long shutter speed night shot help needed 14-06-2010

[JC_PHOTOGRAPHY]

1 night time shot tripod with shutter release used can anyone please tell me what these purple blotches are

heres specs

camera-canon 1000d
mode-manual
exp time 62
fstop 22
metering mode cntr weight avrg
50mm lens
iso 100

all thanks appreciated

[Analog6]

They may be lights that are very faint to your eye but the sensor has picked them up, or they might be reflections. Is the front element of your lens clean? Was it a cool night, could there have been any moisture droplets forming on the lens?

[campo]

i suspect the purple blotches are a kind of "lens flare".

[Astroman]

Look like internal lens reflections, pretty common...

[DAdeGroot]

Definitely look like flare to me. Did you, perchance, have an UV filter on the lens ?

[OzzieTraveller]

G'day JC

What you are seeing are Lens Refractions ... an extremely common feature within every lens on the planet, where that lens is 'seeing' very bright points of light at various locations (across the viewfinder)

If you read the/your lens specs it will say something like "24-105mm zoom lens consisting of 18 elements in 13 groups"

ie: you have several bits of glass that are glued in 2s or 3s, and you have 13 'chunks' that may be a single bit of glass, or 2-3 bits of glass glued into one. Whatever it is, you have 13 x 2sides = 26 very highly polished glass surfaces to reflect light in & around the lens ... as well as permitting 99.99% of the light to go straight thru and onto the sensor/film

The very bright spot is bounced around inside the camera lens - and it eventually reaches the sensor. The colour of the 'blob' mostly comes from the colour of the anti-reflective coating !!! on whichever bit of glass is doing the reflecting

In nearly all cases of this I have seen over the years, the blob is exactly as you have created ... where the purple blob is close to the originating light, and goes off diagonally - often outwards towards the edge

Hope this helps a bit
Regards, Phil