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08-02-2010, 05:54 PM   #1
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The shortest 300m prime

I have been lazy in bringing out my manual focus lens. And this one is kind of a legend within Pentax camp (A300mmF4) for being the "best lightweight hand-holdable long telephoto there is in all of God's creation."

from HTC phone camera





Took it out today for some ready and obnoxious subject always around my house












Daniel, Toronto

08-02-2010, 06:46 PM   #2
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I love that lens. Focus can be tough, especially in a fast-motion situation, but man...it's sharp!
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08-02-2010, 07:01 PM   #3
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Yes, it is a nice lens.


Last edited by tuco; 08-02-2010 at 07:22 PM.
08-02-2010, 07:02 PM   #4
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Oops...that was shot with the DAL55-300mm. This does not, however, change in any way my opinion of the A* 300mm F4.0!

08-02-2010, 07:16 PM   #5
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QuoteOriginally posted by bblang Quote
Oops...that was shot with the DAL55-300mm. This does not, however, change in any way my opinion of the A* 300mm F4.0!
I was going to say that seagull shot is pretty incredible for manual focus. You'll no doubt have a better success rate with auto focus with shoots like those. You'll need 5 to 10 seconds to confirm focus with the green light indicator in a camera like a K-7 with manual focus lenses.
08-02-2010, 07:49 PM   #6
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QuoteOriginally posted by tuco Quote
I was going to say that seagull shot is pretty incredible for manual focus. You'll no doubt have a better success rate with auto focus with shoots like those. You'll need 5 to 10 seconds to confirm focus with the green light indicator in a camera like a K-7 with manual focus lenses.
Have you done some shooting tests with the K7 and a manual lens?
I do use the K7 with some manual lenses and it sure doesn't take that long to get the green focus confirmation light.
Just curious how you came up with this.

JP
08-02-2010, 08:13 PM   #7
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QuoteOriginally posted by jpzk Quote
Have you done some shooting tests with the K7 and a manual lens?
I do use the K7 with some manual lenses and it sure doesn't take that long to get the green focus confirmation light.
Just curious how you came up with this.

JP
Yes, I have. You're lucky then. My K-7 needs you to bounce back and forth across the focus point to know with confidence you've got it.

Edit: I just went and timed that A* 300mm. Easy 5 seconds. It has 270 degrees of turn. Starting at an arbitrary focus on the lens to a focus I needed took about that long give or take a second.

Last edited by tuco; 08-02-2010 at 08:24 PM.
08-02-2010, 09:13 PM   #8
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Right, but who starts at infinity for every shot? Maybe the first shot out of the bag, but from then on, it's just fine adjustments, and you don't need to wait for the focus confirmation. I find I do better with birds in flight using manaul focus than autofocus - at least, when using a lens with a good focus ring.

08-02-2010, 09:23 PM   #9
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Does your guys K-7 do this. I turn my focus, the red square and green light comes on for a split moment while I'm turning it. Then I wonder if I went to far; turn it back and forward again more slowly and finally it indicates?
08-02-2010, 09:33 PM   #10
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Yeah, that's about how it works unless you turn *extremely* slowly. That's why I don't find it a very viable method for focusing when speed is a factor. My eyes are way faster.
08-03-2010, 06:35 AM   #11
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QuoteOriginally posted by tuco Quote
I was going to say that seagull shot is pretty incredible for manual focus. You'll no doubt have a better success rate with auto focus with shoots like those. You'll need 5 to 10 seconds to confirm focus with the green light indicator in a camera like a K-7 with manual focus lenses.
This is what manual focus guys do:
1. Set the distance of the lens to around 150' and try to predict subject at around 100' to 40' away.
2. when bird comes within range, raise the camera and fire non stop in burst the first second. Do not wait for focus confirmation that will be forever in fast subject. Most likely the first shots will be completely off
3. Then you focus in the 2nd second. Your turn of the focus ring is little at no more than 15% degree like the original image I posted at around 50 ft away. It is a lot more foolproof than autofocus as far as I manage.

QuoteQuote:
Marc Sabatella Yeah, that's about how it works unless you turn *extremely* slowly.
Marc ..from around 150' (preset distance) to 40' there is only a 15% degree turn of the focus ring. That takes a split second. Brighter view finder of K7 or K20 helps a lot for manual focus

Daniel
08-03-2010, 06:45 AM   #12
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QuoteOriginally posted by jpzk Quote
I do use the K7 with some manual lenses and it sure doesn't take that long to get the green focus confirmation light.
JP
Do not waste time waiting for the focus confirmation light. The bird coming towards you will be gone by that time. Just fire non-stop in burst mode.


Also from A300mmF4
08-03-2010, 06:53 AM   #13
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This one is much shorter

08-03-2010, 06:57 AM   #14
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QuoteOriginally posted by glasbak Quote
This one is much shorter
Sir,

This is mirror lens with free donuts.


Daniel
08-03-2010, 04:25 PM   #15
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QuoteOriginally posted by danielchtong Quote
Marc ..from around 150' (preset distance) to 40' there is only a 15% degree turn of the focus ring. That takes a split second.
Right, that's kind of my point. If you turn the ring "normally", it's very fast - far too fast for focus confirmation to be of use, because you'll have overshot the mark by the time your eye registers that the light has come on. So if you want to use focus confirmation, you have to compensate by turning the ring extremely slowly so that you don't overshoot the mark before noticing the confirmation light has come one. And while that might work, it's far too slow a method to be viable for shooting birds or other moving subjects.
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