Help with High Dynamic Range (HDR) for Sony alpha?

[JerryV]

I just got a Sony alpha 33 DSLR. I had been using 3 separate “step-ups” of Canon point & shoot cameras over the past 9 years. I had gotten tired of carrying around a film SLR with much equipment and loved the idea of switching to a camera that I could slip into my pocket. But I am shortly going on a trip and decided to go back to SLR (but digital). A major reason I liked this was the ability to take High Dynamic Range (HDR) images to be tweaked with additional software (I will try “HDR Express” for this).

Neither the manual nor David Busch’s “Sony alpha DSLR” were helpful with this. There are 2 distinct modes:

1. D-Range button on top, just behind on/off switch
Choices are off vs D-Range optimizer vs. Auto HDR (which I think I want)
This allow 1-6 EV levels with 6 being the greatest difference between exposures
The camera takes 3 exposures; at playback there are 2 images but neither one is marked. Image 1 (with Display button pressed) says D-R off, while Image 2 states HDR and the correct EV number (so I guess that this is the composite one; it is also the most evenly exposed. This dedicated D-Range button seems not to be available on all 33s, as I note from description in Busch’s book.

2. A separate “Bracketing control button” on the “Drive” choice within the “control” button on the rear, right of the camera. This gives 3 separate images at different exposures (with choices of bracketing images (with choice of exposure differences between either 0.3 or 0.7 EV steps). It yields 3 nicely bracketed exposures at normal, overexposed and underexposed. Are these what I want to start my HDR tweaking to a single image with wide dynamic range between brights and darks?

 

[BigNegs]

The easiest way is to shoot in manual mode and bracket your exposures without changing your aperture setting (use shutter speed instead) until you get 2 to 4 stops overexposed and underexposed plus 1 that is correct. Use photo shop and use the "merge to HDR" under the tools menu. This entire process is best explained in the book Adobe Photoshop CS4 for Photographers (chapter 7) by Martin Evening and published by Focal Press. Dedicated 3rd party plug-ins do a better job than Photoshop, but it works well if you are patient using just Photoshop. I have my high school students do this and the results can be very subtle or very dramatic depending on the "tone mapping" by the individual.

 

[JerryV]

Thank you for your input.

I tried a range of different approaches to get HDR imaging.

1. D-Range Optimizer / Auto HDR (Accessible either through Function button or in my model [alpha 33] through a dedicated D-Range button on top, just behind on/off switch.

D-Range optimizer selection: This calculates optimal exposure dynamic range for a single exposure based on meter measurements throughout image – Choices are 1-5, with 1 being close to normal exposure and 5 showing the most dynamic range. (This seems to reduce overall image contrast with higher numbers but had limited results in my tests.)

Auto HDR: The camera takes 3 exposures with single press of shutter release button (normal, underexposed and overexposed); at playback there are 2 images shown: the first one is the normal exposure the second seems to be a “pseudo” HDR that is a composite of the 3 exposures. Here too, Choices are 1-6, with 1 being close to normal exposure and 6 showing the most dynamic range.

So, with the higher numbers, it seems to function as an HDR system but it doesn’t allow the tweaking you can do with a dedicated HDR approach that feeds from multiple exposures. Also, you have to do too much testing for each scene to see which number (1-6) is most effective.

2. There is a separate “Bracketing control button” on the “Drive” choice within the “control” button on the rear, right of the camera. This gives 3 separate images at different exposures (with choices of bracketing images (with choice of exposure differences between either 0.3 or 0.7 EV steps). It yields 3 nicely bracketed exposures at normal, underexposed and overexposed. So this approach is what would work to get images to start with for HDR processing. But the exposure differences are much too small to do effective HDR processing. (What was Sony thinking?)

3. I tried your suggestion about taking a series of shots at a constant aperture and with a range of shutter speeds. This certainly works. But one has to constantly fiddle with controls to change the shutter speed before each shot. Unless you are using a tripod, the images may get out of register for processing.

Someone else has suggested shooting a single image in RAW and then underexposing and overexposing the initial image to get a range of bracketed images. I did this with PhotoShop Elements and then did HDR processing with “HDR Express”. I like this the best. First, I try to shoot in JPEG plus RAW. So all you need is one exposure to start with and you don’t have to do anything special (although you don’t need the various systems that Sony is touting for their alphas. Any camera that shoots in RAW will do. Then, you can decide which images are worth processing for HDR in the comfort of your computer. I found “HDR Express” to be simple and powerful.

 

[BigNegs]

True - the old manual settings do require a tripod. I use a Pentax K10 and it allows my to choose an "auto bracket" also but it also allows me to choose the range between settings and allows up to 5 bracketed shots at 2 stop intervals (from +4 to -4 plus 'normal' or 9 stops total). This is why I mentioned the old and slow. It will work for any camera sitting on a tripod. Even with a tripod, my size 11 shoes still kick a leg once in a while, but photoshop does a pretty good job of auto-registering of stationary objects (trees trunks are fine but not branches and leaves). I use a slight wide angle lens and leave room to crop in on the final composite before tone mapping.

Your method of bracketing with the exposure slider should work well with the single image approach. Post a few examples that you have done each way to compare results. It would be a pleasure to see each of the different results.

 

[IanBo]

Hi Jerry,
Thanks for posting this, it has really helped me work out what I have not understood so far. I came home baffled once again as to why I was only getting 2 images from 3 exposures. Now I understand.
I have also managed to follow your logic and work out a whole bunch of other things that will help me enormously.
I have been trying hard to get my head around this issue for months, and you gave me enough information to finally get things clear in my mind and at last open that doorway into HDR.
Brilliant!
The Sony Manuals are very concise, but that assumes you know what you are doing - and I didn't. Now I do, with many features of the alpha I have just never appreciated before at all. It will probably take me a week to take my next photograph, but I think I understand now what everything does, so that is a great step forward for me.
- Ian.

 

[DiskoJoe]

I would suggest turning the d-range optimizer off. Turn off the long exposure noise reduction and any image stabilization in camera or in your lens if applicable. Manual is best since it will not have to refocus and prevent shake. Use a trigger cord or the auto timer, trigger is recommended and only like $5. Also remember that you do not always have to do the normal -1, 0, +1 thing. You can use o, +1, +2 in some night time situation or darker settings for day. I would usually do -2, -1, 0, +1, +2 then pick the shots I liked the best. This is really easy to do with photomatix since you can load all at once then pic which you want to use.