This image of the Orion Nebula was taken, not with a telescope, but with a camera lens older than myself attached to an entry-level modded DSLR camera. The lens in question is a 200mm SMC Takumar f4. It was manufactured sometime in the early 1970s and I picked it up off eBay for £22. The total exposure time is about 40 minutes, enough to show hints of structure in the larger dust lane the nebula is embedded in. The internal lens iris was used to stop the lens down to f5.6, which gives better star shapes in the corners. However, this has resulted in large diffraction spikes on the bright stars, for this particular shot I’d have preferred to use a step-down ring as a front aperture mask, a cheap and simple way of producing circular stars.
Vintage lenses like this can provide a very cost-effective route into astrophotography. I’ve used a number of different ones of between 24mm and 200mm focal length for a variety of shots. By shopping around carefully I’ve amassed quite a collection, my cheapest cost me £18 while the most I’ve spent was £65. Below are some of the better images I've taken with them.
This slightly wider shot was taken with an SMC Takumar 135mm f2.5 lens (cost £50) at f4, it’s also just over 40 minutes of data. On the left are the three bright stars of Orion’s Belt. Nothing quite divides astrophotographers like diffraction spikes but in this particular shot I quite like them – they highlight the naked eye visible stars which helps place the scene in context. This particular lens has an eight bladed iris, giving eight tight diffraction spikes. On the left are the aptly named Flame and Horsehead nebulae, while the Orion Nebula is on the right. The Horsehead and Orion nebulae are both star-forming regions but the former is at a much earlier stage of evolution. In the Horsehead newly formed stars are hidden by the concentrated dust clouds, while fast stellar winds and radiation pressure the hot blue stars in the Orion Nebula are in the process of expelling most of the gas and dust back into space. Shooting at f4 rather than f5.6 has doubled the amount of light reaching the camera sensor, as a result more structure is visible in the background dust.
Prior to upgrading to the f2.5 lens I was using an even older and cheaper 135mm lens - an f3.5 Super-Takumar from the mid 1960s - which cost me just £18.
This is just 30 minutes of data showing the Heart & Soul Nebulae along with the Double Cluster, in the constellation Perseus. The field of view with this lens on an APS-C camera is about 9 by 6 degrees, for scale each component of the Double has about the same apparent size as a full Moon. There are a few enormous nebulae like this hiding just out of sight.
The image was taken with the lens aperture wide open, at f3.5, giving circular stars but increasing distortion in the corners (it’s more apparent when viewing the image at a larger size). Shooting at f4.5 gives better results but requires longer exposure times to reach the same depth.
For a wider view of the same region I used a borrowed Carl-Zeiss 35mm f2.4 lens at f5.6.
The view is centred on the w-shaped constellation of Cassiopeia, the diffraction spikes help it stand out from the mass of stars in the Milky Way. Also visible near the centre of frame is the Pacman nebula, at this scale its name is merited.
I’ve heard only good things about the Carl-Zeiss lenses but they are quite expensive on the second-hand market. The Takumar lenses by Asahi Optics tend to offer better value for money. Here’s another shot taken with another Takumar lens, a 50mm f1.4 at f4.
This image is about 1h30m on the busy region of the constellation Cygnus. The bright star on the left is Deneb, a distant blue giant about 100,000 times brighter than our Sun. Numerous nebulae are in view, including the North America, Pelican and the Veil supernova remnant.
There are many versions of the 50mm f1.4 Takumar, they are popular as portrait lenses. Mine is a fairly late model, an SMC from the 1970s with 8 aperture blades, which cost me £65. At the other end of the scale, I’ve also had some success using it as a macro lens with the help of an extension tube.
Prior to getting the 50mm Takumar lens I used a new 50mm f1.8 Canon lens, which cost about the same amount. It’s not quite as good as the vintage glass for AP, bright stars produce larger artefacts as can be seen in the shot of Orion below and the corner stars are not quite as good at f4, but it has the advantage of auto-focus for daytime shots.
Another family of cheap lenses worth mentioning are the family of kit lenses commonly supplied with new cameras. While not ideal tools for AP they are still capable of producing good results, as this wider view of Cygnus shows.
This particular shot is just 20 minutes of data taken with an STM lens at 18mm focal length and f5.0.
Vintage lenses giving a wide field of view are rare, making the kit lens the best budget option for Milky Way shots, but I have used a Vivitar 24mm f2.8 lens that was gifted to me.
Shot at f5.6, this view shows the Hyades star cluster at left with the prominent red giant Aldebaran in front of them, the Pleiades and the California nebula. On close examination the lens appears to be heavily infested with fungus and has since been placed in quarantine. We really don’t know if life is common or scarce in cosmic vistas such as the one shown above, but it is certainly present in the optic used to take it.
All these images were taken using a cheap tracking mount, an EQ3-2, from a dark sky site.
Vintage Lens Tips
Vintage lenses can offer good image quality for AP at affordable prices, and also offer some ergonomic advantages compared to modern auto-focus lenses. The focus rings are larger and offer more resistance making them less fiddly to adjust - with my Canon lenses I have to tape or blu-tac the focus ring to stop it creeping out of position. However, there are a few things to watch out for if you are considering buying one.
The lenses I’ve used all have either a M42 (42mm threaded) or Pentax-K (bayonet) mount. These are common types but there are many others, you’d need to check if an adaptor is available for the camera body you own. To muddy the waters slightly, even with an adaptor not all types will reach infinity focus. For example, M42 lenses can be fitted to Nikon bodies but will not focus anywhere near infinity as the element-to-sensor distance is incorrect (Nikon M42 adaptors with a correcting glass element are available but looking at example images this appears to kill the image quality). Here are some combinations that I know to work:
Another thing to be aware of is that if you have a modded camera it may not reach infinity with camera lenses. Mine was modified by Cheap Astrophotography and the sensor was re-shimmed to prevent this issue, but many self modded cameras suffer from this.
Not all vintage lenses are suitable for AP, some will suffer from chromatic aberration where the red and blue light focusses at a different point. Searching online to see if a particular lens has been successfully used is advisable. Prime, fixed focal-length lenses will typically give better results than zoom lenses. Optical design is a compromise and the extra elements in zoom lenses can reduce light transmission and increase distortions. Finally, a small number lenses won’t quite reach infinity even with the correct adaptor, and might need adjustment of the actual lens itself.
If there are any lenses you’ve used for AP please comment below, I’d be interested to hear from you. There are plenty of good optics out there languishing in attics, boxes and the back of cupboards waiting to be claimed. My vintage lenses hail from the 1960s and 1970s, it would be fun to get hold of a really old one just to see what could be done with it.
Kit lenses, commonly bundled with DSLR cameras, offer a natural entry point into astrophotography due to availability and their wide field of view, allowing reasonable exposure times from a fixed tripod. The difficulties for the first time user are finding the correct camera settings and focussing on infinity. This guide offers a few tips based on my own experiences and blunders.
This was one of my first attempts at shooting the Milky Way, taken while on holiday in Menorca. I didn’t have a tripod with me so I simply laid the camera down on the patio, pointing straight up. It’s a 30 second exposure at 18mm focal length with the camera iris wide open, giving a focal ratio of f3.5.
Camera and Lens Settings
It’s worth experimenting with these settings before heading out, to help avoid the frustration of fighting the camera in the dark.
When shooting from a fixed tripod it’s important to gather as much light as possible. Typically this means shooting with the lens wide open by selecting the lowest aperture setting available.
When shooting the image above I’d forgotten to open up the aperture and it was shot at f5.6. As a result less light is reaching the sensor, giving a dim and grainy image dominated by electronic noise. Despite this I managed to accidently capture the Andromeda galaxy at lower right. The aperture setting is something of a compromise, shooting wide open will result in distorted stars in the corners (coma) but this is preferable to a noisy image. (If shooting with a faster lens or a particularly low-noise camera it may be worth stopping down slightly to improve the star shapes.)
At 18mm focal length, giving the widest field of view, exposure lengths of roughly 20-30 seconds are possible before star trailing becomes apparent. The maximum exposure time varies slightly depending on where the camera is pointed. Close to the north and south celestial poles the apparent motion of the stars is slower, so longer exposures can be used. I usually take 30 second shots regardless when imaging the Milky Way, trading a little bit of star trailing for a brighter image.
Users of entry and mid-level cameras will probably get the best results between ISO 800 and 3200. ISO 3200 will show up the Milky Way much more clearly but at the expense of a noisier image; however, this can be greatly reduced in post-processing.
Selecting 2 second timer mode helps prevent any vibration when releasing the shutter, to avoid producing streaky stars in the final image.
Lens Switches and Zoom
Manual focus must be selected on the lens. Also, some lens models have an image stabilisation/vibration reduction switch which may need to be disabled, depending on the model – some are not suitable for shooting from a tripod with this turned on. The zoom barrel should be set to the widest setting, typically 18mm focal length.
The next step is to take the camera outside, preferably somewhere dark. Finding a sharp focus with a kit lens can be challenging as they are quite slow lenses. Optical design is a compromise and the handy zoom ability results in lower light transmittance compared to a fixed focal length prime lens at the same focal ratio. Even at f3.5 only the brightest stars will be visible through the viewfinder or on liveview.
The first step is to find a rough infinity focus. Auto-focus lenses need to be able to focus past infinity so this won’t be quite at the limit of travel of the focus ring. It’s worth checking in daylight which way the focus ring needs to be turned to reach infinity. For a rough focus turn it to the stop and then back a very small amount.
Fine focussing is best achieved using the liveview feature if the camera supports it; I boost the ISO level to 3200 or 6400 after turning the display on to increase the number of visible stars. The next step is to find an object bright enough to focus on, which may not be in the same area of sky as that you wish to image. This is where some familiarity with the sky helps. A software planetarium such as Stellarium (a free download) will allow you to check what is visible from your location at any given time. Here are some suggested targets in order of brightness:
• The Moon. If the Moon is up you can even use auto-focus then click the lens back into manual mode, however this may not give the best possible focus for reasons given below. Also, if the Moon is too bright the sky will be washed out and fewer stars will be visible.
• The planets. Venus, Jupiter, Saturn and usually Mars are brighter than any stars and easier to focus on.
• Failing that, a bright star. Here’s a list of the brightest visible stars, if you aren’t sure where they are located in the sky you can check using Stellarium.
Depending on your location, a light on the horizon may be easier to focus on.
When focussing on liveview it’s better to place the object a third of the way from the edge of frame rather than in the centre, this gives a better focus across the whole frame. This trick appears to work with all lenses. Make small adjustments back and forth, the goal is to make the star as small and round as possible. Another approach is the ‘disappearing star’ trick. Find a star that is barely visible, as the focus ring is tweaked it will pop in and out of view.
Depending on the model the focus ring on kit lenses can slip slightly out of position while shooting, a piece of micropore tape or a blob of astronomical blu-tack can be used to fix it in place.
Framing the Shot
Once the lens is focussed you’re ready to go. The Milky Way is the most obvious target but familiar constellations or asterisms also make pleasing images.
Adding a foreground object can add interest. For the shot below of the Hurlers, an ancient stone circle in Cornwall, I used light-painting to make the stones visible by flicking a torch around the scene for a few seconds. The more distant stones needed to be illuminated for longer.
To speed things up I usually use high ISO ten-second exposures for framing, it can take a few attempts to line everything up correctly. It’s important to tighten all the controls on the tripod as the action of the shutters can shake the camera and produce streaky stars if it’s not secure. For the final shot I typically reduce the ISO level to 1600 or 3200 and increase the exposure time to 25 or 30 seconds.
Shooting from a dark site will help but moderate levels of light pollution can be incorporated into a composition. The glow of street lighting in this image masquerades somewhat as a sunset.
Some simple tweaks in an image processing program to brightness, contrast and colour saturation can greatly enhance an image. For high ISO shots applying a de-noise filter can clean up a background considerably.
I usually present or print my kit-lens images at a fairly small size to hide any defects in the image.
With a little imagination the kit lens has plenty more to give. For example, multiple shots can be stitched together to make a panorama; Microsoft ICE is a free download that does this. It is also suitable for making star-trail images, something I haven’t yet experimented with.
A better lens, such as the Samyang 14mm f2.8, would yield better results due to its superior light-gathering ability. Compare this shot of the Hurlers with the one at the top of the article:
Full-frame cameras produce very little noise and can be used at higher ISO levels, making them the best solution for fixed-tripod shooting, but are expensive. However, an entry-level modded camera on an equatorial tracking mount can easily out-perform them even using the kit lens, as the image below shows.
The image above is just 8 two-and-a-half minute exposures combined using Deep Sky Stacker, using a kit lens on a modded Canon 1100D (EOS Rebel T3 in North America) on an EQ3 mount. The mount can also be used with much longer lenses, bringing smaller deep sky objects into view.
All images by myself, any typos by myself and any trespassing cats.