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04-02-2013, 11:15 PM   #31
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tromboads -- Hyperfocal! Yes! Let's see... how about f/16 (to dodge diffraction)... 1/400... and let the ISO float in TAv from 100 to 1600? There's probably a Magic Setting that will work from sunup through sundown.

Next, Dofmaster. Let's see. Used 12,000' as my 'infinity' distance --

At f/11, subject at 12' through 12,000', hyperfocal is 11.5 feet. Focused at infinity (12,000'), near limit is 11.4'.
At f/16... H = 8.13 feet. Focused at infinity (12,000') near limit is 8.03'.
At f/22... H = 5.78 feet. Focused at infinity (12,000') near limit is 5.68'.

Will try f/22 tomorrow to see if diffraction is actually a problem. If not, why not? In-focus from 6' to infinity ain't so bad!

EDIT -- just looked at settings for my old 50mm lens. Not so easy. The f/stop distances aren't as close together. But .. At f/22... H = 18.3 feet. Focused at infinity (12,000') near limit is 9.55'.


Last edited by jon404; 04-02-2013 at 11:38 PM.
04-03-2013, 03:27 AM   #32
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yeah diffraction may not be so bad. Its lens to lens dependent after all. Still, f22 still may provide more resolution then f4 mind you

But sh1t. 5m-infinity is pretty gnarly :P
04-03-2013, 07:38 AM   #33
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The saga of how I finally got a working 28mm lens is something I won't bore you with. But FYI, it took a long, long time. I don't know what it is about good 28mm lenses that makes them so much more difficult to obtain in good condition without potentially having to sell an organ first but if my own experience is true it can be tough. I finally found mine via Goodwill online. I suggest you start there, though watch where you purchase from because the further away the store the more the shipping is and some of them are not very accurate in their descriptions besides. Really watch those pics and try to stay away from stores that try to gouge you for more $$$ via shipping they don't actually pay. I've run into several stores on there lately that seem to think making an extra $10-15 per package by inflating the actual shipping costs is okay. Or they will only use the most expensive shipping method possible like UPS or FedExp and it costs $35 just to send a 2lb package according to them...
04-03-2013, 10:25 PM   #34
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I just got mine from ebay.


Takumar... :P

wasn't very difficult

04-03-2013, 11:18 PM   #35
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Got mine from Ebay. If a seller has a 99.5% or better rating, the odds are pretty good. Ken Rockwell has an excellent page on how to bid on Ebay... well worth reading.

Now -- as for my 28mm hyperfocal setting -- I'm going with f/9 (not f/8, not f/11) and Thoog's set the red diamond on 'halfway between infinity and 10-3'. To simplify this (I'm Irish-American), I'm calling it 'f/9 Thoog'. Or, even better, F9T.

But today, I cheated. Focused on the grayish-brown brush halfway down the hillside, to the front of the locomotive. TAv at f/11, 1/200, ISO 400. Worked fine... except that gpoing to f/9 would let me increase the shutter speed... at 1/200 the train has some motion blur, and I can't pan with it for a picture like this. Tomorrow, I'm looking forward to using F9T... set and forget! Zap!
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04-04-2013, 12:26 AM   #36
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Also.. That image looks as if you are about to perform a train robbery :P
04-04-2013, 02:23 AM   #37
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The 28mm lens was exactly what I was wondering in my 'normal lens for APS-C' thread. My wish is not exactly super-fast, but a compact 28mm lens. I have seen the Sigmas 28mm 1.8 and 30mm 1.4, they're not compact. Pentax should make something like limited 21mm, but with 28mm focal length! That would be great walk-around lens for K-01 and dslr's too!
04-04-2013, 05:38 AM   #38
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The M 28mm f2.8 is pretty dam compact.. and since we are not focusing it doesn't matter :P

04-04-2013, 11:19 PM   #39
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Did some testing today, and landed on a hyperfocal setting that works well enough for my Pentax 28mm A f/2.8 lens... in daylight, on f/16 for maximum DOF. I put the 10-3 on the distance scale over the 4 on the aperture scale (pics below). Or, Infinity over f/11, same thing.

You know, hyperfocal is just a 'sort of'. As in 'sort of sharp'. There's really only one sharp point, one sharp focal plane. And digital at 100% really makes it tougher. You really see unsharp. Ow. Film and prints were easier!
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04-05-2013, 07:06 AM   #40
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I would like to see the surfer crossing photo tried without the UV glass on the lens. The overall effect is of non-focus softness.
I tried a number of tests and have discarded all protective filters as damaging to IQ. But every lens has a hefty hood!
04-05-2013, 07:21 AM   #41
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QuoteOriginally posted by jon404 Quote
You know, hyperfocal is just a 'sort of'. As in 'sort of sharp'. There's really only one sharp point, one sharp focal plane. And digital at 100% really makes it tougher. You really see unsharp. Ow. Film and prints were easier!
The key word in hyperfocal focusing is the "acceptable" in "acceptable sharpness". For stuff that is going to go on the web, it's fine, especially if you punch it up a little in Post. But for pixel-peepers and poster printers, it's not the way to go.
04-05-2013, 12:19 PM   #42
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Hyperfocal -- yes, 'acceptable sharpness'. But an apology -- the hyperfocal lens setting I gave above isn't right. Went the wrong way on the ring. For the Pentax 28mm f/2.8 A-type lens, with the lens at f/16, put the Infinity mark over f/5.6 on the aperture scale. That will give the best result, as per the test picture below (images reduced about 4X from the originals). But, as you say, this is only meaningful for pixel peepers and giant print producers. As for me, on f/16 and a sunny day, Inf over 5.6 is snapshot time... my K-01 as a box Brownie!

EDIT -- and yes, I took off my incredibly valuable optical-lab quality, rare and priceless Chinese UV filter for this test.
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Last edited by jon404; 04-05-2013 at 12:31 PM.
04-05-2013, 02:50 PM   #43
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I recently bought a used Cosmicar (Pentax) MC 28/2.8 A manual focus lens for $35 shipped from eBay.
In case my daughter wants a K-01 or Pentax APS-C DSLR I thought she should have a fast normal lens.

Chris
04-05-2013, 03:24 PM   #44
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What a deal! On our digital Pentaxes, it's 42mm (135-format equivalent) field of view is very nice. In between the 35mm and 50mm lenses. Not too wide, not too tight. Next, the camera! Think she'll beat you up for one of the new color K-30s?
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