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Old 25-06-2010, 10:54 PM
luigi
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luigi is offline
 
Join Date: Jun 2010
Posts: 438
At last a thread where I can talk about something I know!

You got very good recommendations already.

I'd add the Carl Zeiss Jena Flektogon 20mm F2.8 in M42 mount with an M42 to EOS adapter. That is cheap and quite good.

I wouldn't discard the fisheye, if you use DxO optics to develop the RAWs you can correct the fisheye distortion almost completely for excellent results.

Finally be careful with ISO, it is not true that higher ISOs produce more noise it's the opposite. The reason why high ISO images seem to have more noise is because of the shorter exposure times and not because of the ISO itself.

F4 30'' at ISO100 has more noise than F4 30'' at ISO200. Believe me.

Usually the signal is

S = [(So +/- Npre) * IsoGain ] +/- Npost

Where
So = Signal (photons)
Npre = Noise before ISO amplification (photon fluctuations + read noise + thermal noise)
Npost = Noise after ISO amplification (A/D conversion + rounding)

While Npre is multiplied by ISO gain Npost is not and that's the reason why as you use a higher ISO you get a better Signal to Noise Ratio.

Hope to have contributed something

Luis
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