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09-15-2009, 07:03 PM   #1
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Focusing my new DA*300

I just got my new DA300 in the mail.
I only have had about 15 minutes to take it out in the back yard shooting so far.
It exhibited some unexpected behavior in AF and I wanted to ask others if this should be expected.

Sometimes when attempting to AF on a distant object, it will not focus. It does not try and miss, it simply does not try. So I have to AF on a near object, and then when I AF on the distant object again, it will focus correctly.

My 18-250 does not have this problem at any focal length, so I was wondering if this is normal, or what the cause is?

I was using my K20D at F4-F5.6 in the middle of the day, so there was plenty of light.

Thanks in advance for everybody's time!

09-15-2009, 07:19 PM   #2
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Seems odd.
Does the AF motor run at all when you attempt to AF on the distant object?
Do you get the flashing hexagon when you attempt it?
Are the AF/MF switches fully engaged in AF?

The lens shouldn't 'know' the difference between AF for short and long distances.
Could it be coincidental?
Are there any other AF nuances you weren't expecting?
09-15-2009, 08:30 PM   #3
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Was your distant subject one with lots of contrast? One time I was using the DA*200 and went from a close-up to infinity and the lens wouldn't focus. When I really looked through the viewfinder, the whole thing looked featureless, a green blob - no contrast at all. I pointed the lens to a larger object with lots of contrast, tried again and the lens focused immediately. Don't know if this would apply in your situation, but its something I think about more now.
09-15-2009, 09:11 PM   #4
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QuoteOriginally posted by mtngal Quote
Was your distant subject one with lots of contrast? One time I was using the DA*200 and went from a close-up to infinity and the lens wouldn't focus. When I really looked through the viewfinder, the whole thing looked featureless, a green blob - no contrast at all. I pointed the lens to a larger object with lots of contrast, tried again and the lens focused immediately. Don't know if this would apply in your situation, but its something I think about more now.
This happens only occasionally with my 300. going from its closest focusing distance to infinity is where I noticed this as well (though the AF didnt freeze up but rather just hunts for a bit). Another tap to the AF and its back on track. I feel like its pretty normal and i find af to be reasonably quick.

09-16-2009, 05:09 AM   #5
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QuoteOriginally posted by Ash Quote
Seems odd.
Does the AF motor run at all when you attempt to AF on the distant object?
Do you get the flashing hexagon when you attempt it?
Are the AF/MF switches fully engaged in AF?

The lens shouldn't 'know' the difference between AF for short and long distances.
Could it be coincidental?
Are there any other AF nuances you weren't expecting?
On these handful of times with the described behavior, no the AF/MF motor does not engage. Yes, the Switch is fully to AF position both on lens and bothe body. No hexagon. I did not find any other odd behavior.

QuoteOriginally posted by mtngal Quote
Was your distant subject one with lots of contrast? One time I was using the DA*200 and went from a close-up to infinity and the lens wouldn't focus. When I really looked through the viewfinder, the whole thing looked featureless, a green blob - no contrast at all. I pointed the lens to a larger object with lots of contrast, tried again and the lens focused immediately. Don't know if this would apply in your situation, but its something I think about more now.
Yes, this sounds very much like what was happening, possibly exactly. Why should the K20 have trouble focusing at 300 F4 on these objects but not have trouble with my 18-250 at 250 F6.3? I am confused. (I don't expect you to have an awnser, I am just pondering.) So maybe this is just behavior that is accepted for the DA300 (And DA200)?

QuoteOriginally posted by iceemn360 Quote
This happens only occasionally with my 300. going from its closest focusing distance to infinity is where I noticed this as well (though the AF didnt freeze up but rather just hunts for a bit). Another tap to the AF and its back on track. I feel like its pretty normal and i find af to be reasonably quick.
Unfortunately a re-tap on the AF did not do the trick, I had to recompose on another target, focus, then I could come back to the original target and the AF would work. Perhaps the focusing ditance change was part of the situation for me, but I do not recall. I will pay closer attentiontion next time I shoot with this lens. That will not be until Friday, unfortunately.

Was everyone else's observed experience with the K20 also?
09-16-2009, 07:54 AM   #6
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I'm sure that my situation had to do with contrast and the AF sensor. You need contrast for the sensor to work and what I saw through the viewfinder had no contrast at all - it was trees so a smooth green blob. I think it has much less to do with the lens (other than the lovely, creamy bokeh both the DA*300 and DA*200 have) as it does with the way auto focus works in general. I'm not sure I've had either of these two lenses on the K20 yet - I only bought them a month ago and have been using them exclusively on the K-7 - I wouldn't imagine that the results would be any different with the K20 though.

P.S. the difference between the 18-250 might have to do with the DOF that lens would have at f6.3 and 250mm focal length and f4 and 300mm - significantly smaller. The DA*300 can focus pretty closely (well compared to the A*300), so there's a huge difference.
09-16-2009, 12:18 PM   #7
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QuoteOriginally posted by mtngal Quote
I'm sure that my situation had to do with contrast and the AF sensor. You need contrast for the sensor to work and what I saw through the viewfinder had no contrast at all - it was trees so a smooth green blob. I think it has much less to do with the lens (other than the lovely, creamy bokeh both the DA*300 and DA*200 have) as it does with the way auto focus works in general. I'm not sure I've had either of these two lenses on the K20 yet - I only bought them a month ago and have been using them exclusively on the K-7 - I wouldn't imagine that the results would be any different with the K20 though.

P.S. the difference between the 18-250 might have to do with the DOF that lens would have at f6.3 and 250mm focal length and f4 and 300mm - significantly smaller. The DA*300 can focus pretty closely (well compared to the A*300), so there's a huge difference.
I ask about K20 vs K7 because I remember someone saying that their new K7 autofocused the DA300 noticeably better than their K20.

The DOF is a good point. I guess I am stuck in the "it is so gosh darn expensive (for me) it needs to do everything absolutely perfect" mode of thinking.

I need to put it through it's paces this weekend since I have the grace period from B&H.

BTW, which do you find yourself using more, the 200 or 300?
09-16-2009, 12:45 PM   #8
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The one thing I've learned when it comes to photography, there's no such thing as "absolutely perfect". And yes, the DA*300 is by far the most expensive lens I've bought or am likely to ever buy. But I think it's well worth the cost - I've been very pleased with the pictures I get from it.

As far as which I use more, the 200 or 300 - they do different things so I use them in different situations. The 300 is a big, long lens and I use it when I want something like that (birds and animals, surfing pictures taken from a pier, etc.). The 200, being shorter, is more useful for quick walk-about targets of opportunity where the 300 will stay in the bag. It really depends on what I'm doing.

09-16-2009, 03:19 PM   #9
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Thanks again for the feedback. I guess I just want to make sure that this is not the beginings of an SDM problem that I have read *so* much about. I guess I could be called paranoid. However like you, this is likely the priciest lens I will ever own, so I am cautious.
09-16-2009, 04:04 PM   #10
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I've found both SDM & HSM to be a bit quirky like this on my K20D. I've gotten to the point where I just more or less intuitively work with it and it's not a big deal for me it but, to tell the truth, I really prefer screw drive AF.
09-17-2009, 04:22 AM   #11
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QuoteOriginally posted by dadipentak Quote
I've found both SDM & HSM to be a bit quirky like this on my K20D. I've gotten to the point where I just more or less intuitively work with it and it's not a big deal for me it but, to tell the truth, I really prefer screw drive AF.
Yeah, I know I am not the first to say this but I wish we could choose. I would just leave it on screw drive normally, and just kick in the SDM if silence was needed.

EDIT: Of course the shutter on my K20 would scare away whatever I am taking a picture of on the first shot, anyway...

Last edited by apisto; 09-17-2009 at 04:41 AM.
09-17-2009, 02:34 PM   #12
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Hi Apisto

I have the 300 and am very happy with it, but it occasionally gets confused focussing on things with regular patterns eg roof tiles, especially if I am a bit shakey.

I'd try putting it on a tripod and see if you still have problems.

It is still a stunningly good lens.
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