1d3 won't focus on a bug's nose, or a flower either

The first thing I notice is that the 1DIII image has a different lens combination than the others. It's a pretty good rule of thumb that most lenses don't take a 2X converter very well. I think the 300mm f/2.8 is a notable exception.

Before you jump to any conclusions about the camera, first make sure you're making comparisons that are equivalent.

One other point: your pictures show which focus point was active. However, you must bear in mind that the camera is not focusing at the time the picture is taken. That task happens before the picture is taken. You must remember or guess well what happened with the camera in the interim to make proper sense of the sensor indicator. As you also indicated, you must take the assist points into consideration.
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http://www.pbase.com/victorengel/

I haven't tried the live view for anything yet (only had it a couple of days) and I use to use only manual focus lenses (except for the 70-200) until I found I couldn't hardly catch a bird in focus no matter how hard I tried. Got some good stuff of flowers and bugs that hang out on flowers for a while (bees and spiders) using manual focus. I also got a lot of pics using manual focus on a dragon fly that kept coming back to the same flower stem. Shot him using remote shutter release. But the butterflies don't stay put long enough for me to focus in on them manually.

Thanks for the suggestion about the assist points (Hans Kruse said the same) but now I need to look up the assist points - I thought I had found them previously and turned them off, but maybe not.

Thanks again,
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PCS St. Louis

Thanks for your observation regarding the 2X converter, but I did get the same results without it (and the same results using the 1.4X converter). I'll have to look back through my shots to confirm the results were the same for the 300 with and without the converter.

Right now, I'm hoping it's the assist points and that I failed to turn them off as I thought I had.

Thanks,
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PCS St. Louis

no text means no text

Ronald Hall said:

Another thing to consider is what focusing point you were using, I
can't tell from your screen capture.. but try using the center if you
are not.. You are at F8 and are pushing the autofocus system to its
limits already.. if you are using something other than center that
would not be ideal, if work at all. I think only the center point
works at F8? Have you tried live view and manual focusing?

Click to expand...

Here is a post of mine some days ago using the Canon 500 f/4L IS with a 2X TC on my 1Ds mk3.

http://forums.dpreview.com/forums/read.asp?forum=1032&message=29508886

and more details here
http://forums.dpreview.com/forums/read.asp?forum=1032&message=29509605

I was actually impressed with the combo compared to what I had expected.

Ronald Hall said:

Since you clearly have an unlimited budget, I'd go invest in a 100mm
F2.8 Macro lens. Use the right tool for the job. And I would also
seriously consider taking some sort of classes to help teach you the
fundamentals of your camera and photography. The best camera and
lenses in the world are useless if you don't know how to use them and
what their limitations are.

Click to expand...

I have used my Canon 300 f/4L IS and 1.4x TC for shooting butterflies and that worked pretty well. But I prefer the 100 f/2.8 macro. A longer focal length and (slightly) sharper lens might be worth while.

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Kind regards,
Hans Kruse
Photo Gallery -- http://www.hanskruse.com
Workshops -- http://hanskrusephotography.blogspot.com

It still looks like a lens issue to me. If it were a matter of acquiring focus, then unless the focus were completely off, there would be some portion of the subject in clear focus -- just the unintended portion. The image, though, seems to not have such a clearly focused portio, unless it is the near antenna of the butterfly. That's difficult to tell, though, because of flare from the bright flower.

On the other hand, the spines on the butterfly's tibia are defined, and individual hairs can be discerned around the body. Perhaps there is some motion blur. The shutter speed of 1/400 second could be a challenge at 1000mm.
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http://www.pbase.com/victorengel/

Those posts look good and are very informative, thanks.
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PCS St. Louis

I looked for something that sounded like turning off the assist points and found C. FnIII: 8 Auto focus/Drive AF Expansion w/selected pt. It was turned off (0isable) but I remember looking at it this weekend and maybe setting it, but I don't remember if it was Saturday evening or Sunday evening (after getting the fuzzy pics).

I also tried some experiments this evening trying to focus on a white eraser on a black plastic pencil taped to the side of a salt box with my 300 from about 8 feet away (measured it ex post). I could get a focus lock on the box, but not the pencil eraser 5 or 6 inches above it even in though it was the exact same distance. I turned on the assist points and it immediately focused on the spice containers 10 inches beyond the pencil.

I then decided maybe the black plastic barrel of the pencil may be affecting the focus, so I switched to a light colored stick of about the same diameter. Both the 5D and 1D3 locked on the stick and the 1D3 gave the sharper image (even considering the size difference). So now I'm wondering if maybe I set the AF Expansion off after getting the fuzzy pictures (like closing the barn door after the horse ran away).

I'll try it all again this weekend, and not just photograph a bug's nose, other stuff, like normal people. I want to thank everybody for your time and suggestions. I'll give you an update when I have one - should be this weekend it the weather allows.

Thanks again,
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PCS St. Louis

Thanks everybody for helping out. It's amazing what a setting change will do. The setting was:
C. FnIII: Auto focus/Drive, 8 AF expansion w/selected pt - 0isable
(also known as turning off the assist points)

The following are full size cuts from this afternoon. They were all taken with the f/2.8 300 with 56mm of extension tubes, no TCs this time. I did take lots of pics with TCs on both the 300 and 500, but the ones below are some of the best bug pics and they were shot without TCs.

These were cropped using PhotoShop Elements and saved with their compression level 8, so there is some deterioration from that, and it seems to me there is even more deterioration coming in from pbase, but they are still pretty good.

A bug's nose
http://www.pbase.com/petestlmo/image/104467348

Another nose
http://www.pbase.com/petestlmo/image/104467369

Bug's irridescent back
http://www.pbase.com/petestlmo/image/104467386

Bug fight - the one on the left chased the other one all around this flower - I got about 7 or 8 shots of the chase (bugs are goofy), and most were very good.
http://www.pbase.com/petestlmo/image/104467399

Once again, thanks to everyone for helping out. I'm very happy with my 1d3 now.
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PCS St. Louis