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02-21-2011, 08:42 AM   #1
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pentax a 28-80

Just got back from town with a Pentax a 28-80mm lens from a second hand shop. 10 . Does anyone have any experience with this lens or should I have left it in the shop??

02-21-2011, 09:24 AM   #2
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Manual zooms do not report the focal lenght and that will make the SR unusable. I like manual lenses, but I stick to fix focals.
02-21-2011, 10:02 AM   #3
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QuoteOriginally posted by elho_cid Quote
Manual zooms do not report the focal lenght and that will make the SR unusable. I like manual lenses, but I stick to fix focals.
not unusable, you just have to input the focal length yourself and then SR works just fine. According to pentax:
QuoteOriginally posted by pentax:
Since the older lenses do not send focal length information to the camera body, the user will need to enter a focal length for the lens into the Input Focal Length screen. If the lens is a zoom lens, enter a focal length value mid-way between the bottom and top of the zoom range for that lens. For example, for a 70-200mm zoom lens, enter a focal length of 135mm. This is an easy way to provide the benefit of shake reduction across the entire zoom range.
02-21-2011, 10:13 AM   #4
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QuoteOriginally posted by enoeske Quote
not unusable, you just have to input the focal length yourself and then SR works just fine. According to pentax:
The trick is to know what focal length to input. If you input the short end of the zoom the S/R undercompensates for the long end. If you input the long end the S/R overcompensates for the short end. After much experimentation with a variety of zooms I imput at about the 1/3 mark of the zoom. For instance with my 70-210 I input 120, for my 35-105 I input 55 etc. I've found that overcompensation causes more problems than undercompensation, so I shade towards the shorter side.

BTW, to answer your original question, I have had no experience with this lens but you can look here for some reviews

NaCl(works for me)H2O

02-21-2011, 10:59 AM   #5
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Interesting. I heard that some manual zooms could be worth having, namely the 70-210 and 35-105. Is there no AF alternative for them?
02-21-2011, 01:21 PM   #6
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QuoteOriginally posted by elho_cid Quote
Interesting. I heard that some manual zooms could be worth having, namely the 70-210 and 35-105. Is there no AF alternative for them?
Some (but not many) old manual zooms are worth having. Tokina ATX, Vivitar Series 1, some (but not all) Pentaxes. Some are splendid -- and AF counterparts cost 10x-20x as much. Some, such as Tamron- and Samyang-made glass under various brands, may be quite decent, especially at bargain prices under US$20. Most are, at best, sub-standard by modern standards, but may be interesting for their 'character' (ie, don't expect great image quality).

One notable exception: the Schneider Betavaron 50-125/4-5.6 fixed-focus enlarger zoom, a weird-to-use beast, brutally sharp. I love it! It cost me US$70, marked down from US$3500. On 30mm extension so that it reaches infinity focus, it's an amazing general-photography lens.

Most modern zooms really are better than most older zooms. I have about a half-dozen each of old manual and newer AF zooms. Average cost of manuals: US$20. Average cost of AF's: US$280. Yow.

SR is a quandary. There's a formula for calculating a median focal length (FL) to tell the SR robot. I'll try to dig it up. Or, you can reset the SR FL with each FL change. Oy. Or, you can leave SR off and only shoot on a tripod or in bright light, just as we did Back In The Day before SR. When I mount my Vivitar Series 1 Version 1 70-210/3.5 onto my Spotmatic II, it's just my nerves vs the world. Same with the Sears-Tomioka 55-135/2.8. Going mano-a-mano with reality, eh? Manual zooms are not for wimps.

--- PS --- Some manual Pentax zooms are real turds. See the lens review database for the harsh truths.

Last edited by RioRico; 02-21-2011 at 01:52 PM.
02-21-2011, 01:45 PM   #7
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QuoteOriginally posted by fourfivesix Quote
Just got back from town with a Pentax a 28-80mm lens from a second hand shop. 10 . Does anyone have any experience with this lens or should I have left it in the shop??
For the price you paid it's a fun lens to play with. You might even get some great results from it. The beauty (that gets lost on some people ) of Pentax carrying over the K mount is that you Can use lenses like this. Pick a focal range somewhere in the middle when the camera asks for it (it won't ask if SR is turned off), focus, compose, expose, shoot. Then do it again. Show us what you can do with it.

02-21-2011, 01:48 PM   #8
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QuoteOriginally posted by elho_cid Quote
Interesting. I heard that some manual zooms could be worth having, namely the 70-210 and 35-105. Is there no AF alternative for them?
There are some Pentax-F lenses with the same range but they're not the same formulas as the A versions.

The Pentax-A 35-105 is a constant f3.5, and the autofocus version is f4-5.6. I haven't heard anyone getting excited about that one. I had the SMC Pentax-F 35-135mm f3.5-4.5, and it was OK, but the focal range was not that useful for me on APS-C. There are a few 28-105 AF options and I have one of those.

The Pentax-A 70-210 is a constant f4 and again, the AF versions are not. Pentax also produced an AF lens without SMC coatings, so check your labels carefully for SMC. Although the SMC Pentax-F 70-210mm f4-5.6 is not the same as the A version, it's a pretty good lens, even at 210mm and wide open. I like mine a lot. It's supposed to be better than the DA 50-200mm, but the DA may have a more convenient range. I might pick up the DA sometime just to compare.

02-21-2011, 03:17 PM   #9
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Thanks for the respones... OK I will not condemn manual zooms anymore.
02-21-2011, 09:17 PM   #10
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QuoteOriginally posted by Just1MoreDave Quote
The Pentax-A 35-105 is a constant f3.5, and the autofocus version is f4-5.6. I haven't heard anyone getting excited about that one..
Which one? The A 35-105 or the AF equivalent? The A35-105 is one of the better Pentax MF zooms, as evinced by the reviews right here in the review section.
02-22-2011, 04:22 AM   #11
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Thanks for the inpot guys, going to take it out this afternoon and decide what to do with it then
02-22-2011, 01:49 PM   #12
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QuoteOriginally posted by fourfivesix Quote
Thanks for the inpot guys, going to take it out this afternoon and decide what to do with it then
Play with it! At 10 pounds it's not like the day will be ruined if it isn't absolutely tack sharp at all apertures and focal lengths. Even if it's only good instead of GREAT, you still got a pretty good buy.

NaCl(like the A 50mm 1.7 I found at a garage sale for $25)H2O
02-22-2011, 02:24 PM - 1 Like   #13
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QuoteOriginally posted by elho_cid Quote
Interesting. I heard that some manual zooms could be worth having, namely the 70-210 and 35-105. Is there no AF alternative for them?
Not really. The "A" 70-210 is a constant F4.0, has a "macro" (read close focus) function at 70mm end, and has the best bokeh of ANY zoom I own. The Pentax A 35-105 is constant F3.5, has a close focus function throughout the entire zoom range, and has super super color rendition, especially reds. I'd almost go so far to say that it does reds better than any other lens I own, except maybe the FA 20mm F2.8 or maybe the FA 77 ltd. It's that good.
There are some very good manual zooms out there.
Pentax 70-210




Pentax A 35-105




NaCl(the best glass doesn't have to be new)H2O
02-22-2011, 10:35 PM   #14
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QuoteOriginally posted by NaClH2O Quote
There are some very good manual zooms out there.
And some quite lousy ones. To wit: A35-80/4-5.6 and Tak-A28-80/3.5-4.5 and M40-80/2.8-4. I had great expectations for the last two, was grievously disappointed, and took ugly losses when I sold them. The first is still in my possession, only because it's hardly worth selling now. Again, prospective buyers should read the lens reviews here.

My excuse on those: I hadn't yet joined PFC. Now I know better. We gain good judgment from experience. We gain experience from making bad judgments. Bother.
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