EOS 20D auto-focus not sharp... - DPChallenge Forums

Canon EF-S 18-55mm f/3.5-5.6

11/29/2004 04:47:50 AM · #1

... or at least not as sharp as my manual focusing.

I checked some shots and found that absolutely all of them were slightly softer focus than when I use my own eye. Anyone else have this?

s4nd3r99

Canon EOS-300D Rebel

11/29/2004 04:50:13 AM · #2

I don't wanna ruin your thread but i had been wondering how can you know the focal length ? estimation ?

Marjo

Canon EOS-7D

11/29/2004 04:55:41 AM · #3

I am finding it to be the same way. I thought it was me. Is it consistent with all lenses? I'm using EF28-135 3.5-5.6 IS. I didn't care for the kit lens because it seemed soft. I don't remember trying manual focus with it, though.

11/29/2004 05:20:28 AM · #4

I've had the same thing with three lenses, including the Canon 17-85mm EFS IS lens. It's a major pain - and it's a shame that one can't adjust its settings to compensate if necessary, since it now means it's almost unusable.

Gordon

RIM BlackBerry Curve

Canon EF 85mm f/1.8 USM

11/29/2004 05:29:20 AM · #5

Originally posted by Imagineer:

Canon can. You can get them to re-calibrate/ adjust the focus points if you send it in for repair. This was a common problem with the 10D.

Jacko

Canon EOS-20D

Canon EF-S 18-55mm f/3.5-5.6

11/29/2004 05:34:41 AM · #6

Autofocus works for me.

Message edited by author 2004-11-29 10:35:49.

Sunniee

Canon EOS-40D

11/29/2004 05:34:55 AM · #7

I am finding that true with my new Digital Rebel as well...

Marjo

Canon EOS-7D

11/29/2004 05:38:11 AM · #8

Originally posted by Jacko:

Autofocus works for me.

Is that worse or works? And anyway, stay out of this, Jacko. You don't play fair....wink, wink.

pitsaman

Canon EOS-30D

Canon EF 50mm f/1.8 II

11/29/2004 05:38:27 AM · #9

It is up to the lens and F stop which does the focusing,camera has nothing to do with that.
And remember when you have larger sensor focal distance get larger too ,so 1/50 sec with Sony 707 is not the same as 1/50 with dslr and 105 mm lens.

Folks who buy this large and heavy cameras have to get used to it and tripod is a must !

Message edited by author 2004-11-29 10:39:59.

Mick

Canon EOS-5D

11/29/2004 05:40:12 AM · #10

Originally posted by Gordon:

Originally posted by Imagineer:
I've had the same thing with three lenses, including the Canon 17-85mm EFS IS lens. It's a major pain - and it's a shame that one can't adjust its settings to compensate if necessary, since it now means it's almost unusable.

Canon can. You can get them to re-calibrate/ adjust the focus points if you send it in for repair. This was a common problem with the 10D.

Yes, I recently sent my 10D in because the 1 year warranty was almost up. They did a complete overhaul, including replacing the CMOS sensor, adjusting the auto-focus, and lube and oil. They only thing they didn't do was clean the winshield (when I got it back there was a bit of dust on the new CMOS.) :)

The turnaround time was surprisingly quick, and the camera works great.

11/29/2004 05:49:34 AM · #11

Originally posted by Jacko:

Autofocus works for me.

Did you have your eyes adjusted by Canon though?

11/29/2004 05:52:29 AM · #12

I suppose I'll have to get Canon to calibrate it then (it's not cam shake etc, Kosta). I've been using a tripod on static subjects with lights and every shot with each of three lenses is the same degree of softness. Manually though the shots have been pin sharp.

EddyG

Canon EOS-1D Mark II

11/29/2004 05:57:23 AM · #13

I never had a problem with the autofocus on my 10D or my current camera.

A lot of "focus errors" are because of user error, such as "focus and then re-compose". See Why Focus-Recompose Sucks for an explanation of why you should never do this.

Another common problem is not understanding that the red focus squares are there to assist you, but that the actual AF sensor is larger than the red square in the viewfinder, so it will detect areas of higher contrast outside of the red square and focus "somewhere else". See this diagram (for the 10D) for details. Also note that AF sensors are sensitive to only horizontal contrast or vertical contrast, unless they are "cross-type", in which case they can detect contrast in both axes. (On the 10D, only the center AF point is cross-type).

If you want to test auto focus accuracy, follow the instructions and methodology at this link. Be sure to use the chart at the bottom labeled "Further Improved AF Test Chart (14th May 2003 update)".

Also, make sure that you understand that AF sensors are only designed to focus "somewhere within the depth of field"â� , and not "exactly, precisely at a specific point". Note the comment in the above article: "This shot showed a back focus of about 6mm, but well within the DOF range, it's not bad actually.". The reason why P&S cameras don't seem to have AF issues is because they have a huge depth of field compared to DSLR's, so AF errors are not nearly as evident. That is also why focus "issues" are less apparent when shooting at smaller apertures (like Æ�/8) compared to shooting wide-open.

â� On the 20D and Canon's 1-series bodies, some AF points are "high-precision" and focus within 1/3rd of the depth of the field but only when using an Æ�/2.8 or faster lens. Otherwise they behave as normal-precision AF sensors.

Message edited by author 2004-11-29 12:32:41.

jimmythefish

Canon EOS-10D

11/29/2004 05:59:21 AM · #14

The camera does the focusing. A large aperture lens will help, though, as it provides more light, and a 2.8 or better aperture helps with the 20D and 1-series cameras. The lens is always wide open when focusing, even if you're stopped down to f/32.

I find that with my 10D the focusing is more hit and miss than any consistent back or front focus problem. With my 70-200 F4L (a common one for 'backfocus' on the 10D) if I stop down to f/8 or so when shooting sports with it (runners mostly) it is more forgiving. With the 17-40, I find that when shooting wide with it I have to zoom in to 40mm to lock focus on something and then zoom back out to take the shot. At 17mm the body has a very tough time with getting sharp focus on something. It's a parfocal lens, meaning the focus doesn't change with focal length. It's another benefit of a constant aperture lens.

Originally posted by pitsaman:

pitsaman

Canon EOS-30D

Canon EF 50mm f/1.8 II

11/29/2004 06:04:36 AM · #15

With the Rebel I can focus where I want with 99 % accuracy,compare to Olympus 5050 where was 50 % missed focusing :-)

vince31874

11/29/2004 06:21:02 AM · #16

I have had no problems with my 20D thus far. Focus is sharp.

11/29/2004 06:36:04 AM · #17

Eddy G- thanks for the links. I'm aware of the focusing plane, etc., and was ensuring that there was plenty of light/contrast. I did no focus-recompose at all and focus was using the centre AF point with no zoom.

pitsaman

Canon EOS-30D

Canon EF 50mm f/1.8 II

11/29/2004 06:43:54 AM · #18

This one is at 640 mm f5.6 camera placed over my left arm :

Message edited by author 2004-11-29 11:45:57.

mirdonamy

Canon EF 24-70mm f/2.8L USM

11/29/2004 08:09:03 AM · #19

Almost all of my photos are slightly out of focus. I am horrible at manual focus, so I mostly use autofocus and I almost never have clear focus. I decided to blame it on my lenses: Canon 28mm to 80mm zoom (bought in 1999 and was pretty cheap), the kit lens for the 20D (18mm to 55mm) was free, and my 75mm to 300mm zoom telephoto Canon (got on ebay for $150). These lenses are all I have, and I am not happy with any of them, but perhaps it's me or my camera. I don't know...

dirkjan_denelzen

Canon EOS-20D

Canon EF 24-105mm f/4.0L IS

11/29/2004 08:54:50 AM · #20

With my 20D the auto-focus is not very sharp with my 24-85, manual is beter. With my 75-300 is has no problems at all.

jimmythefish

Canon EOS-10D

11/29/2004 08:55:34 AM · #21

Is it focus or sharpness? If your lenses are missing focus there will still be some part of the image in sharp focus. If not, it's a lack of lens sharpness. If you got a 50 1.8 you'd perhaps discover this right away.

Originally posted by mirdonamy:

mirdonamy

Canon EF 24-70mm f/2.8L USM

11/29/2004 10:01:41 AM · #22

I should go rent one of those for the day and see if it's me, my camera or the lenses I am using...

jimmythefish

Canon EOS-10D

11/29/2004 10:17:26 AM · #23

Don't rent one, just buy one. They're less than $100. Did you move from a 10D to a 20D and still only have those three zoom lenses? That's a strange move. You'd see a much bigger improvement in image quality just by getting a few decent lenses. The lenses you have are all known to be soft. Get a good lens or two (50 1.8 a must and even a 28-105 3.5-4.5 will be a big step up in a zoom) and you'll be amazed at the difference in contrast and sharpness in your images.

Originally posted by mirdonamy:

I should go rent one of those for the day and see if it's me, my camera or the lenses I am using...

Message edited by author 2004-11-29 15:18:48.