Looking at my zoo pics...

[DocFrankenstein]

When I downloaded my pics from the zoo I was quite dissapointed.

I mainly photographed large animals with the 70-200 Sigma EX. Most of them are not focused properly. :? The focus is close, but not quite... Usually from 10 to 30 cm off the subject.

I was using center AF point, handheld, giving the time to focus... also a Hoya (0) UV filter. :?

Is it a body problem? a lens problem?

[tommykjensen]

Hmm, difficult to judge without any actual photos and exif data. Not that I am expert but I am sure other users will ask for the same to be able to help You.

[IanD]

Doc,
I recall reading about someone on the forum having a similar problem and they took the UV filter off and problem went away. Might want to try some shots without the filter and check the results.

[robertwgross]

Time to pull out the ruler test again.

We keep the master ruler locked up in a glass cabinet. However, in time of emergency, we break the glass and roll it out.

Backfocus and front focus could be caused by a cheap filter, by a faulty lens, by a poorly calibrated camera body, or any combination thereof. It might be caused by user error as well.

Run the ruler test to decide whether there is a real problem or not. Then, if you think it is a lens problem, swap lenses to see if the situation still exists. If you think it is a body problem, then hold your good lens and swap bodies (with a store, if nobody else). Pretty soon you will know what the truth is.

Then, if you know you have a true problem, ship it all off to Canon Repair.

---Bob Gross---

[Chris1le]

My Sigma 70-200EX did the same thing on my 10D. Sent it to Sigma for repair. After a month and a half it finally came back. It does seem to focus better now. I haven't done any ruler tests lately but it does seem more acurate. They also fixed the focal distance problem in the exif data. It now properly reads from 70 to 200. Not 456mm or whatever it used to read. :D

[DocFrankenstein]

It's strange. I did a ruler test in low light. It seems right on focus with both the UV filter and without it. :?

[robertwgross]

So far, you are following the standard script that we read back in the early 10D days. Somebody would be sure that they had a focus problem. Then they did some ruler tests, and about 90% of the time, it turned out that there was no focus problem within the hardware. Then, you know what that left as the possible cause.

Digital Rebel is just about the same story.

---Bob Gross---

[DocFrankenstein]

Then, you know what that left as the possible cause.

The monkey behind the shutter :?

But then I only have the AF to rely on. I point the central AF point at the darn subject, at an object of the plane that I want to be in focus and the focal plane is just not there.

I don't have a diffraction mechanism to assist manual AF. I'm stuck with what I have and it doesn't give me the results I want.

[tommykjensen]

How about posting some photos with exif data then maybe it would be possible to determine if it is caused by


The monkey behind the shutter :?

[drisley]

When I used a G3, because of the shutter lag, I used to half press the shutter and hold it there and let the G3's servo (yes, even the G series have servo focusing) focus, and when I finally wanted to shoot, I would depress the button all the way.
I brought this habit to the 300D, and because of it's darn Auto "Intelligent" Autofocus I used to get alot of out of focus shots because the "Intelligent" Autofocus wouldnt switch to servo when I wanted.
So, for example, if I was at the zoo, and I was taking a picture of a bear, I would half press and hold until the bear was were I wanted, then press. If servo didnt kick in, the shot was out of focus.
Now, with the hacked firmware, I either enable AI Servo, or I make sure not to half press and hold, but rather press all the way down when I want a shot. The results have been SO much better! I rarely get an out of focus shot anymore.
This may or may not be your problem, but I'm just throwing ideas out there.

[Big_B]

Then, you know what that left as the possible cause.

You crack me up bob!

Doc, I've had the same sort of experience as Drisely with moving objects, could this be your issue too?

[DocFrankenstein]

Oh no, I'm not even talking about anything remotely moving...

My main subjects were belching overfed mammals who couldn't move if their life depended on it. :?

I would point the central AF point on the "face" of the animal or a part that I want focused, the focus would lock up giving me green light and would not try to re-focus when I reframe the shot. The focus was off 80% of the time.

BTW: I was far enough from the animal to not be affected by reframing the image.

Right now, I have problems posting pics cause my fotopic collection has crashed and they're supposedly fixing it.

[CyberDyneSystems]

Doc,
I recall reading about someone on the forum having a similar problem and they took the UV filter off and problem went away. Might want to try some shots without the filter and check the results.

It was me,. it was the same lens,. and it was the SAME UV Filter!!!

My Sigma 70-200mm EX focused spot on all the time.. then suddenly I started having issues..

To make it trickier to diagnose.. the misfocusing only occured in certain lighting.. it ONLY happened outdorrs in certian sun lit conditions.

I struggled with this for a month or so before realizing I had swapped an old tiffen UV for a newer Hoya... I was shooting some herons last August.. (go figure) when the "issue" reared it's ugly head.. I unscrewed the Hoya and I was back in business!

See if you can get the trouble to manifiest itself outdoors and then unscrew that Hoya and see if it fixes it.

I'm not 100% sure that swapping the UV for another brand will fix it.. but I seem to think my problems only occured with the Hoya.

Good luck.

[CyberDyneSystems]

It's strange. I did a ruler test in low light. It seems right on focus with both the UV filter and without it. :?

Again.. when I had this trouble.. it only occured under certain lighting.. I had a few hundred shots I had taken indoors in the theatre that were all spot on.. then I would have a handfull of shots in daylight that would be "off"... so randomly "testing" will not prove anything..

You will have to wait for the "misfocus" to manifest itself with the correct (or incorrect) lighting situation,... then test.

Or you could just grab a new filter..

[robertwgross]

I struggled with this for a month or so before realizing I had swapped an old tiffen UV for a newer Hoya... I was shooting some herons last August.. (go figure) when the "issue" reared it's ugly head.. I unscrewed the Hoya and I was back in business!


Well, I've been shooting herons this August. Great Blue, Green, Black-crowned night herons, snowy egrets, kingfishers, etc. Obviously with a very long lens. Due to normal use of the Canon 1.4 TC, I don't get any autofocus, so I can't blame anything on a filter. Besides, my "shooting blind" is under a low shade tree, and as I step back and forth along the trail under the tree branches, I would not want to carry the long lens without any protection of a filter.

---Bob Gross---

[DocFrankenstein]

Hoya 77mm UV (O) Japan

Is this hoya's best filter or not? It says on the box: ""fully coated surfaces increase light transmission and absorb almost all range of UV rays to give cleaner and sharper pictures with less haze. Constant use for lens protection is recommended. "

Is that the "both sides multi coated" version?

[Cadwell]

I would point the central AF point on the "face" of the animal or a part that I want focused, the focus would lock up giving me green light and would not try to re-focus when I reframe the shot. The focus was off 80% of the time.


There was quite an interesting article referenced on here the other day about how focus / recompose didn't really work that well... you're not suffering from that effect are you?



http://visual-vacations.com/Photography/focus-recompose_sucks.htm

[DocFrankenstein]

No... no way...

They were at least 10-15 meters away from me.

[robertwgross]

We know that autofocus depends on the contrast of the target. When shooting at a zoo, I always find that my camera can get an easy autofocus lock on a zebra, but when I go after a normal elephant or a rhino, it is much more difficult. Then, after the elephant gets wet in the waterhole, autofocus gets easier again. I think there is a pattern to this.

---Bob Gross---

[drisley]

Doc,
Are you using the 300D hacked firmware so that you can enable One Shot Focusing?
If not, that is probably your problem. Since the 300D uses Auto "Intelligent" Autofocus only, when you recompose it's probably kicking into AI Servo mode.
This used to happen to me all the time.
Again, the hack saved me. I now can enable One Shot Autofocus when I want to use the focus/recompose method.
Focus/recompose is almost impossible with the 300D without the hacked firmware.

[DocFrankenstein]

Doc,
Are you using the 300D hacked firmware so that you can enable One Shot Focusing?
If not, that is probably your problem. Since the 300D uses Auto "Intelligent" Autofocus only, when you recompose it's probably kicking into AI Servo mode.
This used to happen to me all the time.
Again, the hack saved me. I now can enable One Shot Autofocus when I want to use the focus/recompose method.
Focus/recompose is almost impossible with the 300D without the hacked firmware.
I'm gonna get the hack, but it seems unlikely that it was switcing to Servo. I was using Sigma 70-200 and it "kicks" every time it focuses, so I'd probably feel it... then maybe I didn't that that's the cause of my problem.

Anyways. I'll try the hack.

[drisley]

Just a possibility.
However, before I got the hack, I read ALOT of posts about the focus/recompose technique being nearly impossible on the 300D.
Let us know if that helps.
BTW, you should love the hack. It gives so many options.
Plus the ability to make the embedded jpgs smaller gives a nice increase in the number of Raw pictures you can get on a card (if you shoot raw).

When using the hack, OS means "One Shot", SE means "Servo", and AI is "Auto Intelligent".
You just press the left arrow button to bring it up during shooting.