Canon DSLR

DirtyRat · Jul 30, 2008

Hello. To start, I like both Canon and Nikon DSLR's. I've found an issue with the "focal" points. I purposely set "focus' using the center focal point for my action photography. Often times I find my subject blurred and objects "behind" in sharp focus. I generally shoot with a wide aperature to gain focus on the subject and a soft background. Much of the background in my images I don't want in-focus, ie. trailers, people, cars, etc.

Is there a setting I'm missing? I use a 70-200 Sigma f/2.8 and a Canon 50mm f/1.4, of course the kit lens on the Canon 40D.

Appreciate any help.

Mystwalker · Jul 30, 2008

I think you need to increase shutter speed. Shoot in Tv mode, increase ISO to get faster apperture (this gives you that soft background).

Or, shoot in Av mode - increase ISO until you get shutter speed that is equal to or greater then max length of lens (200 and 50 in your case). 50 may not be fast enough if your subject is moving fast.

With the f/1.4, if you are shooting wide open you have to be almost RIGHT ON TARGET. If your subject is moving eratically (toddler), this can be difficult. I stopped using my f/1.8 because I was having trouble keep daughters face in focus @ f/1.8.

A flash solved my problems

Buszaj · Jul 30, 2008

What AF mode are you shooting in? It should be servo.

Village Idiot · Jul 30, 2008

Mystwalker said:
I think you need to increase shutter speed. Shoot in Tv mode, increase ISO to get faster apperture (this gives you that soft background).

Or, shoot in Av mode - increase ISO until you get shutter speed that is equal to or greater then max length of lens (200 and 50 in your case). 50 may not be fast enough if your subject is moving fast.

With the f/1.4, if you are shooting wide open you have to be almost RIGHT ON TARGET. If your subject is moving eratically (toddler), this can be difficult. I stopped using my f/1.8 because I was having trouble keep daughters face in focus @ f/1.8.

A flash solved my problems

Or it could be an issue with back focusing. That requires a trip to Canon service.

DirtyRat said:
Hello. To start, I like both Canon and Nikon DSLR's. I've found an issue with the "focal" points. I purposely set "focus' using the center focal point for my action photography. Often times I find my subject blurred and objects "behind" in sharp focus. I generally shoot with a wide aperature to gain focus on the subject and a soft background. Much of the background in my images I don't want in-focus, ie. trailers, people, cars, etc.

Is there a setting I'm missing? I use a 70-200 Sigma f/2.8 and a Canon 50mm f/1.4, of course the kit lens on the Canon 40D.

Appreciate any help.

Try shooting with AI servo and then try this:

http://www.focustestchart.com/focus21.pdf

It's a focus testing chart. Test all your lenses at different apertures and follow the directions. That's one sure fire way to find out whether or not you suck and need to learn tracking/panning/focusing better or that your camera and/or lens(es) suck and need to be sent back for service.

DirtyRat · Jul 30, 2008

Village Idiot said:
Or it could be an issue with back focusing. That requires a trip to Canon service.

Try shooting with AI servo and then try this:

http://www.focustestchart.com/focus21.pdf

It's a focus testing chart. Test all your lenses at different apertures and follow the directions. That's one sure fire way to find out whether or not you suck and need to learn tracking/panning/focusing better or that your camera and/or lens(es) suck and need to be sent back for service.

It's true that a digital camera needs contrast to focus. Shooting a black horse at night = NO contrast.Thus no focus. At least I know it's not a fault of mine, nor the camera. I have to rely on luck of the shot.

table1349 · Jul 30, 2008

DirtyRat said:
Hello. To start, I like both Canon and Nikon DSLR's. I've found an issue with the "focal" points. I purposely set "focus' using the center focal point for my action photography. Often times I find my subject blurred and objects "behind" in sharp focus. I generally shoot with a wide aperature to gain focus on the subject and a soft background. Much of the background in my images I don't want in-focus, ie. trailers, people, cars, etc.

Is there a setting I'm missing? I use a 70-200 Sigma f/2.8 and a Canon 50mm f/1.4, of course the kit lens on the Canon 40D.

Appreciate any help.

Post an example with exif data included.

davebmck · Jul 30, 2008

DirtyRat said:
It's true that a digital camera needs contrast to focus. Shooting a black horse at night = NO contrast.Thus no focus. At least I know it's not a fault of mine, nor the camera. I have to rely on luck of the shot.

It's not a matter of luck. If you are consistently getting focus behind your subject you likely have a back focus problem as Village Idiot point out. If thats not it, it is probably your technique. If you didn't have enough contrast or light to focus your autofocus would hunt and wouldn't even get as close as you are getting.

Also as pointed out before, if your subject is moving towards you, servo focus will help. Try it out.

DirtyRat · Jul 31, 2008

That I never heard of. This is a fault of the lens(es)? How are we to know when buying a lens, that it has that flaw? When they run several thousand dollars for a lens, you'd think you were getting a "good" lens!?

I shoot in Servo to catch those moving subjects.

JerryPH · Jul 31, 2008

Post an example with EXIF data intact as suggested. It's all just guessing until we can see what you are talking about.

Village Idiot · Jul 31, 2008

DirtyRat said:
That I never heard of. This is a fault of the lens(es)? How are we to know when buying a lens, that it has that flaw? When they run several thousand dollars for a lens, you'd think you were getting a "good" lens!?

I shoot in Servo to catch those moving subjects.

It could also be the camera if it is a backfocusing issue. You have to rule out which it is.

Buy used from a reputable source. That's about it unless you know that the lens you're purchasing is bulletproof. There are some lenses are known to have soft focus, back focus, or other issues...

Back focusing is just an adjustment that's off though, it doesn't mean what you bought is defective. It's just not calibrate 100% true.

Tolyk · Jul 31, 2008

I'm curious, what does liking Canon and Nikon SLRs have to do with your question?

Bifurcator · Jul 31, 2008

He said it's "action photography" and stated "I shoot in Servo to catch those moving subjects"... so, I wonder if he's talking about blur and not actually focus.

It it IS blur you can pan the cam to follow the target and with a high enough shutter speed >100, the opposite will happen. The BG will be blurred and the subject will be sharp.

That's different than "focus" though so I dunno.

FDSA · Jul 31, 2008

to me it sounds like you're not panning the camera. Follow the subject all the way through the action. The subject should come out sharper and the background will be blurred.

DirtyRat · Jul 31, 2008

Panning, a technique to create blur in the background. I do that, shooting 1/60 sec. Got some great shots. How do I post a pic to show the problem I have. They are not on a URL.