Sunsets


johnboy-22

Link Posted 20/04/2012 - 20:55
I have just run out of the house and taken about 150 pictures of the Sunset with my K5 in the rain. They were all taken at ISO80 f8 and various speeds. 5 brackets each picture.

on my return I had a thought that it might have been better to have highlight and shadow correction on.

Would this have given me a better dynamic range.
Pentax K5, Kx, DA15 ltd,18-135, 18-55, 50-200, M100 f4 macro, M135 f3.5 A28 F2.5

JAK

Link Posted 20/04/2012 - 20:58
If they were jpeg's then possibly (depends if you want to retain detail in the shadows and highlights or not.) If they were RAW, then no.

Edit: Just noticed you bracketed - you can experiment with HDR then!

John
John K
Last Edited by JAK on 20/04/2012 - 20:59

davidstorm

Link Posted 20/04/2012 - 22:08
There's usually no need for any compensation when shooting with a K-5 in RAW as the sensor is capable of recording a very wide dynamic range. During post-processing you can recover a massive amount of shadow detail. The main objective is not to 'burn out' any highlights as these are not recoverable.

Regards
David
Flickr

Nicola's Apartments, Kassiopi, Corfu

Some cameras, some lenses, some bits 'n' bobs

WaypointCharlie

Link Posted 26/04/2012 - 08:15
Skies, and in particular low sun situations, have a large dynamic range and you'll have to perform some post processing if you want to get detail in the sky as well as light in the shadows. With highlight and shadow correction on you're still not going to cover the range with an 'out of the tin' JPEG, as they are quite subtle adjustments. (JAK, my understanding is the dynamic range functions are applied to RAW as well as JPEG)

If you took 150 pictures at various speeds and bracketed you should have plenty of material to get something decent, as long as you shot RAW. As davidstorm says, shoot to expose the highlights correctly. You should then normally have enough information in the 14-bit sensor data to be able to lift the shadows as far as you need, without seeing too much noise.

As it happens, I'm just experimenting with skies and shot a sunset the other evening. It's nothing special but gives you the idea. I suspect your in-camera JPEGs look something like this:

http://www.flickr.com/photos/waypointcharlie/6968885486/in/photostream/lightbox/

Post processing from a single RAW file you can lift the shadows like this:

http://www.flickr.com/photos/waypointcharlie/7105942159/in/photostream/lightbox/

Or you can HDR like this:

http://www.flickr.com/photos/waypointcharlie/6959874622/in/photostream/lightbox/

Personally I don't like the HDR, although I'm not experienced at the technique and I've since found that auto bracketing in M mode varied the aperture considerably, which may not have helped. In fact, you'd be forgiven for thinking that the in-camera JPEG with the dark shadows is the best of the bunch!
Last Edited by WaypointCharlie on 26/04/2012 - 08:32

JAK

Link Posted 26/04/2012 - 13:31
Quote:
... my understanding is the dynamic range functions are applied to RAW as well as JPEG ...

Not really. The camera takes the image as a RAW file and then processes it to a jpeg according to the settings. You can even reprocess the RAW file a second time within the camera with different settings, even if RAW wasn't selected! You can try this by pressing the down button after taking just a jpeg and you have the option to develop its RAW file providing the RAW image is still current in its memory.

The RAW file is just the digital equivalent of an image taken on slide or negative based purely on shutter speed, aperture and ISO - just like a film camera. It isn't processed at all. Most software packages, however, use the camera settings for reconstituting the image for further processing (or development.)

Most DSLRs take a 12 bit image. Newer ones including the K-5 take a 14 bit image. By combining images in suitable HDR software that can be extended further up to 48 bits.

There's no reason for HDR shots to look over the top. Without HDR my original jpeg file for the recent Buildings comp looked like this:




The 5 exposure HDR makes a world of difference:




John
John K

WaypointCharlie

Link Posted 26/04/2012 - 13:55
Whilst I agree that most of the image processing functions (eg white balance, sharpness, distortion) are applied to the JPEG file only, I think that highlight correction and probably shadow correction are applied at sensor level and thus affect the RAW file output too. The fact that enabling highlight correction increases the minumum ISO to 160 suggests it's more than just JPEG processing.

I photographed a silver car on a bright day with highlight correction on and off. The RAW outputs seemed to confirm that highlight correction did get applied, but I appreciate that sort of test is crude and not scientific. Ah, I notice that dpreview think the dynamic range corrections are also applied at RAW level. I'm not saying they're right, just more likley to be right than me!

http://www.dpreview.com/reviews/pentaxk5/14
http://www.dpreview.com/reviews/pentaxk5/16

I can see that HDR has its place but I think it takes skill and an artistic eye to achieve a result that can pass as realistic, although realism is often not the intent. I'm always being told to darken my skies but when skies become a lot darker than the ground my brain says something looks wrong.
Last Edited by WaypointCharlie on 26/04/2012 - 14:08

JAK

Link Posted 26/04/2012 - 14:46
All I can say is the camera manual states on page 202

Quote:
RAW format is a CMOS sensor output format saved without
processing.

If Pentax don't tell us the whole story ...........

John
John K
Last Edited by JAK on 26/04/2012 - 14:46

johnriley

Link Posted 26/04/2012 - 15:01
Probably splitting hairs, but the truly raw output from the sensor has to be processed somewhat to decipher the information and present it as a demosaiced colour image. There is, so to speak, a bare minimum that has to be done regardless.

However, there is no application of colour temperatures, styles, etc. and the save is lossless.
Best regards, John

WaypointCharlie

Link Posted 26/04/2012 - 15:28
Quote:
RAW format is a CMOS sensor output format saved without
processing.

That may be correct. Perhaps dynamic range correction is applied at the sensor level, prior to the data being read? Please don't ask me how, that's way beyond my brain grade.

If you've got time to waste test it for yourself. I reckon it does affect the RAW data.
Last Edited by WaypointCharlie on 26/04/2012 - 15:31

JAK

Link Posted 26/04/2012 - 17:21
Perhaps the kind lady from Pentax could tell us?

John
John K

johnboy-22

Link Posted 26/04/2012 - 19:36
I hope this works.

This was on of my pictures.
link
Pentax K5, Kx, DA15 ltd,18-135, 18-55, 50-200, M100 f4 macro, M135 f3.5 A28 F2.5

JAK

Link Posted 26/04/2012 - 21:33
Yes it's worked John! Picasa may even give you an http link to enable you to show the image in the thread rather than having us go to the Picasa site to it. If they do, just highlight the link as you add it to your comment and click the image button below the 'Add a Comment' box.

Anyhow, that's a really nice twilight photo. That one certainly doesn't need any extra detail in the dark foreground. The picture is of that interesting dark red sky so detail in the foreground might even detract. There's nothing wrong with silhouettes!

As to whether highlight and shadow correction were turned on would make any difference, personally I doubt it would have made much of a difference either way. That function is mainly useful on sunny days (remember them?!) to help keep detail in the shadows and to stop highlights being burnt out. You don't need detail in the shadows here and the sky certainly isn't burnt out!

John
John K
Last Edited by JAK on 26/04/2012 - 21:35

johnboy-22

Link Posted 27/04/2012 - 18:46



Hope this works then. I am just about to go and see if I can get a sunset over the canon.
Pentax K5, Kx, DA15 ltd,18-135, 18-55, 50-200, M100 f4 macro, M135 f3.5 A28 F2.5

johnboy-22

Link Posted 27/04/2012 - 18:54
unable to post picture but I may be an hour early as I posted last night.

link

Smeggypants

Link Posted 27/04/2012 - 20:47
JAK wrote:
Perhaps the kind lady from Pentax could tell us?

John

LOL
[i]Bodies: 1x K-5IIs, 2x K-5, Sony TX-5, Nokia 808
Lenses: Pentax DA 10-17mm ED(IF) Fish Eye, Pentax DA 14mm f/2.8, Sigma 17-70mm f/2.8, Pentax-A 28mm f/2.8, Sigma 30mm F1.4 EX DC, Pentax-A 50mm f/1.2, Pentax-A 50mm f/1.4, Pentax-FA 50mm f/1.4, Pentax-A 50mm f/1.7, Pentax DA* 50-135mm f/2.8, Sigma 135-400mm APO DG, and more ..
Flash: AF-540FGZ, Vivitar 283
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