“If only I could get a bit closer.” You will hear enthusiast photographers mumble this phrase often. A distant bird, a ship on the horizon, an aircraft thousands of feet above…
They all make us yearn for the tens of thousands of pounds of long lens that we drool over when we see the pros. So is there a cheaper way to get up close and personal?

Today I am testing a 3x teleconverter – a non-expensive add on that promises to triple my zooming capabilities.

The particular model I am testing is a Kenko Pro 300. It retails at around £120 and this one is designed for the Canon AF mount.

Kenko Pro 300
Kenko Pro 300

It claims to retain camera autofocus and lens information via the contacts on either end – something that cheaper teleconverters do not do. One may feel however, that manual focus at long focal lengths is much preferred.

So it’s out with the trusty EOS 40D to see how this baby performs.

I needed something that was in the distance but was not going to move. My subject is a Tesco bag stuck up a local tree. It has two of the primary colours and is predominantly white so contrast abilities should be tested. (…and you thought it was just litter!)
Here’s the bag, shot with a standard Canon 18-55 USM Lens, no zoom. Medium size jpeg straight out of the camera:

Normal Lens
Normal Lens

It’s right there in the middle of the frame – trust me. This shows you the type of shooting conditions (if nothing else). November, around 10am – so not the brightest of days.
Now to connect a 70-300 Sigma, at full zoom. I have deployed a tripod as all good zoomers should. Again, medium jpeg, no post production – but with autofocus (for shame). The camera is set to Program, which renders 1/350, f8 at ISO 800.

75-300mm Sigma Lens - Full Zoom
75-300mm Sigma Lens - Full Zoom

There’s our bag! So can we turn our 300mm zoom into a 900mm zoom for a hundred quid?
With teleconverter attached the first thing I notice is the camera will not focus. The lens whirs in and out but no focus lock. No problem, I will do it manually as I am supposed to.

Looking at the exif data, the lens details are passed on, but without mention of the increased zoom. What is noticeable is the reduction in light. Shutter speed is now 1/30 at f5.6. With a long lens this length of exposure is simply no-go without a tripod – or a still object.  Cheaper cameras will be affected by ‘mirror jolt’ and hand holding the camera… well forget it. So, very bright days only.

I click…

With Teleconverter
With Teleconverter

You will notice contrast is reduced and there is some visual lens artefacts – a sort of ghosting. This has affected sharpness and ‘focus’. We can now read what is on the bag however and for a relatively long exposure in a gusty day, this isn’t – for £120 – at all bad.

Let’s see if we can Photoshop it up a bit. I will use the ‘raw’ image and PS Elements 10.

After Photoshoping
After Photoshoping

A little improvement – maybe.  Sharpening always has a trade off with noise – and this picture in full size IS noisy.

So, a reasonably acceptable major increase in zoom.

BUT. Is it possible with today’s high res cameras to simply ‘zoom in’ with crop and resize on the better, non-telephoto shot? Well let’s see. Again RAW, PSE 10…

After Photoshop
After Photoshop

Interesting isn’t it. What I have done here is turned a 300mm lens into a 900mm lens, for free. A little (lot) de-noise and sharpen from PSE brings it to a standard that at least matches the teleconverter shot.

Well in that case – how far can we go? Let’s apply the same principle to the teleconverter image…

Telecoverter cropped
Telecoverter cropped

Oh dear. I guess there’s the evidence. The zoom only shot stands up to further enlarging whereas the teleconverter shot doesn’t.

In conclusion then, you can often achieve the same or better results by using an editor and manipulating the RAW image.

Your £120 can then go towards a ‘proper’ bigger lens…