Is my 50mm f/1.8 faulty?

[Advocate]

Hi all,

Some of you may be aware that I bought a 50mm f/1.8 mkII yesterday and am over the moon with the sharpness of the shots I get with it. However I think I may have a problem with it.

When using the kit lens if I switch it over to manual focus the camera no longer tries to autofocus and instead when I achieve focus over one of the focus squares in the viewfinder that square goes red and beeps (just like when using autofocus).

If I switch the 50mm over to MF the camera still tries to autofocus (can hear the motor going when half pressing the shutter) and I no longer get confirmation that I'm in focus.

Is this right?

TIA

Alistair

If I half-press the shutter button and focus while it is pressed I do get confirmation of focus but all the while I can hear the motor running on the lens. Plus I can't take a picture until I have achieved focus....weird

[peterdoomen]

May seem silly, but maybe you've just chosen a focus point without knowing it. On my 20D, you have to press the focus point choice button again then turn the wheel until all focus points become red again. Probably slightly different in a 350D.

P.

[Advocate]

lol yeah that was the case. When I set it back to using all of the focus points I get confirmation of focus.

I would have thought though that the camera would allow me to take an out of focus shot but nothing happens when I press the shutter button until the camera has confirmed focus and then and only then will it allow me to take a picture. This is in full manual mode btw

Alistair

[Jon]

Full manual relates only to exposure. Continuous shooting mode will not insist on being in focus for every shot, but that has no effect on exposure.

[Advocate]

Thanks for the reply Jon but I'm not entirely clear on what you're trying to tell me :s

I would have thought that putting a lens into MF would mean that

a) the lens/camera then didn't try to focus when I press the shutter button (ie why can I hear the motor trying to focus?)

and

b) that I could then take an out of focus shot if I wanted to (which at the minute the camera won't let me do)

Alistair

[aparmley]

Sounds like to me the lens has a faulty MF/AF switch. I mean, think about it, and I am sure you have thought of it this way. When you switch from AF to MF, you are telling the Body, don't worry about running the lenses motor to acheive focus, I got this one good buddy. So, your body should not be using the motor in the lens at all. It sounds like to me that the lens is in MF mode, but the switch, ie contact closure - perhaps lack of a contact closure, has not be made, so the body still thinks its in AF mode. I have a 50 1.8 as well, and when I am in MF no motor is used and it doesn't matter if I get a focus confirm or not in any mode, if I trip the shutter button, the camera takes the exposure - This is the result of the camera not caring about focus because I told it, let me worry about focus, you just take the exposure when I say - IE MF.
But, alas, it may not be the switch, I have heard of dirty contacts causing the camera/lens to do funny things, I have also heard that an eraser from an erasable pen works best when cleaning the contacts on the lens. You may want to give that a try? ? ? Good luck

[4x4rock]

Use CF4-1 and change the AF function to the *, then you can take OOF pics without problem.

[Advocate]

Sounds like to me the lens has a faulty MF/AF switch. I mean, think about it, and I am sure you have thought of it this way. When you switch from AF to MF, you are telling the Body, don't worry about running the lenses motor to acheive focus, I got this one good buddy. So, your body should not be using the motor in the lens at all. It sounds like to me that the lens is in MF mode, but the switch, ie contact closure - perhaps lack of a contact closure, has not be made, so the body still thinks its in AF mode. I have a 50 1.8 as well, and when I am in MF no motor is used and it doesn't matter if I get a focus confirm or not in any mode, if I trip the shutter button, the camera takes the exposure - This is the result of the camera not caring about focus because I told it, let me worry about focus, you just take the exposure when I say - IE MF.
But, alas, it may not be the switch, I have heard of dirty contacts causing the camera/lens to do funny things, I have also heard that an eraser from an erasable pen works best when cleaning the contacts on the lens. You may want to give that a try? ? ? Good luck

Mate you are an absolute star! :)

Took the lens off the camera, looked at the contacts on both the camera body and the lens, couldn't see anything wrong or dirty so put the lens back on the body but this time making sure I pressed firmly whilst rotating.

Now when in MF the camera body doesn't give a hoot whether in focus or not and there's no annoying motor going trying to focus. :):)

/me is a happy bunny

Thanks again mate, I owe ya one.

Alistair

[Jon]

Thanks for the reply Jon but I'm not entirely clear on what you're trying to tell me :s

I would have thought that putting a lens into MF would mean that

a) the lens/camera then didn't try to focus when I press the shutter button (ie why can I hear the motor trying to focus?)

and

b) that I could then take an out of focus shot if I wanted to (which at the minute the camera won't let me do)

Alistair
You said above This is in full manual mode btw from which it sounded like you expected the exposure mode to make a difference in focussing behaviour. The only instances where it will are Portrait and Sports (on the 20D, any way) where it also sets AI-Servo.