Re: Solar filter for 400mm digital camera lens?
Chris L Peterson
>Can someone suggest a good solar filter big enough to cover a camera
>lens with a 77mm (~3 inch) front element? (One that they've had
>reasonable success with)?
I'd suggest you buy some Baader film, and make a simple plastic or
cardboard holder for it. Since you're using a standard camera lens, you
could get a lens cap and cut a hole in it. You won't find any filters
that give better optical performance than the Baader film, although you
can easily spend a lot more to get equal or worse results.
_________________________________________________
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com
Howard Lester
>
> I've got a quality 400mm f5/6 lens for my digital camera. It
> takes great shots of the moon and shows lots of sharp crater detail.
>
> With sunspot cycle 24 finally beginning, I'm interested in
> photographing sunspots.
And you can buy Baader solar filter material Chris refers to at
Click on Products (left pane)
Scroll down to Accessories
Under Accessories find Baader Planetarium accessories
They sell only by the sheet. They're large enough to make enough material to
make filters for yourself and all your friends. You can choose between
visual and photographic densities.
An alternative, if it's still available, is a 4" square Kodak Neutral
Density filter, density #5 (I believe).
Anthony Ayiomamitis
> I've got a quality 400mm f5/6 lens for my digital camera. It
> takes great shots of the moon and shows lots of sharp crater detail.
>
> With sunspot cycle 24 finally beginning, I'm interested in
> would be the best bet, but the cost of them is greater than my
> interest in solar photography :-)
>
> I bought a square of #12 welder's shade. It works, but the optics
> are terrible through the thick glass. I can't get a sharp picture
> of the sun through it. (But I can just make out current sunspot 1034).
>
> I've browsed the net for 'solar filters' and see there are several
> available in my budget range ($70- $100).
>
> Can someone suggest a good solar filter big enough to cover a camera
> lens with a 77mm (~3 inch) front element? (One that they've had
> reasonable success with)?
>
The best solution out there is Baader's ND5 filter. It is also
available as ND3.8 but it lets in more light and is strictly for
imaging purposes. In contrast, the ND5 material can be used for both
imaging and observation.
All of my work involving the sun's photosphere is done exclusively
using Baader's filter and which I highly recommend. Here are some
examples thanks to its exceptional quality:
(1) http://www.perseus.gr/Astro-Solar-Sunspots-2005-07-05.htm
(2) http://www.perseus.gr/Astro-Solar-Sunspots-2007-06-03.htm
(3) http://www.perseus.gr/Astro-Eclipses-2005-10-03.htm
(4) http://www.perseus.gr/Astro-Eclipses-2008-08-01d.htm
Anthony.