Originally Posted by
Nicola
Hi Frank,
thanks for the feedback. I try to clarify.
My goal was just to capture a night view and understand how the gear respond in this situation. During the night, long exposure are closer to a need than to a tool, as far as I can imagine, and there were (and partially still are) some concerns on what are the milestones of this branch of photography. For instance:
1- I was not sure on how many stops there were from the sky light to the artificial light of the building. The DR can record it in one shot? what about reflection on water?
2- I have got some street lights on my left, could they produce some flares in the lens? With the sun, usually the light coming from the front is much more brighter
3- Is my tripod sturdy enough to keep my camera for some minutes without micro-motion?
4- How long may I expose to get decent star trails?
after post processing I must also add:
5- Why all those hot pixels at low ISO setting (160)?
So, this was a test shot, and I can write the following questions for you:
Do you guys usually get long exposure pictures framing direct artificial light? or do you avoid artificial light surces? or it doesn't matter?
HDR technique is more frequent in night shots than during daytime?
How do you manage hot pixels?
Thanks a lot
Nicola
Book learning is great but really making the best choices comes down to testing (as you are doing) and practice.
Any time that a wide dynamic exposure range is involved, and that is almost every night shot, I always exposure bracket, usually 5 shots wide. For night photography with city lights, I tend to shoot around F11, 20 sec, and ISO 100 on a tripod. For scenes like this I use the camera's metering system and apply some experience if I need to compensate, and use that for my 0EV image. You'll need to capture more light than a city night scene so without the lights on the left, your normal exposure settings are probably good.
So to answer your first question, I don't avoid artificial light sources but rather I use bracketing and image merging to expose those bright areas appropriately. For me, this is one of those areas where you just can't get it right for all parts of the with a single image SOOC.
That's a starting point so now it turns to exactly what is my goal for this image? I usually want the scene to look like it was when I was viewing it, which means for me, being able to see all of the detail without blown highlights, loss of detail in the shadows, and plastic looking water. You may have different goals.
I'm not fond of mushy looking water though some folks love it. I would blend in the water from an image with a faster shutter speed and wider aperture for just the water.
For the blown out lighting areas, I would blend in an image with much lower exposure so that the detail in the bright spots are retained.
Often, I will process using HDR techniques but won't use the result unless I can see a clear benefit to the image. Blending multiple images using layers and masking can avoid much the noise that intensive processing, like tonemapping, can introduce.
I also commonly will use layer opacity to selectively blend the best of the HDR result with as much SOOC pixels as I can to retain clarity.
I've never really noticed hot pixels in any of my images but as I check every image noise and selectively manage it before doing any sharpening I may be addressing hot pixels without realizing it. I would try shooting multiple dark panels to see if they really are hot pixels and not noise. If the hot pixel appears in the exact same location in every image, then you should be able to confirm your suspicions. If you apply noise reduction in dull flat areas it should address the issue. If the area has high frequency sharpness, I doubt you'll be able to see the hot pixels even if they are sharpened.