Telescope Solar Filters to fit Canon Lenses

Question

I am planning on photographing an upcoming partial solar eclipse here in Singapore but I'm having trouble finding solar filters for the lenses I will be using.

I have a Canon EF 500mm f4/L IS II USM and an Canon EF 70-200mm f/2.8L IS II USM.

The 500mm takes a 52mm rear mounted ("drop in") filter and the 70-200mm takes a 77mm front mount filter. To photograph the eclipse I am looking for ND 5.0 (16 f-stop drop!) filters.

I have found Thousand Oaks sells these but cannot find a way to purchase them in Singapore or ship them in time from the eclipse at a reasonable rate.

Additionally I am concerned, based on what I read about using a rear filter on the longer lens for solar photography.

I have find the Thousand Oaks telescope solar filters - but I need to figure out which size - if any - will fit these lenses as they are friction mounts. Does anyone have experience with such a setup?

Answer 1

Do Not Use Rear Mounted Filters For Solar Protection! Especially since the EF 500mm f/4 L IS II has fluorite lens elements that would likely crack from the heat if pointed at the sun when high in the sky for more than a few moments. Yikes!

You can either use a telescope solar filter large enough to cover the front of your lens(es) or, as scottbb has suggested, make one from a sheet of Baader filter.

Don't worry about the friction mount, you don't need to use it. Just make sure the filter is large enough to fit over the front of the lens or, even better, the front of the hood. There's a reason why you should always have gaffer's tape in your camera bag. Gaffer's tape will come off easily and leave very little residue when removed. The residue can also be cleaned easily. Cleaning the outer side of the hood will probably be a lot less stressful than cleaning the actual lens body.

Answer 2

This response is too late for your time frame, but it may be of use to a future searcher. I've found that #14 welder's glass works well in a pinch, and it's more likely to be available locally. I attached it to the lens hood of my Canon 70-200mm lens by reversing the hood (mounting it in its storage position) and wrapping sturdy rubber bands around the lens's petals. I used two bands on each side because the glass is relatively heavy, and I wanted a backup in case one of the rubber bands broke. (See photo.) The glass turns everything green, but that's not a problem with Photoshop or Lightroom.

Answer 3

If you are simply looking for light reduction (that is, you are not looking to filter for H-α wavelengths, for example), you can create your own slide-on front mount solar filter cheaply, using Baader filter sheet. It is inexpensive, lightweight, easy to work with, and most importantly, it is safe to use for viewing the sun.

Regarding rear filter mounts for solar viewing: you are right to be concerned. That is, don't. The high magnification of unfiltered sunlight in the longer lenses will cause all sorts of internal heat problems (separation of bonded lens elements; cracked elements from heat stresses; etc.).

Answer 4

For photographing the sun, I found solar filters for the print of the camera on Ebay. I think I bought the 4" x 4", then found an adaptor for placing it in front of the lens. I shot using a Tamron 500mm F8 lens.

October 2014 Partial Eclipse:
https://www.flickr.com/photos/cngodles/15612161605

That's the cheap way to go. Some will argue that the coloring on this example is off, etc.