MACRO PHOTOGRAPHY

Taking close-up pictures of small things is called "macro photography." I have no idea why. Perhaps because the small things in macro photography are generally larger than the things you are taking pictures of when doing "micro photography". If you really want to be pedantic then you should say you are doing "photomacrography".

What Kind of Camera

You probably want a standard 35mm single-lens reflex camera. You will see in the viewfinder what the film sees. If you have a lot of money, you can get a 6x6 single-lens reflex such as the Rollei 6008. That's more or less the same idea. If you have a lot of patience, you can do macro photography with a 4x5 inch view camera.

In the digital world, true macro photography is possible only with single-lens reflex cameras that take interchangeable lenses, such as the Canon D30, the Fuji S1, the Nikon D1, and the various Kodak professional bodies. One nice thing about these cameras is that their small CCDs effectively magnify the image captured by whatever macro lens you've purchased. Thus a 100mm macro lens mounted on a Canon D30 effectively becomes a 160mm lens. And if the lens gives 1:1 magnification on 35mm film, you get 1.6:1 on the D30's sensor.

Doing it all with a 50mm Normal Lens

In the good old days a 35mm single-lens reflex camera came with a 50mm "normal" lens. These lenses were extremely light, rugged, and high quality so naturally the consuming public abandoned them for heavy, fragile, low quality zooms. But that's another story... Anyway, suppose that you are out in the woods with your Nikon and a 50mm normal lens and you want to take a picture of the tip of a pine needle.

First, though, you want to take a picture of the moon. That's pretty far away, so you feel comfortable setting the lens focusing helical to "infinity". The "nodal point" of the optics will now be 50 millimeters from the plane of the film. [Note: exposure for the moon should be roughly f/11 and 1/film-speed.]

The effort of setting up your tripod is so great that you become tired and fall asleep. When you wake up in the morning, there is a bear standing 10 feet away. You refocus your 50mm lens to get a picture of the grizzly. As you turn the helical from "infinity" to "10 feet", notice that the optics are racked out away from the film. The nodal point is a bit farther than 50 millimeters from the film plane. The lens is casting an image circle somewhat larger than the 24x36mm frame. Some of the light gathered by the lens is therefore being lost but it isn't significant.

After snapping that photo of the bear, you notice that his fangs are glistening. These aren't going to appear very large in your last shot, so you move up until you are about 1.5 feet from the bear. That's about as close as the Nikon lens helical will let you focus. The nodal point is now pretty far from the lens. Extra light is spilling off to the edges of the frame , but still not far enough to require an exposure correction. The bear's face is 1.5 feet high. You've oriented the camera vertically so that the face fills the 36mm dimension. 36mm is about 1.5 inches. So that means you are working at "1:12". The subject is 12 times the size of the subject's image on film.

You're losing some light, but also you notice that you don't have too much depth of field. A 50mm lens focussed down to a foot from the subject only has a depth of field of 1/16th of an inch at f/4. No problem. You haul out a big electronic flash and stop down to f/11. Now your depth of field is a whopping ... 1/2 inch.

Looking down, you become fascinated by some pattern's in the bear's claws. Each one is about 1.5 inches long. You'd like to fill the 35mm frame's long dimension with a claw, which means that the subject and its image will be the same size. You want to work at "1:1". But those scumbags at Nikon skimped on the helical. You can't rack your optics out far enough to focus at 1:1. It looks like that pine needle tip photo is completely out of the question.

Why did Nikon limit your ability to focus close? For starters, at 1:1 your lens would be so far away from the film that it would cast a huge image circle. The standard 35mm frame would only be a tiny fraction. So only about 1/4 of the light gathered by the lens would reach the film. A scene that required a lens setting of f/16 at infinity would require a lens setting of about f/8 at 1:1. All this other light would be bouncing around inside your camera and lens, reducing contrast. Finally, a fixed stack of optical elements can't be designed to form sharp images at so many different focussed distances.

Close-Up Lenses

Your eyes don't focus so great on really small things either. Do you try to pull your cornea a foot away from your retina? No. You stick a magnifying glass in front of your cornea. You can do the same thing for your 50mm lens. Unlike your cornea, it even has convenient threads for attaching a magnifying glass.

A photo shop could never sell you a "magnifying glass" for $50 so they call these things "supplementary lenses" or "close-up lenses". Good things about close-up lenses:

• they don't require any exposure corrections
• you can throw a couple in your pocket in case you need them

Bad things about close-up lenses:

• they aren't very high quality though they might be good enough if you stop down to f/16 and if you can find two-element close-up lenses (e.g., Nikon-brand) instead of the cheapo one-element ones.
• you have to take them on and off constantly if you are taking pictures of things at different distances.

I never use close-up lenses but they are described fairly thoroughly in the Kodak Professional Photoguide.

At right: a model of Sacre Coeur, captured with a Minolta 50mm lens and single-element Minolta-brand close-up lens. The image has lots of problems but I think I was 11 years old when I took it.

Macro Zoom Lenses

Macro zoom lenses are not macro lenses. They don't allow significantly greater magnification than a 50mm normal lens and they deliver low quality.

Macro Lenses

What you want is a macro lens. Fortunately, it is difficult to buy a bad macro lens. This is kind of odd in a world where 90% of the lenses sold are bad. Here's my theory: Every day at least one man wakes up and says to himself "I have a 1.5 inch long penis; I think I will buy a big SLR like a pro. But I don't want to spend money on frills like lenses so I'll get a Tokina zoom." However, no man ever wakes up and says to himself "I have a 1.5 inch long penis. I think I will buy a macro lens so that I can make a 1:1 photograph of my penis and distribute this photo from my Web server. But I don't want to spend too much on this lens so I'll try to find a cheap Sigma."

In short, anyone in the market for a macro lens is already fairly sophisticated and quality conscious. If you read USENET then you know that the world is full of people asking "is this $150 Tamron 75-300 zoom as good as a $900 Nikon 300 prime?" Can you blame Tamron/Tokina/Sigma for trying to separate people like this from their $150? But there isn't apparently a big enough collection of fools in the market for macro lenses to support a junky macro lens subcategory.

In my humble opinion, the best macro lenses are the latest autofocus mount models made by Nikon (my primary 35mm system is Canon EOS, by the way). Nikon makes 60mm, 105mm and 200mm focal lengths. Each lens will focus continuously from infinity to 1:1. You can shoot the moon and capture the bear claw without stopping to change lenses or screw in filters. How do these lenses work? Do they just have a much longer helical than the 50mm normal lens? Yes and no.

Yes a macro lens helical has much more travel than a normal lens helical. You can watch the front element move an inch or two. However, these helicals aren't just pushing a stack of glass back and forth like the 50mm's helical. Inside one of the elements is moving ("floating") so that the optical design changes to a more appropriate one for close-up photography. Thus you get sharp images at all focussed distances.

How do you choose a focal length? The same way you do with a non-macro lens. If you can't get very close to your subject at a soccer game, you don't pull out a 50mm lens; you get a 300. If you can't get close to an insect without it getting scared and flying away, then you want the 200mm lens and not the 50. If you want to compress features in a woman's face, you don't get a 28mm lens; you get a 105mm lens. It is the same with macro work; longer lenses give you a flatter perspective.

What about other companies? Canon makes 50, 100, and 180mm macro lenses. All three incorporate floating elements. The 50 is cheap but it only goes to 1:2 without a "life size converter" (sort of like a telextender) that you stick between the lens and the camera. The 50 is also annoying because it has the ancient non-USM Canon motor. So it can't do simultaneous AF and MF like the ring-USM lenses. The 100 goes to 1:1 but also has the old-style motor. The 180/3.5 is a new design with three low dispersion elements, a tripod mount, and USM for full-time manual focus. It is also compatible with the Canon telextenders. At right, you can see about as close as one can get with the Canon 50 (from my Christina page; part of the reason that photo.net is banned by most of the Net censorship services).

Tamron makes a newish 90/2.8 macro lens that goes to 1:1. It is probably pretty good.

If you feel like spending a lot of money then what you want is a 6x6 cm Rollei 6008. The 120/4 Zeiss Makro-Planar (same lens as for a Hasselblad) will set you back about $3400. That's right, you could buy a Nikon 105/2.8 macro lens and three N90 bodies for the price of the Rollei lens alone. Rollei probably has the most intelligently designed macro system in the world. I photographed these orchids at left in Hawaii with the 120 Zeiss macro lens, Kodak Gold 100 film (120 size naturally), tripod, f/16 and 1/15th of a second.

Exposure

Unless you are using close-up lenses, when doing any kind of macro work, you always have to consider the effective f-stop. Even if you are using the SLR body's built-in meter, which will correct automatically for light loss, you can't turn off your brain. Why not? Because the effective aperture affects picture quality.

Taking pictures through a pinhole results in tremendous depth of field but very low sharpness due to diffraction. This is why lenses for your 35mm camera stop at f/22 and don't go to f/45 or f/64. View camera lenses provide these smaller apertures for two reasons: (1) the lenses are longer (f/64 on a 210mm lens is not all that small a hole); (2) the negative won't be enlarged very much.

If you're at 1:1 and have selected f/22 on the macro lens barrel, you need to look at the lens markings and/or the close-up exposure dial in the Kodak Professional Photoguide to learn that your effective aperture is f/45.

If you're using a handheld meter, then you absolutely must use these corrections (e.g., meter says f/22 but you're focussed down to 1:1 so you set f/11 on the lens barrel).

[Note: the modern Nikons, e.g., 6006, 8008, N90, show you the effective aperture in the viewfinder; the F4 does not; Canon EOS cameras do not. Another reason to go with the Nikon system if you are into macro photography.]

Lighting

A good quick and dirty lighting technique is to use a through-the-lens (TTL) metered flash with a dedicated extension cord (SC-17 in the Nikon system). A modern handheld flash is extremely powerful when used a few inches from a macro subject. That lets you stop down to f/16 and smaller for good depth of field. I sometimes just hold the flash to one side of the subject and have an assistant hold a white piece of paper on the other side to serve as a reflector. Anyway, you have enough power in the flash to pretty much use all the diffusion material that you can find. Let the camera turn the flash off when enough light has reached the film.

Lighting is the most important and creative part of any kind of photography. I've written an entire book chapter on the subject so I'm not going to try covering it here.

The Samoyed nose at right belongs to Alex. I captured it with a Canon EOS-5, 180/2.8 macro lens, and TTL-metered Canon flash. Below: a foot recently pulled out of one of those weird sandals with all the bumps. Nikon 8008, 60/2.8 lens, SB-24 lens with SC-17 cord

Let's combine what we've learned until now: the aquarium

Combining everything we've learned up to this point, let's look at a case study: the aquarium. The items inside are pretty close, so you need a macro lens. If you put a rubber lens hood on the front of the lens, then you can mush it up against the glass and avoid reflections. Now you need light. Well, you can just get a flash on an extension cord and point it into the aquarium from just about anywhere.

Here are some examples from the public aquarium in Monterey, taken with a Nikon 8008, 60mm AF macro lens (set for manual focus), SB-24 flash, SC-17 extension cord. I wiped the glass with a handkerchief, asked my friend to hold the flash, and pushed the lens hood up against the glass:

I'm still trying to figure out how I managed to get a lawyer in that last frame...

Focus

With a depth of field of around one millimeter for precise macro work, camera positioning and focus become critical. If you have a good tripod and head, you'll find that you have at least 10 controls to adjust. Each of them will move the camera. None of them will move the camera along the axis that you care about.

That's why people buy macro focusing rails. These are little rack and pinions capable of moving the entire camera/lens assembly forward and back. You use the tripod to roughly position the camera/lens and then the macro rail to do fine positioning.

I snapped the photos below in the garden of the Getty Center and, though I had a fancy Canon 180 macro lens, I didn't have a tripod. So I couldn't focus precisely and couldn't stop down enough to get sufficient depth of field. The results are rather disappointing...

Beyond 1:1 the Canon Way

In the Canon EOS system, going beyond 1:1 is as simple as calling up one of the photo.net recommended retailers and ordering a Canon MP-E 65 1X-5X macro lens. Mount lens on tripod, mount camera on lens, twist ring on lens, release shutter:

(Flower interior at above left was captured with a traditional EOS film body; the jelly bean image at above right was taken with a D30 digital body.)

Beyond 1:1 with Nikon, et al

Going beyond 1:1 requires more than buying a Micro-Nikkor and turning the focusing helical. In fact, you probably should read a real book by a real macro photographer. [Bob Atkins likes John Shaw's Close-ups in Nature .]

Here's a basic introduction to the tools, though...

First, you can get a bellows (flexible accordion) and/or some extension tubes. These will let you push the lens farther away from the camera body. Extension tubes are rigid and tough; they only let you separate your body and lens in fixed increments. Bellows are delicate but they let you continuously control the lens distance from the body. How much magnification this extra extension will get you depends on the focal length of the lens. If you have a 1000mm lens that already needs its nodal point 1000mm from the film plane to focus at infinity, then a 50mm extension tube isn't going to be worth much. However, if you have a 50mm lens, then that same 50mm extension will take you all the way to 1:1.

Second, you probably want a "reversing ring" for your lenses so that you can turn the back element of the lens toward your subject. Why? Think about the normal way you use a lens. You are taking a picture of the Statue of Liberty. The Statue of Liberty is larger than 24x36mm. So you point the front element of the lens at the statue and the back element at the (smaller) film. Your lens is designed to work like this, taking the large and compressing it into the small. However, if you are working at 10:1, where the tip of a pine needle is going to take up a big portion of the frame, you want the lens to take the small and expand it into the large. So you want to just flip the lens around.

Third, once you've reversed the lens, you probably want some way to retain the automatic diaphragm. You want the aperture to remain fully open until just before your exposure and then close down to the selected shooting aperture. My old Rollei 6008 had all-electric lenses so you could do this with a clean and reliable electric contacts. Nikon has mechanically stopped-down diaphragms for backward compatibility so they can't do this; you end up with a strange dual cable release contraption. Canon EOS has all-electric lenses but in 10 years they haven't figure out how to engineer a bellows or reversing ring so don't hold your breath (instead they make a kludge to adapt their ancient Canon FD macro system to the EOS).

Beyond 1:1 the Lazy Way

At left are a couple of Ant Robots built at the MIT AI Lab by James McLurkin. Photographed with Canon EOS-5 and Canon 50/2.8 macro lens (lit by off-camera 430 EZ flash). This lens only goes to 1:2.

At right is a detail of the ant claws, which was taken with the Raynox MicroExplorer. The Raynox is a set of close-up lenses available for about $150. I mounted the 6X lens on a Canon 35-350L zoom lens (the kit also comes with 12X and 24X lenses). Yes, in the end I stuck a magnifying glass in front of my lens.

Here is the original ant claw picture. You can see that vignetting was severe at f/16. Fortunately, I could see this in the viewfinder to a large extent with the DOF preview and Adobe PhotoShop papers over a lot of photographic sins. Vignetting is the principal drawback of the MicroExplorer and it is apparently worse at small apertures.

A couple more example MicroExplorer shots (at left is an Ant robot detail; at right is a quarter on a $20 bill, full frame at f/8 (I think)). Note that vignetting is not as severe as it was at f/16 (above left).

Back Off and Show the Terrain

Don’t set up every picture so that your friends are ten feet [three meters] away from your camera. Get some variety in your shots. Back up and show your surroundings.

Rather than make the two mountain bikers the main subject of the frame, the photographer hiked away to get an angle showcasing the setting.

Barrel Distortion Correction

..and Pincushion Correction Typically, wide angle lenses tend to suffer from barrel distortion and tele lenses from pincushion distortion. Both effects tend to be stronger at the extreme ends of zoom lenses, especially on compact cameras.

The good news is that for digital cameras, these problems can be rectified very easily. Here's how. Installing Panorama Tools Panorama Tools (download here for PC or here for Mac) is an excellent freeware plug-in for Adobe Photoshop Elements 1.0 and higher, and Photoshop 5.0 and higher. The plug-in allows for amazing barrel and pincushion distortion corrections. The Readme file of the plug-ins explain all the parameters. For those of you with limited time and only interested in barrel and pincushion distortion, simply install as follows for Photoshop in Windows 95/98/Me/2000/XP (for Mac and/or other software please refer to the Readme file): Place the file pano12.dll into the same directory as Photoshop. Place the files adjust.8bf, correct.8bf, perspect.8bf, and remap.8bf into the Plug-ins folder for 'Filters'. For the scope of this tutorial, these are the only files you will need. So don't worry about the other files in PanoTools.zip. Restart Photoshop. You should find Panorama Tools in the Filters submenu. For barrel and pincushion distortion compensation, go to "Filter-> Panorama Tools-> Correct". Highlight "Radial Shift", click on "Options", set 'a' and 'c' to zero for all colors, choose a value for 'b' and choose 'd' so that d + b = 1. For barrel distortion compensation 'b' must be negative, for pincushion distortion compensation, 'b' must be positive. Start with b = -0.015 or 0.015 (1.5%) respectively and increase or decrease until the picture is straight. The Readme file also explains 'a' and 'c', but you probably will not need those parameters. The sample pictures below are downsampled, but be assured that there is virtually no visible loss of quality or sharpness between the original before and after pictures, provided the Photoshop's default bicubic interpolation is used. The perfectionists among you may notice small differences when viewing the image at 400% or more. These differences are irrelevant to image quality and are definitely a bargain price to pay for the very relevant and obvious elimination of the distortion. Barrel Distortion Correction Notice the very curved horizon and right building in this wide angle shot. Settings: a=0, b=-0.016, c=0, and d=1.016 results in straight horizon and building. Another example of barrel distortion with wide angle lens. Settings: a=0, b=-0.018, c=0, and d=1.018 results in a straight window. Pincushion Distortion Correction Example of pincushion distortion with a tele lens. Settings: a=0, b=0.013, c=0, and d=0.987 straighten the building. After pincushion distortion correction you will have to crop the image about 25 pixels on top, bottom, left and right to remove the black pixels in the corners and around the edges resulting from the transformation. Conclusion Barrel and pincushion distortion can easily be eliminated without visible loss in quality.

This article is based on content of The 123 of digital imaging Interactive e-book, which explains barrel and pincushion distortion correction in more detail.

If You See It, Shoot It

Don’t spend all of your time and energy trying to get one perfect shot. Experiment and take as many pictures as you can.

If you see something that strikes you, photograph it. You may find that your spontaneous photos are better than the ones you spent a long time composing.

It’s easy to pass by a good shot. You might be out backpacking and think, “Do I really want to stop the group and pull out my camera to take this photo?” You have to. Because you might not see it again.

Storing Your Digital Images

If you value your digital images, you should have a proper backup system in place. In this article, we will look at two storage methods and some backup tips so that you can enjoy your images not only in the short term, but also much further into the future.

Magnetic Storage - Hard disks

The building blocks of digital images are "bits", which can either be "zero" or "one". Magnetic storage devices such as hard disks distinguish a "one" from a "zero" by changing the magnetic properties of the disk in that location. The great thing about hard disks is that their capacities are constantly increasing while prices are constantly dropping. Two hundred gigabyte (1) hard disks (3.5" IDE 7200rpm with 8 MB cache) currently retail under US$100. Such hard disks can hold about 70,000 six megapixel JPEG or 23,000 six megapixel uncompressed RAW images. That's about 700 JPEG or 230 RAW images per dollar.

Portable housings exist with built-in international 100-240V power supply, USB 2.0 (Hi-speed), and FireWire IEEE1394 connections, costing between US$50 to US$100. To avoid overheating, get a case with a large diameter cooling fan below the hard disk. Note that the market is gradually moving towards SATA (Serial ATA) drives and away from the older and slower IDE drives. However, the choice of external housings for SATA drives is still limited.

If you store images on your computer, it is recommended to store them on a dedicated partition (or if you have multiple hard disks, then ideally on a different physical drive) than your operating system (e.g. use C:\ for the operating system and software, and D:\ or E:\ for your images). This ensures that if your operating system crashes and you need to reinstall it, your images will be preserved.

(1) Usually "200" stands for 200 billion bytes, which is equivalent to 186 gigabytes.

Optical Storage - CDs and DVDs

Optical storage media such as CDs and DVDs are polymer disks which contain the "ones" and "zeros" as "pits" and "lands" that vary the strength of the drive's laser beam as it passes through the polymer and gets bounced back to the receiver via the "mirror", which is at the back of the printed top surface.

CDs

Writable CDs (CD-Rs) come in 650 and 700 MB versions. An average CD-R costs 25 cents and can hold about 250 six megapixel JPEG or 80 six megapixel uncompressed RAW images, so about 1,000 JPEG or 320 RAW images per dollar.

DVDs

Single layer DVDs (2) currently have a maximum capacity of 4.38 GB (3), about 6 times more than a CD. DVD drives can read CDs but not the other way around. A key benefit of CDs is that they are very universal. DVDs come in DVD-R, DVD+R, DVD-RW, and DVD+RW formats. Not all DVD drives recognize all formats but nowadays most DVD burners support at least -R and +R. It is not recommended to use -RW or +RW for long term archiving purposes as they are rewritable (and pricier). The -R and +R read-only formats prevent accidental overwriting.

(2) Double layer DVDs allow for 8.5 Billion Bytes but are less compatible.
(3) 4.38 GigaByte or 4.7 Billion Bytes (which is what is usually printed on the packaging).

Burning Tips

If you burn for example 300 MB of images onto a blank 700 MB CD-R and "close" the disk, you will not be able to add information in the future. However, if you select the "multi-session" option in your CD-writer software, you can add additional information in subsequent sessions in the future until the CD is full. Note that this is not without risks. Sometimes adding a new session can render previous sessions inaccessible. This is especially true if previous sessions were created using another CD-writer and/or burning software. One of many reasons to have more than one backup copy.

Most burning software packages have a "verification" option. This will considerably lengthen the burning session but is safer because the software will verify that the data on your hard disk corresponds to that on the CD/DVD. Burning errors are not uncommon, especially if you have been using other applications during the burning process.

Note that the "X" read and write speed specifications of DVD-writers are lower than those on CD-writers. However, for a CD-writer, 1X stands for 150 KB of data per second, while for a DVD-writer it is 1,385 KB/s or 9.2 times more. So an 8X DVD-writer will write as much data per second as a 74X CD-writer (8 x 1,385 KB/s = 74 x 150 KB/s).

Data Stability

Just like magnets become weaker over time, the magnetic properties of a hard disk will diminish in the very long term and can be affected by environmental factors such as strong magnetic fields. The materials which are used to make CDs and DVDs decay over time and the problem is that even minor changes in the data can make the whole disk unreadable. Different brands and different grades of optical media advertise different life spans. It also depends on how they are stored, how well you take care of them, how often they are read, etc.

But regardless of the above lifetime issues, even a simple scratch can render your CD or DVD unreadable. Hard disks are high precision mechanical devices spinning at high speeds, typically 7,200 rpm. So there is always the possibility of failure due to a shock or a power surge. But even without a physical failure, it is possible that you suddenly lose the content of your whole hard disk, e.g. due to corruption of the file structure. So it is important to have multiple backups because data recovery is tricky, as explained below.

Data Recovery

Once a CD or DVD is damaged or corrupted, it is very unlikely that you will be able to recover anything.

Chances of data recovery from hard disks are usually very good, but by no means guaranteed. Also, data recovery can be time consuming and expensive. So if you store your images on a hard disk, you should have at least one extra copy on another independent hard disk or on a CD/DVD. By "independent" hard disk I mean an external hard disk which is only connected to your computer when you do the backup. Two internal hard disks provide insufficient protection because both can be affected in case of damage due to lightning or loss of data due to a virus attack. Also avoid storing images in the root directory of a partition as that significantly lowers chances of data recovery via software.

Data Removal

Sometimes you may have the opposite problem: getting rid of your images permanently, e.g. destroy old backups or cleanup up your hard disk before you sell your computer. CDs or DVDs are easy to destroy, but securely erasing data from your hard disk is not as straightforward as it seems. There are plenty of affordable recovery programs which can recover data from a formatted hard disk. Formatting the hard disk, then copying dummy data to the hard disk until full capacity, followed by a format will prevent software based data recovery and should be sufficient for most of us (4).

(4) Advanced note: (expensive) hardware based recovery techniques used in forensics and intelligence agencies can reconstruct the overwritten data based on physical differences between areas which have been "zero" for a long time and areas which have been "one" for a long time and which were only recently changed into a "zero" via overwriting and erasing. More sophisticated erasing programs with multiple and random write-and-erase cycles will make even hardware based recovery impossible.

Long Term Storage: "Migrate, Consolidate, and Refresh"

If we think in terms of decades instead of years, certain media will become useless in terms of capacity, or incompatible, or both. A typical example is the floppy disk which can barely store a single 2 megapixel JPEG image and few computers still come with a floppy drive.

In the nineties, I used 80 MB "magneto-optical" disks (5). My magneto-optical drive only had drivers up to Windows 98, so I recently migrated these onto my hard disk via an older computer which still had a parallel port and Windows 98.

(5) They have characteristics of optical and magnetic storage and are very reliable. Currently they come in higher capacities but are less frequently used, rather expensive, and require a dedicated reader/writer.

Some of the CDs burned with older burners are no longer recognized by newer drives.

So to avoid compatibility issues, it is advisable to migrate your data to newer media. Since capacities of magnetic and optical storage are constantly increasing, you can at the same time consolidate your data. For instance, 500 floppies can be consolidated into a single CD, 58 magneto-optical 80 MB disks can be consolidated into a single DVD, 275 CDs can fit on a single 200 GB hard disk, etc. So once or twice a decade you will have to migrate and consolidate your old and small capacity media to the new and larger magnetic or optical media that become available. This has the additional benefit of "refreshing" your data to overcome the earlier mentioned issue of long term data stability.

Storage Cost

Medium	CD	DVD	200 GB Hard disk
Type	Optical	Optical	Hard disk - Magnetic
Cost (US$) (6)	0.25	0.75	100
Capacity (GigaByte)	0.68	4.4	186
Number of six megapixel JPEG images (7)	250	1,500	70,000
Number of six megapixel uncompressed RAW images (8)	80	500	23,000
Number of six megapixel JPEG images per US$ (7)	1,000	1,500	700
Number of six megapixel uncompressed RAW images per US$ (8)	320	660	230

(6) Estimation only. Prices vary a lot depending on where you buy, the quantity, the quality, the barnd, and the speed rating, and in case of DVD whether it is DVD+R or DVD-R.
(7) Estimated, depending on the compression and content of the image.
(8) Estimated, depending on the content of the image and the camera. Compressed RAW will allow for about 60 to 70% more images.

Since US$1 allows you to store hundreds of images, deciding whether or not you want to keep an image is not worth your time. So I just back up and keep everything I shoot. Then in a later stage I then create a second series with the best images. Image management will be discussed in a future article.

Magnetic Versus Optical Storage

.	Magnetic	Optical
Cost	Low, but higher than optical	Low
Compatibility	High	High for CDs, lower for DVDs
Data Stability	Relatively stable, but less than optical	Stable, but lifetime depends on quality
Accidental Deletion of data	High (9)	Low as it is read-only (10)
Environmental Resistance	Sensitive to shocks and power surges	Sensitive to scratches
Data Recovery	Excellent but can cost time and money	Virtually impossible
Backup Convenience	Very convenient	Requires burning
Reorganizing data	Easy	Requires re-burning
Traveling Convenience	One 200 GB disk is relatively compact	275 CDs or even 45 DVDs are bulky.

(9) Can be reduced by setting the file attributes to "Read-Only".
(10) As explained earlier, risks are higher for multi-session burning.

So if you make at least one magnetic and at least one optical backup, you are combining the benefits of both media.

Backup Tips

1. Always maintain at least two independent copies of your images, for instance:
- one magnetic and one optical (recommended)
- two magnetic (e.g. internal and external (disconnected) hard disk)
- two optical

2. To have even more peace of mind, consider:
- two independent magnetic backups and one optical backup, or
- one magnetic and two optical backups

3. As a protection against unfortunate incidents such as fire, tornados, floods, etc., store one of your backups in a different location.

4. Be careful with multi-session CDs or DVDs and make sure you verify the data.

5. When buying a new system, "migrate and consolidate" your data to new and larger capacity media. This will at the same time "refresh" your data.

This article is written by Vincent Bockaert, author of
The 123 of digital imaging Interactive learning Suite.
Click here to visit 123di.com

Capture a Moment

Try to capture a moment. Look for an expression or gesture or quality of light that elevates an image beyond the ordinary.

The next time you’re photographing a friend rock climbing, look for the moment when he’s stretching, his knee is up, he’s really going for it. When you are out kayaking, wait until his paddle is down and water splashes across the frame.

MAKING PHOTOGRAPHS

Most photography books start out talking about the various kinds of cameras that are available. Then they talk about lenses, film, and exposure. Only at the very end do they talk about light. Yet even though I'm a photography nerd and own about 20 cameras, I never think about making a photograph in this order. Pulling together light and subjects and composition occupy my mind first and foremost. Only when I've figured out all of that do I start rummaging through my equipment cabinet. So I decided to try to write a photography textbook that reflects the way that I think about taking pictures.

Is this the best textbook for beginning photographers? Certainly not. There are many excellent ones on paper, a few of which are reviewed in the dead trees section of photo.net. However, if you like this way of thinking about photographs and you don't have a paper book in front of you, this online book might be useful.