Jonathan's blog

I went out for a scout this afternoon to find some new places to take pictures. As well as finding good locations, I needed to know which lenses to bring next time. None of the stuff in this article is ground-breaking but I think it’s a useful rule of thumb (literally).

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.

I have a large music collection, and today I wondered how physically large it might be in various obsolete formats (not including the playback equipment).

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

A friend of mine is a researcher in the field of chemical physics. This week, he invited me to his lab to take a photograph of his 5 megawatt laser, which strikes a copper target and makes a plume of plasma that lasts for just a few fleeting nanoseconds. Normally, I like taking photos of landscapes or architecture, but there’s no way a geek like me can resist the invitation to play with a frickin’ laser.

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

Last year I wrote about the darkroom I had set up in my loft. Since then I’ve moved house, so I need to build the darkroom again. This time I have a windowless utility room on the ground floor, with running water and a worktop, so it’s already better than what I had before. Here’s how I’ve set it up.

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’m no stranger to medium format photography. I’ve owned a few box cameras, a basic folding camera, and a cheap TLR for a while. Last year I started to take it seriously by buying a Mamiya RB67 outfit. I’ve been using it mainly for landscape photography and perhaps inevitably, I ran into the need to have movements on the camera.

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

I decided to have a quick count of the film I have in stock.

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!

Once in a while, you might run into a situation where you need some extra RAM (or swap) for a short time. (I ran into this situation today while stitching some really enormous images in Hugin). Adding a new swap partition isn’t practical if you only need the extra swap space for a short time.

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

Processing black & white film at home is easy. You just need a changing bag to load the film into a tank in darkness, and the rest can be done in the bathroom with the light turned on. The chemicals for black & white are normally used at 20°C but can be used at room temperature if you compensate for the time. You could even pop the chemicals in the microwave for a few seconds.

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!

Background

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.

I love photography, and I have an interest in astrophysics and astronomy. It only makes sense to combine them, and have fun with astrophotography. But which equipment is best for the beginner without breaking the bank? Let’s explore the options.

Some interesting photographs can be captured using a wide-angle lens to view the whole sky, but here I am specifically talking about long, telescope-like lenses. There are three solutions that I have at my disposal:

• Meade 60AZ 700mm f/11 telescope, with T-mount adapter for 35mm SLR or DSLR
• Tamron 70-300mm f/4-5.6 telephoto lens, native mount on DSLR with 2× teleconverter to make it a 600mm f/11
• Tokina 400mm f/5.6 telephoto lens, native mount on 35mm SLR with adpater for DSLR and 2× teleconverter to make it a 800mm f/11

So the “zoomiest” lens is the Tokina but that isn’t the only factor. Which lens is sharpest? What about chromatic aberration? What about other things affecting practical use for astrophotography?

First let me say a few words about each lens (and offer my apologies for the quality of the photos of the lenses – as you can see, my DSLR is in each picture so I was using my phone).

Meade 60AZ

The Meade 60AZ is an inexpensive 700mm telescope. The front element is 60mm in diameter, making it an f/11.7. There’s no variable aperture. It has the usual 1.25″ eyepiece fitting, so it’s easy to get hold of an adapter to turn this into a T-mount fitting. Once you’ve got T-mount, well, Bob’s your uncle, and you can adapt T-mount to anything else – including 35mm and digital SLR cameras, such as my AE-1P, EOS 450D and EOS 300. I bought mine from a car boot sale for £15, and then paid about £20 for the adapter to mount the camera.

Meade 60AZ on Canon 450D

It has an optically simple design with few elements, so chromatic, comatic and spherical aberrations may not be so well corrected for. This isn’t important for viewing by eye with an eyepiece, but aberrations show up more significantly in photographs that can be studied. Technically it is not a telephoto lens, since it does not have a telephoto group, and is correctly known as a long-focus lens.

Being a telescope, it comes with its own tripod which is a little flimsy, but easily capable of taking the weight of a camera.

Tamron 70-300mm

The Tamron 70-300mm is an inexpensive autofocus SLR zoom lens, offering a maximum aperture at 300mm of f/5.6. It mounts natively to the Canon EF mount, for use with 35mm and digital SLR cameras, including my EOS 450D and EOS 300. The 13 elements are coated to reduce flare and correct for various aberrations. My sample was bundled with my 450D at Jessops, but it costs around £100 new at the time of writing. I bought a Kenko Teleplus teleconverter for £30, second hand.

Tamron 70-300mm on Canon 450D

Autofocus is practically useless for astrophotography since there isn’t enough available light. On this lens, the focus ring is quite sensitive, undamped, and hard to use accurately. This will count against it in practical use.

Using a 2× teleconverter will double the effective focal length to almost match the Meade telescope, at the cost of a couple of stops of light and some sharpness – but still faster than the telescope.

This lens does not come with a tripod mounting collar but should be used with one, since the fully-extended lens with teleconverter is quite heavy, and unstable when the tripod attaches to the camera.

Tokina 400mm

The Tokina 400mm is a fixed focal length prime lens, with a maximum aperture of f/5.6. With a 2× teleconverter this gives me the longest effective focal length at 800mm while still being faster than the Meade telescope. It’s a manual focus lens with a large and well-damped focus ring which actually makes it easier to use than its contemporary rival, the Tamron. I paid £50 for this lens, second hand, and the Super Paragon teleconverter was about a fiver, I think.

Tokina 400mm on Canon 450D

It mounts natively to Canon FD-mount manual focus cameras like my AE-1P, but will work with Canon EF-mount EOS cameras with an adapter, which I wrote about recently. This adapter has the effect of making the lens a bit zoomier. I haven’t exactly measured the amount, but it could make this 800mm lens produce an image like a 900mm. We shall see.

This lens also does not come with a tripod mounting collar but should be used with one for best effect, because it is long, metal and heavy. They sure don’t make lenses like they used to.

Sample images

This article is about astrophotography really, but taking test photos of the moon or other celestial objects means carrying equipment to a dark place. I’m not sure I can be bothered to carry these three heavy lenses and two tripods and other accessories out at night, so for now you’ll have to make do with these images of the chimney at Frenchay Hospital, which is about one mile away. This is a city, so the atmosphere is quite hazy.

These pictures were taken with a Canon EOS 450D. The main images are exactly as they came out of the camera – no editing. The second images are cropped around the top of the chimney to show fine detail.

Meade 60AZ

Meade 60AZ

It’s immediately obvious that the image from the Meade telescope suffers from very poor contrast and colour saturation. This is perhaps obvious given its inexpensive and crudely coated elements. It might be possible to improve the contrast by using filters and shooting in black & white, since colour isn’t always important in astrophotography.

In its defence, the sharpness is good and I’m frankly shocked at how small the chromatic aberration is, given that this is a cheap 2-element lens.

Tamron 70-300mm

Tamron 70-300mm

The Tamron 70-300mm, a modern multi-coated lens, has no such problems with colour and contrast. The colours are vibrant and bold. However, it suffers badly from chromatic aberration. We might expect this from a cheap zoom lens – the effect will be less prominent with a fixed focal length prime lens.

As before, it might be possible to reduce the effect of chromatic aberration by using a coloured filter and shooting in black & white.

Tokina 400mm

Tokina 400mm

It’s immediately obvious that the Tokina 400mm is the zoomiest lens, with its teleconverter and FD-EF converter to mount it on the 450D. The colours and contrast are good, especially for a lens manufactured in the 1970-1980s.

The effect of chromatic aberration is also extremely small, presumably because it is a fixed focal length prime lens. I think the overall image quality is best out of the three lenses tested here.

Summary

The Tokina 400mm definitely seems to be the most useful for astrophotography and lunar photography. It has the longest effective focal length, the best sharpness, the best chromatic aberration and reasonably good contrast. Its manual focus ring is easy to use

Don’t forget that these images aren’t the best that each lens can produce – they are the lowest common denominator of what each lens can do. With careful processing, the images could be sharpened and have their contrast boosted. For some subjects, it might be appropriate to stack the images. For certain images, coloured or other filters could be used to work around the effect of chromatic aberration and atmospheric haze.

In the past, I experimented with a catadioptic mirror lens but the results were not great. In theory, mirror lenses should be well suited to astrophotography, so perhaps I had a bad sample. I also wrote some thoughts on other types of long-focus lenses for general use, and some of it might be relevant to astrophotography.

That’s enough discussion of lenses. I’m now waiting for a clear summer’s night when I can go for a short drive out of the city and hopefully capture some great images of the moon, and maybe other things in the sky. I should probably read up on astronomy so I know what to point the camera at!