunset, and you could shoot the sun without a filter anyway.

I have used a thousand oaks optical filter.

2. It is a total eclipse and it is during the few seconds of totality.

200 mm is not long enough. The sun will be too small.

Here is a shot I did at sunset without a filter:

[TCampbell]

Are you going to be viewing from a location on the path of totallity?

IF you are location somewhere ON the path of "totality" (a path which stretches from Oregon to South Carolina and is only about 60 miles wide) THEN you can safely remove the filter and take direct photographs of the solar corona ONLY when the sun is 100% eclipsed by the moon.

When the sun is NOT 100% eclipsed then you need a proper solar filter installed on the lens.  

You can get solar filters from lots of sources.  I tend to buy my solar filters from Thousand Oaks Optical.  

A Thousand Oaks "77-T" filter is a proper safe solar filter with 77mm diameter screw on threads (it fits the Canon EF 100-400mm f/4.5-5.6L IS USM II (or any lens with a 77mm filter thread).

You can also order filters that are not threaded - they fit over like a cap.  You order these based on the physical outer diameter of the lens barrel.  They come with felt strips that you use to line the inside of the filter to give it a better fit.

Ignore things you might read on the internet about things you can use as substitute filters to look at the sun.  If it isn't actually designed to be a solar filter, then I don't trust it and I wont use it.  I wont use welding goggles, for example (and most of them aren't safe).

Here are a couple of shots taken using my 5D III, a Canon EF 300mm f/2.8 IS USM and a Canon 2x Extender during a partial eclipse back in Oct 2014.  These were taken using a thousand oaks filter (it also happened to have the largest sunspot group during the entire solar cycle).

During totality, everything is different. No filters are used.  But you also need to capture about 10-12 stops of exposure to create a composite image of the solar corona.

Ideally to capture corona shots, the sun should occupy at least 1/4 of the vertical size of your view but no more than 1/2 of the size (and 1/3rd the size is perfect.)

For an APS-C size sensor camera (such as your T5i) a 400-800mm focal length is ideal for totality photos (but photographing totality is complicated and since totality only lasts slightly over 2 minutes (on the center line) it's generally discouraged (if you're head is in the camera gear trying to get the exposure... you'll miss a lot of stuff that happens in a total eclipse.)

[Waddizzle]

In addition to the filter advice, be sure to have a good stable tripod.  You can practice by taking photos of the Moon, because it has nearly the identical angle of view.  Use Live View to manually focus on the Moon, and note the settings.  You will use nearly identical focus settings when you photograph the eclipse. 

I think 800mm on a crop sensor should fill the frame very well.  Again, practicing with the Moon, you will notice that the Moon can move out of the frame fairly quickly.  The Sun will do the same thing, and at about the same speed, which mostly comes from the speed of the Earth's rotation.

Using a VERY sturdy tripod and a strong tripod head becomes even more critical at the super telephoto focal lengths.  Manual focusing can look like a violent earthquake with most gear.  Not raising your center column will help in keeping your setup more stable.  I would advise using a tripod and head that are rated no less than 5x the combined weight of your camera and lens, and that's for average everyday shooting.  For a supertelephoto, you may want to use something that can handle close to 30 pounds, or more.  

[EDIT]. I use ball heads rated for loads over 50 pounds.  Ball heads can suffer from backlash, which means the ball position can drift slightly as you tighten it down.  A pan/tilt head would be easier to use, because it would be easier to re-adjust for Earth's rotation than a ball head.  That, and good pan/tilts seem to suffer less from backlash.  

Shooting video requires solid gear in order to get smooth pans.  A good video head can serve as an excellent platform for shooting stills with a DSLR.  Likewise, video tripods tend to be far more robust than tripods that are supposedly designed exclusively for photography.  The biggest difference between a "video tripod" and a "photography tripod" is that a video tripod lacks a center column, and uses a bowl to mount a video head.  

The best "photography tripods" lack a center column, and offer an interchangeable flat plate, on which you mount your head.  You would use a "bowl adapter" on a video tripod to give a flat surface, on which you could mount a flat bottom head.  In the above photo, the tripod has a flat plate, instead of a center column.  Between the flat plate and the ball head, there is a leveling adapter, which allows me to level the the base of the tripod head, for accurate pans, which serves the identical function as a video bowl, but is more exact and easier to set.

[ebiggs1]

Now for the simple answer..............

"Can this lens be safely used and does it need a special filter?"

No.  Yes it can.  Never, without a filter.   Corrected.  

"...with a Canon 18-200mm lens..."

As far as you are concerned, the Sun is the same size as the Moon.  Go out a take a few shots of the Moon.  The Sun will appear the same size in your frames as the Moon presents.

Ef 100-400mm zoom is a good choice but still on the short side.  Try the Moon first !

[kvbarkley]

---

@ebiggs1 wrote:

Now for the simple answer..............

"Can this lens be safely used and does it need a special filter?"

No.  Never.

---

I have no idea what you are saying here. Any lens should work fine with a filter. More than that, we have already provided two instances when a protective filter is not needed:

1. At sunset/sunrise (with examples!)

2. During totality to get a shot of the corona.

[ebiggs1]

kvbarkley,

I have no idea either what I was thinking but I got interrupted by the grandson in the middle of it.  That's my excuse and the best I can come up with.

Edited;

Now for the simple answer..............

"Can this lens be safely used and does it need a special filter?"

No.  Yes it can.  Never, without a filter.   Corrected.  

[ebiggs1]

kvbarkley,

This part is still legit,

"...with a Canon 18-200mm lens..."

As far as you are concerned, the Sun is the same size as the Moon.  Go out a take a few shots of the Moon.  The Sun will appear the same size in your frames as the Moon presents.

Ef 100-400mm zoom is a good choice but still on the short side.  Try the Moon first !

And I will add there is no safe way to look at the Sun without proper protection.  Now you may say at certain times there is relatively safe moment but the general rule is, NEVER LOOK DIRECTLY AT THE SUN.

It similar to the "All guns are loaded" safety rule.  Of course, all guns may not be loaded but you must consdier them so to be safe.

[jrhoffman75]

http://www.learn.usa.canon.com/resources/articles/2017/eclipse.shtml

[TCampbell]

I always like to make a few points on safety.  

Here's an article by Dr. Chou at the University of Waterloo, School of Optometry and posted to a page at NASA:

https://eclipse.gsfc.nasa.gov/SEhelp/safety2.html

I'm more concerned about YOUR safety then your camera's safety.  You can always get another camera.  Replacing your own eyes... that's quite another problem.

Make sure YOU have proper safe solar viewing film.  I suggest you do this WELL in advance of the eclipse (e.g. order them today).    

Prior to the Transit of Venus event back in 2012 (not NEARLY as popular as the total solar eclipse) vendors were sold out of solar filters a couple of months prior to the event.  And while they were making filters as fast as their production could manage (lots of overtime hours... I'm sure) they were so backlogged with orders that there was no guarantee you'd get your order in time.

But also... the vendors that were managing to get them in stock were charging "opportunistic pricing" rates.  

Buy them NOW and they're rather cheap.    Solar filters are not particular expensive.  Within a month or two of the August eclipse I imagine they will be (already some places have started raising rates).  They should become more affordable on August 22nd... they AFTER the eclipse is over.

Though you've likely heard that YOU should never stare directly at the Sun, if your camera doesn't have a filter and you look throgh the viewfinder with a telephoto lens attached... you're now MAGNIFYING the sunlight.  Basically you're using the nice large objective of your camera lens (which is always using it's widest aperture when not actively taking a shot) -- a diameter much much larger than your eyeball -- and your concentrating all that light into a small area so it can fit through the pupil of your eye.  So as bad as it is to stare directly at the sun... it's much worse to look through the camera UNLESS that camera has a safe solar filter attached to the lens.

There is sometimes a bit of confusion over whether it is safe to look at a partially eclipsed Sun.  It is absolutely NOT safe.

The confusion is along these lines... if the moon is obscuring, say, 80% of the Sun, then that means we're only getting 20% of the sunlight.  In fact the landscape around you will be noticeably dimmer.  So... it seems like it would be safe, right?  Nope!

What really happens is your pupil is focusing light onto your retina.  As the moon blocks more of the Sun, the area where the sun is hitting your retina is getting smaller... but for any area that is getting hit... is getting hit with just as much sunlight as if the sun weren't eclipsed at all.  In other words you'll destroy fewer cells... but you'll still destroy cells.

This is why safe solar filters are required at all times while any part of the Sun's disk is still visible.  Once the Sun is completely eclipsed by the moon you can remove filters and enjoy a direct view of the Sun's corona.

I'm going to photograph the eclipse in totality, but I'll be using special eclipse software on my computer to control the camera. The software uses my GPS location, accurate date & time (also from GPS) and the eclipse prediction data by Fred Espenak with an extremely accurate profile of the lunar limb to determine the precise second of the start of totality.  This is significant in Eclipse photography because a few seconds before that we get the "diamond ring" effect and a few seconds before that we get the "bailys beads" effect.    The software calculates the optimum time to capture these shots.  

Once totality begins, it requires about 10-12 stops of dynamic range to capture the whole solar corona.  The software also starts taking the massively bracketed exposures necessary to capture the entire dynamic range of the corona.

My camera will be on tracking mounts ... following the sun/moon as the Earth spins.  

This means that I personally will be enjoying the spectacular visual event... while a computer does all the work and I ignore it.  There are only two times when I need to intervene.... about 20 seconds before totality an alarm goes off and the computer announces that it's time to remove the filters.  It does this again about 20 seconds after totality ends.  The entire rest of the time I'm taking it all in visually.

The best experts on the topic of eclipse photography all suggest that if you've never witnessed totality before, you should probably not attempt to photograph the event.  You're likely to miss out on all the fun and amazement.