[rorensu]

I have a IXUS55 but I donno what are the difference between Fous Lock, AE lock, and FE Lock. I read the manual for many times and I still don't get it. What are their use? Thanks for helping

[tyuen]

Focus lock -- this is to lock the focus.

AE lock -- automatic exposure lock. This is to lock the exposure setting, the f-value and shutter speed value.

FE lock -- flash exposure lock. This is to lock the flash exposure level. Usually a preflash will fire to check the exposure first.

Ok, let's try to test the effect of these:

1. Focus to a distant subject say 10m, then set focus lock. Try to focus a closer subject, say 1m. It fails because the focus has been locked at 10m.

2. Focus a subject under sufficient light condition, set AE lock. Notice the aperture number and shutter speed. Go to a darker place and focus another subject again. See if there's any change in aperture and shutter speed. Shoot at this darker place to see what happens. (You can also try the effect of FE lock similarly.)

[liumk]

so as me

[tyuen]

As you use DSLR, half press the shutter button may engage focus lock + AE lock together. Check the custom manual in your camera to see what has been set first, if any.

[rorensu]

How different is AE lock and FE Lock?

[tyuen]

rorensu, I don't remember clearly how a 350D operates. But you can try:

- use the custom function 4 of the camera under different settings;
- for each setting, press * in the camera. See how it focus and note the aperture / shutter number by "focusing" at different subjects at different lighting.

See the differences yourself.

[rorensu]

tyuen, when I press the FE Lock on my IXUS55 the flash blink once. Is the first blink means the camera is detecting the best output setting for the flash at the environment? So if I want to have dimmer flash I always have to go to bright place and do the FE Lock?

[tyuen]

I don't have IXUS55, but the "blink" should be a check of the flash metering.

If you go to a brighter place and do the FE lock, it'd be difficult to manage the flash exposure IMHO. Can IXUS55 do Flash Exposure Compensation?