At what point would you require a tripod for good focus on a 70-300mm

[Larry13]

When using my 70-300mm lens I have an issue with focus at the closer ranges.  I find it to be true on my 150-600 as well.  Is it just me or should I expect to need a tripod when getting 80% or higher zoom?

[rs-eos]

By "closer ranges", do you mean longer focal lengths (getting closer to the subjects)?

Unless the lens has very good IS, I would say that at least a monopod would really be needed for long focal lengths.  A sturdy tripod would take that further.

[JoeySnaps]

There's a rule of thumb, rather less relevant than it used to be with modern camera features such as image stabilisation. The slowest shutter speed at which you can expect to get a sharp picture without a tripod is 1/focal length. So if you're using a 400mm lens, the slowest shutter speed you should be using is 1/400sec. Using a 200mm lens it'll be 1/200sec - and so forth. And if you need to use a shutter speed slower than that, you'll need a tripod.

In practice there are many factors which may require you to modify the above rule, such as how steady your hands are, how fussy you are about sharpness, how large are the prints you hope to make of your pictures. But perhaps it can give you an idea.

[shadowsports]

These gentlemen know what they are talking about.  If you are hiking around, cold, fatigued, overly tired or had too much coffee you may not be a steady as you want.  I agree with both trains of thought.

[Waddizzle]

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@Larry13 wrote:

When using my 70-300mm lens I have an issue with focus at the closer ranges.  I find it to be true on my 150-600 as well.  Is it just me or should I expect to need a tripod when getting 80% or higher zoom?

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I will also assume that you are referring to using the zoom lenses at the longer focal lengths.  Could you better describe what you are doing so that I could reproduce your issue?  When I use either of those lenses it is almost always outdoors on a bright sunny day.

I would begin by pointing out that focusing on an image and capturing an image are two separate events that are undeniably joined at the hip.  One occurs before the shutter fires, while the other occurs when the shutter fires.  

Focusing on a subject is pretty straight forward.  All you need to do is half-press the shutter button. In most cases this should cause at least on AF point to lock focus.  In One Shot AF mode, the AF point locks focus and the camera maintains that focus until the shutter button is released or fully pressed to fire the shutter.  This AF mode is best for subjects that are not moving.  Notice that the shutter will NOT fire if an AF point has not achieved a focus lock on a subject.

In AI Servo mode, half pressing the shutter causes one or more AF points to acquire a subject and begin continuously updating a focus lock on the subject.  This continues until the shutter button is released or the shutter is fully pressed to fire the shutter.  This AF mode is best for moving subjects.  Note, the shutter will fire irregardless of whether or not an AF point has achieved a focus lock on your subject.

By using the Shutter Button you can cause the camera to focus, and you can also cause the camera to fire the shutter.  These are literally two separate events, but they are joined at the hip.

Let’s assume that we have an AF point that has achieved a focus lock when the shutter fires.  This is not a guarantee that the captured image will appear to be in sharp focus.  Factors such as camera shake, subject motion, and shutter speed play a large role in determining the final image.

Using a tripod can only help correct for the first factor, camera shake.  Compensating and correcting for subject motion is often corrected by selecting a suitable shutter speed and AF mode.

[kvbarkley]

No one has asked how close to the subject you are. Are you within the minimum focus distance? Do you have a focus limiter on?

[ebiggs1]

"At what point would you require a tripod for good focus on a 70-300mm"

I don't own that lens but I do have the Sigma 150-600mm Sport. If I have good enough light where I can keep SS up in the 1/500, perhaps a tad slower, I never use a tripod. When conditions require a very slow SS I always use a tripod. The problem with a tripod is, it is not mobile. It is very difficult to capture a BIF when using a tripod for example.

No tripod and my Siggy Sport at 600mm.

Tripod and my Siggy Sport at 600mm.

I would advise referring to the recommendation by JoeySnaps and practice more. Always use One Shot never Ai-servo at least until you get really good at focusing. Using just the center focus point will help too. Try setting the camera to Av mode. Select the aperture you want perhaps one stop down from wide open. You can try Auto ISO but make sure you set an upper limit to it. Now the camera will select the fastest SS it can for proper exposure. When you look at your shots in post check the SS in the exif to determine what the SS was and whether it worked.