Jonathan's blog

Whether or not they have an interest in astronomy, at some point most photographers are likely to take a picture of the Moon. There’s a lot more to astrophotography than you might think, so I’ll walk through this step-by-step guide on shooting the Moon.

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

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!

In 1987, Canon introduced their new autofocus-capable EF lens mount for their EOS series of cameras – including today’s digital SLRs. It was incompatible with the older manual focus FD lens mount. The flange focal distance of the newer EF lenses is slightly longer meaning that an adapter for mounting FD lenses on an EF body must contain an optic to allow infinity focusing. This immediately means the image quality will be affected by the adapter. But to what extent?

I bought a Kood adapter (although there are many, many brands available) to use my FD lenses on my EF-mount EOS 450D camera. For £15, I thought it would be a fun way of getting some extra use out of my FD lenses, even if the quality wasn’t great.

Kood FD-EF adapter

The competitors

I decided to do a side-by-side comparison of my Canon 50mm f/1.8 lenses – FD and EF mount respectively. I shot at ISO400, 1/60s, f/4 with flash. (Perhaps some other time I will think of this experiment when it’s not dark, and try it in daylight.) The camera was on a tripod.  I used autofocus and centre-weighted program exposure with the EF lens. I used the same shutter and aperture settings for the FD lens, and focused manually using live view, magnified to 10× in on the LCD.

Canon FD 50mm

Canon EF 50mm

Results

For a start, you might notice that the FD lens is slightly more zoomed-in than the EF lens. This is a side-effect of the correction optic to allow infinity focus. I’ll show both photos here, including 100% crops at 1024×768. Click the images to view them at this size. Other than cropping, no sharpening or any other editing has been done on these images.

EF lens	FD lens
EF lens	FD lens
EF lens (100% crop)	FD lens (100% crop)

I am honestly staggered by these results – the sharpness of the FD lens is much better than that of the EF lens. It’s possible that the autofocus didn’t do its job properly but it does prove that this third-party FD-EF mount adapter isn’t so terrible. I can only speak for mine – I’m sure there are terrible ones out there.

Pitfalls

There are some other things to be aware of though. Obviously the FD lenses don’t support autofocus, so you have to focus manually. This is no problem on a genuine manual focus SLR body, but autofocus SLRs lack the split-circle and microprisms on the focus screen, so it’s a lot harder to focus using the viewfinder. Using live view is a workaround, and it is also possible to swap out the focus screen for one with a split-circle, microprisms, or both.

While FD lenses do support an aperture controlled by an FD body, it won’t work using an adapter like this. You will need to take your meter reading using any appropriate method, and then set the aperture – this is stopped-down metering. The viewfinder will darken when the aperture is stopped down. This particular Kood adapter has a switch to flick between fully open and stopped down, which helps.

Summary

But if you are in the same position as me, with an EOS SLR and a load of FD lenses, I don’t think you’ll regret spending a few quid to be able to use them on your digital body. The quality, at least of this Kood adapter, is perfectly good – perhaps flawless.

Update

As promised, I have now added some outdoor photos taken from my window. I slightly cropped the zoomed-out version this time, to give a comparable field of view. I’ve taken a 100% crop of the unaltered original to test edge sharpness.

Both photos were taken at ISO100 and f/5.6, but the EF version was taken at 1/50 and the FD version at 1/40 as the darkness was coming in. Both are a little underexposed, I think, due to the pale sky. and the FD version is a little darker.

EF lens	FD lens
EF lens	FD lens
EF lens (100% crop)	FD lens (100% crop)

On this occasion, the autofocus seems to have got it spot-on and my manual focusing isn’t quite perfect. Image sharpness otherwise seems good, especially towards the edge of the photo where you might expect softness,  and I can’t see any chromatic aberration around the chimney.

The real test will probably be using this lens in strong sunlight – which I shall try to find the time to do at the weekend.

For a while I’ve fancied a Mamiya RB67 medium format SLR. I’d read about the tech specs, the wonderful lenses, the high resolution, and all the other benefits of such a powerful camera, and last week I splashed the cash and bought one. Optically, it was just what I was expecting – but nothing could have prepared me for the size and weight of this beast.

Sure, I’d seen figures online that said it weighed so many grammes and was so many millimetres wide. But that didn’t mean anything to me as an abstract number. Now I have the RB67 in my possession, I decided to take a few photos to put the figures into context. Most other photography equipment websites concentrate on how the gear performs, but I’m going to ignore that and focus solely on size and weight in a light-hearted and unscientific way.

I’ve got several other medium format cameras, although they are not SLRs. I knew the RB67 would be bigger than the others, but here the RB67 dwarfs my Coronet Conway Synchronised – not a small camera itself.

Mamiya RB67 with Coronet Conway Synchronised

And to put this size into a more tangible context for normal people who don’t collect box cameras, here it is with my Canon AE-1 Program – a popular consumer SLR in the 80s. It’s slightly larger and a little heavier than a modern digital SLR.

Mamiya RB67 with Canon AE-1 Program

And then we come to the matter of lenses. The RB67′s lenses have a longer focal length due to the larger film format, but they are also chunkier in every dimension. Here I have photographed a Mamiya-Sekor 50mm wide-angle lens with an equivalent Canon 28mm wide-angle lens for the AE-1 Program.

Canon FD 28mm with Mamiya-Sekor C 50mm

Canon FD 28mm with Mamiya-Sekor C 50mm

The Mamiya-Sekor 50mm lens on its own weighs about the same as the whole Canon AE-1 Program camera with a lens. It also weighs about the same as a collection of four Canon FD-mount lenses (135mm, 35-70mm, 28mm and 50mm, if you’re interested).

Mamiya-Sekor C 50mm with FD lenses

A basic RB67 set-up with standard lens, waist-level finder and film back weighs in at around 2.5kg, or about the same as a bottle of Pepsi and a can of soup.

Mamiya RB67 with Pepsi and soup

With a bigger lens and a few accessories, you can easily add a kilo or more to the RB67. Meanwhile, the Canon AE-1 Program with lens weighs about the same as a pint of Pepsi in a glass.

Canon AE-1 Program with Pepsi

Well, I hope this has proved entertaining and possibly even useful to someone who may be considering buying an RB67. It is most definitely a camera for use in a studio, or perhaps on a tripod for landscapes. Don’t even think about sport.

I offer my apologies for these poor still-life shots of camera equipment. My flashguns are in the loft and it’s cold up there, so I used a single macro LED ring flash, and it seems to have done OK. For examples of better tabletop photography, see Stu’s recent photos of Lego.

Consumer photographic lenses are almost always sold by their focal length when used on a 35mm camera (or full-frame professional DSLR). It’s already confusing enough to work out what their effective focal length is when used on an APS-C sensor (most consumer DSLRs), but since I’ve been getting into medium-format photography it’s even more confusing to work out what each focal length does what on which camera.

So I’ve done a little research, and prepared a table. I’ve included data for five “common” photography formats with their crop factors. The numbers are the approximate focal lengths in millimetres. Of course the boundaries for each category of lens are rather woolly at best.

If you want to take photos at the so-called “super telephoto” range, then you have a few options. They have relative costs and relative merits. Let’s go through the main ones.

Genuine super telephoto lens

I’m a Canon shooter, so I will refer to the Canon lenses – but the same applies to Nikon, Sony and others.

If you’re doing it by the Canon book, and you want a 500mm lens, then you are supposed to go out and buy a Canon 500mm or 600mm (or longer) lens. At the time of writing the 500mm and 600mm telephoto primes are £8,280 and £10,820 respectively.

Canon EF 500mm f/4.0L IS USM

That’s a lot of cash to throw at a lens. It might pay off for a professional sports photographer, but for an amateur like me, a specialist lens like this would only see occasional use.

There are third-party options, such as the Tamron 200-500mm and the Sigma 150-500mm. These are both priced at under £1000, but do not offer the same quality as the genuine Canon lenses. The quality would be fine for my uses, but a thousand pounds is still too much for me to spend.

Tamron SP AF200-500mm F/5-6.3 Di

As I said, I don’t have any of these lenses, so there isn’t a sample picture in this section.

Mirror lenses

On the face of it, mirror lenses seem like a cheap way of getting a very long focal length. For under £100 you can buy a 500mm mirror lens.

Opteka 500mm f/8 Mirror Lens

Even on the outside of the box we can get an indication of how crude these lenses are. They are fully manual-focus. There is no electronic communication with the camera body. The aperture is fixed, and is usually quite slow (e.g. f/8). They are usually manufactured by names you’ve never heard of before. The sample I tried was the 500mm mirror lens from Opteka.

I knew this before buying, and I was happy with the risks. I have a collection of old cameras so a manual, mechanical lens is nothing new to me. In the end I was extremely disappointed with the lens for two reasons. The sharpness was very poor, and the manual focus ring was extremely sensitive. It was near-impossible to get the moon in focus.

This is the best picture I managed with it. It’s blurry and there is a lot of chromatic aberration. And this was with the moon – imagine trying to take a photo of a bird in flight with this lens. Forget it.

The moon

I wrote a post on my blog entitled “Mirror lenses: worth it?“. You’ve already had a taste of my sentiment here, but there’s more detail in that post.

Preset lenses

Preset lenses are a sort of halfway house between mirror lenses and proper telephoto lenses. They use glass lenses rather than mirrors, but are otherwise like the mirror lenses. They are fully manual, no electronic control and either a fixed aperture, or a choice or 2 apertures that can be flipped in and out of the optical path. If you’re lucky it might have a diaphragm.

Opteka 500mm f/8 Preset Telephoto Lens

Pretty much the same conditions apply to these as to the mirror lenses. They’re slow, hard to focus and have poor quality glass. Some people online have posted surprisingly good pictures, although I think these are the exception, rather than the rule. Opteka (among others) sell a 500mm preset lens.

I don’t own a preset lens, so there’s no sample picture in this section.

Teleconverters

Last but not least, I’ll cover teleconverters. These are small adapters that fits between your lens and your camera body, and increase the focal length, either by 1.4× or 2×.

Kenko Teleplus MC7 2x Teleconverter

The advantage is that you can use your existing 300mm lens, or buy one. They are common, and not too expensive. In most cases, there is a small loss of sharpness but usually this loss is acceptable.

I bought a Kenko Teleplus MC7, which is one of the cheaper teleconverters, at a little over £100. There are also superior offerings from Kenko (£145) and Canon (£236).

I already owned a Tamron 70-300mm zoom lens which came as a bundle with my DSLR, but can also be bought for around £100. Almost every lensmaker sells something that can reach 300mm. Adding a £100 teleconverter has given me a 600mm lens, with autofocus (in bright light), with proper lens glass and a variable aperture. It is a far superior solution to a preset or mirror lens.

Aside from some loss of sharpness, the other main snag is that you lose two stops of exposure from your lens. For example, my Tamron lens has a maximum aperture of f/5.6 at 300mm. With the teleconverter, it’s stopped down to f/11. This isn’t enough for the autofocus to work except in very bright sunlight. Bear this in mind. Fortunately, manual focus on the Tamron is nice and the ring has enough granularity to be able to focus accurately.

While not perfect, within minutes of attaching the teleconverter I took several photos like this.

The moon

Summary

So my advice to anyone wanting to move into longer focal lengths is to buy a teleconverter for your 300mm lens. If you don’t have a 300mm lens, buy one with a teleconverter. It’s much cheaper than a Canon L-series telephoto lens, and much, much better than messing around with a mirror or preset lens.

A few weeks ago I attempted to take some photos of the moon with my 300mm lens. The results were pretty good, but I wanted more, more, more! At 300mm, the moon is still quite small in the frame, and the photo I just linked was cropped a fair bit to “zoom in” some more.

The trouble is, telephoto lenses are expensive. I looked at various options and eventually got an excellent deal on an Opteka 500mm f/8 mirror lens.

Using a lens with a focal length of 500mm (or 1000mm with supplied teleconverter) was never going to be easy. At such a huge zoom, the tripod needs to be rock-steady, otherwise the image will move all over the place.

The Opteka 500mm lens was manual focus, like most (all?) mirror lenses. In principle this didn’t bother me, since I frequently use manual-focus Canon FD lenses. But in touching the barrel of lens, no matter how lightly, you send the moon ricocheting wildly around the viewfinder. You have to wait ten seconds for it to stop wobbling to see if your focus adjustment was any good.

Which brings me onto my next point. The focus ring is extremely sensitive. Even for an infinitely-distant object such as the moon, moving the focus ring just a millimetre sends the image to a blur. It’s a bit like using a rangefinder – when not perfectly focussed, there are two ghost images that slide past each other as you adjust the focus. I never managed to make them line up properly with this lens because it was too sensitive.

After an hour with the lens and camera on a tripod, I hadn’t managed to get a well-focussed picture of the moon. And in cases where I had got the focus not too far off, the general image sharpness was terrible, and there was considerable chromatic aberration. The following image is the best I got out of the mirror lens in an hour of shooting.

The moon

That could have been a really nice image, as the moon almost fills the frame.

I won’t give up just yet, but I’m reasonably confident that I won’t be able to improve on that picture. I might do better to buy a Canon 2× teleconverter to make my 300mm lens into a 600mm. I guess the L-series glass is a little out of my league for the time being

So, to answer the question in the title…

No. Mirror lenses are not worth it.

The background

For ages I’ve wanted a decent fisheye lens. Back when I was shooting with my Fuji S9600, I bought a filter-thread screw-on fisheye adapter. It was only about £30 and the chromatic aberration was awful, even in the viewfinder. But it opened up a new world of photography to me, and I enjoyed using it, taking pictures like this self portrait and these shots of Bristol.

Fast-forward a couple of years and I upgraded my S9600 to a Canon EOS 450D. Presumably due to the larger sensor size, the fisheye adapter had practically no effect. I never used it again, but I missed it and I kept looking at proper fisheye lenses (as opposed to the fisheye adapters). I rather liked the look of Canon’s 15mm fisheye lens. Trouble is, it has a list price of £880 (although can be had for around £600 on Amazon). For an occasional-use lens, this is just too much.

Recently I had another craving for more fisheye photos and I decided to have a look at third-party options.

The manufacturer options

Of course Nikon and Canon do their own lenses, and most of the “big name” lensmakers such as Sigma and Tamron also have offerings. But there are also some from lesser-known names. Peleng, Samyang and Opteka all offer fisheye lenses for Canon SLRs for around the £200-£250 mark.

It seems that the Samyang and Opteka lenses are virtually the same, although they have different advertised focal lengths – 8mm and 6.5mm respectively. I haven’t quite worked this one out yet, but I think it’s because of the projection that is used. I settled upon the Samyang since it’s available for a few pounds less on eBay and Amazon.

Samyang 8mm

Samyang 8mm

I was a little hesitant about buying a lens from a virtually unknown manufacturer. £200 is in that “danger zone” where it’s too expensive to risk wasting the money, but not quite expensive enough to be sure you’re getting something that’s any good. So I read some reviews, primarily these:

• Lenstip
• Photozone

Amazingly, both reviewers gave the Samyang lenses a glowing review. They both noted that there is some chromatic aberration, but for the price, this can’t be argued with.

The thing that’s most likely to throw a spanner in the works is that this lens has no electronics. It can’t communicate with the camera, so there is no autofocus and no automatic aperture. This isn’t a problem for me, since I usually use Canon FD lenses which are also fully mechanical. But be aware, if you don’t like manual focus, think twice before buying this lens.

My thoughts

There’s nothing so formal here as a detailed review. I haven’t taken any measurements, but I can say a few things about using this lens.

• When mounting or removing the lens from the camera body, it’s really hard to hold and twist the barrel of the lens without also twisting the aperture ring. I know it’s hardly a big deal, but it stands out from all my FD-mount lenses in this respect.
• Having no electronics, you have to use the camera in aperture-priority or full manual mode. In Av mode, my 450D seems to consistently overexpose the image by about 1¹/₃ stops. This is easily fixed with exposure compensation.
• Again having no electronics, you have to manually open up the aperture when composing your shot, and then stop it down for taking the photo. If you don’t, the viewfinder can be very dim and difficult to focus.
• The lens feels heavy and expensive – I guess due to the large glass elements inside. The focus ring is damped and feels much nicer than the manual-focus mode on most of Canon’s newer EF-mount lenses.
• Despite some warnings about chromatic aberration and flare, I saw very little evidence of this in my photos. I deliberately challenged the lens in unusual lighting conditions by taking silhouettes against the sun and so on, but they all came out nicely.
• Aside from adding some electronics, there’s not much that can be improved about this lens. For the price, the optics are incredible.

Sample photos

I can’t be bothered to duplicate my photos on this blog, but you can see the results of my evening photo-walk to the Clifton Suspension Bridge over on my photo blog

I quite enjoy macro photography. When I used to use my Fuji S9600 as my main camera, it had a super macro mode, which allowed me to focus on objects as close as 1cm. That was pretty handy for macro shots and the results were generally good – such as this disgusting pupa.

Since swapping the S9600 for a Canon EOS 450D DSLR, I don’t have a macro facility. The best I could get was my Tamron 70-300mm telephoto zoom lens which allowed 1:2 magnification at full zoom. But the subject had to be at least 1.5m from the camera and image quality wasn’t great, so it wasn’t really a solution.

I bought a set of EF mount macro extension tubes from eBay. These sort of replicated the behaviour of the S9600, by allowing the camera to focus closer. By spacing the lens further from the camera body, it’s possible to focus down to just a few millimetres away from the end of the lens, so tiny objects can fill the frame.

However, as EF lenses are electronically controlled, you lose autofocus and the ability to shoot with the aperture anything other than wide open. Naturally, the depth of field is then very shallow. Sometimes it works, like in this photo of a pound coin, but it’s quite frustrating not being able to stop down.

The other disadvantage of “cheating” at macro by focusing closer is that it’s hard to get light onto your subject, because the snout of the lens casts a shadow. When I use my macro LED ring flash, some of the objects I photograph have to be so close to the end of the camera that they are within the ring flash and hence get no light.

So I decided the only real solution would be to buy a proper macro lens with 1:1 magnification. I considered the Canon 60mm macro as the cheapest entry-level macro lens, but unfortunately it’s EF-S mount and can’t be used on 35mm SLRs, such as my EOS 300. If I’m going to shell out for a lens, I want it to work on all my cameras.

The next lens up in Canon’s range is the 100mm macro, which is EF mount, but is unfortunately quite a bit more expensive. I watched a few second hand lenses on eBay but the auctions always closed for prices significantly higher than I was willing to pay – especially as macro photography is only an occasional treat for me.

The two main rivals of the Canon 100mm are the Tamron 90mm and the Sigma 105mm. The Sigmas are rarer but there were plenty of Tamrons on eBay. The first few auctions for the 90mm finished at quite high prices but eventually I found one ending at an awkward time and won the auction for a bargain price. The lens is second hand but very new; mint condition and boxed in all original packaging.

The main disadvantage of the Tamron compared against the Canon is that the Canon has an ultrasonic autofocus motor, and full-time-manual focussing. As nice as those things are, they weren’t worth an extra £150 to me. The Tamron lens flips between manual and autofocus by sliding the whole focus ring back and forth, which is much nicer than fumbling for a small switch on the side of the lens barrel.

The Tamron 90mm feels solid compared with some of my other lenses – most of them budget ones. It’s reassuringly heavy and feels like an expensive lens. The autofocus is quite slow and quite loud, but this doesn’t matter. When I’m composing a macro scene, I can take all the time I like.

The main gripe is that the lens barrel extends by about two inches when focussing. You have to be careful not to bump into your subject if you are working at close range.

I’ve only owned the lens for a few hours, but I can see it’s a fantastic lens. The images are very sharp and almost completely free from any aberration. When I have some time to experiment with some small subjects, I’ll see what I can come up with. But for the time being, here’s a picture of a piece of Velcro.

Back in September 2009, I was given a 35mm SLR camera – a Canon AE-1 Program. I loved it, it was fantastic to use, and I wrote a blog post about the possibility of upgrading to a DSLR.

In March 2010, temptation got the better of me and I bought a Canon EOS 450D. My main concerns beforehand was the loss of the large LCD viewfinder of my Fuji S9600, and in particular, not being able to flip it out for awkward shots, and not being able to see useful information about the camera settings in the eyepiece.

Well I needn’t have worried – the 450D is of course more advanced than my AE-1 and has a small LCD under the optical viewfinder for that information. I hadn’t realised until I tried it out in the shop.

The issue of having to put my eye up to the camera still hasn’t been addressed, but it hasn’t been a problem. I just find myself lying on my belly more, or simply pressing the button and guessing about the composition.

In the two months that I’ve owned the 450D, I’ve taken over 2,000 photos^[1] and I’ve thoroughly enjoyed all of them. I feel more in control of the photos, and I can’t recommend an SLR strongly enough to anyone who is serious about photography.

I now have three EF mount lenses for this camera. Unfortunately they don’t fit the AE-1 (which uses the FD mount) but this very evening I bought a Canon EOS 300, which is a consumer-level 35mm SLR with an EF mount. You can pick up 35mm camera bodies on eBay for a fiver so I thought it might be nice to make even better use of my lenses.

If you’re actually interested in any of my camera facts and figures, you might like to look at my page of cameras. If you’re more interested in the pictures themselves, then why not browse my photo blog.

[1] That’s about 1.4 each hour I’ve owned the camera