My first post, first HDR and some questions

[Deefstes]

Hi all,

I'm taking a bold step here by making my official first post on Photocamel, yay! Actually, it's my fourth because I had to make three posts before I could post an image. So hello from sunny South Africa. I've had my DSLR for all of two weeks now so I still have lots to learn, not just of HDR but of photography in general.

Anyway, here is a HDR attempt that I shot over the weekend and my first real attempt at making a multi-image HDR. I used five images, keeping the aperture constant (f/5.6) and using five different shutter speeds (1/2, 1/4, 1/10, 1/20, 1/30) plus a tripod of course. All five images slapped into Photomatix and tweaked the settings a wee bit to get this result.


Your comments will be appreciated, and I'm more interested in "what I should've done different" than "why it's a nice picture"

Now I have some questions for the HDR gurus:

1. Getting different exposures. The way I see it there are four different ways to obtain different exposures.
   
   a. Keep everything constant but vary the aperture. I can understand why this is stupid as your depth of vield would differ from one exposure to the next.
   b. Vary the shutter speed (as I did with the image above). I'm using it because it's the only one that makes sense to me.
   c. Use auto bracketing. I'm not sure I really understand what auto bracketing does. Does it bracket your shutter speed, aperture, ISO setting or combination of shutter/aperture?
   d. Keep the shutter speed and aperture constant but vary the ISO setting. I've never tried this but my gut feel tells me it's a dumb idea.
   
   So the question, which method produces better results? Are there any other ways that I'm not aware of?
2. Number of exposures. How often would five exposures really be necessary? Of course this all depends on the dynamic range of the scene but realistically how often do you encounter a scene of which the dynamic range is bigger than what three shots at -2EV, 0, +2EV could capture? Am I correct in saying that, if you're using three shots, the following should be true in order to get a satisfactory HDR:
   
   a. The darkest parts of the scene should be sufficiently exposed in your underexposed shot.
   b. The brightest parts of the underexposed shot should overlap with the darkest parts of the normally exposed shot.
   c. The darkest parts of the overexposed shot should overlap with the brightest parts of the normally exposed shot.
   d. The brightest part of the scene should be sufficiently exposed in your overexposed shot.
   
   If a and d can be satisfied but not b and c, only then do you need more than 3 exposures. Or have I got it all wrong?
3. Photomatix or Photoshop? How often do you obtain satisfactory results using something like Photomatix and how often do you feel that you really need to exercise more control over the blending and do it yourself in Photoshop?
4. Other PP. Have you established a certain sequence of Post Processing that HDR images typicaly require? By looking at the most excellent shots that are often published in this forum, I get the impression that saturation is often pushed a little higher than normal (or is the world just that more colourful in your neck of the woods?)

Hope I didn't bore you to tears with all that but I'd love to learn a little more about HDR and how to get better results.

[Epphoto]

welcome here my friend
I have only 2 things here i don't like
1st is your main subject looks to me out of focus. I don't know if you F stop is to sallow, or is because of a slow shutter speed
2 ND i see the clouds have a very nice red color saturation, and your eye goes there nicely
But after you start browsing the rest of the picture you find out very quick the colors/contrast and clarity they don't much with the rest of the picture
Get some life in the picture , let us see a litle more detail ,color, and brightness
Thanks emmanuel

[prometeus]

all things the poster above me said.
plus I always use bracketing I have my bracketing set up that it does exposure bracketing. (I can shoose white balance and aperture but I see no need for that in hdr's)

[Serrator]

Very good questions.

I don't have much time but the short of it is that I always use AEB. So depending on your camera, I have Canon XT, so I have a 3 shot AEB system that can range up to 2 step offsets (-2ev 0ev +2ev). I usually go with this for most daytime scenes that do not include the sun. Anyway here is a real detailed and informative link on HDR:
Bracketing & Number of Images « Before the Coffee

Have fun.

[jfrancho]

1. use your A method in manual mode. One other way is to use exposure comensation in Av mode. Also, you can use auto bracketing in Av mode. Since you are using a tripod and either remote shutter or delay shutter, there is no reason not to be in the lowest ISO available.

2. Spot or Partial Meter the brightest and darkest areas of the scene, noting the shutter speed in each. Those will be your bookend exposures. Fill the gap with exposures one to two stops apart. Make sure your intervals are consistent. Alternatively, you can auto bracketing. I use -2, 0, +2 for my AEB settings. If you can do more with your camera, go for the max.

3&4. Photomatix or Dynamic Photo HDR are two excellent tools. Its worth noting that I generally shoot raw and my work flow is Photoshop ACR to make a 16 bit tiff > Photomatix to make a 32 bit HDR and then tone map to a 16 bit tiff > back to Photoshop for final processing, which can include NR, sharpening, B&D, cloning, color adjustments, contrast, etc.

[Deefstes]

Thanks for the responses and especially your comments Emmanuel. I think I understand what you're saying but I'm not sure I now how to do it. That will come with time and more knowledge of photography, I'm sure. I think my DoF was probably a bit shallow (f/5.6).

I've tried tonemapping the image again and got different results. The first one here I also processed a bit afterwards to give mre saturation to the foreground and sharpen the main subject a little. I'm not sure it's really all that much better but it seem to give the picture a little bit more impact.


And another one where I tried something else, tonemapping the image twice. I'm not sure I really like this but I can imagine that for other scenes this might be a useful approach.


Serrator, thanks a lot for the link, that's exactly the type of info I'd been looking for. Have yourself some karma.

As for the issue of AE bracketing, I seem to have found the answer to that. AE Bracketing varies the shutter speed (if you're shooting Av) or the aperture (if you're shooting Tv). So it would seem that the way to go would be to shoot Av and use bracketing of +-2EV (I have a Canon EOS 350D).

Again, thanks for all the help everyone.

*Edit*
Hey, I was typing my message when jfrancho replied with another very good response. Thanks for that, some karma flowing your way too. Just a quick question, what is B&D?

[Jason Hermann]

I'm a little pressed for time right now, so I just wanted to say welcome to the Camel and very nice first post!! I'll read through and give my take on your questions as soon as I get a chance

Best,
Jay

[Epphoto]

If you can sent me a litle bigger picture I can work on it and sent it to you back
This way you can see what I'm talking about
Email: ep.photo@comcast.net
Thanks E.P

[ceg]

I like the 1st image of your second post the best.

I have been shooting the way you have done it.....tripod, constant aperture (although I have used f8 or f11 instead of f5.6), I vary the shutter speeds exposing for 4 to 5 shots, 2 second timer, run it through Photomatix and tweak it in Lightroom or CS3 as needed. ***Disclaimer - I am a complete novice at this and am eager to read everyones' responses to your questions as well. I just thought I would share what I have been doing so far, with OK results.