What are particular potential problems to watch for when using a telephoto zoom?

Question

I recently got the Canon EF-S 55-250mm IS II lens as a complement to my 18-55mm kit lens for my 550D. I was looking for some advice\best practices for using a telephoto zoom, any associated accessories like hoods that would be useful and any gotchas that I should watch out for. My intended usage for the lens is to shoot stage shows and portraits.

I found a similar query for Point & Shoot cameras

Background

I decided to buy this lens based on the advice to an earlier question I had asked. The lens is fairly light for a telephoto zoom (~400g), and not too large either. However, it is considerably longer than the kit lens. One of the main reasons I picked up this lens was to understand the longer focal lengths better without investing in a high end lens right away (photography is a hobby).

The 70-200mm f4 L IS was one lens I did consider, but that was in a different league - both in terms of price\quality and size\weight. I wish to explore the longer focal lengths before I make serious investments on pro quality lenses - zooms or primes.

Answer 1

Main thing you have to be careful with is to make sure your shutter speed is high enough for the longer shots to limit blurring due to camera shake. The rough rule of thumb here is it should be at least 1/n of a second where n is the focal length with IS turned off; note this would be the effective focal length so for a crop body you have to apply the crop factor of 1.6 for Canon. With IS on it gets you maximum 3 stops reduction in this but in my experience you should only ever really halve it. One thing to note about IS is that it takes a little time to settle down after activation so when you take a shot half press the shutter button then pause for a second before taking the shot to let the IS settle down.

Outdoors its always a good idea to use a hood because on bright days it lowers the chance of lens flare and also protects the end of the longer lens from hitting things; it does happen and a damaged hood is easier/cheaper to fix than damaged glass. For indoor work extra focal length gives you a lot of possibilities but with a slower lens like this you will have to pay particular attention to lighting. This is why pro photographers go for faster and way more expensive glass like f/2.8 because it makes lighting less of a concern.

Best thing to do is just start using it as it will take you a little time to get used to the weight and balance of the new lens on your camera.

Answer 2

In my opinion, telephoto lenses are the easiest to shoot with. The angle covered is narrow, so you have good chances of excluding stuff that should not be in the frame. Perspective gives tells about distance from subject, so it's still a good idea to get closer to subject and not rely on the "tele photography" too much. I quite often prefer an ancient manual-focus 58mm prime to my modern zoom because it has smaller minimum focusing distance.

Since your lens is a consumer-grade zoom, it's very likely not a strong performer at its extreme focal lengths, and stepping down at least a stop or even two will show improvement in sharpness and less vignetting. Unfortunately consumer-grade zoom stepped down by a stop in long end is f/8, which is quite dark and you'll need to use a higher ISO sensitivity almost anytime to avoid subject motion blur, which will often become problem sooner than camera shake with image stabilization.

Accessories - lens hood is almost always a good idea, offering protection from physical impacts, smearing of front glass and stray light. If you use tripod, sturdiness is more important than with shorter focal lengths, because longer focal length amplifies influence of camera shake on image and image stabilization does not work on tripods.