Tips for using zoom and gettn clear shots

[learjet035]

Hey all, I have been messing with my 75-300 zoom and have found that when @ 300 it's super hard to get a really clear shot. I have been using the "rule of thumb" shutter/ focal length but still gettn an unsharp pic. Here are two examples I took 27 shots of this cat and 1 came out clear. What can I do? IS lens? =) Thanks

[learjet035]

PS both @ 1/400 f5.6 200 iso 300mm

[robertwgross]

What autofocus mode was used?

---Bob Gross---

[tim]

If it sometimes get clear shots, the two most likely causes of the blurry shots are subject movement and camera movement. Try (maybe 5 shots of each)
- Cam on a tripod taking pictures of something that doesn't move.
- Cam on a tripod taking photo of something moving.
- Hand held taking photo of something still

That should help you narrow the cause down.

[DocFrankenstein]

Stop down to F/8...

Or get yourself an L zoom

[Big_B]

I think bob and tim are on the right lines. There are two probable causes: Camera shake or focus problems. You can test for the first by keeping the camera still while taking photos (e.g. by using a tripod).

If that doesn't solve the problem, it may be that the camera is focusing on the wrong point in the photo or that you are taking the picture before the focus is locked. Again, experimenting under controlled conditions will help you to isolate the problem.

[David1943]

Seems more probable to me that the cause of your blurred pictures is camera shake. Looking at your example, I can't seem to see any plane which is sharp, so I'd tend to discount the fact that your camera is focusing on the wrong area.

Regards, David :)

[learjet035]

Thanks for the tips. Bob, it's set to "one shot" if that's what you are talking about. It does seem that when I am zoomed, it's so hard to hold steady. I may have to start saving for the IS I think.

[PhotosGuy]

It might be too slow a shutter speed, or it could be that you locked the focus by half pressing the button, & then swayed back/forward & moved the plane of focus since the leaves under the left eye in the 1st pic seem sharper than anything else. At 1/400 sec, I'd guess the latter, & the focus point is somewhere between the eye & the leaf.

[Big_B]

It might be too slow a shutter speed, or it could be that you locked the focus by half pressing the button, & then swayed back/forward & moved the plane of focus since the leaves under the left eye in the 1st pic seem sharper than anything else. At 1/400 sec, I'd guess the latter, & the focus point is somewhere between the eye & the leaf.

That's very much what I was thinking. Depending on what focus mode I'm on, my camera doesn't always insist on a locked focus before taking the shot. This can cause these problems if you have a slow motor in your lens and it takes you longer to focus then expected, particularly when switching between focussing on teh foreground and background.

[etaf]

the rule of thumb is extended by the crop factor on digital camera
so the rule is 1 / focal length x the cropfactor
so thats 1/300x1.6
= 480
so 1/500th would be the minimum
and that also depends on individuals ability to hand hold
I would try a tripod and a cable release or selftimer to trigger the camera.
I had a 70-300mm that had a big focus problem and had to send back to canon - but it wa sway out and on all pictures

also that lens is known to be a bit soft at the 300mm end - so a higher aperture f8/f11