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06-15-2010, 10:40 AM   #661
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Sooo, would it be ok to post a couple shots taken with a K mount Sigma 400mm 5.6 APO BUT taken using my GF1? Or is that marriage too unholy for this thread?

06-15-2010, 11:12 AM   #662
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QuoteOriginally posted by pxpaulx Quote
Sooo, would it be ok to post a couple shots taken with a K mount Sigma 400mm 5.6 APO BUT taken using my GF1? Or is that marriage too unholy for this thread?
Post them. I would be interested in comparing your results with mine from the M 400/5.6.
06-15-2010, 11:21 AM   #663
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Question about Magnification

About a telephoto lens magnification ability. I have several lenses from 135 mm up. I noticed that some will, as an example, have a focusing range like on one of my 200's that runs up to 200 feet just before being at infinity. I also have a 200 mm that goes up to 50 feet just before infinity. I do not think that this focusing range has anything to do with magnification but I am wondering why the much longer lenses do not go much higher in the distance of the focusing range? Yes, I know infinity is higher than any number on the barrel. I think that the focusing range has to do with placement of elements and this is where the designers come up with the ability of a say 300 mm lens to focus clearly at 2 feet, as an example. I think that same 300 mm lenses(just made it up people) would then have a short, say out to 50 feet, focusing range before reaching infinity. Would that 300 mm have less magnification ability than some 300 mm that had a focusing range out to 300 feet? I know this is confusion in my own head but I am trying to understand plus learn about some of the principles in lens design. Does anyone have an answer that could help me?

Last edited by kacansas03; 06-15-2010 at 11:22 AM. Reason: spelling
06-15-2010, 11:24 AM   #664
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Here we go! These were a couple from a walk a few weeks ago - first one with a monopod, 2nd hand held I think (no SR with the GF1). I have some from the twins game that I have to upload, will do sometime this week. Anyway, here they are (nothing special but not bad for a first test either):





Did I mention getting the lens for $10? the body is beat to crap, AF screwdrive is chewed to hell and doesn't work, and aperture doesn't work in A setting. the aperture works fine though, but it looks like it doesn't quite get to f5.6 (I can see the blades are slightly closed down when set to f5.6). Glass? Perfect! The shop was going to toss it.

06-15-2010, 11:33 AM   #665
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QuoteOriginally posted by smc Quote
Hey Nubi...looks like you're having fun with the Tak 300...nice clear shot. You ended your LBA?....is thta possible?

Here are a few from the weekend.....DA*300






Yes. This lens is a lot of fun. Nice pics there! I think that from IQ standpoint, Tak 300/4 is to me every bit as good as DA* 300, which I no longer own . . . . . I don't miss AF either.


Yes I did end my LBA . . . . .


https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/104657-end-my-...diction-4.html
06-15-2010, 11:40 AM   #666
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QuoteOriginally posted by kacansas03 Quote
Does anyone have an answer that could help me?
The focus distances are merely marks on the lens barrel. They have no other purpose or effect than to estimate focus distances.
06-15-2010, 11:40 AM   #667
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QuoteOriginally posted by kacansas03 Quote
About a telephoto lens magnification ability. I have several lenses from 135 mm up. I noticed that some will, as an example, have a focusing range like on one of my 200's that runs up to 200 feet just before being at infinity. I also have a 200 mm that goes up to 50 feet just before infinity. I do not think that this focusing range has anything to do with magnification but I am wondering why the much longer lenses do not go much higher in the distance of the focusing range? Yes, I know infinity is higher than any number on the barrel. I think that the focusing range has to do with placement of elements and this is where the designers come up with the ability of a say 300 mm lens to focus clearly at 2 feet, as an example. I think that same 300 mm lenses(just made it up people) would then have a short, say out to 50 feet, focusing range before reaching infinity. Would that 300 mm have less magnification ability than some 300 mm that had a focusing range out to 300 feet? I know this is confusion in my own head but I am trying to understand plus learn about some of the principles in lens design. Does anyone have an answer that could help me?
The near focus is set by the lens designer, but distance scale has a lot to do with the focal length and the change in depth of field as the focal length increases. For example, a 28 mm lens at f/8 has a hyperfocal distance around 10 feet on 24x36 mm film or sensor - focused at 10 feet with the f/stop at f/8, and 8x10 print will appear sharp from about 5 feet to infinity. On the other hand, the hyperfocal distance for my M 400 at f/45 (that's right 45, out beyond 32) is a bit over 300 feet, and will be acceptable on an 8x10 print as close as 200 feet.

The other factor about the focus scale is the amount of turn the focus ring has. The 400 has a focus turn of somewhere around 270 degrees which leaves lots of room to engrave numbers, so the scale reads all the way up to 300 ft and 100 meters. Another brand of 400mm lens may only have 180 degrees of rotation, which would leave less room to engrave the numbers on it. The 300/100 would run into the infinity mark.

In short, the distance scale needs a lot more numbers at 400mm than at 28mm. I hope this clears the mist up a bit for you.
06-15-2010, 12:55 PM   #668
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QuoteOriginally posted by pxpaulx Quote
Here we go! These were a couple from a walk a few weeks ago - first one with a monopod, 2nd hand held I think (no SR with the GF1). I have some from the twins game that I have to upload, will do sometime this week. Anyway, here they are (nothing special but not bad for a first test either):





Did I mention getting the lens for $10? the body is beat to crap, AF screwdrive is chewed to hell and doesn't work, and aperture doesn't work in A setting. the aperture works fine though, but it looks like it doesn't quite get to f5.6 (I can see the blades are slightly closed down when set to f5.6). Glass? Perfect! The shop was going to toss it.
Those are great test shots.

QuoteOriginally posted by Nubi Quote
Yes. This lens is a lot of fun. Nice pics there! I think that from IQ standpoint, Tak 300/4 is to me every bit as good as DA* 300, which I no longer own . . . . . I don't miss AF either.
I shoot exclusively manual anyways....so the AF on the DA* never gets used

06-15-2010, 01:41 PM   #669
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QuoteOriginally posted by smc Quote
Hi Phil. That is an excellent price. There is something wonky with the focus grip, but it's superficial.

It sure would have stood out last weekend between all of the Canikons....



Steve
Stand out, I bet at an air show they would have stopped you bringing in you’re A*1200!! (It looks too much like a weapon of mass destruction) Nice shots with your DA*300.

Phil.
06-15-2010, 01:43 PM   #670
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QuoteOriginally posted by pxpaulx Quote
Here we go! These were a couple from a walk a few weeks ago - first one with a monopod, 2nd hand held I think (no SR with the GF1). I have some from the twins game that I have to upload, will do sometime this week. Anyway, here they are (nothing special but not bad for a first test either):





Did I mention getting the lens for $10? the body is beat to crap, AF screwdrive is chewed to hell and doesn't work, and aperture doesn't work in A setting. the aperture works fine though, but it looks like it doesn't quite get to f5.6 (I can see the blades are slightly closed down when set to f5.6). Glass? Perfect! The shop was going to toss it.
Great shots, really like the flower one! What a bargain for $10.00!!

Phil.
06-15-2010, 03:05 PM   #671
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QuoteOriginally posted by gofour3 Quote
Great shots, really like the flower one! What a bargain for $10.00!!
Yeah the roses are spectacular!
06-15-2010, 04:10 PM - 1 Like   #672
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SMC Pentax M 400/5.6

I'm in agreement on the roses. Well done.


Managed a shot or 2 of a Song Sparrow today with the 400






Tom G

Last edited by 8540tomg; 06-15-2010 at 04:11 PM. Reason: typo
06-15-2010, 05:55 PM   #673
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I especially like the bottom of those 2 bird pics. Though it's a blackbird, not a song sparrow.
06-15-2010, 09:00 PM   #674
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Thanks for the comments! I will get some pics from the twins game online in a few days- haven't offloaded them but hoping some have turned out.
06-16-2010, 04:35 AM   #675
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QuoteOriginally posted by mcrogner Quote
I especially like the bottom of those 2 bird pics. Though it's a blackbird, not a song sparrow.

Mcrogner,

Duhhh! You're right they are Blackbirds.

Tom G
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