55-250mm Telephoto Zoom Lens help

[tina1138]

I can not get a sharp image with this lens no matter what I do.

please can someone help me.

I tried taking pictures of some birds this morning and they are not sharp at all.

I used a tripod too.

thanks.Tina

[TCampbell]

We would probably need to see your image (along with the embedded EXIF data so we can see the camera settings that were used for it.)

But I'll offer a few general tips...

The default shooting mode of most bodies is to use "One Shot" mode. Canon bodies have a "One shot" mode, an "AI Servo" mode, and then a special mode called "AI Focus" which really just means the camera evalutes whether it should use One Shot vs. AI Servo mode on the fly.

In "One Shot" mode, the camera uses "Focus Priority" and does NOT focus continuously for moving subjects. Once it locks focus on something it's ready to shoot but it will not adjust the focus for a moving object. This means that at some point your subject was in focus... but has since moved from that position. You can fix this by switching to AI Servo mode.

In "AI Servo" mode, the camera WILL focus continuously... as your subject moves, the camera will continue to adjust focus... but the camera also uses "release priority" when in AI Servo mode. So whereas in One Shot mode (which uses "focus priority"), if you press the button all the way, the camera will not actually take the shot until it can lock focus first (which is why some people think their camera is malfunctioning when it wont take a photo in a very dark room -- because it can't lock focus) -- in "AI Servo" mode (which uses "release priority") the camera WILL take the shot when you fully press the button and it will do this whether it has had time to focus or not (so that's an important detail to remember). Half press to get the camera to lock focus and keep tracking your subject with your focus point (and it will continuously focus)... then fully press the button to take the shot .

The EF-S 55-250mm lens does not have particularly fast focusing motors... the STM lenses are faster and the USM lenses are the fastest. Action photographers will specifically seek lenses with fast focusing motors... without a fast motor, sometimes it may not be possible for a lens to track focus adequately -- however Canon does use "predictive" focus when tracking an object whose distance to your camera is changing at a uniform rate.

Also... you'll want to give yourself a nice broad depth of field so that a small amount of focus error wont really impact the final outcome. It will be easier to keep things in acceptable focus at f/11 (or even f/16) than it is when you're using a lower f-stop such as f/4 or f/5.6.

BTW, Canon does not recommend just leaving the camera in AI Servo mode. It turns out there are some nuances of the way this works which can trick the camera into thinking there was movement and altering focus when taking a non-action shot... resulting in missed focus. Use "One Shot" when shooting non-action. Use "AI Servo" when shooting action. I don't actually recommend "AI Focus" (that's the mode that auto-decides if it's an action shot or not) BECAUES there's a slight delay while the camera evaluates which mode to use and that can cause you to miss the "decisive moment" to grab the shot.

Hope this helps... I'll try to find the YouTube videos that Canon has which explain how your auto-focus system works. It is quite informative and tells you more about how your camera "thinks" when it comes to focus.

[TCampbell]

Here are the links to the aforementioned video on how the autofocus system works.  It's a 3-part video, but enormously useful to understand this.

Part 1 of 3: A Look at The Canon Autofocus System

Part 2 of 3: A Look at The Canon Autofocus System

Part 3 of 3: A Look at The Canon Autofocus System

Again... post a sample photo if you'd like more specific advice but please make sure the EXIF data (the embedded data that contains the settings you used.)

[ScottyP]

There are 3 main possible causes of un-sharp images:
1.) Bad focus (which T. Campbell just did a good job of explaining), or
2.). Camera shake blur (from your hands), or
3.). Subject motion blur (from the shutter speed not being fast enough to freeze a moving subject).

You say you used a tripod so camera shake is not likely the problem. In any event a shutter speed as fast as the reciprocal of your focal length will generally eliminate camera shake. Zoomed in to 100 mm, you want a shutter speed of at least 1/100th. Zoomed in to 200 mm, you want a faster shutter, 1/200th. However, your camera is a crop sensor model, so it magnifies your zoom X 1.6, so you have to multiply your shutter speed accordingly. If your lens is at 100mm, you need a shutter of 1/100th x 1.6, so you need 1/160th of a second or faster. If your lens has Image Stabilization, as yours does, you can break these rules to some extent, as the lens compensates for some camera shake.

Subject motion could be it, as birds move pretty fast, even when they are just standing still because they are twitchy. The fix is a high shutter speed. If you can get enough light to pull it off, you probably want at least 1/400 th of a second. Faster would be better (1/500th? 1/640th? 1/1000th?).

Bad focus is the other likely culprit. See if Tim's advice fixes it. It could be both motion blur and bad focus at the same time, of course.

Photography physics are just a series of trade offs though. For example: A narrow aperture (f/16 or f//22) does give a nicely forgiving deep depth of field, but it blocks out a lot of your light. But you need a lot of light to get a fast shutter you want to freeze action. So you are forced to find a compromise between the fastest shutter and the narrowest aperture.

Good luck!

[tina1138]

[tina1138]

here is the imaged cropped .
f5/6 200mm iso 200

[ScottyP]

What was shutter speed?

[tina1138]

f5/6 av mode iso 100 about 200mm

[ScottyP]

The bird is kind of inside these branches, so the camera would not know it is supposed to focus on the bird. The camera may focus on one of the branches, or try to pick an average focus between several objects.

You can help a lot if you will set the camera to use only the center Autofocus point, and then you be sure to put that particular red AF square on the bird as you are shooting.

Also, your shutter might have been set a little slower than you needed it for freezing the action.

[ScottyP]

2 other things:

That picture looks like it was cropped quite a bit. There is a limit to how much you can crop before you lose sharpness. Birds are tiny, and even with a crop sensor and a 250 mm lens, you still kind of have to get up close to them.

The other thing is, when you are putting the red autofocus point on the bird, put it on his eye. At the very least the eye needs to be in focus, whenever you're photographing something that has eyes, that is.