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Shooting Brackets For Exposure Fusion and HDR – Part 1

April 11th, 2010

There are many real estate photographers that have realized that shooting a series of bracketed exposures and using the Exposure Fusion (EF) feature in Photomatix or one of the many other EF applications is a quick and easy way to getting good quality interior shots. Not as high a quality as multiple off camera flashes but good quality.

To say it in a little different way, using EF is many times faster than using HDR (tone mapping) and then doing post processing in Photoshop, Lightroom or Aperture to get the images to look “natural”. With EF you usually get closer to “natural” without extensive postprocessing.

We Canon shooters are limited to only being able to shoot 3 frames when shooting brackets. This raises the question, are 3 bracketed shots enough? Of course, the answer is it depends on the situation. Some times 3 bracketed frames 2 stops apart are enough. But then there is always those bright summer days and large south facing windows where 3 brackets 2 stops apart won’t do the job. But how do you know if 3 brackets are enough?

As a demonstration that 3 shots aren’t always enough and what the final image looks when the brackets don’t capture the whole range of contrast, I did some test shots in a room with a large window in a moderately (not extreme) bright situation. I’ve put the processed images in a slide show that will go fullscreen so the differences can be seen easily. These are all shot with my Canon 5D MK II with a 24-70mm f/2.8, processed in EF in Photomatix.  All the shots were done within a few minutes so there is not a significant change in outside lighting and there is no inside lighting. No adjustments were done in Lightroom except the ones mentioned in #3. The tests are as follows:

  1. 3 JPGs shot 2 stops apart: I did this because I wanted to see if it was possible to tell the difference between shooting JPG and shooting RAW and exporting TIFF to Photomatix.
  2. 3 RAWs shot 2 stops apart then exported to TIFFs and processed in Photomatix.
  3. 3 RAWs shot 2 stops apart and expanded to 7 shots 1 stop apart in Lightroom… this is a Canon shooters way of getting 7 shots with a body that only shoots 3 auto exposure brackets. I know you Nikon guys are laughing. Note: the original post and the post says I expanded 3 to 9 frames. That was an error, I expanded 3 to 7 frames in Lightroom.

When shooting only 3 brackets the tendency is to not recognize when you aren’t capturing enough highlights and enough shadows. Here are some observations about the results:

  1. There is a slight but noticeable difference between processing JPGs and TIFFs in Photomatix. There is a slight color difference which is to be expected since the JPG processor in the 5D is baking in some color rendition choices in the JPGs.
  2. There is a big difference between the image created with 9 shots and the two created with 3 shots. Probably the difference is more to do with the wider dynamic range given to Photomatix than the fact that the frames are one stop apart.

This demonstration raises the question: How do you make sure you are capturing a wide enough dynamic range when you are shooting brackets? Do you just bracket like crazy or is there a way to easily figure out what the dynamic range in a scene is? In Part 2 I’m going to go into these issues.

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10 Responses to “Shooting Brackets For Exposure Fusion and HDR – Part 1”

  • Very timely post, Larry. I have been exploring the very same ideas over this past week and I agree with everything you have said, so far. Granted I get better results with the HDR function in PP, I think the approach to blending multiple exposures is a great workaround for those that don’t have the time or money to invest in a multi-strobe set-up.

    The trick is feeding Photomatix the best possible images to start with. sometimes the -2 exposure is of little worth save the window pull or lamp glow. I send the +2 and 0 exposures to PSE 6 and extrapolate the RAW files to get whatever other exposures I need (usually a +1 and a -1 EV) and do my color correction, shadow recovery, etc. before I save to tif. Once I have 4 – 6 exposures that covers the range I’m trying to capture, I send them back to PP to render the HDR/EB. If I need more window pull I send the tonemapped tif back to PSE and blend in the windows from my -2 exposure. This method is time-consuming, but faster than what I can currently accomplish using just my two flashes on location…

    As far as your parting questions, I suppose a light meter could give you the extremes, but my camera’s built-in meter works well enough for me. Set the camera for auto-bracket, adjust exposure compensation, shoot, adjust EC and shoot again, etc… Of course when in doubt, bracket like crazy and select the exposure range you want. Memory cards are cheap.

  • thanks larry!
    this is a topic I keep a close eye on as I have yet to really learn/master multiple off camera flashes, or HDR.
    cheers-
    jeff

  • I have been doing 3 exposures converted from raw files and fused in Enfuse. I am also using on camera flash through a Gary Fong. Are these 9 exposure tiffs with out any flash? Is there a large difference between Photomatix fusion and Enfuse? I have the Photomatix software but have just not taken the time to learn it. I use the Enfuse plug-in in LightRoom and then finish up in PhotoShop CS4.

  • Larry, If you take the 3 RAW shots 2 stops apart, then expand each by 1 stop you will have 9 shots but two of them will be duplicates leaving you with 7 right? -3-2-1 -1 0+1 +1+2+3 You can discard one of the -1 and one of the +1 shots. Now you have -3 -2 -1 0 +1 +2 +3. Sorry about all this but I’m not too swift with numbers 🙂

    Now if you have a room with bright windows and are using a Canon, maybe you could start your three exposures with:
    -3 -1 +1 shots. You’d then end up with (after trashing the duplicates) -4 -3 -2 -1 0 +1 +2.

    Now, my question is where would you meter for the starting (middle) exposure. Meter the brightest part of the window?

    I think I’m starting to get the hang of this though… Can’t wait to try it next time we get some sun here in Rochester.. I figure Julyish 🙂

  • I have been taking 6 to 9 shots two stops apart then blending in Enfuse. And getting very natural results.

    While a Canon shooter, I don’t use the auto bracket feature. I manually dial it down to get a very dark shot (historgram shows no whites) then start dialling it up 2 stops apart and shoot. I just use the remote shutter release and give the camera a few seconds to settle down after I adjust the stops between shots.

    Michael

  • This is a very timely post indeed! I have been thinking about these exact issues over the last couple of days. Usually I shoot exteriors using the “3 RAWs shot 2 stops apart” and use LR, exporting to Photomatix Pro. I wondered why I wasn’t doing the same thing for the interiors. For inside I usually shoot using four speedlights, cable release, tripod and take multiple exposures (often moving the SB’s around between shots). This time and I thought I’d throw in and extra “3 RAWs shot 2 stops apart” and then process both and compare the results–see which I liked better. In the speedlight technique I would also take one or two shots without the flashes, just exposed for the window-pull. Then, from Lightroom I would open all the flash exposures and one good window pull exposure using “Open as Layers in PS”, use “Lighten” mode on each but the first layer and manually mask, etc.

    When I processed the first shot, after using my usual method, I went to the “3 RAWs shot 2 stops apart” group in LR and processed in Photomatix Pro, and used the “Exposure Blending” option (I usually like the look better than the HDR option). When that image was processed, I bring it back into LR and then just opened that finished image AND the one shot without flash for the window pull and “Open as Layers in PS” (only two images now) and used one of Larry’s techniques for masking out all but the windows. The last step for me would be to add some adjustment layers for levels, curves, color balancing and saturation.

    So now I basically just have an ambient with a layered-in window pull exposure. I found that I liked the end result much better and it was taking me 2-3x less time in post. I’m not sure if I have the confidence to only shoot the bracketed shots and not used the flashes, but if I do it will cut my shooting time a bunch and same for post. I know you (Larry) talk about the progression of newer photographers starting first with no flashes, then one, then several, etc. And I was sort of thinking this might be regressing in technique, but I think I’m going to try it a few more time and see if I can get consistent results, maybe only taking a couple with my flashes as a safety net.

    What do you all think?

    ~Jeff Kaiser

  • That’s strange Larry as your tiff samples have more punch to the furniture and look ‘cleaner’ than the jpegs . I’ve just compared a 9 RAW Nikon shot (RAW) with a window similar to yours. Outputted using DxO in both jpeg and tif and ran them through Photomatix. There’s hardly any difference between the two though the walls look a little cleaner and brighter with the JPEG (surprisingly) The furniture on both looks the standard washed out as normal with an unedited HDR shot. Given that the tiffs are over four times the file size it deson’t seem worth it in Photomatix to use tiff.

  • @Phil- Dan Achatz (http://www.danachatz.com) who in my book is a master HDR/EF shooter has told me he only uses JPG. Yet I’ve heard others claim that TIFFs give better results. I think the difference is slight and may not always appear in all situations or with all bodies. I tend to agree, when you are trying to maximize your efficiency, the possible difference in quality doesn’t seem worth the added file size and processing time.

  • For optimum results with HDR/Exposure fusion, I think it is best to use the absolute minimum number of exposures necessary to cover the dynamic range. To this end I shoot RAW and minimize the black clipping and maximize the highlight recovery (only enough to hold whatever detail is available) of the component exposures before doing a Photomatix exposure fusion, which seems to allow me to use one less exposure than would otherwise be necessary. If the subject is not moving, it is fine to adjust the shutter speed by hand, as long as you are careful and the camera is well supported, and you use a remote release. The only time I really need to autobracket is when there is a breeze and I am trying to minimize ghosting of foliage using high shutter speeds. For this kind of situation, a camera with an extremely fast motor drive is helpful.

    While some argue that brackets in smaller increments are superior, I find that 2-stop brackets work just fine for most pfre.

    A bit of fill flash can also help to reduce the number of exposures needed for the HDR/blend. You don’t have to be a flash master to do this. Just look for ways to bounce a flash so that you get very wide, even coverage, without reflections. You are just trying to fill in the shadows a little. Of course, if you are dealing with complex spaces and/or poor ambient lighting, that is another issue. HDR/blending is a useful tool, but it cannot make up for extremely uneven or poor ambient lighting. To make a silk purse out of that rotten sow’s ear, you need supplementary lighting for pfre. An architectural photographer might also modify the ambient lighting itself, but we do not generally have time for that.

  • Three can sometimes do the job, but five is what I normally use. I probably take seven (using remote) most of the time in order to make sure I have the best five possible. It’s not necessary to shoot RAW. All the interior phots at my site are done with Enfuse.

    I disagree with this statement. “There are many real estate photographers that have realized that shooting a series of bracketed exposures and using the Exposure Fusion (EF) feature in Photomatix or one of the many other EF applications is a quick and easy way to getting good quality interior shots. Not as high a quality as multiple off camera flashes but good quality.” The quality of the final image depends on the photographer.