Please Help - Focus/ Aperture Question

[triangle]

Ok, I have purchased the 50mm f/1.8 and the Tamron 24-70mm f/2.8 for low light sport/action shots. I have taken several pictures that come out great in daylight and I even have some that turned out fine in the darker sittuations. But I can not for the life of me figure out what is going on with some of my shots. I would like some feedback on the shots I am posting and hope that it will help me understand what I may be doing wrong. I am planning on saving for some "L" glass and an upgrade to the 20D but that may be down the road. Meanwhile people have asked me to shoot pics of their kids in these events and I may or may not be able to produce the shot.

I would like to know also, if the 20D would make that big of a difference using my same lenses, or get the glass "L" first. But the shots I am now taking are not turning out - HELP!!!:cry:

I am posting some of the photos below, with the focal points showing. I use center-focus almost 100% of the time because I place my subject in the center of my frame. But I am noticing that I am focusing on the subject (shown below by my focal points) and the people behind or on the sides are the ones the camera actually focuses on. Can someone please explain what is happening and how I can avoid this? I am missing important shots because of this.

NOTE: I have used my 580ex sometimes at night, but I decided to shoot with available light. I was under the impression that the aperture- f-stop was what made a "fast" lens. Since I was shooting at 1.8 and 2.8, should that not be "fast" enough to use in these pics?


#1 - Aperture-Priority AE, Tv - 1/640, Av - 4.0, ISO 100,
Lens 70.0 - 300.0 mm, Focal Length 70.0 mm

http://www.trianglephotography.com/tests/focus_track.jpg

And she was looking right at the camera - arghhhhhhhhhhhhhh!:mad:


#2- Shutter Speed Priority, Tv - 1/320, Av - 4.0, ISO 200,
Lens - 70.0 - 300.0 mm, Focal Length -104.0 mm

http://www.trianglephotography.com/tests/focus_track2.jpg

:cry:



#3- Aperture-Priority AE, Tv - 1/400, Av - 1.8, ISO 1600, Lens 50.0 mm

http://www.trianglephotography.com/tests/focus_track3.jpg

What a lovely shot of the ladies in the stands. :cry:



#4- Aperture-Priority AE, Tv - 1/200, Av- 1.8, ISO 1600, Lens 50.0 mm

http://www.trianglephotography.com/tests/focus_track4.jpg

On this picture the leader was not focused on but rather the girl in the back (black & gold) is the clearest. :confused: ??????????????



I did get some good shots here are a few.

http://www.trianglephotography.com/tests/focus_track5.jpg

http://www.trianglephotography.com/tests/focus_track6.jpg

[v6Goose]

Hi Triangle...

It does seem a bit 'hit and miss'. I use L glass on my rebel and dont have that problem (unless 'I' screw it up) but I'm not sure your lens is the problem.
To trouble shoot the issue, can you see the same problem when using some of your other lenses?

I have seen issues similar to this on other sites with 300D's when the camera is used in aperture priority, as AI-servo can kick in when your subject is moving towards the camera. AI servo is a constantly refocussing system to track moving objects. Having said that, I have had very limited success with it on the 300D.

A selectable version of AI is something i am sorely missing in the shots i take, tempting me to upgrade.

As a lot of your shots here are 'action' based, i would suggest shooting in shutter priority and setting it to perhaps 1xfocal length. Of course you will need to experiment with it, but at that speed a good panning technique should render your subject sharp and movement in all the surrounding objects giving the feeling of movement and speed.

Practice now on things that dont matter, so next time you have to shoot things that do, your success rate will be higher.

I hope this makes sense and helps - please write more if you wish...

good luck!

Goose

[RDKirk]

The setting you want is AI Servo focus, at least. I'm not sure you can set that directly on the Rebel in a "creative" mode, but you get it if you go to the sports auto setting.

Your track and field subject should not cause much trouble for AI Servo even for the DRebel (maybe the long jumper would have caused it a problem)--that is the kind of straight-direction action that AI Servo is designed to capture.

Be sure to start following the subject and half-press the shutter release before you intend to take the picture so that the camera can start following and predicting the action.

Turn on all the focusing points so that the camera can continue to track the subject if it "wanders" from the center point. The AI Servo system is biased to find the nearest subject to the camera if it loses the intended subject. This is actually the right thing to do most of the time.

One thing you might do in track and field, though, is go back to methods we used in pre-af days: Remember that much of the action will occur in a quite precisely known area.

1. High jump: Prefocus in manual on the bar.
2. Hurdles: Prefocus in manual on a hurdle that the runner your're interested in with leap.
3. Any race: Sprint, prefocus in manual on the near stripe of the lane your runner is in. Long run where they don't remain in a lane, prefocus in manual on the inside edge of the track.

For more hints, check this Canon pamphlet:

[triangle]

For more hints, check this Canon pamphlet:

?

As Paul Harvey states; can you tell me the rest of the story.


One thing you might do in track and field, though, is go back to methods we used in pre-af days: Remember that much of the action will occur in a quite precisely known area.

1. High jump: Prefocus in manual on the bar.
2. Hurdles: Prefocus in manual on a hurdle that the runner your're interested in with leap.
3. Any race: Sprint, prefocus in manual on the near stripe of the lane your runner is in. Long run where they don't remain in a lane, prefocus in manual on the inside edge of the track.

I was prefocusing on the bar in the highjumps, but I left the lens on AF. I guess I should have turned that off. What do most sports shooters use when shooting? Is it AF or manual focus? I have talked to some others that use the manual focus.

I have seen issues similar to this on other sites with 300D's when the camera is used in aperture priority, as AI-servo can kick in when your subject is moving towards the camera. AI servo is a constantly refocussing system to track moving objects. Having said that, I have had very limited success with it on the 300D.
The second picture was shot in TV mode at 1/320 and it still did the same thing. But as I said above I had focused on the bar and left the lens in AF, maybe it refocused as I took the shot.:oops:


Thanks for the replies, anything else would be appreciated and well noted.

[v6Goose]

Hi Triangle... I did see your second shot in TV mode, and can only assume the 300 is trying to refocus in AF mode and missed the shot. I would be keen to hear how your testing goes and see if we cant fix you up :)
PS. I use TV mode for high speed sports to 1 to 1.5 times focal length with good results. Each photog will have a favoured method, find one that works for you and perfect it.

Cheers

Goose

[triangle]

Hi Triangle... I did see your second shot in TV mode, and can only assume the 300 is trying to refocus in AF mode and missed the shot.


Goose, the photos above have the AF point highlighted from where the camera was focused on at the time of the shot. The photos were captured from my Zoom Browser window. That is why I can not understand the reason for the AF (red) that the point is supposed to be focused upon (but is not) but there is clarity on a subject behind the AF.

If anyone can explain this I would appreciate it. I'm dumbfounded.:confused: :oops:


I would be keen to hear how your testing goes and see if we cant fix you up :)

Cheers

Goose

Thanks Goose, I will take all of the fixing that I can get. ;) I would really like to perfect my photography.

[triangle]

Ok, now I am ready to pull my hair out. Here is a pic from a school program I was asked to shoot tonight. No action just a student standing there singing. I decided to shoot in TV mode, 1/60 sec, 4.0 AV, 400 ISO, Lens 28-75mm @ 75mm focal length. Please elaborate on the possible reasons for this.




http://www.trianglephotography.com/tests/mtg.jpg


A little closer

http://www.trianglephotography.com/tests/mtg_closeup.jpg


1. Is it the Lens?

2. Is it the camera?

3. Is it the photographer?

I will fix the one that needs fixing.


:cry: :cry: :cry: :cry:

[chris.bailey]

1) Lens. If so it is a long way out and as you other shots were with a different lens..erm
2) You focussed on something else and with your finger still down, re-framed.
3) Your camera has a mind of its own and was seeking students at the back who had fallen asleep.

[snibbetsj]

2) You focussed on something else and with your finger still down, re-framed.


Is it possible this happened?

[triangle]

1) Lens. If so it is a long way out and as you other shots were with a different lens..erm


#2 of original post was the same lens.

[Bodog]

I think you need to check into the possibility you have a back focusing problem. There are probably threads about this on the forum.

[snibbetsj]

Go to http://www.photo.net/learn/focustest/and see if you have a focusing problem with your camera/lens combination. If that's not it, then it almost has to be a focus-recompose issue (in the last photo).
:)

[Hellashot]

There was no EXIF data in the images. Was the lens set to autofocus?

For the action shots:

I would say that your shutter speeds probably aren't fast enough for the action you are trying to capture, which is why you think the camera focused on the background when it appears that way because the background was hardly moving - your subject was moving.

As for the classroom - was the lens set autofocus? When the lens is set to manual focus, the center red square will show up as red in that program you are using even though autofocus wasn't used.

[triangle]

There was no EXIF data in the images. Was the lens set to autofocus?

For the action shots:

I would say that your shutter speeds probably aren't fast enough for the action you are trying to capture, which is why you think the camera focused on the background when it appears that way because the background was hardly moving - your subject was moving.

As for the classroom - was the lens set autofocus? When the lens is set to manual focus, the center red square will show up as red in that program you are using even though autofocus wasn't used.


Yes, the lens was set to AF in all of the shots. One thing I failed to mention, is that in the school pic I was using my 580ex set to ETTL. I had focused on the girl in the center, but does ETTL refocus as the photo is snapped?

I was noticing the ETTL focus when I was attempting the focus tests that snibbetsj had suggested. As far as the shutter speeds are concerned, I believe they are fast enough aren't they? I was shooting in AP mode in most of them and the camera determined SSP. The 1st pic was 640/ss in daylight, that should have been plenty fast I think. Correct me if I am wrong.

[mbze430]

no the lens are in focus, but its complete focusing on the wrong subject. You can tell, look at picture #1 and #2. Everyone in the background is focused except the intended target.

#3 and #4 the lens is focus to infinity or close to it. As you can see the everything in the far back ground is sharp.

Without actually testing the camera its hard to say. However if you have it set to One-Shot mode, and it locks focus, and beeps.. And the picture is out of focus with that AF point, than its the camera.

Unfortunately I don't know much about Rebel lines. But in situation where I need to track motion, I usually set CF4-1 or CF4-3, with AI Servo.

[tim]

Like someone said, the two options are:
1) Inexperience.
2) A bad lens.

The way to work it out is to put the camera on a tripod, use autofocus to focus on a stationary object, and take the picture. If the correct thing's in focus, then it's option 1.

All the photos that didn't work out are action photos, and they're all focused behind where they should be. That could be because you focused then the subject moved before you took the picture. Until you work this out I strongly recommend manual focus - just focus on the position you want to be in focus (eg the bar in the highjump).

Again, I strongly recommend you do the tripod thing I suggested above. Report the results of that back, until you do no-one can really help you.

[triangle]

All the photos that didn't work out are action photos, and they're all focused behind where they should be. That could be because you focused then the subject moved before you took the picture. Until you work this out I strongly recommend manual focus - just focus on the position you want to be in focus (eg the bar in the highjump).

Tim, the last shot from the school was not an action shot. As I stated the girl was standing in one spot singing. I was shooting using my monopod and 580ex flash.

I will conduct the test shots with my tripod later today. I will post the results later and check on input afterwards. I appreciate everyones input. :cool:

[tim]

Yeah that last one's strange. I'd still like to see a tripod test though. Lets hope it's just a lens that needs calibration.

[Tom W]

Test all 3 of your lenses, using Pekka's suggested test method from this thread:

http://photography-on-the.net/forum/showthread.php?t=10526

If the problem is certain lenses, then they need adjustment. If all 3 lenses are out of focus in the same manner, its likely to be the camera that needs adjustment.

This doesn't rule out technique problems, but it will help deal with equipment problems.

[chris.bailey]

I would have thought they are too far out to be a lens problem. If its something equipment based it looks more like an Autofocus system fault.

[Tom W]

The lens is part of the autofocus system. The lens offers feedback to the camera, and has parameter settings to account for focus system inertia, speed, and start/stop times. If these aren't adjusted properly, the lens will overshoot or undershoot the accurate focus point.

I had a Tokina lens for 2 days (sent it back) that displayed similar symptoms as here - severe backfocus. But I wasn't shooting moving objects. They were stationary. All my other lenses work fine. The result for me was no more Tokina.

[DwightMcCann]

I'm very new to Canon and not familiar with the lens, but is there any chance, since all out of focus images are focused on the background, that you have the limit focus switch set and are simply too close to focus? You haven't mentioned if they look in focus to you through the viewfinder ... how do they look?

[mtndew]

Hi triangle on #3 were you panning in AI servo on a tripod/monopod or did you prefocus on that area? I also noticed in the first 2 your using a slower ISO speed try starting with 400 ISO with any sport or higher.