Posted by: In: In-Camera, Just Chat, Techniques 28 Jan 2013 0 comments Tags: , ,



It’s funny how sometimes you might think that a landscape should be treated with a camera in actual landscape format. However sometimes it works really well to rotate the camera through 90 degrees and try it that way.

As can be seen with the images to the right, such a wide-angled view of the world allows for interesting creative possibilities. It really allows you to generate foreground, middle-ground and background interest – forcing the viewer to “read” up through your picture.

Whilst ploughing through my 52 I have really discovered that a portrait orientation for my camera can really generate some striking images.

So what are you looking for when creating a landscape image in a portrait format? It’s all about “interest” in the three main areas of the image. Dividing the image very roughly into thirds is a general rule that applies moreso in this instance.

Foreground interest is an important detail that many images lack. If I look at the slideshow to the right, I prefer the images that have a degree of foreground detail. Middle-ground is usually obvious. Something in the middle-distance that is of interest to the viewer. Finally, consider your background. Is the sky flat & grey, or are there some fluffy clouds there to add that last sprinkling of detail to your image?

Lastly, when thinking about having a sharp image right through the scene, you need to think about where to focus. My post on Hyperfocal Distance explains how you can get nearly all the scene in focus if you have the settings in your camera set right. Needless to say, this technique works best with wide angled lenses and also works well if you can get down low.

In this article I want to talk about hyperfocal distance.

What is Hyperfocal Distance?

Do not let your eyes glaze over, it’s really interesting and can improve your landscape photography over night. I promise. Or your money back?

We’ll also review some cool apps for your iPhone that will help! (I only own an iPhone, and nothing else, but I’m sure these apps are available on other smartphones!). We’ll take a look at some online calculators too.

Before we begin though, I’m assuming you know something about depth of field. This is the term used to describe the bits of a photo that are in focus, and is closely related to the Aperture of a lens. If you have no clue what I’m on about, please consider buying Bryan Peterson’s “Understanding Exposure” which is an amazing resource on understanding how the camera deals with light. In terms of sharpness though, if you imagine refilling your wine bottle with leftover wine (stay with me…) without using a funnel (a wide aperture of say f1.8), you end up with wine everywhere. Mostly over the bottle, the carpet, your hands… If you use a narrow aperture (f22), then all the wine goes in the bottle and nothing is spilled.

Now imagine wine as light, and you can see that with a narrow aperture, we have all the wine where we want it – in focus. Using a wide aperture, we only have a tiny amount in focus, and lots splattered everywhere else (out of focus, known also as Bokeh).

That’s the simple view.

But there is a way to measure how much of the front-back area of an image will be sharp in relation to where you are focussing. By understanding this relationship, and being able to calculate it, you can very roughly know how much of your image will be in focus.

Let’s explain further. The below image shows our cat – Oscar, as a playful kitten (rather than the miserable lazy curmudgeon he is now)

Cat demonstrating depth of field

As you can see, his eyes are nice and sharp, but his front paws and the carpet at the back of the image are blurred. If you’ve been photographing a while, you’d expect this. What I can tell you from a mathematical point, is that if I assume his nose (my point of focus – it’s an old photo and should have been his eyes) were half a meter away from the lens… I have 39mm (millimetres!) of focus beyond the nose, and 33mm of focus in front of it. So his nose, whiskers and eyes are in focus, the rest is blurred.

Had I used f1.8 instead of f4, I would have just a 30mm of sharp focus and the eyes would probably be out of focus… Conversely if I’d have used f11, I would have 79mm in front of the focal point, and a massive 131mm beyond.

So you can see that from a creative standpoint as well as a technical one, knowing the rough hyperfocal distance gives you an idea of where to focus. In terms of portraiture and sports, it’s not something everyone has the time to calculate. Also, some people are limited by available light. Aperture after all is a key component in getting light onto the sensor, and in dark lighting, a wider aperture often is neccessary.

However for landscapes, the term Hyperfocal Distance is used to represent the distance at which you need to focus in order to ensure everything beyond that point (out to infinity) and half that distance back towards the camera is in sharp focus.

So, let’s look at this scene.

An example of hyperfocal distance

Where would you focus in this image? Before I learned about proper focussing techniques I would have aimed for the tree on the left. Maybe the “middle” of the picture.

Let’s look at the setup. This was taken at f14 with a focal length of 35mm. That tree is about 80m away from me. My Hyperfocal distance extends from about 5m in front of me, off to infinity. So those reeds in the bottom right hand corner are only a few meters away, but they would be blurred and out of focus.

So where do I focus?

I focus at the Hyperfocal Distance. I know, that if I focus there, everything beyond it, and everything (roughly) halfway between me and it will be sharp. I also know that that is the best place to focus for maximum sharpness through the depth of field. With the settings above (35mm, f14, 70m to my main subject), I can focus at 4.6m and still get everything sharp. So instead of 5m to infinity, I now have 2.3m to infinity. Sounds ridiculous doesn’t it? But it’s true.

Imagine these distances multiplied by kilometres as you focus on that big mountain in the distance, and you’ll begin to understand what I mean.

How Do I Calculate Hyperfocal Distance?

You don’t. You let something else do it for you. This is where the iPod, iPad, iPhone (and other smartphones) come into their own. They are portable, and handy for little applications such as this. There are many online free hyperfocal distance calculators, but out in the field, you tend not to have a computer to hand. So these apps are very useful.

And they’re cheap!

A Paid Hyperfocal Distance Calculator

Hyperfocal distance calculators are common. It’s a mathematical equation, so there are many free apps out there. However the ones I tried had little niggles that left me wanting more. But I couldn’t complain – they were free! So I plumbed for a paid app, and PhotoBuddy was the one I went for. Not only did it have the Hyperfocal distance calculator with a handy visual guide (that you can drag with your finger), but it has a host of other little functions too. Sunset/Rise times, phases of the moon, a bulb timer for your long exposures, WB lists etc etc. The list goes on… Just click the link and read “More”…

Other paid apps just didn’t have the functionality and/or useability of this app, (to be honest, all the little extras did it for me) and since downloading it, it’s been worth every penny.

A free App…

I haven’t reviewed all the free apps out there, but if it’s not costing you anything, what harm is there in downloading them all and trying them for yourself. Of the ones I tested, I found iDof Calc to be the best. It has a simple, fast, easy to use interface that does exactly what is says on the tin. No adware, and smooth functionality.

So next time you’re out taking landscapes, have a think about your hyperfocal distance, and focus on something a bit closer than the mountain in the distance. It’s surprising (at middle aperture ranges like f11) how close you can focus and still retain front-back sharpness.

Online…

You may be determined to look online, in which case I can recommend the excellent DOFMaster website for further reading and interest as well as an online calculator. As an aside, they also have an iPhone app – cunningly titled DOFMaster.

-Sc

Posted by: In: In-Camera, Techniques 28 Jan 2011 0 comments Tags: , , ,

This is a follow up post to “What is HDR” and is the second in a trinity of posts about HDR. There are two phases to getting a decent image for HDR. Camera-side and Software-side. This post looks at the camera functions.

So – what do you need?

The answer to that, is that you need some form of manual control over your camera. You also need to know how to manually control your camera! Finally, you need a tripod, or a steady base for your camera (so that it doesn’t move)

As discussed in the last post, HDR is all about getting a balance between the lightest and darkest areas of your image. What I’m going to explain here, is how to take a range of images at different exposure settings so that you capture all the information. Beyond that (in the third post) I will detail how to blend these all together. But it’s important you know now that you’ll be blending these images in post-processing. That’s why the following is important:

– The camera must not move once you’ve started. The HDR software will cater for small movements in-camera, but you’ll be most likely shooting at low shutter speeds, and you need crisp, unshaky images to get the best results. Additionally, it’s probably wise to turn OFF auto focus and any image stabilisation. By reducing the light, the lens may want to hunt for focus giving you blurred images. When you’re set up with a tripod, find focus using auto-focus if you like, but then switch AF off.

– The Aperture must not change once you’ve started. Different apertures give different depths of field, so if you change the aperture through your shooting, some images will be out of focus beyond the focal point, and some will be sharp. When they are blended, it looks messy. That’s why Manual mode (M) or Shutter speed priority (Tv) if manual mode scares you, are the best options.

– The camera must be changed to shoot in RAW mode. JPEGS do work, but the effect and clarity is much better in RAW mode. There is simply more information in the RAW files for the post processing software to work with.

– The camera should be set to spot metering. You’re going to take light readings from different parts of the scene (the darkest and the brightest) and averaged meter readings will mess everything up. Set to spot metering and the middle 3% of the sensor is where the light will be measured.

So let’s walk through this with an example. My living room is a great place to start, as it has content in shade, and content in bright light. Just snapping a shot of the sofa shows the problem. When we expose for the sofa, the light coming through from the room beyond is totally white. We can’t see any detail.

Shows how a scene with multiple=

So what’s the solution?

Here’s where you need to know how to understand your camera. Looking at the display, when I point the camera at the sofa (the middle point of the viewfinder – spot metering meters this point), it shows a correct exposure at 1/10 sec, f5.6, ISO 500. However, when I point the camera at the bright areas, it shows 1/125 sec (f5.6, ISO 500 unchanged remember!)

Exposing for the highlights to get the top reading for HDR photography

So now we know that to capture all the detail in the image, we need to shoot exposures between 1/10sec and 1/125 sec.

Most modern DSLRs shoot in anywhere from 1/3 stop increments to 1 stop. I generally set my camera to shoot in 1/3 stop increments to get the best exposure possible.

So, in 1/3 stop increments, I need to shoot the images at: 1/10, 1/13, 1/15, 1/20, 1/25, 1/30, 1/40, 1/50, 1/60, 1/80, 1/100, 1/125.

“Twelve shots for a sofa?” I hear you cry. Yes. In the above instance, I wouldn’t take twelve, but then I don’t see a lot of artistic merit in a sofa… Outside, with a nice landscape, those twelve shots would merge into a lovely looking HDR.

In all seriousness, taking this number of shots isn’t a big deal. If you have shutter speed set to one of the wheels on the camera, it’s just a case of shoot, rotate wheel one click, shoot, rotate wheel, etc etc.

Misconceptions about HDR: i.e. “Why does my HDR look bad?”

“Five Exposures is best”

Some people will tell you that 3, 5 or 7 exposures are best for HDR, but that must be taken as a guide. If you want the best image possible, you need to take the number of photos equal to the number of stops (or fraction of stops) between the lightest and darkest area. In the above example, that’s 12 exposures. If we went in full stops rather than thirds, it would be 1/125, 1/60, 1/30, 1/15, 1/8 (five exposures)

“Auto-bracketing works fine”

Yep. It does. But the quality of the HDR can be a bit hit and miss. Auto-bracketing basically takes one shot at the correct exposure, then more shots +/- one or two stops. This is fine if you meter for the “middle ground” and there are no more than 4 stops difference between the brightest and darkest areas. If you’re in a hurry, by all means use this method – I did for years, but I’m now a convert to using a tripod and taking two light readings, then  a sequence of shots from light to dark.

“Hand holding works”

Also true, but you’re asking the software to marry up images that will have moved, and the end result is an image that has ghosting around the edges of your lines. Even the brightest day (equating to fast shutter speeds) will need slow shutter speeds for the dark areas. Again – by slowing down with a tripod, you get perfectly aligned images, as well as having to pause to consider other artistic elements that make up a good image. Composition being the most important!

For the tl;dr Crowd

  • Use a tripod, turn off Image Stabilisation.
  • Stop and think about composition.
  • Make sure you’re shooting in RAW
  • Once you’ve focussed, turn off Auto focus.
  • Make sure the camera is set to Spot meter and then meter the brightest and darkest areas.
  • Take shot #1 at one end of the shutter speed scale (1/125 in the above example)
  • Step through the range, taking one shot at each stop (or fraction of, depending on how you set up your camera). The more images you take, the better the HDR result will be!

Next time: How to blend the images in HDR software. You could make your sofa look like this!!

A final example of an HDR image

Yeah – it looks terrible, but as I said above, I wasn’t going to take 12 exposures of the sofa! In this case, I took just four exposures to “see what would happen”. For the software tutorial, we will use a proper image.

Next… Using Photomatix to create the HDR image

-Sc