Interesting Article on ISO - Astrophotography

[TheBigE]

I do not usually share articles, maybe because most are not all that great - but I found this one to be pretty interesting and good discussion of ISO

I would be interested in the thoughts of others on this article...it certainly allowed me to look at the topic in a bit different manner.

[Polar01]

Interesting article, have read "Lonely Speck" for some info on astrophotography, somewhat similar to Bob DiNatale's "The Optimum Digital Exposure" work to get not the correct exposure but the optimum exposure for the scene then in post you adjust for the exposure. Both are similar as you are trying to get the most data to create the image, well that is how I see it.

Cheers: Allan

[rpcrowe]

Thanks for posting Erik... Although, I have no interest in astrophotography, my neighbor is quite interested in it. I sold him my Canon 7D after I purchased a 7D2. It was a good deal for him because, in addition to getting the camera at a good price, he also gets a steady source of photo information from me. I have to read this article because his photo knowledge is about on the par with my knowledge of astronomy; which is - there is a sun and a moon up there somewhere

[dem]

I don't know... The facts are correct but many conclusions are wrong. The author really tries to make a sensation out of it but falls on his face at the first set of test images. He lifts the shadows up in images that received different amount of light and then compares them to images that received the same amount of light with their brightness brought down. This was supposed to prove that both aperture and shutter speed increase noise but ISO does not.

If you can reduce shutter speed to say a minute, you will always be better off shooting at low ISO. So the author introduces the first hurdle, say you are limited to 8 sec exposure. You are obviously going to use all 8 sec to maximise the amount of light captured. Do you shoot at ISO 100 and then push the image 5 stops in post processing or do you simply record it at ISO 3200? It turns out that it does not really matter if you are shooting modern Sony or Fuji (recent Nikons are also quite ISO-invariant). But if you have got a camera with an oldish sensor, in this case Canon 700D, you will be silly trying to push it 5 stops in post. So, here is the second hurdle, your camera is "ISO-variant" and it does not like being pushed too much (due to a high downstream electronic noise at the analogue to digital converter, but this is not that important).

That's the gist of the article.

[xpatUSA]

thanks for posting!

Regrettably, my eyes glazed over as soon as the "triangle of exposure" got mentioned. Doesn't apply to my ISO-less cameras at all.

It got worse when the link to ISO 12232:2006 went to the ISO site, where you pay big bucks to actually read The Standard.

No doubt the article will help some folks here - but not me, sorry.

[chauncey]

Like I've mentioned in the past, my Canon has a live view function that incorporates an exposed
histogram. Which, IMHO, is the greatest thing since sliced bread.