Taking photos of the sun

<p>What sort of filters are needed to take sunspot photos, transit of venus, etc? I have a Canon 100-400, and can get great shots of the moon with it, but when I try to find sun filters, everything seems to be telescope oriented. Does anyone make sun filters for camera lenses?</p>

<p>Very dense ND I suggest. Probably ND of about 5, may be even more. Not something you pick up everyday, try Google. This link might be helpful to calculate the exposure http://www.kodak.com/global/en/consumer/products/techInfo/p150/p150b.shtml . I see that Amazon sell ND filters<br>

http://www.amazon.co.uk/ND2-ND4-ND8-Neutral-Density/dp/B004EVX63Y/ref=sr_1_1?s=electronics&ie=UTF8&qid=1314634483&sr=1-1</p>

<p>Check out Bob Atkins' article here<a href="../learn/nature/sunmoon"> http://www.photo.net/learn/nature/sunmoon</a>. In it he provides advise as well as references to external sites that should help you out.</p>

<p>The main issue for using high ND filters is to minimise damage to the sensor (if using live view), the shutter if shooting with the mirror up or your eye if using the viewfinder.</p>

<p>You can try a Hoya ND 400x</p>

<p><a href="http://www.hoyafilter.com/products/hoya/oef-07.html">http://www.hoyafilter.com/products/hoya/oef-07.html</a></p>

<p>Note that a filter for photography isn't the same as a filter for visual solar observation. Visual filters have to be denser and need to efficiently filter UV and IR as well as visible light.</p>

<p> </p>

<p>Is there a guideline for identifying the need for protecting the sensor, and does this effect the image quality too?<br>

This shot at 1/8000s f/11 ISO-100 would probably be a good candidate for a 6stop or more ND filter. I think it was shot bare since with a filter there is flare [October, Arizona]<br>

<img src="http://www.robertbody.com/cities08/images/2008-10-05-tempe-plane-32358.jpg" alt="" /></p>

<p>This shot [August, Arizona] was at 1/8000 f/11 as well ISO-100, 600mm + 1.4x<br>

<img src="http://www.robertbody.com/arizona10/images/2010-08-13-powell-sunrise-22498.jpg" alt="" /></p>

<p>I haven't used it for shooting the sun but there's a B+W ND 3.0 says "N Density 1000X," which can be used to produce 30 second exposures in daylight. I should think one of those and 1/8000 and f? would give you something.<br>

I don't know how you would focus though, in daylight photography, you have to focus in manual and then attach the filter. I'm not convinced I would like to look at the sun through a 400 mm lens, even through the filter.</p>

<p>Most photo filters (including the Hoya 400x) won't be dense enough for shots of the sun unless it's fairly near the horizon. During the day you really need to use a solar filter designed for solar astronomy use.</p>

<p>Google "BAADER AstroSolar". It's a thin film product designed for either visual or photographic solar observation. It's a thin plastic film with a metal coating and you'd need to make some sort of mount for photo use. Works well though.</p>

<p>Below is a shot taken through the Baader visual filter (suitably colorized!). The limb darkening is real. Three sunspots are visible, two in the center ond one way over on the left. 300mm lens.</p><div></div>

<p><a href="http://www.thousandoaksoptical.com/solar.html">Thousand Oaks Optical</a> offers glass solar filters designed specifically for this. The filters have an optical density of 5 (equivalent to 16 stops). You can look though them all day without damaging your eyes <em>or</em> your lens/camera. The same cannot be said for ND filters that do <em>NOT</em> block all harmful light spectrums. I would not trust my eyes or my photo equipment with anything not specifically designed for this.<br /><br />As an added benefit, they're fairly inexpensive at around $70 (up to 101 mm). </p>