Flycatcher plus questions on ISO

[Craig Brelsford]

Dark-sided flycatcher photographed last month in Shanghai. My default ISO setting is 200, but I'd been taking some shots at dusk the night before and had left my ISO at 800. None of my images of the flycatcher are noisy at ISO 800. Why? How is it that I can set my ISO to 200 and sometimes (esp. in low light) get more noise than I got here at ISO 800? Note that I use the Nikon D300, not the ISO champion Nikon D3s.

Other specs:

Lens: VR 600mm F/4G
Aperture: F/9
Shutter speed: 1/400s
Exposure mode: aperture priority
Exposure comp.: -0.3EV

[Colin Knight]

Nicely done! I like how the perch enters and exits the frame. Nice pose and eye contact.

The difference in visible noise could be due to the lighting, background texture, shutterspeed, or most likely due to the ISO 800 images being more properly exposed and therefore showing less noise.

[Nancy A Elwood]

Craig I routinely use iso 800 with my D300. It is all about exposing. The shadows are what go noisy at higher iso's. The trick to using the higher values is exposing to the right of the histogram. If you shoot at the time of day that gives you the best light for nature photography, iso 200 would rarely be used. I use aperture priority also, matrix metering, but use the exposure compensation to work the histogram.

[Fabs Forns]

Very nice backlit BG showing off the bird, which could be placed a bit more to the left. Agree on the comments regarding ISo. One more thing I have observed, noise is more present in flat than warm light, your BG is very light and very warm, so chances are you're not to get noise there.
Thanks for sharing, Craig.

[Craig Brelsford]

If you shoot at the time of day that gives you the best light for nature photography, iso 200 would rarely be used. I use aperture priority also, matrix metering, but use the exposure compensation to work the histogram.

Hi Nancy, thanks for the informative response. What you mean (correct me if I'm wrong) is that in the softer light of the early morning and late afternoon I'm going to need higher ISOs. When you say you use exposure compensation to work the histogram, what exactly do you mean?

[Colin Knight]

I don't want to put words in her mouth, but make sure you're filling up the histogram on all three channels to the right, even have some blinkies which can be recovered. Exposing to the right will help minimize noise. This may be what Nancy was referring too.

Also, "golden hour" requires higher ISO just because it's a lower light scenario.

[Craig Brelsford]

I'm having a conceptual problem here. What is noise? I thought noise was the graininess that arises as a result of the degradation of the "film" caused by high ISO. I saw it as a zero-sum game: "Lower ISO, less noise; higher ISO, more noise." I.e., ISO = noise. I thought I could program the level of noise/ISO the way I program the shutter speed, aperture, etc. What piece of the conceptual puzzle am I missing here? (If this forum isn't the appropriate place for this sort of discussion, please let me know.)