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Old Aug 29, 2006, 11:03 PM   #1
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I am a fairly new owner of a *ist dl. Took my camera to a coworkers retirement party last weekend, but had a lot of trouble with the aout focus in the low light. Even when the flash lit to do focus assist, it was very slow to focus - sometimes 10-20 seconds, and sometimes not at all.

Is this normal, or am I doing something wrong?
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Old Aug 29, 2006, 11:12 PM   #2
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10-20 seconds seems a bit long, but yes - it is pretty common to have low light focus issues.

What lens were you using? That can make a difference as well.

sometimes the best thing to do is switch to Manual Focus if its really giving you fits...
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Old Aug 29, 2006, 11:20 PM   #3
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All autofocus mechanisms need a some sort of contrast between light and dark to focus on. If you aim at a well lit, white wall with autofocus, it will have trouble focusing as well. If there is a dark line on that white wall, it will focus. No matter the lightning conditions, you need something that has a sharp contrast in shading. Without that, you probably are better off using the manual focus.
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Old Aug 30, 2006, 10:55 PM   #4
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Try this: Manually deploy thecamera's built-in flash and thecamera will use short pulses from the flash to achieve focus quite easily. That is how it works onmy DS.

MT
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Old Aug 31, 2006, 5:08 AM   #5
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AZRick wrote:
Quote:
I am a fairly new owner of a *ist dl.* Took my camera to a coworkers retirement party last weekend, but had a lot of trouble with the aout focus in the low light. Even when the flash lit to do focus assist, it was very slow to focus - sometimes 10-20 seconds, and sometimes not at all.

Is this normal, or am I doing something wrong?
DL low light ability is really good. Go to a SMALL storage room pitch dark with no light at all. You will have no trouble. The key is the distance. In a larger area, the assist light cannot reach all the area resulting in hunting back and forth.
Solution is to be closer to the subject using wider angle.
Try it. Does not cost you a penny.

Daniel
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Old Aug 31, 2006, 11:40 AM   #6
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Check your batteries, i've found that the AF hunts more with weak batteries (maybe just my imagination).

Also, are you using Spot AF? If not, give that a try two, I asked this same question, and someone suggested using Spot, putting the object in the center, focussing, and then recomposing the picture.
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Old Aug 31, 2006, 12:03 PM   #7
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intence wrote:
Quote:
Check your batteries, i've found that the AF hunts more with weak batteries (maybe just my imagination).

Also, are you using Spot AF? If not, give that a try two, I asked this same question, and someone suggested using Spot, putting the object in the center, focussing, and then recomposing the picture.
Yes, I have found that low batteries will give focus errors.

I always use spot AF because I first used MF film SLRs that had centre focus aids, so I focus then recompose, then I used first generation Minolta Maxxums (5000 and 7000), again they had only a centre focus point so I would focus and recompose. All of the focus points just give me one too many things to think about so I have my camera set on spot focus.

Ira
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Old Aug 31, 2006, 12:39 PM   #8
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Monza76 wrote:
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intence wrote:
Quote:
Check your batteries, i've found that the AF hunts more with weak batteries (maybe just my imagination).

Also, are you using Spot AF? If not, give that a try two, I asked this same question, and someone suggested using Spot, putting the object in the center, focussing, and then recomposing the picture.
Yes, I have found that low batteries will give focus errors.

I always use spot AF because I first used MF film SLRs that had centre focus aids, so I focus then recompose, then I used first generation Minolta Maxxums (5000 and 7000), again they had only a centre focus point so I would focus and recompose. All of the focus points just give me one too many things to think about so I have my camera set on spot focus.

Ira
I should give credit to Ira for those suggestions since I asked a similar question about focussing a few weeks back, and I believe it was him who responded. Another suggestion I received was to try the following:

Something else you may want to try if you don't think you'll be almost exclusively using Spot-AF, is to set the option where Spot-AF gets enabled when the OK button is pressed. Under normal circumstances, you depress the shutter halfway and regular AF is used, but also hold the "OK" button and Spot-AF is used. You'll need to enable this feature in the Custom menu, but it's quite useful.

In my experience, i've also found that some lenses have problems focussing when at extreme wide-angle or extreme zoom.


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Old Aug 31, 2006, 1:37 PM   #9
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Thanks folks for the ideas.

I am set for spot focus, and the flash was popped up and doing focus assist.

I did have to change batteries half way (I didn't pay attention, but it may well have gotten better after that).

From your comments above, I suspect the biggest thing was the distance. It was a big crowd, and many shots wereof larger groups, thus at greater distance. If I remember correctly, shorter close ups did better.

Time for some experimenting (I am an engineer after all).

Rick
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Old Aug 31, 2006, 3:08 PM   #10
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intence wrote:
Quote:
I should give credit to Ira for those suggestions since I asked a similar question about focussing a few weeks back, and I believe it was him who responded. Another suggestion I received was to try the following:

Something else you may want to try if you don't think you'll be almost exclusively using Spot-AF, is to set the option where Spot-AF gets enabled when the OK button is pressed. Under normal circumstances, you depress the shutter halfway and regular AF is used, but also hold the "OK" button and Spot-AF is used. You'll need to enable this feature in the Custom menu, but it's quite useful.

In my experience, i've also found that some lenses have problems focussing when at extreme wide-angle or extreme zoom.

intence I need more students like you, who can pay attention

Ira
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