Sigma 10mm f2.8 lens - test images

I don't know whether there are Russian developers or not involved. It's open source though and was designed to deliver some of the features that Magic Lantern provides for later models to the 400d. It's not a full firmware hack in the sense that it replaces your existing firmware, rather it loads from the CF card on boot and is accessible via the printer button.

I was looking at fisheye lenses for light pollution measurements. Though the standard equipment used for that is the 8mm Sigma and a full frame camera (most use the 5D). Using SQM's for light pollution readings is fine for the zenith but you need to photograph the sky to build up a real measurement of all sky light pollution.

I've never tried the 70-200 for astrophotography. Mainly just for sports and nature. Mine is the f4 version without image stabilising. I'd love to have been able to afford the 2.8 but the step up in price was far too much. I must try piggybacking it on the scope some night and see how it does.

The magic lantern firmware will allow a custom colour temperature to be used, I've used this on my own 600d to good effect. Useful for setting up timed exposures.

For the custom colour, a point on a grey card is probably better than a white card. If the photos are stored in RAW. then it's fairly easy to get the right colour balance afterwards as it's "baked into" the image instead of the image changed to reflect it.

Here's a possible improved firmware addon for the 400d : code.google.com/p/400plus/ Haven't used it, but it appears to be okay.

Thanks lads.
I will take a look at them.

I took some additional test shots this evening.
|Modified 300d 30secs f2.8
versus
400d 30secs f2.8

Also tried adjusting the aperture:
400d 30secs f2.8
versus
400d 30secs f4.0
Noticeable improvement at f4.0. Don't quite understand why though. Surely I'm gathering more light at f2.8??
Or am I getting too much skyglow from the Moon?

I also found the button to select the temperature. Doh!
It's not contained in the MENU (where I was looking) but in the down arrow button to the right of the LCD screen.
400d 30secs f4.0 Tungsten (Approx 3,200K)
400d 30secs f4.0 White Florescent (Approx 4,000K)
400d 30secs f4.0 Cloudy (Approx 6,000K)
400d 30secs f4.0 Shade (Approx 7,000K)

In terms of exposure time, using a trpod (i.e. no tracking)
30secs
45secs
60secs
Realistically, I think 30secs is the max before trailing is obvious.
I would have expected longer exposures, TBH.

Hi Michael,

seems to be working a treat for you.

When that moon is gone i think you will get some cracking widefield shots.

why is it better at f4? Every lens ( well most ) are sharper stopped down one step. Its to do with the where the focal point lies on the sensor and how much is in focus. In college i would be encouraged not to take shots below f2.8 and above f16. Even on a few grands worth of a lens its never going tom be perfect.