Tag Archives: techniques

In the workshop

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Thanks to the nice fellows at Malling Repair Services in Maidstone – disclosure: we’ve have our cars serviced there for many years – I was given free rein with my camera around their workshop. If you live in the Medway Towns or Maidstone areas, you could do worse than give them a call if your motor needs attention: 01622 663960. Tell them I sent you.

It was an interesting exercise for a couple of reasons. First, it forced me to make pictures in fairly restricted circumstances. Second, it was quite dark, and I had to push the camera with high ISO and exposure compensation to get usable shutter speeds (you will, of course, recall my aversion to flash photography). Consequently, I had to spend some time in post-processing in order to get things looking right again, and overcome the extra noise. Newer cameras would have coped with this much better than my poor old 400D, but that’s another story.

I restricted myself to using an ƒ/2 35mm prime lens (equivalent to 50mm on the APS-C body), partly for the brightness, partly to stop myself getting lazy with framing.

Anyway, I’m pretty happy with the way the shots came out. I’ve put my favourites in my Flickr Photostream, and a lot more have found a home over at Britstock Photo.

How to photograph your models, part 2

This is the second part of a two-part article, first printed in the ScaleSeven Group Newsletter. The images are from the printed version, and are greyscale for production purposes. Link to part one.

In this second part, I’ll look at more complex digital cameras. Just to reiterate, there are no arcane secrets here, no requirement to understand complex calculations of exposure and shutter speed. The object is to show how to take effective and attractive photographs of your modelling.

What do I mean by complex? Well, effectively, any camera which lets you take control of the functions that affect the photograph: exposure, ISO, aperture and focus. By default, this applies to any DSLR or similar camera, but it also applies to more expensive compact digital cameras.

For this article, I am working with a Canon PowerShot G9 and one of its DSLR siblings, the EOS 400D with the kit lens. Somewhat necessarily, especially if you didn’t read the last article, there is a level of repetition in what follows.

Canon PowerShot G9.

Canon EOS 400D with kit lens.

What do you need?

It really pays to have a solid understanding of your camera’s features and operation, so thoroughly read and understand the manual. I can’t emphasise this enough. While many functions are common across manufacturers, some are subtly different, so I don’t want to get into details. One important thing is the minimum focus distance for your camera or lens—how close can you get before it stops focusing properly—followed by macro mode. Another important thing to learn is how to switch to manual modes, or at the very least understand the difference between the modes available.

You really need a tripod, or some method of holding the camera steady. This avoids camera shake, which becomes more likely depending on how long the shutter remains open. A remote shutter release is also useful, or learn how your camera’s timer works.

Things to remember

What we’re trying to do is make a photograph of a scale model look like a photograph of the real thing. Get the camera as low down as possible. No matter the scale, nothing spoils a model shot more than looking down on things. If you get down so the lens centreline is about solebar height, things take on a much more realistic aspect.

Try to keep things level. While it’s easy to adjust for a little crookedness in software later, it only takes a second to check things are as square as possible before you press the shutter.

Many cameras have a minimum focus distance. In macro mode, the PowerShot G9 will almost literally focus on the front element of the lens! The 400D’s kit lens minimum focal distance is around 100mm. Anything inside that distance will be out of focus, no matter what. Try to frame the shot by moving the camera rather than using the zoom. Keep at wide angle whenever possible.

The DSLR set up on the tripod. Notice the use of a sheet of black card as a backdrop.

Set image quality to the highest level you can. With memory cards being relatively inexpensive these days, there’s no real reason to use anything but the highest setting. Besides, it would be a shame to spend a lot of time taking images at a low resolution setting, which would be next to useless for publication.

Set the ISO level to the smallest your camera supports. On the G9, it goes to 80, the 400D manages 100. High ISO allows you to take images in lower light, it’s true, but high ISO also means more noise in the image. Film grain is nice; digital noise is not. As we’re looking at fairly lengthy exposures anyway, a high ISO will make digital noise more of an issue, so keep the ISO as low as possible.

Finally, and probably most importantly, remember to use the smallest aperture in order to maximise the depth of field. The corollary to small apertures is longer exposures (and increased noise), so a tripod and remote shutter release is mandatory. You need to ensure you don’t inadvertently move the camera while making the exposure, and that’s very critical with the long exposures we’re expecting. In some low lighting circumstances, don’t be surprised to find exposure times heading towards the ten second mark or higher. One or two of the examples in this article were about 15 seconds. If you don’t have a remote shutter release of some kind, then learn about the built-in timer release and use it.

The camera has decided it needs 30 seconds at ƒ/22 to expose the image.

Lighting

I’m a great fan of available light, and no lover of using flash—especially on-camera flash. Turn off the flash on your camera.

If you’re working around a layout, or in an exhibition hall, the overall lighting level can be quite low which often means lengthy exposures. As explained in part one, avoid flash if at all possible. Work with what you have, use reflectors, desk lamps, move closer to windows, etc. If you get serious about it, you can acquire lighting rigs, soft boxes, studio flash units and so on, but that’s a bit beyond what I’m trying to explain here! I remember once seeing Barry Norman working on photographing a layout, and he used a single naked 60-watt light bulb as his extra light source.

While browsing around our local DIY emporium we came across some tiny battery-powered LED desk lamps.

Cheap LED lamp without homemade diffuser

Cheap LED lamp with homemade diffuser.

At less than £3 each, we bought a couple to play around with. They’re a little too blue in colour, but nothing that can’t be overcome with white balance. I’ve modified them with tracing paper diffusers, which helps a bit. They are very handy for throwing light into nooks and crannies. One of the depth of field sets in this article was taken using these lights.

Reflectors are indispensable. I have a home-made one, aluminium cooking foil stuck to a piece of A4 board.

Homemade reflector.

It’s ideal getting a bit of light under a model to illuminate below the footplate, even in low light situations. Don’t forget, with long exposures, you don’t really need a lot of light to make a difference.

With a single light source, the end of the van is thrown into shadow.

Using the reflector, light is bounced into the shadow.

Camera set-up, part one

Let’s look at the compact camera first. The size advantage means it’s possible to get into places on and around layouts all but impossible to achieve with a DSLR. The downside is it may not always be possible to see what you’re about to photograph. With digital, though, there is no cost to trying a shot, reviewing it, and then trying again. Some cameras also have adjustable screens that flip out, but I digress…

Setting the camera up for model photography involves a good understanding of its workings. I’ve already said you should read and digest the manual, and you at least should be familiar with switching to the various modes, changing aperture and shutter speed, and focusing. It doesn’t hurt to be completely comfortable with total manual control either, but that depends on the camera.

I assumed aperture priority on the G9 would equate to the same setting on the 400D. I was wrong. The camera wouldn’t allow for exposures beyond a second, so the smaller the aperture the darker the exposure. To get correctly exposed images, I chose Manual, the desired aperture (ƒ/8 maximum), then adjusted the shutter speed until the correct exposure was indicated. While I was at it, I selected one of the timed shutter release options so pressing the shutter button gave a two-second delay before the image was taken.

The G9 controls set for ISO 100 and manual control.

I mentioned manual focus earlier, but automatic focusing gives acceptable results. It’s really a matter of knowing where you want the focal point to be, and making sure the camera uses it. There’s a method called “focus and recompose”, where you aim the camera at the subject you want in focus, half press the shutter button so it focuses and locks, and recompose the shot before finally taking the photo. This is a bit awkward, especially when you may not even be able to see the camera’s screen to check the composition. Then again, using manual focus, you can “fix” the focal point where you want it, and leave the camera to work out the rest. Most high-end compacts also let you move the focus point, assuming you can see the screen. The fact you can review the image after taking a shot is a bonus here: you could take several images to get it right.

You may have noticed that your compact digital camera has an uncanny ability to get almost everything pin sharp no matter what the subject. Compact cameras have tiny image sensors, no larger than your little fingernail, placed generally close to the optical system. This appears to mean that ƒ/5.6 on a compact is equivalent to a 35mm ƒ/22 or so. Bad for arty blurred backgrounds, but great for model photography! In short, most compacts have superb depth of field acquisition.

Camera set-up, part two

The techniques used for analogue photography generally still stand for digital. Rather than get technical and cover all the various lenses and whatnot, I’ve assumed we’re using the standard camera kit lens, in this case a Canon EF-S 18mm–55mm zoom. This lens, while built down to a price, is perfectly adequate for model photography, with a nice wide angle at one end, and a reasonable amount of zoom to allow for framing.

My 400D is now obsolete. Newer relatives have a feature called “live view”. This lets you see what the viewfinder sees on the rear LCD, like a compact camera.

When I first set out using my DSLR, I tried to do it the analogue way: setting up the shot, taking a light meter reading for the shadow areas, reading off the exposure time against the chosen ƒ-stop, and opening the shutter for the indicated time. Every shot ended up overexposed by a huge margin. After some experiments, I realised I could let the camera do most of the work. Now, I tell the camera to work out the length of exposure from the aperture I’ve chosen (aperture priority) and its own meter reading. It seems to work very well, and is easier than the compact, that’s for sure!

Taking photos

The generally smaller size of compacts means mounting on a tripod is probably even more essential. The smaller form factor only adds to the possibility of camera shake. I defy anyone to be able to hold a camera still while its shutter is open for more than 1/25th of a second!

In the example, I’ve set up a macro shot using a beanbag for support. The camera’s macro mode is selected (tulip icon), as is the timer release. Being in manual mode (apart from focus) I had to use the control dial to adjust both aperture and shutter speed.

Using a beanbag to support the camera.

Manually adjusting the shutter speed.

Depending on make and model, shutter speed is normally the default adjustment, so a toggle button must be pressed to allow changing aperture to ƒ/8. Partially pressing the shutter button lets the camera focus and take a quick exposure reading, when the button can be released again.

Once the exposure is taken, using the graduated scale visible on the right, I used the control dial to adjust the shutter speed down, which moved the marker point to the centre of the scale. Higher up the scale is over exposed, lower down is under exposed. In the centre, the image should be correctly exposed. In this case, the required shutter speed for ƒ/8 was five seconds.

Now, pressing the shutter button halfway again confirms the focus is locked, and pressing it all the way down activates the timer to fire the shutter. Once the shot is taken, it’s displayed on the screen for review.

The four images show the effect on depth of field and exposure time of increasing aperture from ƒ/2.8 to ƒ/8. The focal point was at the far end of the van and was not changed.

For very close-up shots, engage macro. However, even at the smallest aperture, depth of field in macro is very shallow. Notice how the buffer and rail furthest from the camera are out of focus. This is an extreme example, but it is fairly typical of the very close-up image you may want to illustrate model construction or a particular detail.

A scary amount of detail can be seen with a good macro setting. In this case, the camera was about 30mm from the model.

Something else to consider when using macro mode is an optical effect called “barrelling”. This shot was taken using macro mode, and you can see the roof line and rails are bulged outwards. To avoid it, consider moving the camera further away, and zooming in for the detail, or look at an alternative set-up to avoid the problem.

The way macro optics work can result in optical effects like barrelling, rather like a fisheye effect.

With the DSLR the overall process is similar, though as noted the Aperture priority mode works properly! There are a couple of things you may want to consider. One is switching focussing to manual so you control the main focal point. Another is to find out where the depth of field preview button is on your camera. On the 400D, it’s near the lens mount. When you stop down the aperture, it doesn’t show in the viewfinder. To get an idea of how much of the image will be in focus, holding the DoF preview button activates the aperture diaphragm in the lens and you see it in the viewfinder. In a dark environment with a small ƒ-stop, the viewfinder will go almost totally black, but if there’s plenty of light you should be able to make out the extent of the depth of field in your image. Of course, you could just take a shot and then pixel-peep with the LCD.

As a rule of thumb, don’t focus at one extreme or the other. Aim for the focal point to be about a third of the way along a model. Please note, for the example shots I’ve purposely focused in the wrong place (the nearest end) so you can see the effect of increasing DoF as the aperture stops down.

These enlarged images show the effect of stopping down the aperture on the DSLR. The focus was set at the near end of the van.

Hyperfocal distance

I did say we weren’t going to discuss arcane secrets, but occasionally they rear their heads, and need some explanation.

http://en.wikipedia.org/wiki/Hyperfocal_distance

Wikipedia says of hyperfocal distance: “In optics and photography, hyperfocal distance is a distance beyond which all objects can be brought into an “acceptable” focus.”

Put more simply, by adopting the “third of the distance” rule of thumb mentioned earlier, and not having objects closer than the minimum focus distance of your lens, we don’t need to do any complex maths or use tape measures to get an image that is more or less in sharp focus everywhere.

Focus Stacking

This series of articles has been an attempt to show how you can take good images of your models and layouts with fairly ordinary equipment. So far, I’ve concentrated on getting it all done in the camera, which is something I prefer to do.

If you don’t mind spending time working with your images on a computer, then there’s another technique you can try which will give you almost infinite depth of field. It’s called focus stacking, also known as focus bracketing.

http://en.wikipedia.org/wiki/Focus_stacking

The idea is to take several images, focussed at different points across your subject, which are then combined into one image later. There are many techniques you can use, and even software to help you do it. There’s plenty of information available on the Wikipedia link.

Submitting your images

Finally, some brief guidelines on how to get the images you’ve slaved over to print.

JPEG is the universal standard file format. Most digital cameras save JPEGs as standard. If, like me, you prefer to work in RAW format, export to best quality JPEG when you’re finished.

Don’t edit, or over edit, images before submitting them. Leave any major editing to the editorial team. Don’t be tempted to resize your images. Nothing is gained by saving to an apparently smaller file size, apart from data loss. If you think your images are too large to email, contact the Editor and see if there are alternative ways to get submit them, like CD.

Don’t crop too much. Apart from anything else, an uncropped image gives the editor or designer something to play with in their page layout! You can always indicate you’d like an image cropped for publication. Most cameras have a sufficiently high megapixel count an image can subsequently be cropped without losing much resolution.

Please do not enlarge an image if it’s too small. Digital images are made of pixels, many thousands of tiny little squares of colour. By enlarging an image, all you do is make bigger squares and you lose detail. Use the highest quality image setting, as mentioned earlier.

Conclusion

I hope I’ve shown the techniques are not difficult to grasp, and like most things just take a little patience to master. I’m happy to answer questions, too, so please drop me an email if there’s anything you feel I haven’t covered.

Link to part one of this article.

Useful web links

http://nevardmedia.blogspot.com
Chris Nevard is a professional model photographer, whose work has been seen in various railway modelling magazines.

http://www.dofmaster.com/dofjs.html
A technical web site, which explanations of depth of field, and information about how to calculate it.

http://en.wikipedia.org/wiki/Focus_stacking
Useful information and links on the post production technique for increasing depth of field.

http://en.wikipedia.org/wiki/Hyperfocal_distance
Lots of technical information about hyperfocal distance.

LNER K-2 Class 2-6-0 No 1742

There are regular open meetings of the ScaleSeven Group around the country. This past weekend saw the Thames Valley Group host a meeting in the delightfully-named Brightwell-cum-Sotwell, near Wallingford in Oxfordshire.

I’ve posted this image to illustrate two of the problems you can face photographing models in a public environment. The first is the lack of control over the backgrounds, despite this model being posed on a test track with a nice tall white backdrop. The second is the variable lighting conditions.

The hall is a light and airy venue, with tall windows high in the walls. The day was sunny and clear, yet we also had the hall’s fluorescent lighting on. As you can see, on a slightly shiny model, the reflections from the surroundings can be a little distracting.

I tried to counter the light spilling from the bright window above and behind me to the right by using a board as a block, and moving my own body around to act as a baffle. Under some circumstances, I’ve even used several bystanders to act as a shield!

Still, it’s all good fun.

Tilt-shift reprise

You may recall I posted about the tilt-shift fad sweeping the online photographic world. This is where a photograph (and increasingly video—no, really) of a real place is manipulated to make it look like a photo of a miniature.

Well, I’ve been fiddling about in Photoshop:

These images were taken last summer, with this experiment in mind, at the Buckinghamshire Railway Centre, Quainton Road, Bucks. There’s a distinct knack to getting the blurred areas looking right, and rather too much time spent with layer masks and soft-edged brushes. Working out the detailed areas where the depth of field ought to be sharpest is fun, too.

Will I do it again? Not really. It was fun to try, and the effect can be stunning when done properly, but it’s not something I feel will enhance my work. I’m definitely not about to rush out and buy a proper TS lens, either!

In the Zone

This was posted by Nick Miners. It’s a very clear and concise explanation of what the Zone System for exposure calculation is, and how to do it.

The Zone System is something I’ve looked at for a while, but never clearly got my brain around what it achieves over existing exposure methods I can do with my camera. Nick has very adequately covered the why and the wherefore, although I’m discovering with my poor old stunted EOS 400D, it’s not actually capable of spot metering in the accepted sense.

So, I have to consider alternative methods, such as an 18% grey card and all other kinds of paraphernalia. I think getting properly into the Zone is going to have to wait until I get a better camera!

 

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Light-headed

Light. It’s how cameras work. Light bounces off the subject, and some of it passes through the lens and hits the light-sensitive film or electronic device to record an image. Without light, it’s all but impossible to capture an image.

I’m a big fan of available light. Almost all of my model photography has been done using available light, relying on lengthy exposures to capture the image. Obviously, there are potential pitfalls with this, especially if you’re working in a busy exhibition environment—anything that moves in an exposure over half a second will become a blur.

For various reasons, I dislike flash photography for model work. If you use an on-board flash, such as that fitted to most compacts and relatively low-end DSLRs, the light is too harsh. On a DSLR, in close-up mode, you may well end up with a shadow thrown by your lens! If you have half-decent external flash, it’s cumbersome, and still ends up with a harsh light which throws dark shadows in a most unrealistic way. And let’s not get into the harsh spots of light on bright surfaces…

So, for most shots, I will try to use the available light. This may come from a layout’s own lighting rig, or from hall lighting, or even from adjacent windows. In an exhibition environment, there is the danger of passers by causing momentary shadows, but on a long exposure these become blurred and can be discounted. The problem can be that the lighting is not controllable, may contain daylight as well as artificial leading to colour balance issues, and you need to think on your feet to compensate for areas of shadow, or for situations where lighting is behind your subject.

Here’s a shot taken at a major model railway exhibition. I was using the available light from the hall, but this view really shows the perils of not being able to control the background of a model!

I find it’s beneficial to carry some sort of reflective material. You can buy some very nice professional reflectors, which I intend to acquire at some stage, but I like to improvise. I’ve used just a sheet of white paper before now! In the end, to ensure I had something a little more manageable, I created my own simple reflector. It’s a piece of hardboard, A4 in size (210mm by 297mm), which I’ve covered in aluminium cooking foil. I scrunched up the foil to give a randomised reflective surface. I can now often be seen peering through the viewfinder of my camera, while apparently randomly waving the shiny material about—what I’m looking for is the best amount of reflected light illuminating a shadowy area. When I’m happy, I will fire the shutter.

I am considering making a reflector which I can poke a lens through, although that will mean I lose an amount flexibility in positioning the bounced lighting.

So, what about “proper” lighting? I’m happy to improvise lighting where I can, but nothing can really beat a dedicated lighting system. True professionals may well have vast lighting rigs that use a flash system, but I’ve acquired a set-up that works for video as well as stills.

A while ago, a close friend of mine, an ex-professional photographer, was trying to sell a set of equipment she no longer required since she had retired. Amongst the collection was a pair of kilowatt tungsten halogen photographic lamps, with stands, all in a nice luggable holdall. I jumped at the chance, and got them at a knock-down price.

Suited better to a studio environment—they pump the heat out nicely—I have set these up in an exhibition environment for a “mini studio” where I could pose models for portrait work. They’re a little awkward to use in such environments, but with plenty of time to set up, and no people trying to squeeze by, they are an ideal solution to lighting a model shoot.

Photographed in the “portable studio” using the lighting rig. This image has been colour balanced in post-production, and I’ve left the sides in to show the roll of semi-reflective material I was using as a base. For future work, I’ll try to source a non-reflective material for the “infinity base”.

They do have problems. Being tungsten, they cause a distinct orangey-yellow cast in photos. This can be alleviated by setting a custom white balance in the camera, or adjusting in post-production. The key advantage is the lighting is controllable, and allows me to shoot using small apertures in short exposures. The stands can also be awkward in confined spaces, too. Using these lights is not ideal in exhibition halls.

At this stage, I don’t have a soft box systemfor the lights. I’m a bit wary of fitting anything like that over the heads due to the heat output and potential fire risk. I get around the problem by bouncing the light from nearby walls and ceilings, but it’s not completely ideal. I really don’t want to throw harsh shadows by pointing the lights directly at the subjects, so this is an ongoing problem in search of an ideal solution.

If I want to photograph small items, I use a portable soft box which can be lit by desk lamps. Ideal lamps for this are daylight balanced fluorescents, which can sometimes be found in DIY stores. Two of these lamps, either side of the box, provide lovely even lighting.

A typical “portrait” using the softbox, which is a cube about 40cm on a side. Here, I used two fluorescent desk lamps to light the model. The downside is the background is hard to remove cleanly, and the wide angle tends to show the edges of the background. It’s not easy, this small scale photography lark!

An additional item in my lighting armoury is a large white bedsheet. Where I can control the conditions I work in, I will, but there are times where I may be asked to photograph a layout in an environment where the background may be cluttered by ceilings, other layouts and stands and so on. The sheet, a king-size white linen sheet, can be held aloft by two willing volunteers to provide a manageable background to the photographs. It is certainly easier than having to painstakingly retouch extraneous background clutter later on.

File this under “I Don’t Get It”

When I sketched out my list of topics I wanted to cover in this blog o’mine, HDR was quite high up the list. I can be slow on the uptake sometimes, and it was only really last year I discovered what HDR actually was.

For those of you who are still in the dark, High Dynamic Range Imagingis a technique, actually a range of techniques, designed to give an image a much wider tonal range than can sometimes be achieved at the time of firing the shutter. As the linked Wikipedia entry puts it:

The intention of HDRI is to accurately represent the wide range of intensity levels found in real scenes ranging from direct sunlight to shadows.

Further research surprised me, because the techniques and ideas have been around a lot longer than digital imaging, yet HDR has only really come to prominence through the ready availability of digital cameras and suitable software for subsequent manipulation of the image.

I won’t go into the how and why, because I’ve got some links to tutorials and how-tos which you can follow if you like. I really wanted to raise the topic because, well, I just don’t get the appeal.

From what I have seen, HDR or tone mapped images done well are simply stunning. It really suits some landscapes and architectural photos, bringing out details otherwise lost in a flatter and more accurate colour representation. When done badly, however, extreme halos and the almost pop-art colours only serve to emphasise the desperation of the photographer to salvage anything remotely artistic from a rubbish photo!

Here’s some links for you to explore, with examples good, bad and downright ugly:

That Wikipedia entry again

Digital Photography School, an introduction to HDR

Digital Photography School, discussion of HDR

I haven’t been tempted to try any of the techniques, I have to say. I do like a nice contrasty image, and while playing with sliders in Aperture, I can almost get an HDR effect without all that tedious mucking about with multiple shots or duplicated layers.

There’s another technique that’s been bubbling about the interwebnet, and it has a crossover with HDR. I’m talking about “tilt-shift”. Again, a technique that predates the digital age, but it’s only really come to the forefront because of the aforementioned accessible manipulation software.

Tilt-shift refers to special lenses which can be adjusted so the imaging elements can be held parallel to the camera focal plane while the whole lens can be shifted up or down. I think. Proper TS lenses are expensive: I think the one that would fit my Canon DSLR is just a smidgen under £1000. Such lenses are ideal for architectural photography, because the adjustments can correct for distortion (where a building may appear to be leaning backwards when framing with the camera pointing slightly upwards).

Why have I brought tilt-shift up at all? Well, the technique is being used to make the real world look like elaborate miniatures. By either using a proper TS lens that gives a true narrow depth of field, or “faking it” later in post production by cunning use of masks and gaussian blurs, the effect of tilt-shift can be startling.I think it’s kind of ironic to be discussing the idea, since this whole blog was aimed squarely at making miniatures look real—polar opposites, if you like!

If you’re still not sure what the fuss is about, here are some links. Be warned: some of the photos are absolutely stunning (and some use subtle HDR to emphasise the detail, which actually works well)!

Flickr set of Fake Miniatures

Smashing Magazine looked at 50 “beautiful examples”

Some of those images are taken with a proper TS lens. Others have been digitally manipulated. Can you tell which is which? No, neither can I, but I can make educated guesses in many cases.

Unlike HDR, I am intrigued by tilt-shift. I will definitely be having a go at this, using software, if I find suitable subjects.

By the way, happy new year! A little late, but there we go. Not sure what the next post will be about, so you’ll have to wait until next time!

 

Be sharp: learning about Depth of Field

Depth of Field (DoF) is one of those terms you see bandied about in photographic circles—a bit like bokeh—but it’s usually assumed you already know what it is and how to do it.

Put in the simplest terms, depth of field is how much of an image is in sharp or nearly sharp focus from your camera’s imaging sensor (or film) to the horizon. There’s plenty of discussion, including useful links and a series of hideously complex-looking tables that help you calculate DoF at the

Dofmaster.com web site. If you’re lucky enough to own a PDA or even one of those shiny Apple iGadgets, then there are also useful downloadable bits of software that will do all the complicated stuff for you. But, I digress—something I tend to do a lot…

Rather than go into all the technical stuff about focal lengths and circles of confusion, which Dofmaster does with alacrity and far, far better than I ever can, I shall concentrate on the practical use of DoF in model photography. As you will see, I take a more laid-back attitude to working it all out, but first, a quick resumé of why DoF is important in this sphere of photography.

The chief aim in taking photos of models is to fool the viewer into believing they are looking at a picture of the real thing. We achieve this by setting the camera at the right angle, and by ensuring that as much of the image as possible is in sharp focus.

Here, then, in a nutshell, is the technique I use to take a photo:

  • Set the camera to Aperture Priority (Av) mode, and switch focusing to manual. Yes, you can use it in full manual mode, but let’s just say I’m happy to let the camera’s sophisticated electronics work out the exposure for me.
  • Get the camera as low down as possible, preferably on a sturdy tripod, in relation to the subject. Remember, we’re aiming for a view that looks as if you’re holding the camera to your eye at head height if you were in the real world, say about 1.6m above the deck.
  • Frame the shot, and manually focus about a third of the way along the subject. It’s also useful to check the nearest and furthest points of the subject will be in focus at this stage.
  • Set the camera’s aperture to ƒ/22, or higher if the lens will do it.
  • Press the aperture preview button (check your camera’s user manual to find it) and have a good squint through the viewfinder to see if it sort of looks like it might actually be in focus where you expect it to be.
  • Nearly forgot to connect the remote release cable! This is important so you aren’t likely to jog the camera when you press the shutter button. You can set the camera to timed release, where you press the shutter and there is a countdown of several seconds before the shutter fires, but the remote cable looks more professional! Camera shake is not much of an issue with shutter speeds of 1/100th of a second or higher, but very likely to be a problem with the shutter open for several seconds – which it most likely will be.
  • Once you’re happy that all is set, stand away from the camera and tripod, and fire the shutter. Depending on how long the exposure turns out to be, make light conversation with those around you, or go for a long lunch. Do not be tempted to move the camera until you hear the shutter close again, or the new image is displayed on the camera screen.

With DSLRs, you can see a preview on the back of the camera, so you have a fair idea if the shot worked or not. This, however, is really only good enough for exposure, so focus checking has to wait for viewing on your computer later.

When I can, I like to take my MacBook Pro with me on a shoot, and tether the camera via USB so the download occurs as soon as the image is being dumped to the CF card. This allows me to view the new shot very quickly to assess for lens flare, straightness and, of course, DoF.

I’ve cooked up some samples to show how changing the aperture changes the depth of the sharply focused area. I apologise they’re not particularly photogenic model shots, but I wanted something reasonably extreme to demonstrate how DoF works. I’ve also thrown in a couple of zoom shots to show why such lenses are not ideal for this kind of work. Remember, several posts back, I said that one of the secrets is to “go wide’.

The first image is telephoto. According to the EXIF data, the focal length was 96mm, 1.6 seconds at ƒ/29. Technically, it’s not a bad photo. A lot is in focus, but it lacks a certain something. The viewpoint appears to be a long way from the subject, making the viewer feel cut off, away from the action.

The second image, on the other hand, places the viewer right in the action. This time the lens is a wide angle, 20mm focal length, with a two-second exposure at ƒ/29.

In the next post, I’ll post a sequence of photos taken from the same vantage point, but using increasingly smaller apertures.

Minnie versus larger stuff

Okay, so the Minolta with added close-up filters was adequate in “studio” situations. What was it like in other environments, such as photographing whole layouts while at exhibitions?

(All the images used in this blog are of models built to a constant scale of 7mm to 1 foot, or 1/43rd scale.)

Well, to be honest, it was okay. Not brilliant, but okay. I was asked by some fellow members of the ScaleSeven Group to photograph their new layout Ellerton Road at its first outing at Telford (the Gauge O Guild convention) in 2006. I had access to the layout before the show opened to public, so I could take my time, while the guys set things up around me.

The problems I encountered were these:

  • Taking images from a low angle means you see a lot of ceiling. Convention and exhibition hall ceilings are not that nice to look at, unless you’re a heating and ventilation engineer.
  • The hall lighting was orange. You don’t notice this when you’re looking about, but electronic devices (and film cameras) end up with a distinct colour cast if you don’t consider white balance. 
  • The lighting caused lens flares.
  • Lack of depth of field.

Let’s take these problems in order, and look at how I solved them.

  • I had to live with the ceiling. I will not take photos of models from a helicopter looking down, because it instantly ruins any illusion of realism. I figured I could remove the worst excesses of air conditioning ducts and lights in post production, so I concentrated on getting nicely framed shots as best I could.
  • I let the camera handle the lighting. The Minolta Dimage, being a sort of hybrid digital stills camera with video camera technology, usually managed reasonably well with auto white balance. I decided to let it do its own thing, and adjust in software later.
  • Lens flares were all but impossible to avoid. Looking generally upwards, there were lighting systems in frame most of the time. Anything that obviously caused a flare could be shielded by holding my hand to block it.
  • Depth of Field.Not one of the Minnie’s strongest points. To counter this, I did a series of long-ish shots to take in the general view of the layout, then concentrated on small detailed sections.

Here are the results:

That sky looks wrong, doesn’t it? There’s also a bit of flaring going on up there. But, on the whole, it works well. Nothing half an hour in Photoshop with an alpha channel or two couldn’t cure. In fact, the DoF here looks really good. I put this down to the Cokin close-up filter.

The next shot suffers badly from the stand beyond with their own lighting. It sort of gives the impression of the foreground action taking place under floodlights – hardly appropriate for 1910! Again, the DoF is adequate, if a little soft in the foreground, but a bit of creative cropping to lose those lights would work wonders.

The third shot works quite well, with the locomotive framed nicely between wagon on the left, and the sheeted load on the right. Even the walkway at the back, actually part of the main exhibition hall, doesn’t look too out of place. Sadly, the DoF lets the foreground down. Pity.

The close-up filters let me take some shots inside the goods shed, which was perched at the front of the layout. This image shows the lighting problem well. It’s very bleached and orange in tone, which meant that any colours on the layout simply did not reproduce well. In context with the period in which the layout is set, it doesn’t look so bad, but orange mercury vapour lights (or whatever they were) were not ideal for this job. What I didn’t see until back at base and downloading the images to the Mac was the dust on the filter. Live and learn!

At another exhibition, this time in London, I took a series of shots of Clydesdale Iron Foundry. This is an industrial layout, set unsurprisingly in the network of lines of a foundry, and is one of the S7 Group’s Scottish area group layouts. Of note is the tramway style electric loco. 

I didn’t have my tripod with me, as I hadn’t been expecting to take any photos. However, while the exhibition was quiet, I managed to get some very good shots handheld. I did this by boosting the ISO to 400 so the shutter speed could be faster with a smaller aperture. Luckily, the barrier I was leaning on was sturdy, and my hands weren’t shaking too much! 

Again, I was using available light, but this time I didn’t have the close-up filters on. I guess I was just lucky.

Well, the Minnie was okay for working with the larger stuff. Still, it wasn’t perfect, and certainly limited what I wanted to do with the small scale model photography. It seemed the only way forward was to move to a proper camera. It was back to the saving for the proper DSLR.

Next time I’ll take a look at why Depth of Field is so important to what I do.

Images – at last!

I promised some sample model images, so here we are. I’m presenting these in some sort of chronological order. We start with images taken with the Minolta Dimage 7, so you can see some of the issues I encountered with what was then a high-end digital camera.

The first image is of a 1/76th scale model lorry. 1/76th means literally that one inch on the model is equal to 76 on the real thing. It’s also known as “four mill”, because 4mm equal 1 foot.

(For the truck spotters, this is a British Road Services Bristol HA6L motive unit, coupled to a BTC 4-in-line semi-trailer of the late 1950s. I built this from a Langley Miniature Models whitemetal cast kit.)

The biggest issue in this image is depth of field. We’ll get to DoF in more detail another time, but you can see that the cab is fairly sharply in focus, while the nearer end of the trailer is slightly out of focus. The goal for anyone photographing scale models trying to make them look convincingly like the real thing is to maximise the amount of the model that’s sharply in focus. The problem I faced with the Minnie was that it had a smallest aperture of ƒ/9. This came as a bit of a blow to me, as my work with film SLRs had been around ƒ/22 or higher! The result was as you see above. Not a bad photo, but not technically that good.

Here’s a tip for the budding model photographer — go wide. Don’t think that a zoom lens will make things easier, because all it does is close down the field of view, and compress the effect of distance. In worst cases, telephoto will give you an even smaller DoF. In almost every case I will show you, I’ve had the camera set at the widest angle and the smallest aperture (largest ƒ-stop) possible. In the case of the Minnie, I think had an equivalent to a 35mm lens, which is not an ideal model photo lens but, as it was fixed to the camera, I had to put up with it!

The next image is also of a Langley kit, this time an Austin FX3 taxi. To overcome the shallow DoF, I’ve changed the angle at which the model sits in relation to the camera. I was reasonably successful, though if you look carefully the rear bumper is just going slightly soft.

Both these models have been in what I laughingly call my “Studio” – a large sheet of white paper, stuck to the wall and draped across the desk to give the infinity curve effect. The lighting here was two standard desk lamps, one each side. I think I also used a reflector, fashioned from a sheet of A4 cardboard and cooking foil, to bounce some light into the shadow areas. The “Studio” is fine for these small scale models, but becomes a bit of an issue when I try to photograph anything larger – especially since a wide angle lens, and low camera position, will often end up showing the top edges, and the detritus on my desk! You’ll see what I mean later.

Incidentally, I needn’t mention I’m using a tripod at all times, do I? Thought not. 

By adding Cokin Close-up filters, I could actually force the Minolta to focus a little closer to the subject. I used the Cokin Close-up 1, 2 and 3, sometimes in multiples. 

Here, for example, is a heavily modified Airfix/Dapol Scammell Scarab. Again, I’ve opted to have the model broadside to the camera in order to maximise the DoF available to me. The close-up “filter” allowed me to bring the subject much closer to the camera than the standard minimum focus would allow. The effect is a cruel enlargement of a model that is only about 25mm in length.

Okay, so photographing small scale models was acceptable with the Minolta. How did it cope with the larger stuff? That’ll be the subject of my next post. Thanks for reading.