Contrary to the myth of getting hot spots with slow shutter speed.
Here's an extract of Deadpixel's post on the explanation why hot spots occur in some pictures.
Thanks to Deadpixel for the writeup and links.
I've found that the exposure speed isn't the biggest issue in the creation of hotspots. The quality/shape of the aperture, makeup of the glass and the overall lens design seem to play a bigger part. You're going to find that a slow, $50 lens you get from eBay is likely to out perform a fast, $2,000, state-of-the-art, super-whatever-coated lens with every suffix from A-Z tagged to it.
One thing for sure, the smaller your aperture used for your photo, the more likely you are to encounter a hotspot and the larger the hotspot will be; this is a phenomenon consistent with diffraction through a circular aperture.
Here are some more (simplified) explanations about diffraction:
Look at the diagrams (actually photos) of the diffraction pattern at these 2 sites, do they look familiar?
Pattern 1
Pattern 2
This site has an interesting Java model that shows how the spot gets bigger as your aperture gets smaller
Java Model
And some explanations from everyone's favorite online encyclopedia
Diffraction
Airy Disc
Here's an extract of Deadpixel's post on the explanation why hot spots occur in some pictures.
Thanks to Deadpixel for the writeup and links.
I've found that the exposure speed isn't the biggest issue in the creation of hotspots. The quality/shape of the aperture, makeup of the glass and the overall lens design seem to play a bigger part. You're going to find that a slow, $50 lens you get from eBay is likely to out perform a fast, $2,000, state-of-the-art, super-whatever-coated lens with every suffix from A-Z tagged to it.
One thing for sure, the smaller your aperture used for your photo, the more likely you are to encounter a hotspot and the larger the hotspot will be; this is a phenomenon consistent with diffraction through a circular aperture.
Here are some more (simplified) explanations about diffraction:
Look at the diagrams (actually photos) of the diffraction pattern at these 2 sites, do they look familiar?
Pattern 1
Pattern 2
This site has an interesting Java model that shows how the spot gets bigger as your aperture gets smaller
Java Model
And some explanations from everyone's favorite online encyclopedia
Diffraction
Airy Disc
