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Not authentic manual focus with Xsi?

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Joel Melgar

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Sometimes, when I need Manual Focus, as indicating in the camera's manual, I move the lens switch to MF, but the camera refuses to fire, until it can confirm any of the 9 focus points. It's frustrating because I want to shoot with the freedom of my old manual camera. With this method it takes precious time to archive the results I want. Can You suggest another method?
 
Impossible... the lens switch must be broken. The XSi will always fire when the lens is not AF.
 
Same issue with other two canon leneses. Perhaps camera´s fault.
 
The XSi does not even have a function you can set to force focus priority... what you are describing is impossible. If it would be possible, focus trapping would be possible with an XSi (and it is not).

So, either you are trying to pull our leg, or you have a very weirdly malfunctioning XSi.
 
Have the camera set to Focus Priority and not Release Priority? I know on Nikon that AF-S (single) and AF-C (continuous) have those settings set up differently by default. I'm sure canon has similar settings? I know on Nikon you can focus trap with AF lenses (set to MF mode) and with Pentax you can focus trap with MF lenses.
 
Colin Stuart said:
Have the camera set to Focus Priority and not Release Priority? I know on Nikon that AF-S (single) and AF-C (continuous) have those settings set up differently by default. I'm sure canon has similar settings? I know on Nikon you can focus trap with AF lenses (set to MF mode) and with Pentax you can focus trap with MF lenses.
Click to expand...
One can't focus trap with an XSi. What he is describing is not possible (with a normally functioning XSi).
 
I have XSI and for kicks tried it . I thought maybe in full auto or P mode it might make a difference but I can shoot MF an purposely focus it out of focus and shutter fires no matter what focus is (green light or not) .

Ed
 
Try back button focus (focusing with the * button) see the custom Fn menu to set it up. That should allow you to shoot without the AF locking on as well I think. If the AF switch is broken this may be a quick fix until you can get it repaired.

Also be sure you're in a creative zone mode, M, Av, Tv or P mode. I'm not sure what green box/scene mode does to force AF. Also try center AF only instead of using all AF points if you aren't already.
Joel Melgar said:
Sometimes, when I need Manual Focus, as indicating in the camera's manual, I move the lens switch to MF, but the camera refuses to fire, until it can confirm any of the 9 focus points. It's frustrating because I want to shoot with the freedom of my old manual camera. With this method it takes precious time to archive the results I want. Can You suggest another method?
Click to expand...
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I would look to the camera body as the fault, particularly if you get the issue with more than one lens.

If only one lens has the issue, the problem lies in the lens' AF switch mechanism.

cheers,
S.
--
beam me up captain, there's no intelligent life down here!
 
Canon dslr doesn't wait for focus confirmation for shutter-release. It is very easy to take an out of focus photograph as camera doesn't prevent shutter released.

Have you Reset Camera Setting? Most likely explanation is your somehow mix up camera's own default setting. Try resetting both
  • Camera Setting and
  • Custom Funcitons
If that didn't help, try flashing the camera with newest firmware.
brightcolours said:
The XSi does not even have a function you can set to force focus priority... what you are describing is impossible. If it would be possible, focus trapping would be possible with an XSi (and it is not).

So, either you are trying to pull our leg, or you have a very weirdly malfunctioning XSi.
Click to expand...
 
WilbaW said:
brightcolours said:
One can't focus trap with an XSi.
Click to expand...
This one can! You just have to achieve focus before the system does a focus search again.
Click to expand...
Hi WilbaW,

Ok, I remember that it's possible in AF mode, by something like forcing the lens to hunt and give up (e.g. lens cap on) ...and then while still holding the shutter release, remove cap and move the camera towards the object. (the photo is taken when focus is achieved)

But is it also possible in MF mode??

Please feel free spill the beans if so!!

Regards

Andy.
 
Andy C Knight said:
WilbaW said:
brightcolours said:
One can't focus trap with an XSi.
Click to expand...
This one can! You just have to achieve focus before the system does a focus search again.
Click to expand...
Ok, I remember that it's possible in AF mode, by something like forcing the lens to hunt and give up (e.g. lens cap on) ...and then while still holding the shutter release, remove cap and move the camera towards the object. (the photo is taken when focus is achieved)
Click to expand...
That's it. I just put the subject inside the MFD, full press, then back away.
Andy C Knight said:
But is it also possible in MF mode??
Click to expand...
Funny you should ask... I was checking this out for another purpose earlier today. No, AFAIK, you can't do trap focus with a 450D in MF, and you can only do trap focus with a 450D in AF by starting with the subject inside the MFD.
Andy C Knight said:
Please feel free spill the beans if so!!
Click to expand...
Splat!
 
That is not possible because the EF lens switch is not connected to the camera body. Either the switch is broken and the auto-focus is still activated, and you have the shutter button linked to the auto-focus, or the problem is not related to the focusing system.

--
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WilbaW said:
Funny you should ask... I was checking this out for another purpose earlier today. No, AFAIK, you can't do trap focus with a 450D in MF, and you can only do trap focus with a 450D in AF by starting with the subject inside the MFD.
Click to expand...
Sigh... I was getting all excited for a moment there!

I guess what we need is a legacy lens adapter (with AF chip) that tells the camera it's an AF (instead of MF) lens fitted.

Hmm... I'm thinking do I really need my old 18-55 lens - I could remove the AF motor and get trap focus with MF! :-)

Perhaps if the OP's lens has some kind of AF/MF switch fault (i.e it disengages the mechanical link, but is electrically defective and hence remains in AF mode), it may explain the odd behavior reported.

Edit: - Nope... Just read that it occurs on 2 other lenses that he has - very odd...

Regards

Andy.
 
Last night I checked my lenses. I tried with my lens kit and was right, the problem were with my two old lenses from my film era (from 2 years ago). The two lenses have something in common: A few years ago, I send them in two different times to technical service due fungus problems. Besides, when I set switch to MF in any of these lenses I hear a little "tic" sound when I'm trying to shoot. Here in my country: Guatemala in Central America the Canon Service is really poor. Thanks for your advices and, I not have another choice but go back to this bad canon service.

Thanks.
 
Andy C Knight said:
WilbaW said:
Funny you should ask... I was checking this out for another purpose earlier today. No, AFAIK, you can't do trap focus with a 450D in MF, and you can only do trap focus with a 450D in AF by starting with the subject inside the MFD.
Click to expand...
Sigh... I was getting all excited for a moment there!

I guess what we need is a legacy lens adapter (with AF chip) that tells the camera it's an AF (instead of MF) lens fitted.

Hmm... I'm thinking do I really need my old 18-55 lens - I could remove the AF motor and get trap focus with MF! :-)
Click to expand...
That's an interesting idea. People talk about "taping the pins" with things like teleconverters, to interfere with the communication between the body and the lens. Maybe there's a way to do something like that.
Andy C Knight said:
Perhaps if the OP's lens has some kind of AF/MF switch fault (i.e it disengages the mechanical link, but is electrically defective and hence remains in AF mode), it may explain the odd behavior reported.

Edit: - Nope... Just read that it occurs on 2 other lenses that he has - very odd...
Click to expand...
Sounds like a fault with the body, doesn't it?
 
Joel Melgar said:
...the problem were with my two old lenses from my film era (from 2 years ago). The two lenses have something in common: A few years ago, I send them in two different times to technical service due fungus problems...
Click to expand...
One thing you could try is working the AF/MF switch. If there is an oxide coating over the switch contacts, it's possible that could cause the symptoms you describe. Flicking the AF/MF many times, may clean up the electrical contacts.

Failing that - I guess repair is the only option.

Regards

Andy.
 
WilbaW said:
That's an interesting idea. People talk about "taping the pins" with things like teleconverters, to interfere with the communication between the body and the lens. Maybe there's a way to do something like that.
Click to expand...
Yes - Taping pins would be far less destructive - I've just seen the price 18-55's are fetching on Ebay (in mint condition), so I'm not so keen to pull the thing apart now!
(Although if I find a defective one real cheap...)
WilbaW said:
Sounds like a fault with the body, doesn't it?
Click to expand...
Just read a later mail from the OP - It only occurs with 2 old lenses that have previously had fungus problems... I'm guessing its possible that the AF/MF switch contacts are dirty/defective

Regards

Andy.
 
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