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


Posted by: In: Other, Techniques 26 Jan 2011 2 comments Tags: , , , ,

Photography is all about capturing light. Every image is a collection of pixels that have recorded the amount and colour of light falling on the camera sensor (or film).

In most cases though, the camera will have a problem with scenes that are lit with extremes.

Take a typical landscape scene. The foreground is usually dark, and the sky is usually bright (unless you live in England, in which case it’s overcast and featureless!). When you set the exposure settings on the camera, you’re telling the camera how much light to allow onto the sensor. If you’re on auto, then the camera makes the decision. In cases of extreme contrast (lots of bright lights and lots of dark shadows) the camera gets confused, and doesn’t know what to expose for. In most cases, a single shot of the scene will expose for one or the other, leaving you with half an image as you either can’t see into the inky black shadows, or the bright areas just show as white.

HDR is a means of capturing both the light and dark areas, revealing more closely the scene as you remember it.

The process is twofold. Firstly, you need to take multiple exposures of the scene. Then, you feed those exposures into some HDR software which blends the exposures together.

Take a look at the example image below of Castlerigg stone circle in the Lake District.

castlerigg stone circle hdr

As you can see, there are bright areas in the sky, and yet the shadows behind the rocks still reveal detail and colour. This is an HDR image.

Some photographers argue that using a neutral density graduated filter can achieve the same result. Quite simply, it can’t. A graduate filter blocks light from a certain part of the image, and is generally used to “darken down” a sky to bring the exposure times in-line with the foreground.

The problem with ND Grads is that they can leave a “band” across your image. Light is measured (in photographic terms) in “Stops”, where each stop doubles or halves (depending on whether you increase or decrease) the amount of light. So if there are 3 stops of difference between the foreground and sky, quite a severe filter is required to “reign in” the exposure difference.

With HDR, multiple exposures are taken, in “stop” increments, to capture all the detail from the darkest to the lightest areas. When processed in the appropriate software, this ensures a complete picture of the scene.

HDR has been lambasted in the past, and every photographer I know who has tried it has initially gone too far. However, as a tool to recreate the scene before you, and when used appropriately, HDR is an excellent weapon in a photographers arsenal.

Next: How to get it right in-camera…

Posted by: In: Other, Techniques 23 Jan 2011 17 comments Tags: , , ,

What I’m going to be demonstrating – Blue Peter style, here, is how to make a mount for your image. The great thing about making your own mount, is that you can fit any picture into any frame. Just alter the size of the mount. For a few pounds at a charity shop/boot sale, there are some great frame bargains to be had, and you can have a really professional looking mounted image for very little cost once you have the right tools. Once you’ve done a couple of these, it’s also a very quick and easy thing to do. You also get to play with a knife.

Yes. You’re going to be playing with sharp pointy things, so if you’re irresponsible, get an adult to help.

First up, the tools:

You’ll need:-

– A sharp stanley knife or something that will cut through mountboard. These can be obtained at pretty much any hardware store for a few pounds.

– A cutting mat. This will prevent your knife from gouging holes in the table. Amazon sell these, as will any large stationary shop. I’d get one as big as you can afford.

– A tough straight edge with a handle.

– A 45 degree mount cutter. This is the expensive bit. I use a Logan mount cutter as they seem to be the best. You may wish to consider a cheaper alternative, but if you’re going to be doing a few frames (and as a photographer, what better way to display your photos than on the wall at home!) it’s worth the investment of a decent cutter.

– Some mount board. Comes in all shapes and sizes, but it’s worth getting good quality boards.

– Mounting pins. These are small triangles of steel used to hold the backing board in place.

– Tape. I use masking tape, but sellotape works just as well. To remind you, this is not a “how to proudly display your fine art prints” – as the acid in the tape will damage the photo eventually (mine are still on the wall after 5 years with no sign of decay) but unless you’re saving your prints for your grandchildren’s grandchildren, masking tape will do!

– A frame. Go to the charity shop and pick up a frame. Any frame. As long as it’s bigger than your print. Just make sure the glass is intact, and there’s a backing board. You don’t want to be hacking up hardboard, or cutting glass to size. Or you could get reasonably cheap frames from Ikea.

– A print. One of your precious photos.

– The dining table. Or its equivalent. Don’t start this at lunchtime!

tools for mounting a photograph

1. Preparing the frame

Take your frame from the charity shop and turn it face down. If you’re lucky, it’ll have bendy bits of metal allowing you to get the picture out with ease. If you’re unlucky, you’ll need a pair of pliers to pull out the old mounting pins. Watch your knuckles, and your language! Pull off excess tape until you’re bored.

Take out the glass. Carefully. Give it a good clean with vinegar and newspaper. Or use a glass cleaner…

Have a look at the frame. If it’s dented, scratched, chipped, or the wrong colour, then it might need a touch up job. Take it outside and do what you want with it. I’ve taken some frames as they are, but others benefit from a coat of paint. You may even want to go the extra mile and sand it right down to the wood and varnish it. It’s up to you. If you got a good quality frame, you won’t need to touch it, but if it was 50p from a car boot and is chipped and cracked, then a thick coat of black paint, followed by a light sprinkling of silver makes a good surround for a monochrome image.

2. Cutting the mount.

Now for the tricky bit. You can take as much time as you want with this, and that will dictate how the finished product will look. In all honesty, you don’t need to be that precise.

Make sure your cutting mat is clean. Nothing worse than making a lovely mount only to find it’s got black smudges of dirt on the front that you can’t shift without sandpaper.

Examine your mountboard. Decide which is the “good” side – i.e. the side that will be facing your audience. Place the good side FACE DOWN on the cutting mat. Write “bad side” in pencil on the back, just so you don’t start drawing all over the wrong side. If you’re not an idiot, like I am, skip this step.

If you’re lucky, you’ll have a piece of mountboard the same size as your frame. I’m never that lucky, so the first job is to cut the mountboard to the right size. You can do this one of two ways. Either measure the backing board, and cut the square out, or draw round the backing board. I prefer the latter. I know the backing board fits the frame, and I don’t want to be trimming bits off my lovely mount before I’m done.

It’s really important that you keep the mountboard square – this is where the lines on the cutting mat come in handy.

Put a lot of pressure on the ruler. That’s why you bought one with a handle. Mountboard is quite tough, and you need to cut through it with a sharp blade. If it’s not sharp, you’ll make a mess if you don’t cut through it on that first pass. Practice cutting scrap mountboard first to get an idea of how much pressure you need to apply.

Now, you have a piece of mountboard that fits the frame. All you need to do now is cut out the hole for your print.

This is done in a few simple steps.

3. Get the picture central on the horizontal plane.

The picture needs to be in the middle of your frame. To ensure this is done:

– Measure the width of your mountboard. (m)

– Measure the width of your image. (i)

– Calculate “x” where x=(m-i)/2.

centralising the photograph on the mount

As you can see from this example, the mountboard is 14″ wide, and the image is a 10×8, so 10-14 = 4. /2 = 2″ gap at either edge.

– Measure in from the left hand edge of the board at the top, “x” and make a mark.

– Measure in from the left hand edge of the board at the bottom, “x” and make a mark.

– Draw a line joining them up.

– Measure in from the right hand edge of the board at the top, “x” and make a mark.

– Measure in from the right hand edge of the board at the bottom, “x” and make a mark.

– Draw a line joining them up.

You should now have two vertical tramlines across the back of your mountboard.

vertical tramlines for horizontal positioning of the photo

You can see the marking points, as well as the lines defining the inside edge of the frame

4. Get the picture wherever you want it on the vertical plane.

I like to have my image towards the top of the frame, so I work on a 2:1 ratio. There’s nothing stopping you putting it in the middle though. Personal taste is all!

getting the photograph central on the vertical plane

Get it vertically central

Not so simple this one. The height of the board is just over 10″ whilst the print is 8. I went for a 1″ gap at the top, with the remainder at the bottom

– Measure the height of your mountboard. (m)

– Measure the height of your image. (i)

– Calculate “x” where x=(m-i)

*Example* Mountboard is 20in high. Image is 8in high. x = (20-8), or 12

– To put your image in the middle, just divide by 2 as you did above. x = 6

– To use the 2:1 ratio divide by 3 to find x. The gap at the top, is x (4), whilst the gap at the bottom is 2x (8)

– Another alternative is to have the same gap at the top as you have at the sides. Using this example, x would be 2.5in at the top and (12-2.5) 9.5 inches at the bottom.

– Measure in from the top of the board on the left edge, “x” and make a mark.

– Measure in from the top of the board on the right edge, “x” and make a mark.

– Draw a line joining them up.

illustrated image of inch measures on the mountboard

With an inch gap at the top, then I measured down 7.25″. This allowed for overlap to stick the image to the mountboard, and the fact that the crop of the image left a couple of white bands at the top and bottom of the image

– Measure in from the bottom of the board on the left edge, “x” (or 2x if you’re using the 2:1 ratio) and make a mark.

– Measure in from the bottom of the board on the right edge, “x” and make a mark.

– Draw a line joining them up.

You should now have a “box” drawn on the back of your mountboard, and if you’re like me, there’ll be some sums on there too. The technical part is over. You can turn the calculator off now.

photograph of the mount cutting guidelines

5. Cut the mount.

If you mess this up, your mountboard goes in the bin. Take care!

One problem I have with the mount cutter is that it slides like a greased monkey down a pole across the cutting mat. One hefty push and you’ve sliced your mount into bits. To combat this, I ALWAYS rest a bit of scrap mountboard under the cut I’m about to make. The mount cutter then “bites” into the scrap and is much more controllable.

If you’re left handed, reverse these instructions!

– Hold the ruler in your right hand. Offer it up to one of your lines, JUST INSIDE the line. The reason I say “JUST INSIDE”, is because you need to cut a hole thats SMALLER than your print, so that the print will have something to stick to.

how to hold the ruler for the mount cutting process

– “Roll” the ruler down so it’s flat. Don’t let it move. Swap hands so that your left hand is now holding the ruler down.

holding the ruler flat for the mount cut

– The mount cutter should have a white marker. Slide it up against the ruler so that the marker is level with your perpendicular line.

where to position the mount cutter on the board

– Push the thumb-slide down. This will make the first cut. Keeping the slide locked down, slide the mount cutter along your line, tight against the ruler, up to the other intersecting line.

– Release the thumb-slide

– Repeat for the other three lines.

– Lift your mountboard and marvel as a small square the size of your image is left on the cutting mat, or swear as you realise you didn’t go far enough with one stroke, and the “insert” dangles in front of your eyes.

the final cut showing the mount

6. Fix the print to the mount.

– Lay a piece of (masking) tape, sticky side up, on your mat.

– Offer up your print and half-stick it onto the tape.

how to mask up the photograph for mounting

– Offer up your mount and position it over the print.

– Lay the mount onto the print and tape, and press down firmly.

– Flip the mount over, and tape down the other three sides, starting with the side opposite to the one you just did.

the final mounted image

With this being a white print, a black mount works better, but doesn’t show up the lines well for this demonstration. Hence the Blue Peter “here’s one I did earlier” moment.

7. Refit to the frame.

If you’ve got bendy bits, you’re done. Put the glass back, the mounted print, then the backing board, then press the metal clips back into place.

If you need to re-pin the backing board…

– Lay the triangular clip on the backing board.

– Using a pair of pliers, grip the frame and the clip, and push the clip into the wood. I find that masking tape on one jaw of the pliers prevents the frame being damaged.

– Once you’re done, tape it all up again to keep the pins secure.

8. Admire over a cuppa.

the finished mounted photograph in the frame

All finished and done. Bought this frame today from a charity shop for £3.99

This really is quite simple, and means that you don’t need to crop your images to certain dimensions to fit into shop bought frames. It’s also a great way to present your images relatively cheaply.

Here’s what you need again:

– Knife £5. A lot of art sites sell scalpels for goodly sums of money, but in the end, you’re going to be using this to cut the mountboard to the size of the frame and that’s it. A Stanley knife from the hardware store will do the job just as well. And with a retractable blade, it’s relatively safe too.

– Cutting Mat £10 : I’d recommend a Ryman Cutting Mat Self Healing A2 610x457mm – Color: Green from Amazon. A2 is a nice big size and you’re not continually shuffling it about under your mount. You could go smaller, or cheaper quality, but mine was worth every penny.

– Mountboard £3: Again, Amazon has a shop selling A1 Mountboardat a very reasonable price. A1 will last you a LOT of frames! Art shops do sell mountboard, but generally, prices run to £3-4 for A2 size.

– Mount cutter £22: When I was doing this at college, we had several mount cutters, and the Logan mount cutter was by far the best. It may seem expensive, but it’s an essential tool for cutting the angled mounts that look so good when framed.

– Ruler £5: I spent an age scouring the internet for this, but in the end found it at our local hardware store! Builders use these types of rulers with handles, so they are good and sturdy.

– Tape & mounting pins… peanuts

– Frames: Varies… Personally, I prefer distressed frames from the charity shops for a few pounds here and there. Car Boot sales are an excellent source of frames too, and if you can handle the odd looks as you walk off with an awful image in a frame, knowing you’re going to be binning it when you get home, this is the cheapest option.

As you can see. Once you have your tools, the expense of mounting a print in any frame is minimal. This is just your outlay!

Once you’re proficient, you can cut double mounts, or even cut titles into the space below your image. It’s the same process repeated, just with different measurements for “x”. I find it very therapeutic too, and a nice break from Photoshop. Believe me, the end result is well worth it.