gunflint wrote:
Last week I posted this question and got good feedback: "For my daytime exposures I have been attempting to always expose to the right and watching the histogram as to not clip any whites or blacks. It does seem to help with the dynamic range.
My question is (and I will do some tests myself) does this "rule" apply for night photography such as city lights after dark? Any tips from those with experience at this is appreciated!"
Then I was in the Tetons and tried this for scenery with stars and I am attaching 4 photos (RAW unedited) taken 30-40 minutes before sunrise. I realize they are not the same settings but the histogram is the issue. The darkest one was exposed with the histogram going only half way to the right (in the center), then a little more, and a little more, with the 4th one almost to the right. With the darkest one you can make out some stars but they are gone as it is exposed more to the right. So in this case with stars, I don't see how it is possible to expose the image any where near to the right and still see the stars.
Any feedback? Thank you
Last week I posted this question and got good feed... (
show quote)
ETTR buys less noisy shadows at the price of possibly blown highlights. In the sample photos
the OP posted, the hightlights are snow fields, which has almost no detail anyway. This is almost
certain to make ETTR look good.
ETTR is a work-around for noisy digital sensors. Night photography involves long exposures
and/or cranking up the ISO. Either way, you get more noise than normal. So on the face of it,
a bit of overexposure is a good idea for night photography.
In long exposures, digital sensors don't have reciprocity failure like film does, but they accumulate
chroma noise. Also turning up the ISO always increases noise. Over-exposure can help improve the
image-to-noise ratio in shadows, which helps to justify risking a few blown highlights.
The real solution would be to have less noisy sensors. This is achieved in astronomical applications
by supercooling the sensor. That's not practical for everyday photography, but there has been some
improvement, with newer sensors being -- on the whole -- less noisy than old ones. If this trend continues,
we should less and less about ETTR for well lit situations.
Any "rule" for exposure that doesn't take the photographer's intentions (for how he wants the subject to
look) into account is just another form of automatic exposure. It will look how it looks, you may like it,
you may not.
I don't like colored speckles, so I use film and long exposures for night photography (and have to deal with
reciprocity failure). For a given brand/type/speed film, the manufacturer usually provides a curve of that
film's reciprocity failure. This graph can be used to estimate normal exposure. If a mathematical function
is fitted to the curve, then you can even have an exposure calculator for that film. If done correctly, the
resulting negative is no better or worse than one made in normal light.
Photography is about the final image. Camera's can't read minds, so the photographer has to play a role.
Only he knows what the objects in the scene are and how they generally look in real life. Only he knows
the image he is trying to create.
Rules can be helpful, but there are always multiple considerations. The "shoot lots and cull" approach
often amounts to picking the best of a bad lot.
So the answer is yes, ETTR is a helpful rule in digital night photography, but it's no substitute for visualization--
and choosing the exposure that produces the image
you want. It's just another consideration: when
shooting with a noisy sensor, over-expose a bit.