Capturing the best source image

It’s important to capture the best raw image data that we can, which will make the whole process easier. In this guide, I am assuming that you have a DSLR with a removable lens. Most of the advice also applies to film SLRs and digital compact cameras though, so don’t worry if that’s what you have.

Equipment

The lens has a lot more to do with the picture than the camera. For shooting the Moon, I recommend you use a telescope or a telephoto lens. The longer the focal length, the better. For most people, this means using a 70-300mm zoom lens, although if you have a 500mm camera lens, or a telescope which can be anywhere from 700mm up to 2000mm, then you can use that. On most crop-sensor DSLRs, a focal length of about 1400mm will make the Moon fill the viewfinder.

Tokina 400mm f/5.6 on Canon 450D

If you want to get a bit more reach, you could use a teleconverter. This fits in between your lens and your camera, and effectively multiplies the focal length of your lens – at the cost of losing some of the light and sacrificing some sharpness and quality. Common teleconverter sizes are 1.4×, 2× and 3×.

Kenko Teleplus MC7 2x Teleconverter

At these long focal lengths, the tiniest vibration will make your picture blurry. A tripod is absolutely essential – the sturdier the better.

Always use a cable remote to trigger the shutter without touching the camera. All SLRs support these, but most compacts probably won’t. If you can’t use a cable remote, the self-timer is your second choice. Set the timer, carefully press the button, and hope that the vibrations have died down by the time the photo is taken!

Canon Remote Switch RS60-E3

If your camera has mirror lock-up, you should always use it. This means the first time you press the button, the mirror flips up and the viewfinder blacks out. Then you wait a few seconds for the vibrations to die down, and then press the button again to fire the shutter. Mirror movements are a common source of vibrations and are probably the biggest cause of blurry Moon photos.

Technique

Forget autofocus. If your camera has a manual focus option, use it. It will be more accurate, faster, and will prevent your camera from re-focusing on each shot you take. If your SLR offers live view, use that and magnify the view if possible. Once you’ve set the focus, leave it alone

The Moon is bright (brighter than you think) and it is set against a dark sky. This really confuses the camera’s auto exposure, so it’s best to use full manual mode (usually marked M on your camera dial). You’ll need to tinker with the settings, but if you set the ISO to 200 then some reasonable starting settings for the full Moon might be a shutter speed of 1/250 and an aperture of f/11. Take a few snapshots until you get an exposure that looks about right. The most common mistake is to overexpose the Moon. We often think of it as being white, but it should be grey in the camera.

Keep your shutter speed fast. If you let it get too long, you will start to get motion blur. Shoot at least as fast as 1/250.

Choose a middling value for your aperture. Most telephoto lenses have a maximum aperture of around f/5.6 at full zoom. Usually this gives poor image quality, so it helps to stop down a few stops. Usually f/8 or f/11 is OK. Much smaller than that, and you start to lose sharpness again due to diffraction. If you’re not sure where your lens’s sharpest aperture is, check some reviews. Failing that, a good rule of thumb is the the sharpest aperture is 2-3 stops down from the widest.

Feel free to set the ISO as high as you like. You may be aware that higher ISOs cause more noise in the picture – especially in low light conditions. This is absolutely true, but in this case it doesn’t matter. We will discuss effective noise reduction techniques for astrophotography later in this guide. If choosing ISO 1600 enables you to keep a fast shutter speed and to use the sharpest aperture, so be it. Don’t be disheartened by the grainy pictures that come out – these are not the end product.

For reasons that will become clear in a minute, once you’ve found the ideal focus and exposure, you’ll need to take a few near-identical pictures. The Moon will naturally drift across the viewfinder – this is fine. You might want to place the Moon in one corner of the viewfinder and repeatedly take photos until it reaches the other side. Anywhere between 3 and 10 pictures is fine – just don’t forget that when shooting repeatedly, you still need to give vibrations time to die down after each mirror lock-up.

This next picture shows how fast the Moon moves across the sky. These exposures were taken just three minutes apart each, using a 300mm lens. Even leaving time to fiddle with the mirror lock-up between each exposure, you ought to be able to shoot at least one picture a minute, which will give you quite a few pictures at the end of the session.

Moon moving across the sky

Post-processing

Now that you’ve taken a handful of source images, we need to work on them to bring the best out.

Stacking

Stacking means taking a set of similar images, shifting and rotating them so they line up, and adding them together. This has the effect of averaging out noise from your camera, and distortions from atmospheric turbulence. The best free piece of software for Windows is called RegiStax. Those using Linux might want to consider ALE.

I wrote about ALE on this very blog not so long ago, but if you need a helping hand with RegiStax then I recommend you read this RegiStax tutorial. For the mostpart, you just follow through the steps it gives you – but there are a lot of scary options.

No matter which program you decide to use, after stacking, you will end up with a single image file which will look like a slightly improved version of a single frame. Now we move on to post-process this image in a more conventional photo editor. If you have Adobe Photoshop and you are familiar with it, then use that. I prefer to use GIMP which is similar to Photoshop but also free. It runs on Windows, Mac or Linux.

Colour channels

If you are shooting the Moon, it is effectively black & white, so we can do a trick with colour channels to improve sharpness at the cost of converting the image to actual black & white. (This doesn’t work if you want to end up with a colour photograph, by the way. If you’re shooting colour images of planets or similar, skip this step). Open your stacked image in GIMP.

Go to the Colours menu, Components submenu and choose Decompose. Make sure colour model is set to RGB, uncheck “Decompose to layers” and press OK.

This will split your colour image into its red, green and blue components, each of which opens as a new monochrome image. Now you can close the original image to save confusion.

Examine the three monochrome images you’ve got. They should be similar, but subtly different. Which one is sharpest depends on how much light pollution there is in your area, what colour it is, how well your lens/telescope performs at different colours and a million other factors. Zoom into each picture at 100% (do this by pressing 1) and have a look at the craters for comparison. When you’ve chosen the sharpest image, close the other two.

Unsharp mask

One of the best techniques for sharpening a slightly blurry picture is to use an unsharp mask. I won’t go into the theory here, but the basis of a blur is that a tiny dot becomes a small circle. Unsharp masking studies the image, and tries to convert the small circles of blur back into dots.

For this to work, we need to estimate the radius of the blur. Zoom into your image as far as possible (1600%) so you can clearly see the individual pixels as squares. Find an area of high contrast – either the edge of the Moon, or the edge of a crater. The edge of a crater or the lit edge of the Moon should be a sharp, defined line, but you’ll see that it is actually a gradual change, a few pixels wide. Count the number of pixels that it takes to cross the boundary.

In this example the middle red line (roughly) shows where the true edge of the Moon is. The outer two lines approximately show where the blur extends to. The distance between the two outer lines is roughly 5 pixels in this example. Work out the equivalent number for your image, and remember it.

Go to the Filters menu, Enhance submenu, and choose Unsharp Mask. Set Radius to the number you found in the previous step. Amount is set to 0.5 by default but you can change this if you wish. Numbers between 0.5 and 1.0 seem to work best.

Scroll around in the preview window to look at interesting parts of the image. Repeatedly tick and untick the Preview box so you can see what effect the unsharp mask will have. When you’re happy, press OK.

Colour curves

The name is a bit misleading – colour curves don’t have anything to do with colour in this context. They are a good way of enhancing contrast, though. Bring up the curves window by going to the Colours menu and clicking on Curves. The default “curve” is actually a diagonal line.

Arrange the curves window and your image alongside each other so you can see both at the same time. Drag the shape of the curve into a gentle S-shape. The exact shape and amount of the curve depends on your needs, but have a look at the next two screenshots to see what effect the curve has had. Click on the images to view them larger and use the arrow keys to go back and forth. You can immediately see that the dark patches are darker and the pale patches are paler.

Saving

That’s it! You’ve now finished all the basic editing in this tutorial. Save your image, but make sure you do Save As and choose a different name, so you don’t overwrite your original.

Summary

This guide touches upon a few of the most common techniques in astrophotography. It is by no means the ultimate guide. If you’ve got any questions, extra tips or if you spot any mistakes in this guide, please comment and let me know. Also, I encourage you to post your Moon photos at the bottom of this page, share your work and show off what you’ve done.

Further reading

On this blog

• Lenses for astrophotography – a comparison
• Astrophotography and stacking software
• Long telephoto lenses
• Mirror lenses: worth it?

Elsewhere

• RegiStax tutorial
• How to Photograph the Moon and Planets with Your Digital Camera
• Digital SLR Astrophotography

For now, let’s forget about lens focal lengths in millimetres and think of the angular field of view of a lens. Hold your arm out straight in front of you. You can judge the angular size of a distant object by comparing it against the angular size of different parts of your hand.

Image from http://chandra.harvard.edu/photo/scale.html

So when you get home, you’ve got a list of places and the field of view you need to take each photo. Now you can use this table to figure out which lens you’ll need to give you that coverage. I’ve rounded the focal lengths to the nearest commonly-found focal lengths for APS-C DSLRs, 35mm full-frame (D)SLRs, and medium format cameras.

So to give a real example, if you are out on your scouting walk, and you note that you can cover part of a landscape with the palm of your hand, you know the angle subtended by the landscape is 10° and that you’ll need a 135mm lens for your DSLR when you return.

I hope this is useful to someone – I’ll certainly be using it from now on.

1. Usually the diagonal angular value is given, but in this example I think it makes more sense to use the horizontal dimension.

SD card	MiniDisc	CD
Cassette	LP	1/4" tape

In its current form, it is stored on a hard disk as 59GB of MP3 and other digital compressed formats. It has a total playing time of 718 hours – just a touch under a month.

OK, so EP was a slightly facetious choice of format for storing an entire music library, but if we compare the SD card to a stack of LPs, the LPs weighs 86,000 times more, and is 248,566 times larger. In fact, the LPs would be about the same size as a wheelie bin, and weigh as much as two people.

While the reel-to-reel tapes are a bit smaller, they also weigh almost half a ton!

If you’re curious about the definitions I’ve used in these back-of-the-envelope calculations, see the following section.

Definitions

• Audio CD – Playing time 80 minutes, in hard jewel case with paper inlay
• MiniDisc – Playing time 74 minutes, in hard case
• Cassette – C60 cassette, playing time 60 minutes, in standard hard plastic case
• Reel-to-reel – ¼” 1800′ tape on 7″ reel, 7½ips playback speed, playing time 48 minutes, in card box
• LP – 33¹/₃rpm 12″ vinyl, playing time 50 minutes, in thin card sleeve
• EP – 45rpm 12″ vinyl, playing time 25 minutes, in thin card sleeve

Naturally such a powerful laser is potentially rather dangerous, so I was under strict instructions not to touch anything, lest I get my hand zapped off or something. Laser safety goggles were the order of the day. As they say, “do not stare into beam with remaining eye.”

Laser sign

The laser table is large and complex. The laser itself is on the far side of the table, behind the computer screen. The beam then bounces around various mirrors and lenses in the section of the table on the left, which has black safety screens to catch any stray reflections. I am told that if any dust gets on the mirrors, it will absorb enough laser energy to become hot enough to damage the mirror.

The beam then enters the metal tube at the front of the table, and finally zaps the copper target in the square metal box in the near-left corner. The box contains a near-vacuum, with a pressure of just 3 ten-billionths of normal atmospheric pressure. The box has an observation window, and if you look carefully you can see my black camera over the hole, peering through the window.

The white box in the very foreground is a specialised laser detector, fitted out with all sorts of gizmos, including the computer on the trolley.

Laser table

Finally, the image we’ve been waiting for. This picture shows the inside of the box. The green laser beam enters the picture from the right, but you can’t see it because there is no mist or smoke for it to reflect from. The centre of the bright flash is where the beam strikes the copper, and you can see a bit of green in there. The plume of plasma then spreads back along the beam, heading right. It isn’t also going left – what you can see there is a reflection of the plume on the shiny copper surface. Not sure what else I can say about this. I’m no expert!

Laser plume

Click for a larger version, and see below for a bit more explanation. Apologies for the poor quality of this picture – I used my phone as my DSLR is currently tied up in a laser lab at Bristol university’s chemistry department. Hopefully photos to follow!

1. Safelight. This is a very old Paterson safelight, emitting just a dim red glow. Note that this is only suitable for black & white paper – all films must still be handled in total darkness.
2. Liquid concentrates – Various Ilford products, (including Multigrade developer, Ilfostop and Ilfotol), Rollei Digibase C41 chemicals and a bottle of Agfa Viradon New sepia toner.
3. Powdered concentrates – At the moment, just Ilford Microphen. Usually I would choose to use ID-11, but someone gave me 15 litres  of Microphen powder, so who am I to complain!
4. Universal film tanks. These are Paterson tanks and can take 35mm, 120 or 127 film.
5. Graduates, or as most people call them, measuring cylinders. I don’t know why the photography word is different. I also have some funnels for getting stuff back into bottles and some measuring jugs.
6. B&W film chemistry, diluted and ready for use in processing black & white films.
7. Gloves. Developer is quite alkaline and can make your hands sore if you handle it too much. Wearing gloves also helps prevent getting fingerprints on the film.
8. Colour C41 film chemistry – in this case, Rollei Digibase C41. It is diluted and ready for use.
9. Paper squeegee for getting most of the water off finished prints.
10. Film squeegee for getting most of the water off processed negatives. Seems that most people are divided on squeegees for film – they avoid water drying marks, but can cause scratches. Always clean your squeegee!
11. Scissors for cutting film up.
12. Pop-up drying rack for hanging prints over the sink to drip dry.
13. Rinsing tray. This is a normal paper tray, but I made some holes at one end so water trickles in from the tap, over the prints, out of the holes and down the drain. It’s an effective way of washing prints and saves buying an expensive print washer.
14. Paper processing trays for developing, stopping and fixing prints. There are extra trays in the cupboard under the sink for occasions where I also want to tone prints. I also have other sizes.
15. Paper easel. This one is a Durst 8×10″ but there is plenty of room for a larger easel on the baseboard.
16. Dust blower for getting dust off negatives before printing from them. It’s a Giottos Rocket Blower, and works well.
17. Focus finder for inspecting the magnified grain in the negative before printing.
18. Warm water bath. C41 colour processing must be done at 38°C, so I fill this wallpaper pasting trough with warm water and place the bottles of chemicals and the film tanks in it.
19. Thermometers & pencils, also some stirring rods. The thermometers are used to check temperatures of chemicals (20°C for black & white, 38°C for colour). The pencils are essential for making notes about the prints I make, so I can make more copies the same way in the future.
20. Enlarger. Mine is an LPL C7700 medium format enlarger, and can make prints from negatives as large as 6×7cm. I have 50mm and 75mm lenses for 35mm and 120-format negatives.
21. Work light, because sometimes you need to see what you’re doing

Not pictured:

• A clock that ticks loudly so I can time things in the dark
• A room thermometer so I can estimate how warm the chemicals on the shelves might be without having to check.
• A place to hang films to dry. A 36-exposure film is about six feet long, and obviously won’t fit on my print drying rack above the sink!

Most of the photography-specific equipment was purchased either from FirstCall Photographic or second-hand from eBay. Most of the more generic fixtures and fittings were bought from Ikea or other DIY shops.

If you are a darkroom enthusiast, buy Ilford film, paper and chemistry! It might not be the cheapest brand but it’s probably the best and it’s good to support a British company. Too many traditional photographic companies have discontinued products, changed focus or shut down entirely. Support traditional photography, and buy more film!

I don’t have a scanner or an enlarger capable of taking 5×4″ negatives, and with the added cost of the sheet film, it would be an expensive venture. So I decided to buy a medium format technical camera, aka field camera. After looking around, I settled on one of the Horseman cameras – 970, 980, 985, VH or VH-R.

Horseman 980

But this isn’t my life story, nor is it a review of the Horseman 980. This is supposed to be a few snippets of information that I have found out for myself about the 980, and have decided to publish here given the scarcity of information about the Horseman 6×9 technical cameras.

Mamiya RB67 backs

Compatibility with RB backs is an important factor for me, since I already have several Mamiya backs for my RB67. Information is hard to come by, but as far as I can gather…

I think this can be roughly summarised to say that the Horseman cameras with rotating backs can take Mamiya RB67 backs. The older ones can’t.

The baby Graflok mechanism is the same, but the older Horseman models have raised silver metal areas around the film gate that do not allow the Mamiya backs to get close enough to the camera body for the sliding Graflok blades to mate. To mount a Mamiya back on a Horseman 960, 970 or 980 you will need to modify the camera itself. I haven’t seen a later Horseman body to compare.

Horseman 980 film gate

Film counter

This note particularly concerns the older roll-film back (pictured) with a chrome knob advance rather than a lever – although I have no idea if the same also applies to the lever-advance backs.

Horseman old-style 6×9 back

When loading a new film, there is no painted or engraved mark to align with the arrow on the paper backing. Instead you have to wind the paper on until you see the arrow peeping through a hole in the pressure plate. At this point, you close the back and wind until number 1 appears on the film counter.

However, in my experience, this means the film is wound about 5cm too far before the first exposure, meaning the last exposure is cut off. Now that I’m aware of this, I’ll just advance a little less to begin with. After I’ve figured out the best way of doing this reliably, I’ll comment on this post.

Shutter release

These Horseman cameras do not take a standard cable release. The standard type of cable release found on 99% of (non-digital) cameras has a small screw thread on the tip of the cable, and screws into a socket somewhere on the camera or lens. There is no threaded socket on the Horseman lenses. Instead, there is a tube that the cable release sits in, with a screw clamp to hold the cable in place. Sounds OK, except the diameter of the tube is 6.5mm and almost all cable releases are too thin to be gripped by the clamp.

Horseman cable release socket

The Horseman cable releases seem extremely rare – I haven’t found one anywhere online. There is also an adapter that exists but is very rare. I’ve searched extensively and found them only occasionally supplied with lenses – never on their own. I’ve pinched this photo from an eBay auction, to illustrate what the adapter looks like. It’s the small chrome thing in the shutter release hole.

Lens with shutter release adapter

I’ve contacted the Analog Photography Users Group and a camera shop that sells Horseman accessories, but neither were able to offer any insights.

I have worked around this by taking a standard cable release and wrapping it in a few layers of electrical tape to fatten it up a bit, so it gets clamped in the Horseman shutter release. It works reliably enough for me, and even looks OK when mounted.

Modified cable release

Modified cable release in Horseman socket

Film

It seems I have 37 rolls of 120-format film, and 10 rolls of 135 (35mm) format. That’s a total of 730 pictures, assuming I shoot the 120 film as 6×7 negatives with 10 frames per roll, and the 135 film with 36 frames per roll. That’s getting on for around £200 worth.

For comparison I’ve also included a tiny 8GB MicroSD card which would be able to hold about 3000 pictures from my DSLR.

In stock, I have:

• Ilford FP4 Plus (my favourite B&W film)
• Ilford HP5 Plus
• Kodak Ektar 100 (my favourite colour negative film)
• Fuji Pro 160 NS
• Ilford Pan 100
• Tudor 200 (embarrassingly cheap, but cheerful)

Film is fun, kids!

If you have enough space in your home directory (or elsewhere on your filesystem) then you can use this as a temporary swap file without making a partition.

First we allocate the file that will be used as swap. This is where we set the size. In this example, I’ve chosen 10GB.

truncate -s 10G ~/tempswap

Now we tell this file to be a swap file:

mkswap ~/tempswap

And finally we can tell our system to use the new swap file (on top of any existing swap files):

sudo swapon ~/tempswap

To check on your memory and swap availability and usage, try:

free -m

This swap file won’t be used as swap on next boot unless you add it to your /etc/fstab, but you’ll still have to delete the file to get the space back. To clear up after yourself manually, do this:

sudo swapoff ~/tempswap
rm ~/tempswap

Many amateur darkroom enthusiasts (until recently, me included) are wary about developing colour film with the C-41 process, on the assumption that it is difficult, confusing, expensive, or all three.

It is true that colour process has to be more accurately temperature-controlled, and that the development should be done at 38°C. Immediately, this conjures up images of having to buy an expensive electronic water bath, such as the Jobo CPE-2. These machines do help, and they do cost hundreds of pounds. However, they’re not necessary. The development usually takes only 3-4 minutes and the later stages do not have to be quite so accurately controlled. This means it’s possible to use a plain warm water bath.

It’s not too expensive or confusing, either. There are beginner’s kits such as the Rollei Digibase C-41 LT20 which include all of the chemicals you need, with instructions. I paid £25 for a kit that can do about 20 films. There are bigger kits which are better value too, and it’s possible to restock on the individual chemicals in future. I’m no expert on the C-41 process, so you should probably read up on C-41 chemistry yourself.

I bought a wallpaper pasting trough for £2 and made a cardboard lid with holes for my bottles and tank to stand in the water. I filled the trough with water at 50°C and stood the bottles and tank in the water to reach the right temperature. The temperature of the water bath fell rapidly at first, and then slowed down. After about 5 minutes the water bath was at about 40°C so I waited until the temperature fell to 38°C, checked the temperature of the developer as well as the water bath, and set the development process going. The thermometer still read 38°C after the development was up.

By the end of the entire process of developing, stopping, bleaching, fixing and stabilising, the temperature of the water bath had fallen to 35°C, but this is still within tolerances.

My message to photographers who are wary of processing colour film at home: don’t be. You have to be careful, but you don’t need any special equipment other than what you’ve already got for your black & white work.

Have fun!

I’ve dabbled in infrared photography a few times, originally using Maco 820c. The results were varied and I didn’t shoot it often enough to get a good feel for it. More recently, I bought some Efke IR820. If you’re reading this post, you presumably know vaguely about the film already, so I won’t go on about it.

I decided to make a renewed attempt to understand how to expose the film reliably so I can start taking decent shots with it. I don’t have a proper light meter. If I can be bothered to carry my DSLR, it makes an excellent spot and average meter. If not, I use an iPhone app called Pocket Light Meter, which is surprisingly good.

There are various methods of metering for infrared film. The light meters in some SLRs can meter infrared accurately through the filter; unfortunately the one in my Canon AE-1 Program doesn’t. Some photographers work out an “effective ISO speed” for their combination of film and filter, and use this with an unfiltered light meter. Different forums recommend different effective speeds and it’s hard to compare filters. The only way to work out what’s best for you is to sacrifice a couple of rolls to trial and error.

Filters

I am using a generic 720nm filter, which is a little stronger than a Hoya R72. The most comparable branded filter is a Wratten #88A. Refer to this comparison of infrared filters if you need to work out which type you’ve got.

Using Efke IR820 with an #88A filter, I decided to start with a speed of roughly 1.5 ISO. If using my DSLR’s light meter, this means metering at 100 ISO and then adding 6 stops of exposure. If using my iPhone light meter, I can meter as low as 6 ISO and then add 2 stops. I bracketed my exposures by varying amounts, and recorded the exposure information, and the way I arrived at it.

Procedure

I decided not to “waste” the film by risking taking badly-exposed artistic shots, but instead to take technically interesting shots that included foliage, sky, clouds, concrete, water, and other materials as a learning exercise. Once I’ve learnt the right effective film speed and the right amount of compensation for my meter readings, it’ll be easy to go out and take well-exposed shots almost every time. Then I can focus on taking artistic photos for publication.

My procedure was like this:

• Take one frame without the IR filter, using the camera’s meter set to ISO100. This is to rule out development errors later on.
• With the filter on, take infrared photos using any method you like for metering. This might include using the camera’s meter, a handheld meter, intuition, the sunny-16 rule, or something else.
• Bracket the exposures by ±2 stops, so you have a choice of exposures to study later.
• Record what each exposure was of, the aperture, the shutter speed, and importantly, how you arrived at the exposure. I kept a table like the one below (and these examples are a selection of my actual data).
• After developing, and making sure the unfiltered exposure is correctly exposed and developed, I inspected each negative and decided which were under- or over-exposed, and which ones were OK. Then I have a handy reference of which metering methods gave the best results.

My results

From studying the data I gained from these 39 exposures, the best-exposed images were achieved with a handheld meter set to ISO6, and then adding 2 or occasionally 3 extra stops of exposure. This indicates that the effective film speed of Efke IR180 with an #88A filter is ISO1.5 – ISO0.75.

The reason that the exposure compensation varied between 2-3 stops is probably due to the makeup of the composition of each scene. Foliage comes out near-white in the infrared region, but is relatively dull in the visible spectrum. The handheld light meter wouldn’t take account of this, so scenes with a lot of foliage probably need +2 stops added. Scenes that include a lot of sky, which is rendered black in infrared, will probably need +3 stops.

To see all of my favourite shot from the roll, see my photo blog.