Month: April 2021

Using Telephoto Lenses

Nigel using his telephoto lens in the New Forest

Telephoto lenses have long reaches and are great to ‘bring the subject closer’ to achieve detailed, frame-filling photographs. They can be tricky to use and there’s a huge range of lenses available. Here are six tips and hints to get the best out of your lenses.

Prime lenses – these are a fixed focal length and for wildlife 300mm to 500mm or longer work very well. They are fast (have wide apertures) and sharp (can resolve fine detail). They can also be very expensive and heavy.

Zoom lenses – these have the flexibility of getting a frame-filling shot or a wider composition that shows the subject in its habitat and can be particularly useful for when the subject moves nearer or further from the camera such as birds in flight. Typical zoom ranges are 70-200mm, 100-400mm and 150-600mm. Many have a variable aperture through their zoom range: my 100-400mm lens has an aperture of f4.5 at the 100mm end and f5.6 at the 400mm end. Some zooms have a constant aperture throughout their zoom range but these are more expensive than the more affordable variable aperture lenses. The image quality can be almost as good as a prime lens –  you might be hard pushed to tell the difference and they are lighter.

Teleconverters – teleconverters or extenders go between the camera and the lens to multiply the focal length by, typically, 1.4x or 2x. Other magnifications are available but these are the most common. They don’t add much weight and are reasonably small and are an affordable way to make your lenses more flexible. They can work very well with prime lenses and with high quality zooms but the image can be degraded a little. I use a  1.4x with my 100-400mm zoom with some success but the 2x can make the image too soft. Not all lenses are compatible with them so check before you buy. The downside to using them is a loss of light and a slower auto focus. A  1.4x teleconverter reduces the light falling on the sensor by 1 stop and 2 stops with a 2x. If you are shooting at f5.6 that will become f8 with a 1.4x and f11 with a 2x. Beware that some cameras may not auto focus beyond f8.

Support the lens and camera – Some telephoto prime lenses can be hand-held and most zoom lenses are light enough to do without a tripod. When using a big, heavy lens, especially at lower shutter speeds, a tripod is all but essential. Choose a high-quality tripod that will easily cope with a heavy payload of camera and lens. A flimsy tripod will vibrate and wobble. You will also need a tripod head which sits on top of the three legs and into which the camera/lens is mounted. Gimbal heads are great as are ballheads. I have recently ‘converted’ from a gimbal to ballhead. When properly set up the camera/lens is balanced on the tripod and seems ‘weightless’ in use. Long telephoto lenses usually come with a foot mounted on a collar that fits around the lens. It is this that is mounted in the tripod head rather than the camera so as to protect the camera’s lens mount. Consider using a monopod. This can be easier and quicker to use than a tripod – it is lighter and usually does not have a dedicated head. I mount a camera/lens directly to a monopod. 

Steady as you go – telephoto lenses amplify small camera movements as well as subject movement so it is essential to employ good technique when taking the picture. If hand-holding support the lens with your left hand and tuck your elbows against your body and ‘tighten up’. Take a deep breath and hold it – this stops your chest moving and helps keep the camera steady. Squeeze the shutter rather than stab at it. If using a tripod or monopod press the back of the camera against your face and drape your left arm over the lens to dampen any vibrations. Some tripod heads have a little hook on the underside. This can be used to hang your backpack to add more stability. I keep a small cloth bag which I fill with rocks, clods of earth or half-bricks etc. Hanging a weight in this way really helps to dampen vibrations. I often use spikes on the end of the tripod legs when on soft ground in a wood or meadow rather than the standard rubber feet. A fast shutter speed is essential to freeze action and to overcome camera movement. As a rule of thumb use the lens focal length to determine the slowest shutter speed to use: 1/300th second with a 300mm lens and 1/500th second with a 500mm lens etc. It generally needs to be faster than this to freeze wing beats: 1/2500th second is a good starting point. Image stabilisation should be used, too. This can be incorporated in the lens or the camera body. It’s a high-tech system that either shifts lens elements or the actual camera sensor to help compensate for small accidental camera/lens movements. It will not compensate for subject movements.

Calibrate for pin-sharp accuracy – telephoto lenses and wide apertures make for a wafer-thin depth of field so it is essential that the focus is where you want it to be. Slight variations in manufacture of the lens and camera can result in a lens focussing a little in front or behind where you expect. For instance, if a bird is sideways on and you focus on the eye but the folded wing is sharp and the eye is blurry the lens is focussing in front of where you expect and the auto focus needs adjusting. Mirrorless cameras don’t have this potential problem because they use the actual imaging sensor for focussing but DSLRs use a separate sensor dedicated to this important task. Most DSLRs have an AF calibration feature in their menus to correct for this. It’s straightforward but a little time-consuming. I use a special target to calibrate the auto focus. Essentially you focus on one particular point and then see how far off your focus might be and make the appropriate adjustments. Here’s a link to the process, and you can use a clearly marked ruler set at an angle instead of a special target, copy and paste the entire line into your browser:

Adjusting Focus With Datacolor Spyder LensCal (

There are lots of other resources on YouTube and the Web, too.

This is a basic guide to using telephoto lenses. If you have any questions just drop me a Facebook message via Ealing Wildlife Group and I’ll do my best to help.

Lighting up Lammas Enclosure: bad news for biodiversity!

Several concerned residents have been in touch with EWG to ask if we could advise on a proposed new floodlit tennis facility in Lammas Enclosure, a sanctuary for people and nature between Walpole and Lammas Park. We won’t go into too much detail here as it’s all in my comment below, and want to reiterate that we can’t always wade in on local planning proposals. But this is another classic example of poor planning that will have a seriously detrimental impact on an important wildlife corridor and pocket of green space in our urban landscape.

Lammas Enclosure (Go Parks London)

Here’s where to search for the proposals on the council website:

The application reference is 212116FUL.

And here is the objecting comment from me:

“The main issue that makes this proposal inappropriate is that it’s yet another encroachment and fragmentation of important green space for biodiversity in our already pressured urban landscape. We are in a biodiversity crisis, and pockets of green space like this are crucial so that both flora and fauna can survive. They are also crucial as wildlife corridors allowing threatened wildlife species to move from one habitat to the next as well as being important habitat in themselves. The more we chop up these spaces, or light them at night, the more pressure our biodiversity faces and ultimately it is lost over time through this perpetual chipping away and degradation of the quality of the habitats within.

My objection to this from an ecological point of view (apart from increased flood risk due to yet more hard standing) is the impact of lighting and activity on biodiversity in the area. Bats in particular are very prone to lighting disturbance, and the Lammas enclosure is without any doubt an important transit route for bats through the urban landscape. Even with so-called ‘bat-friendly’ lighting, certain light sensitive species will struggle to commute from feeding and roost sites across an area that is floodlit. We at Ealing Wildlife Group have records of several bat species using Lammas and Walpole Park spanning the last 4 years. We have also detected bats around the perimeter of this site. Lammas enclosure is undoubtedly a flight route for them between these habitats. I notice on the ecology report it says there is a tree on site with moderate roost potential for bats. It also says rather bizarrely that there is low suitability as foraging habitat on site and adjacent. I have to categorically contest this as we have reports of and ourselves detected foraging bats around the enclosure and adjacent gardens.

The report also admits that “Without mitigation there is the potential for adverse impacts through lighting”. The amount of floodlighting in what is currently a dark refuge for wildlife at night is extremely damaging, even if apparently ‘bat-friendly’.

There are also confirmed hedgehogs and at least two species of owl (Tawny and Little) confirmed in this immediate area which rely on the cover of darkness and in the case of hedgehogs are declining rapidly due to encroachment of urban development and loss of habitat.

It’s important to note that the ecological impact report was carried out two years ago in April 2019 and is not in line with CIEEM guidelines on effective duration. It needs to have been carried out within 12-24 months depending on species, site and potential impact so is effectively now invalid. In terms of bat activity, April is also just the start of the season when bats become active and may not fully reflect the suitability or use of the site by bats, hence the incorrect assertion in the report that it’s of low suitability for foraging. Ideally the site should have been visited to assess specifically for bats on two occasions when bats are most likely to be active. Which is not in the middle of the day in April.

Herein lies the problem with ecological assessments that don’t factor in the connectivity and wildlife corridor potential of the site between other sites. And fail to even survey for active foraging bats in the first place.

We are not so concerned about the footprint of the hard standing referred to as “the site” so much as the impact of the lighting and increased activity in the whole space surrounding “the site”. It’s shortsighted to say there are no bats or breeding birds “on the site” when the proposed works’ wider impact is way more far reaching.

As outlined in the report itself: “Given the mobility of animals and the potential for colonisation of the site over time, updating survey work may be required, particularly if development does not commence within 12 months of the date of the most recent relevant survey.” So the proposal cannot legally be granted permission without further ecological surveying being done in an appropriate manner.

On enhancements, a few token bird boxes and some tree planting will do nothing in the short or medium term to mitigate for the increased activity and lighting in this space at night time which will have seriously detrimental impact on already beleaguered wildlife species such as bats, hedgehogs and owls. With all due respect, we have plenty of Blue Tits!

Finally, I do find it worrying that Will to Win appear to be recruiting supporting commentary for this proposal from so many people who don’t live anywhere near the borough of Ealing let alone Lammas Enclosure. I hope like others that the opinions and concerns of local residents and groups such as ourselves are taken into account and given greater weighting.

Yours sincerely,

Dr Sean McCormack BSc (Hons), MVB, MRCVS
Founder & Chair, Ealing Wildlife Group”

If you too feel that it’s important to preserve this space for wildlife and nature, and perhaps a more appropriate place for the proposal should be found then please make your voice heard.