Canon A70 - Spot Metering

[Photonak]

Hi All,

I'm not too excited about auto foucusing ability of this camera. I read all about it before I bought it. People seem to imply that if Center Weighted Avg is used, as opposed to Evalutive, the rusults are better.

I'm too happy with that either, having shot some typical party pictures recently. Soem were in farily dark places, others did not even need a flash.

Started testing and it seems that in Spot Metering mode, the focus is better. However that mode is not "sticky" - it resets, when you turn off the camera.

Anyone find a way to "keep" the Spot Focus mode?

Photonak

[adas]

No, light metering has nothing to do with focusing. And againg, all three methods are good methods, it's just they're intended for different situations.
Don't use the spot metering unless you don't care about the sorounding of your subject on wich the spot was placed. It is commonly used for very bright or very dark subjects.

[Don Schaeffer]

I don't like auto focus on my A70 either. If forces me to use all kinds of post process tricks to salvage photos. I wish I could afford a dslr so I could actually focus my lens manually. I so miss that aspect of film photography. Maybe I shouldn't have given away my film camera.

[Photonak]

No, light metering has nothing to do with focusing. And againg, all three methods are good methods, it's just they're intended for different situations.
Don't use the spot metering unless you don't care about the sorounding of your subject on wich the spot was placed. It is commonly used for very bright or very dark subjects.

I was under the impression that if you used "Beam Assisted AF", it would point somewhere in the center. Agree that AF and Spot Metering are two different animals.

Anyone have an idea where the "beam" points when you use it? Is it not the center of the screan?

While the beam is implied to be useful, when it's dark, wonder if it is given a preference in good light.

Regards...

[jrobert]

In some situations, focusing to the lens's hyper-focal distance may give you good results - that's the focusing distance that will include everything from some point to infinity in acceptable focus. "Some point" depends on the aperture and focal length you are using. The A70 will set this for you in modes other than Auto, if, once you've zoomed to the focal length you want to use, you double-click the Manual Focus button. A manual focus indicator will pop up showing the focus pre-set at (typically) somewhere between 5 and 10 feet.

Doing this also eliminates some shutter lag (that portion due to the auto-focus mechanism).

-jeff-

[Photonak]

Hi Jeff,

That's a very nice piece of info. Where did you dig that up? -)) Is there a bag of tricks for the A70 that some accumulated?

To clarify: Auto Mode you are referring to is the Green Auto on the dial. All other modes this should work? In fact I just confirmed it.

I wondered once about the distance the Manual Focus started with. Apparently it's a calculated value, and it's hyper-focal distance.

You are suggesting that I leave the focus in Manual, set to that distance, for a given focal length/aperture combo.

Photonak


In some situations, focusing to the lens's hyper-focal distance may give you good results - that's the focusing distance that will include everything from some point to infinity in acceptable focus. "Some point" depends on the aperture and focal length you are using. The A70 will set this for you in modes other than Auto, if, once you've zoomed to the focal length you want to use, you double-click the Manual Focus button. A manual focus indicator will pop up showing the focus pre-set at (typically) somewhere between 5 and 10 feet.

Doing this also eliminates some shutter lag (that portion due to the auto-focus mechanism).

-jeff-

[jrobert]

That's a very nice piece of info. Where did you dig that up? -)) Is there a bag of tricks for the A70 that some accumulated?
I don't actually remember, but it came from another user, probably someone here.
To clarify: Auto Mode you are referring to is the Green Auto on the dial. All other modes this should work? In fact I just confirmed it.
Right.
I wondered once about the distance the Manual Focus started with. Apparently it's a calculated value, and it's hyper-focal distance.
I'm not sure. Manual focus, when started by two clicks (as opposed to a double-click) seems to preset to ~18 inches on my camera. Double clicking starts it at around 7 feet or so, subject to aperture and focal length.
You are suggesting that I leave the focus in Manual, set to that distance, for a given focal length/aperture combo.
Yes, for those photos for which you want or can accept maximum depth of field. Also note that the setting does not survive a power-down.

BTW, a number of users have mentioned the poor performance of the so called "artificial intelligence autofocus", especially in low light and and prefer to turn it off ('AiAF', the first item on the recording menu). This feature selects which of five fields surrounding the center of the image to use for auto-focus. With AiAF turned off, the camera will still auto-focus but always uses the center focussing field, and, with your help (aim at a vertical (relative to the camera) edge, half-press to focus and hold, recompose and shoot), will mostly do a better job. Some experimentation is probably in order.

-jeff-

[Photonak]

...with your help (aim at a vertical (relative to the camera) edge, half-press to focus and hold, recompose and shoot), will mostly do a better job. Some experimentation is probably in order.

-jeff-

Are you saying that the Auto Focus system responds better, if you point it at a vertical line in the subject? Sort of like SLR manual focusing was easier when you picked a vertical line?

Photonak

[jrobert]

Are you saying that the Auto Focus system responds better, if you point it at a vertical line in the subject? Sort of like SLR manual focusing was easier when you picked a vertical line?

Photonak
That's right, it seems to use a high-contrast vertical edge for focusing.

-jeff-

[ekrunaj]

In some situations, focusing to the lens's hyper-focal distance may give you good results - that's the focusing distance that will include everything from some point to infinity in acceptable focus. "Some point" depends on the aperture and focal length you are using. The A70 will set this for you in modes other than Auto, if, once you've zoomed to the focal length you want to use, you double-click the Manual Focus button. A manual focus indicator will pop up showing the focus pre-set at (typically) somewhere between 5 and 10 feet.

Doing this also eliminates some shutter lag (that portion due to the auto-focus mechanism).

-jeff-
When I try this, the focus pre set shows at 10 ft if the lens is pointing at something close like your lap and double click, but shows closer to infinity if you point the lens at a point across the room and double click. This happens at wide angle or telephoto.

[jrobert]

The hyper-focal distance depends on the focal length of the lens and on the aperture. Was the focal length different between the two tries? The two scenes' brightness will probably have been. I've usually found a HF distance of 5-10 feet, but that would vary with brightness (further out in lower light -- unless the aperture has been set to a fixed value).

-jeff-