Wow, I think that's my longest blog title yet!

There's been a lot of info lately on HDR, blends, bounce flash etc. Much of it good info (some of it not unfortunately) but very little objective comparison of methods all in one blog.

I'm going to cover the following topics:

• single exposure (available light)
• multiple exposure blend (available light)
• multiple exposure HDR (available light)
• single exposure HDR (available light)
• Civil Twilight / Dusk (available light)
• Bounce flash (speedlight)
• Strobes (flash)

Thanks for being patient, this is a bit of an undertaking. :)

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1. SINGLE EXPOSURE:

Anyone who's ever picked up a camera and taken a photo of an interior knows the problem with single exposures backward and forward. It almost never produces a usable photo. Even a $40K D. Medium Format simply can't cope with the dynamic range of interior light versus an average window.

Let's look at a quick example (bonus points if you can find the barrel distortion prior to correction).

Here we have the classic case. The first exposure accurately portrays the view from the window but the room is almost completely black. The second exposure produces a nicely 'lit' room but the window is almost completely blown out. If you have interior lights on they'll often behave the same way as a window, and you'll get these super bright spots where the lights are (commonly called 'burn in').

I'd like to point out that in some cases a blown out window is very desirable (pick up a home mag sometime). Unfortunately that's seldom the case in real estate photography (unless there's something really dismal right outside). Typically we want that view!

So what can we do? Not much. Forget robbing a bank, there simply isn't a camera you can buy that can capture that much range in a single shot. Unfortunately that's not likely to change soon either unless some dramatic new technology no one knows about is suddenly invented. It's a physics problem as much as anything else.

Can single exposure work? Surprisingly, sometimes they can. Let's look at some more examples.

The above are all essentially single exposures. What do you notice right away? No big windows. Single exposures generally work best when they are tighter crops, avoiding large areas of light contrast. That doesn't mean the photos need be dreary, in fact 'close in shots' are quite popular (I quite like them for them for ambiance). They can still exhibit strong color and contrast and of course your composition skills will only enhance their value.

I should also mention that dusk shots are essentially single exposures where we wait for the sun to actually match the light we need just as if we controlled it on a dimmer. We'll cover that in the dusk section.

Summary:

Single Exposures are quick and simple but are almost entirely incapable of handling anything above +/- 8-10 EV. Good for close in or artistic shots where we like the windows blown out. Dismal at capturing views.

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2. MULTIPLE EXPOSURE (BLEND):

So, we've seen that by zooming in a bit and avoiding high contrast areas (such as windows) we can make the single exposure work from time to time. However, let's face it we can't rely on that all the time, or even often. Real Estate shots require wide angles as well as close ups and those windows are crucial part of many scenes.

In this case well look at taking more than one exposure and doing a quick (manual) 'blend' of the two (or more).

Let's look at an example:

Here comes our old enemy. The left side in the first photo looks great...the right side is totally overexposed. In the second photo the area the door looks good but the rest of the room looks like the batcave. 

BTW, I produced these photos quickly and easily using a function called "bracketing" which allows me to set my camera to automatically take three exposures @ 0, +2 & -2 (approximately). If you have a DSLR your camera almost certainly has this function. It's easy to set and makes getting your multiple exposures quite simple (and no additional fiddling with the camera while making the three shots which prevents movement).

So what happens if we combine the two images?

We can use photoshop to quickly (and I mean quickly) put these together.

This is probably a good time to mention that if you aren't familiar with photoshop you are missing out on some powerful capabilities. You don't need to be an expert but it would be good if you gained some basic understanding of what the software can do. Most of these techniques aren't actually that complex...but they do take some practice.

I'm going to create a very quick and crude mask (which is all we need).

Let's take a look:

Above we have the image on the left which shows you approximately where my mask is (in red). The image on the right is  the final version after the blend. Elapsed time, ~60 seconds. I'm letting my window blow out a bit but that's ok...there's a bunch of stuff on the deck I don't want to show and more importantly I want the viewer to really experience the 'warmth' and brightness of the sun coming in.

Summary:

Much more versatile than a single exposure, quick and easy to shoot. Fast to edit but requires at least a basic comfort level with photoshop or similar program. Requires a tripod at minimum, may also benifit from a cable release and mirror lockup. Attempting to blend too great a light range may produce odd artifacts (visible errors). Longer exposure will shift color temp upwards and the blends may not match.

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3. MULTIPLE EXPOSURE, HDR

There's been a lot of excitement around a recently developed technology called 'High Dynamic Range' (HDR - sometimes also referred to as Extended Dynamic Range). And for good reason, HDR can sometimes solve problems that are very difficult to manage by 'traditional' methods. Unique as it is, it also carries with it some serious drawbacks. It's important to know when it's going to work well and when to avoid it.

First, let's cover how it works.

HDR images are composits of multiple exposures (minimum 3, typically 3-6, sometimes 8 or more). These 'low dynamic range' (LDR) images are then run through a software process which attempts to fill in clipped and blown areas smoothly without too much mangling of the color temperature or luminance. How well this works depends a lot on the operator, the software, and the images captured.

Above are the 'LDR' images...left is -2EV, center is 0 (metered), and right is +2 EV. As you can see, none of them by themselves is a suitable photo. We know a single exposure isn't going to work (obviously) and blending isn't a great candidate either as the curtains make a good merge very difficult.

Let's see what happens when we run these through an HDR program:

Ok, now that is looking much better. Our curtains are no longer blown out and the chair is suitably bright. At this point you might be asking yourself; 'Why isn't everyone using this miracle technology?'.

I used to be a big fan of HDR, I used it for practically everything. The current HDR software leader offered to feature me in their portfolio. 

However, I was spending a lot of time (and I mean a lot) photoshoping each image to correct for the problems with HDR. Despite all that some images just still weren't working right.

Let's look at a few of the problems with HDR and how to avoid them.

• Light Blooming
• Window 'realism'
• Strange color temperature
• Lens flare
• Low Contrast 'muddy areas'

HDR PT.II (Avoiding Problems)

I want to take a moment to cover a few of the critical problems with current HDR tech and some ways to avoid them (or at least know when they are going to crop up). I don't want you to think I am way down on HDR however...and it's light years ahead of the single exposure. Just keep in mind it's not quite ready for prime time yet (at least without a ton of photoshop). However, the good news is there is more and more competition all the time and the software is bound to get better! :)

BTW, I cringe as I look at some of these images...go easy on me. THey are here for demonstration purposes only and are purposefully worst case scenarios for purpose of illustration. ;)

  Light Blooming

Unfortunately an all too common problem, especially in areas of very high contrast (dark wood / paint around a bright window for example).

Notice how the edges of the window are overly bright and low contrast? HDR software sometimes has real problems averaging the blend in these areas.

You can sometimes solve this by lowering the blinds and getting a low contrast shot to use (along with the blinds open shots). You can mask / and paint (a bit of a pain). You can somtimes change your camera angle to avoid so much light from the window. Or you can live with it. ;)

 Window Realism

Here's another common issue. HDR rarely renders the outside scene accurately. I've never been satisfied with a single view shot (I always ended up masking in a shot of my one).

Color temp tends to get sent to strange places (in this photo, much too cool) and saturation is pushed too far. Of course tweaking settings can help reduce this but typically fixing the outside view buggers up the interior temp. Headache!

If you run into this there's not much to do here but mask and replace. I do think this will improve with new software so keep your eye out for competing technology.

 Color Temperature

Here's a particulary egregious example of wonky color temperature created by hdr tonemapping.

The problem is most 'scenes' contain multiple temperatures and as the hdr is attempting to blend all the luminance channels then apply colors to them (usually by pushing saturation).

Do keep in mind that sometimes this works really well, and sometimes...it doesn't. Fiddling with settings a bit may help. You may also manually color balance (a pain). It might help to color balance each shot prior to merging as well.

You could always paint everything white as well prior to the photos. ;)

 Lens Flare

The lenses available today are fantastic, far outstripping gear of even a year ago...but they have a dark side: Many more elements (my standard RE lens has 17 elements!) and a more highly reflective inner surface when compared to their film counterparts (along with the sensor itself).

How does this impact HDR you ask?

Multiple images and little light means longer exposures which dramatically increases the risk of lens flair.

If you see this happening try to change the angle of your lens to avoid the offending light source (cloudy & bright skies are sinister culprits here because they send so much light into your lens at mutliple angles).

The only other way to avoid this otherwise is by doing a fast exposure but this typically means you need to add light.

 Low Contrast 'Mud'

Here's another extreme example. It's hard to be too hard on hdr, we are asking it to do an aweful lot.

It's got to look for blow or clipped areas, and figure out how to replace them...all the while matching luminance and color (not to mention avoid creating noise!).

It doesn't always get it right. The common complaint is that hdr images can be 'flat' or 'muddy'. Actually, this should come as little surprise because that's exactly the goal...to take overally contrasty areas and even them out. The downside is this just doesn't always work.

You can add a little contrast in photoshop globally (or with a mask to just bits of the image). You can also blend in a standard shot or as always, you can attemtp to tweak the settings to produce a better merge. Tripod and bracketing highly suggested.

Summary:

Uses 3-8 images (typical) to create a blended image. Can be very effective at handling situations otherwise made quite difficult by 'standard methods' but may also introduce a host of problems and or restrict the freedom of the photographer to comform to hdr limitations. Unrealistic views and color temperatures can be a rpbolem as well as lens flare and low contrast. Requires a large amount of photoshop to produce a professional grade image.

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4. SINGLE EXPOSURE HDR:

You can actually get away with creating an HDR image from a single exposure (keep in mind it's not magic though, multiple exposures are much better). Still, there are times when this might make sense (you are forced to handhold the shot or when you just didn't get the other shots as expected).

To the left is an image that I "HDR'ed" from just a single exposure.

The process is basically the same as creating a standard HDR image however in this case we need to create the 'multiple exposures' necessary for the HDR software to work from.

Its probably a good moment to talk a little bit about RAW vs. JPEG file format.

Most professionals (just about all of us really) shoot RAW. There's a number of reasons for this. The most important benifit of RAW over JPEG is that a RAW file contains far more information than the JPEG. JPEG images are 'flattened' to include only the information related directly to the image is it appears. Not surprsingly the JPEG images are much smaller but that's about the only advantage. RAW files are far superior in just about every other way.

If you plan to HDR from a single image you'll be much more sucessful using a RAW file as there is a lot more tonal information available. That's not to say you can't make this work with a JPEG but you'll need a wing and a prayer to do so.

Anyway, back to the actual process.

Assuming you have a good 'standard' exposure you'll need to create at least two (and two is probably all you can push it) 'new' exposures from the base file.

If using a RAW file this is quite easy, as you can simply adjust the exposure slider on your favorite RAW loader / converter and save yourself a 'bright' file and a 'dark' file for your HDR program to work with. If using a JPEG this will be a bit more tricky as you'll need to manually brighten and darken it.

Don't get stuck feeling you have to be mathmatically perfect about the two new exposures however. The key is to creat one that's bright enough to bring out some details in the dark areas, and one that's dark enough to bring out some detail in the highlights. You may have to give your HDR program some hints as to the EV range of the photos. Don't worry if you know what those are...just get proportions right. (+2 bright, -2 dark etc).

Once you've got images you are happy with run them through your HDR program and you should be all set. :)

Summary:

Not nearly as effective as multiple exposure HDR but workable. May be good as a rescue operation (not enough exposures) or when no tripod is available. Far more effective when used in conjunction with RAW file format. Requires some basic level of photoshop expertise.

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5. DUSK / CIVIL TWILIGHT:

I'm always surprised that I don't see more dusk shots by realtors. They solve almost all of the photographic 'problems' above and require very little technical expertise. Even more importantly, they can be quite striking!

Let's have a peek:

Dusk shots are among my favorite and I'm fortunate to have a client or two that regularly requests them.

Get ready for this:

Dusk shots require no lights whatsoever! If that wasn't enough good news...

Dusk shots require virtually no photoshop whatsoever!

Why are dusk shots so incredibly simple to produce? Well, if full day is too bright...and full night is too dark...there's bound to be some point in between when exterior light is roughly equal to the interior light, right?

Voila dusk (or dawn for that matter)!

Some considerations when creating dusk shots:

• You'll need a tripod of course, these shots are going to be longer exposures (several seconds or more).
• You'll need to have a good feel for the change in light in the evening (this can be tricky at first but comes with practice)
• A lot of DSLRS come with sharpness and color 'pre-boosted' when the camera creates the file. Do keep in mind that dusk shots are going to naturally produce very color intense photos anyway (longer exposures shift color temp and saturation in a similar way too film). You may want to turn that feature off (I personally never use these 'features' as they evetually limit your flexibility later).
• Dusk doesn't last very long. You're looking at maybe 20 minutes max. I never promise more than 2-4 shots and that's usually only acheivable when I pre-set my shot patterns / positions in advance.
• If you are doing a close in shot of a window with a view you may want to turn off unecessary lights...they may reflect in the windows.
• Inclement weather is actually a good thing for dusk shots! Couldy skys turn rich blue and can create a creamy texture (if the clouds are moving). A huge improvment over a day shot with plain white clouds.

Summary:

Dusk shots can be quite dramatic. Good in poor weather and require no lights and virtually no post processing (a little never hurt but you don't need photoshop here). Requires tripod and timed exposure. Need to be cognizant of weather and time of year that dusk falls. Also realize there's minimal time to capture the shots in question. The other thing that can be a problem...you may have to stay up late (dusk is around 9p here at the moment)!

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6. BOUNCE FLASH:

Coming soon. :)

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7. STROBES (FLASH):

I admit it, I used to be a bonafide card carrying HDR lover. However, after a year of so stuck in my office trying to endlessy correct visual defects still present I decided it was high time to invest in a good set of strobes. Strobes are extremely good for capturing views / balancing light from windows.

Imagine my surprise when I discovered using additional lighting not only produces much better image quality (in most cases) but there is far less to bother with in photoshop making the overall process a lot faster! I also found I was able to produce shots which were simply not possible with out lights.

Of course, I won't lie...strobes take a little more know how (mostly in regards to having a good eye for light and the balance there of), they are obviously an additional cost...and let's not forget you have to lug them around and set them up for each shot. They do take more time (but not a lot more I've found).

Considerations when using strobes:

• If you are going to get started with strobes I suggest you don't run out and buy an expensive set (they can easily get into the thousands per light!). Get your feet wet with a small kit at first.
• You'll need some way for your camera to talk to the strobes. A simple wireless trigger is probably going to be your best bet. Avoid the more complex sets which have a lot of controls on them - you'll spend more time trying to make sure all your settings match than you will shooting.
• You'll need an umbrella for each light (to greatly soften the light). Without it the light will be quite harsh.
• When you are ready to shoot, you'll need to look around carefully. Where do you need the most light? Where is there the most contrast?
• If you are having difficulty getting the expousre + lights right, try getting the exposure right to match the view...then add light via the strobes to brighten the interior.
• Experiment! Move your lights here and there...try different configurations. Bounce them off of walls / surfaces.
• Try to add enough light to the room to brighten it but not so much that the scene becomes overly washed out or flat. If you can still see a band of sunlight coming through the window or a glow from a light you probably have a good balance.

Summary:

Among the highest possible image quality when dealing with high contrast areas (windows etc). Minimal post processing required (good if you don't want to be stuck with photoshop). Additional cost, learning curve, and baggage to lug around each shoot. It will take you longer to shoot each room when using lights.

Cheers, -B