Help - Blurry Captures

Jim Stafford

TPF Noob!
Nov 30, 2008
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Lake Odessa, Mi
Can others edit my Photos
Photos OK to edit
I am getting frustrated. I have been working hard at eagles and waterfowl but not getting quality tack sharp images. I am using a Canon Xti with a new Sigma 100 - 400 F4/5.6. It seems to be autofocus issues but I cannot nail it down. Maybe it is just lighting?

This eagle was taken on an overcast day

This was on a bright day

Same as it flew out of the tree, note the glow

This was better as it came back around

A goose on the same outing that is much better
Let's start with some EXIF info ... looking that that will give you a 90% chance of solving the problem.

Sorry, it is available in the pics. I think all were shot with shutter priority at 1/1250, gave me about F7, ISO was at 400 on the sunny day and 1600 on the overcast, white balance on auto. Anything else?
Are you using a Teleconverter ?

The image quality is not to good ... I am thinking that there is more too it than just Focus ... or it may be just the quality of the lens.

Shutter speed and Aperture are OK for what you are shooting.
The high ISO on image 1 did not help.
No teleconverter. The reviews I read said this Sigma lens is on pr with the Canon L 100 - 400.
You need to stop it down some more, to say 8 or 9. And lower the ISO, you shouldn't need a 1250 SS. 500 would work just fine to freeze the motion, if there is any.
On sunny days you don't need the ISO to be so high. On really sunny days just leave it at 100 and maybe 200 on cloudy days.

I totally agree with Kegger on your shutter speed and aperture.
Have you done any controlled indoor tests with your lens. Here is why I ask...I own a Sigma 50-500 that gave me excellent results. I then bought a Canon 600 f/4 IS and loaned the Sigma to a friend. His camera body and my Sigma when paired together suffered major front focusing issues. What can happen with tolerances is this...say the lens focus right at the front of a subject but is within tolerances. Works fine on most camera bodies. Say a different camera body is within tolerances, but also at the front of the tolerance range. Now paired together, they front focus a tad. Easiest way to determine this is a tripod mounted test indoors with mirror lock-up and either the self timer or a shutter release cable. I found it useless to do the whole print test sheet, 45 degree angle thing. Hard to do on a long lens with a long minimum focusing distance.

Here's what I did... a got a cardboard box and stabbed 4 ink pens in it. Each pen is about 2 inches behind the one in front of it and staggered so that all can be seen. The paint diagram illistrates this from an over head view, and is color coded to the ink pens in the test shot. I took the shot at around 20 feet. Focused on the 3 pen back and with my camera body, focus was spot on.



Here is how the lens focused on my friends 30D.....bad front focusing.


Not sure if this is your problem, just throwing out an idea here.

Thanks Montana, I'll run a test. I keep thinking it is me becouse I can get some shots very sharp.
If its of any consolation to you, I've had a problem when using a Sigma 70-300mm zoom macro. I even went so far as to try it a second time using manual focus and it still wouldn't focus clear and tack sharp as you say. Someone posted to me that they too have this lens and it rarely works on auto focus. So perhaps you lens is the same way even though its a step up to 400mm. I also agree that you shouldn't need more than a shutter speed of 500 with that lens and keep the ISO at 100 or 200 for best quality.
Not sure about the Sigma lens, but the Canon 100-400 is one of the hardest lenses to get tack sharp results with. It's just a real finicky lens to use.

I thought it was a bad lens until I gave it to a 'birder' to test out, he put it on his MKIII and well let's just say it was a lesson. Nothing wrong with the lens, it was aaaaaaaaaall me.. ;)

You may need to employ the same or more attention to shooting with the Sigma version. :thumbup:
I did a couple focus tests last night and I think in regards to focus distance things are OK. What I did find however is that if the light is not good I cannot get sharp focus with my xti no matter which lens I use. The sun went from bright to setting as I was playing around. As soon as the light level dropped my captures went blurry and no matter what settings I tried I could not get them sharp. I also tried my external flash with no success at 20'. This somewhat matches up with things that I have been thinking, in my original post I mention lighting. A coworker brought me his 30D to do some comparisons with.
You need to stop it down some more, to say 8 or 9. And lower the ISO, you shouldn't need a 1250 SS. 500 would work just fine to freeze the motion, if there is any.

1/500 isn't fast enough for flapping bird wings. 1/800 will catch most of them, though not a humming bird.

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