Tag Archives: photography

Tutorial #6: HDR Photography

High Dynamic Range Photography is fairly easy to do with a tripod and some HDR software and an image editing program. I’ll go over several ways to do it.

Dynamic range simply means the range of values between lightest and darkest visible tones. The idea behind HDR Photography is similar to the Zone System. I think of it as an extension to the Zone System and one of the modern applications of it in digital photography. It’s not just about making cool almost surreal photos, the goal is to capture tones in every zone. For more info on zones and tonal values see my previous post: [Tutorial #5: The Zone System]
 
For this tutorial, I’ll be using both Photomatix to quickly create HDR images and Photoshop to create them manually. First I’ll go over Photomatix. It’s reasonably priced at $99 for the pro version and $39 for the light version. http://www.hdrsoft.com/ Anyone can use the trial version which never expires but does watermark images made with some of the advanced features.
Photoshop CS5’s new feature is not very good…it really REQUIRES raw files for actual HDR images…and just gave me an error message about my images not being the same size…so converting to JPG or shooting in JPG will result in a terrible image.


no, not ok, adobe. :<
It once even rendered a completely black image. Not very HIGH in dynamic range at all. :-/

Step 01: Shooting
 
If you want to do HDR the right way, you will need to Bracket. This means taking anywhere between 3 and 5 different exposure values of the same image. One correct exposure and then over and under exposed by 1 and 2 stops. I would strongly recommend using a tripod and shooting in RAW. If you take your photography seriously you should always shoot in RAW – even if right now you aren’t using or editing those files.
When shooting try to work quickly and shoot with similar lighting which may be difficult with landscapes if it suddenly becomes overcast or sunny. Clouds and plants also move pretty quickly on windy days. When putting the images together later it will cause ghosting from the different objects not being in the same place in each photo. That’s why the tripod is important. There may be similar difficulties with motion blur and ghosting on longer exposures. You want each of the 5 images to be as identical as possible so they line up properly.
 
Step 02: Pre-Processing
 
It’s definitely a bit tedious if the image is made from multiple shots, but it is possible to create them from one correctly exposed RAW file so you don’t have to worry about ghosting from any moving objects. You wont get all the dynamic range you can get from shooting multiple images but you can still get a similar effect.
When processing the RAW file export an image at the EV values of -2, -1, 0, +1, +2. For more on this see my previous post [Explaning Exposure]

EV -2EV -1EV 0EV +1EV +2
For demonstration purposes i’ll be using this one exposure method.
   
Step 03a: Processing in Photomatix
 
The first thing you do is load your bracketed photos [3-5 photos].


If the different photos were made from one file the meta info will have the same exposure value recorded for how it was shot. You will need to manually fill in the exposure value and the increments at which they were adjusted to. I did them in whole stop increments from -2 to +2.
 

 
When you press “ok” it will give you a few options for automatically dealing with several things, such as alignment and ghosting. I didn’t need to check any of these since I did mine off the same image.



It will then composite a preview image that you can adjust. The screen will look like this:

[click image to enlarge]
 
There are several detailed settings on the left and the filmstrip along the bottom contains various presets that you can apply and then fine tune on the left panel. You can use the loupe to magnify details. The top bar has all the zooming/viewing options, and there is a histogram toolbar as well.
 
The settings you decide on will depend on your taste. Some people love the “painterly” look and some hate it because it starts to look more like a painting than a photograph. Reducing the “smoothing” setting will increase the effect while increasing it will reduce it. The rest of the settings are best explored depending on the photo and what look you’re going for.
 
Step 03b Processing in Photoshop:

This step is more advanced. You need some familiarity with layers & blending modes and layer masks. First, open the correctly exposed image [EV 0]. Then “Place…” the underexposed images over the the original layer and place the over exposed images on top of those. If you need to adjust the alignment you can do so as you place each image by reducing the opacity of the placed layer and moving the layer until it matches the one under. ghosting elimination will come later.

        
You can play around with different layer orders and opacities – even blending modes – but i recommend setting any underexposed images to “Mulitiply” and overexposed images to “Screen.” Mulitply blends only the dark values into the final image composited and Screen only blends in the light values. this way your correctly exposed base image is being enhanced by the values in other images.
 
You can get even more tones values by using other filters such as “Diffuse Glow” and a Layer Mask to hide and reveal dark and light parts of each layer.
The Diffuse Glow settings I used are below, but yours may vary. You just want it to have a a soft glowing effect on the highlights. The final touch for this layer is to set it to screen mode and adjust the opacity as desired.
 

 
I added a bit of a vignette by using a copy of EV -1 layer in multiply mode over the screened layers and then using the layer mask to hide the center of the layer with a large brush in black.


 

The Results.
[click images to enlarge]
 
 The images that are done manually aren’t as detailed and simply have an HDR effect, but it is possible and actually more time consuming in comparison… After trying Photomatix i highly recommend it. I know a lot of others do too.

I’ll do a proper HDR image later on to show how color can be exaggerated, and how the results from multiple images differ and are ultimately better.

Tutorial #4: The Basics of Photography

In this tutorial, I aim to demystify the seemingly complex technical aspects of photography. If you delve deep enough, yes, there are some very complex formulas that go into shooting a photograph, but with today’s camera technology it’s not necessary (but can be very useful) to know about all that stuff. Still, you want to be able to control the look of your photos, and learning how to use manual settings is the best way to do that. Be aware that not all cameras will have fully manual controls (M mode), and if this all seems like beginner stuff keep reading anyway. There will likely be some stuff you don’t know – even if you already shoot with manual settings.
 
My point here is to get to the essence of photography – which can be broken down into balancing the three most fundamental components utilized in achieving a proper exposure: Aperture, Shutter Speed and ISO. The very first thing you need to learn is how to control the balance between the three, and what their different settings mean in relation to the resulting effects produced in photos.
 
Before I start to delve too deep into the mechanics of exposure, you need to become acquainted with the three variables through which you will set your exposure. [For more on the mechanics of exposure see my previous post Explaining Exposure] First, I’ll go over aperture.


Use of Aperture:
The larger the aperture, the better the light can enter to reach the film or sensor. The size of the aperture is one of the variables that determines the Depth of Field (the other’s are focal length and focus distance). The Depth of Field is the area that appears sharp in an image. The larger the aperture the more this narrows. This means you will get more blurry (bokeh) areas and will be able to shoot in lower light. Small apertures widen the depth of field so that parts of both the foreground and the background will appear in focus, but this also lets in less light and you will need to compensate by changing your Shutter and ISO settings. You can set your camera to Aperture Priority (AV) so that you determine the aperture and the ISO, while the camera decides the shutter speed to use. This is useful for getting quicker shots while maintaining control over the depth of field.


Use of Shutter Speed: 
Slow shutter speeds will capture elapsed time in low light (or with Neutral Density Filters). Faster shutter speeds freeze motion, and by using the Reciprocal Rule you can avoid camera shake as well (more on this here: The Reciprocal Rule in Photography). On a normal lens (around 30-50mm) a shutter of 1/60 or faster  will be enough to freeze motion, while 1/30 will capture motion blur. For longer focal lengths you will need faster shutter speeds to hand hold the camera. Even if you have your camera set to Aperture Priority you still want to pay attention the shutter speed, OR set it to Shutter Speed Priority (TV). In this setting, you select a shutter speed and ISO while the camera determines the aperture. This is useful for maintaing control over motion blur and for freezing action.



Use of ISO:
While it is ideal to use the lowest ISO available in order to achieve the greatest image quality, using a higher ISO will increase the depth captured in a photo – particularly coupled with the use of a flash. The reason for this is that a high ISO picks up more ambient light so you get the most detail out of a low lit scene. It will also help balance the flash and ambient light in low light situations, AND use less powerful flashes so there is less recharge time. This is a good technique to practice when shooting events or on location in low ambient light situations where you want to capture as much background detail as possible to avoid flatness from the use of a flash. Just be aware that using high ISOs will increase file size due to increased noise. The more noise there is, the more variation in pixels. The more variation in pixels, the more stuff that needs to be recorded.
 
The Key is Balance:  
To get a correct exposure, you will usually have to make a compromise unless you have completely controlled lighting. If there isn’t enough lighting even at the highest possible ISO and largest aperture, you will just have to use a longer shutter speed. If there is too much light (and there is never really too much light) you can purchase Neutral Density (ND) filters that will allow light to pass through without affecting the balance of lights and darks and  take your exposure down as many stops as the filter indicates. This allows using large apertures in very bright light so you can get very shallow depth of field.
 
If you haven’t already read my post Explaining Exposure you should probably do that right now. It has more information that you can use in conjunction with the knowledge in this tutorial.