Quote:
Originally Posted by Ric
Hi Shane and thanks for the explanation.
As a scenario,
if I was imaging for 30 seconds @ f/10 and at a setting of say ISO 600. If I then changed to f/3.3 via a focal reducer I could then take the same 30 second image with a higher ISO speed say ISO 800 for example.
Does that sound right or have I gone off on a tangent.
Cheers
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If you use a focal reducer then I would say you could then go down to say 400 or 200 with the iso. Because you have reduced the focal length your iso setting can go down. I believe Dennis has summed it up very well.
The higher focal length allows less light into the camera so if you used say 100 iso with a f/10 you would need a long exposure. with the f/3.3 if you used 100 iso you would need less exposure then the f/10.
Its hard to get a handle around it until you practice. I read up on it got text books and looked at various sites on the net and then practiced and i got it.