Imaging in monochrome

[Peter Reader]

Hi all!

I plan on capturing M51 tonight. However I am limited to around 40s exposures. Would imaging in black and white give more detail?

Thanks

Pete

[jgs001]

I don't think it will Pete... not with the D80 at least... you just need to capture loads of subs... aim for at least 150 (about 100 minutes) and the highest ISO you can manage, in fact, even more subs might be a better bet...

[Peter Reader]

OK thanks for the reply. How do I decide what my highest ISO should be?

[jgs001]

I've heard, but don't know, that nikon apply a blur of some sort on the nef file at high iso, that maundering the maximum. If that doesn't happen push it all the way to the top.

[Peter Reader]

So all the way to 3200? If it's too high what will I see? Just more noise?

[jgs001]

Tricky, loads of subs will help with the noise. You could try 1600 and see if the faint stars disappear. If so then drop to 800 if not then use 1600 or if 3200 isn't too bad that.

[Peter Reader]

How come the faint stars will disappear? I thought that ISO was a measure of how sensitive the camera chip was... can you clear this up for me as I'm obviously getting this wrong :S

Thanks for the help so far

[jgs001]

I can't state this for certain, I've never used a Nikon. I've read that Nikon applies a median blur to high iso images to remove some of the noise. Unfortunately, that'll also take care of the faint stars, as they are very small in the image. This blur, I've read, is applied to the image, prior to saving in the nef (nikon raw) format.

[Peter Reader]

Ahh ok. That's annoying... I suppose there's no way of preventing that either...

Will give it a go

Thanks for the advice!

[pook]

You can turn it off on mine. High ISO Noise Reduction. Just turn it off.

[Peter Reader]

Found it. Sweet cheers. Will try again if weather persists...

[jgs001]

Ah good... I knew of that option on the Canon, but everything I'd seen, it was fixed on, with the Nikon... good news.