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04-25-2014, 12:00 AM   #1
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Old manual lenses IQ

Hey all,
Question regarding old manual lenes from the 80's. I've read about how some are quite pleased using old lenses as they are small and all, but despite my best efforts I'm not seeing how these lenses, which I own, a 50mm Pentax and a 28mm Tokina from my Pentax K1000 compete with my newer Sigma 2.8 lenses. I know that the newer lenses cost quite a bit more, so am I correct in assuming that the older lenses should not be able to produce images as sharp as the new ones? Ones a Sigma 70-200mm f/2.8 DG HSM II Macro Zoom Lens and the other is a Sigma 17-50mm f/2.8 EX DC OS HSM FLD. I'm thinking it's just a matter of better quality glass. Pentax k-x btw. Just curious...
Thanks

04-25-2014, 01:34 AM   #2
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QuoteOriginally posted by mkquist Quote
Hey all,
Question regarding old manual lenes from the 80's. I've read about how some are quite pleased using old lenses as they are small and all, but despite my best efforts I'm not seeing how these lenses, which I own, a 50mm Pentax and a 28mm Tokina from my Pentax K1000 compete with my newer Sigma 2.8 lenses. I know that the newer lenses cost quite a bit more, so am I correct in assuming that the older lenses should not be able to produce images as sharp as the new ones? Ones a Sigma 70-200mm f/2.8 DG HSM II Macro Zoom Lens and the other is a Sigma 17-50mm f/2.8 EX DC OS HSM FLD. I'm thinking it's just a matter of better quality glass. Pentax k-x btw. Just curious...
Thanks
Some old lenses are good, others are not. What's really improved over the years is aberration control and coatings, as opposed to sharpness. I recommend stopping by the lens database to see which lenses are worth hanging on to:
Pentax Lenses - Pentax Lens Reviews & Lens Database
Pentax Lenses by Sigma, Tamron, Zeiss, and more - Reviews and Specification Database - Pentax Lens Review Database

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04-25-2014, 04:04 AM   #3
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The op should also go to the sample image archive to see what lenses can do.
04-25-2014, 04:19 AM   #4
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I do not own the lenses that you are having but I own a Tamron f2.8 28-75mm lens and also several primes. From my experience most of my primes will blow any zoom I ever had or own out of the water hands down. In some cases as other mentioned - the aberrations or flare will reduce old lenses output - but many of these defects are easily correctable in post processing. One of the reasons that you are not seeing any significant advantages is that you might be shooting old manual primes in AV mode with your kx - where they would be used wide open no matter what setting there might be on the aperture ring. In order to use them best to their abilities they need to be used in M mode. I honestly cannot believe in any other possible explanation ( despite the faults in your lenses - like haziness or excessive dirt ) of not achieving MUCH better resolution when both your lenses : zoom and a prime , would be used at the same aperture e.g. f4.0.

--manntax

QuoteOriginally posted by mkquist Quote
Hey all, Question regarding old manual lenes from the 80's. I've read about how some are quite pleased using old lenses as they are small and all, but despite my best efforts I'm not seeing how these lenses, which I own, a 50mm Pentax and a 28mm Tokina from my Pentax K1000 compete with my newer Sigma 2.8 lenses. I know that the newer lenses cost quite a bit more, so am I correct in assuming that the older lenses should not be able to produce images as sharp as the new ones? Ones a Sigma 70-200mm f/2.8 DG HSM II Macro Zoom Lens and the other is a Sigma 17-50mm f/2.8 EX DC OS HSM FLD. I'm thinking it's just a matter of better quality glass. Pentax k-x btw. Just curious... Thanks


04-25-2014, 05:15 PM   #5
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QuoteOriginally posted by mkquist Quote
am I correct in assuming that the older lenses should not be able to produce images as sharp as the new ones?
No.

That is not a valid assumption. I have several older lenses that are quite capable of supporting the sensor on my K-3 and are as good as, if not better than many popular current offerings. A good example might be the dozen of my photos displayed in my section of the Pentax Photo Gallery. Five were taken with lenses manufactured before 1980 and two more were taken with a Russian lens of archaic design. Only one was taken with a premium modern lens (FA 77/1.8 Limited). The other four were taken with modern lenses having unremarkable reputations. The images don't look so hot on the current PPG site (the original uploads are inadequate resolution for the current display frame), but the same can be viewed on my Flickr account:

Fotostevia on Flickr: Pentax Photo Gallery


Steve

Last edited by stevebrot; 04-25-2014 at 05:20 PM.
04-25-2014, 07:20 PM   #6
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I don't know about the 28mm Tokina, but most of the old Pentax 50s we're excellent performers, and very sharp. Both of my Pentax 50s are among the sharpest lenses I own.

Just a thought: If your images aren't as sharp with those old manual focus lenses, it might be that you're not quite nailing the focus with them.
04-26-2014, 01:43 AM   #7
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QuoteOriginally posted by GibbyTheMole Quote
Just a thought: If your images aren't as sharp with those old manual focus lenses, it might be that you're not quite nailing the focus with them.
Absolutely. Using the focus confirmation light with a manual lens will get you close to being in focus, but usually not perfectly. It's surprising how far you can turn the focusing ring while the focus confirmation light stays on.

And focusing by eye with the stock screen might not give you perfect results either. In my experience, the screens in DSLRs tend not to be calibrated precisely enough straight out of the factory. I'm guessing that Pentax doesn't waste too much factory time worrying about exact focusing screen shimming with cameras designed for autofocus lenses, since the focusing screen is not part of the autofocus system.

Before you start blaming your lenses, get hold of a focusing test chart and a set of replacement shims from the Pentax parts department, and be prepared to spend a few hours carefully shimming your camera. Or you can even try cutting your own custom shims (worked for me). It can be a frustratingly fiddly job, but you'll be amazed at how sharp even fifty year old lenses can be once you're able to nail focus properly.

If you use lenses faster than f/2, or you feel the need for a focusing aid such as a split prism, have a look at the offerings from Katzeye and focusingscreen.com.

Last edited by Dartmoor Dave; 04-26-2014 at 02:52 AM.
04-26-2014, 03:08 AM   #8
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QuoteOriginally posted by Dartmoor Dave Quote
Absolutely. Using the focus confirmation light with a manual lens will get you close to being in focus, but usually not perfectly. It's surprising how far you can turn the focusing ring while the focus confirmation light stays on.

And focusing by eye with the stock screen might not give you perfect results either. In my experience, the screens in DSLRs tend not to be calibrated precisely enough straight out of the factory. I'm guessing that Pentax doesn't waste too much factory time worrying about exact focusing screen shimming with cameras designed for autofocus lenses, since the focusing screen is not part of the autofocus system.

Before you start blaming your lenses, get hold of a focusing test chart and a set of replacement shims from the Pentax parts department, and be prepared to spend a few hours carefully shimming your camera. Or you can even try cutting your own custom shims (worked for me). It can be a frustratingly fiddly job, but you'll be amazed at how sharp even fifty year old lenses can be once you're able to nail focus properly.

If you use lenses faster than f/2, or you feel the need for a focusing aid such as a split prism, have a look at the offerings from Katzeye and focusingscreen.com.
+1

A well set up good focusing screen, such as the Canon EE-S from focusingscreen.com, makes all the difference. Since on APS sensor you are only using the centre area of old lenses, sharpness, distortion and CA are often as good or better than that of modern lenses. It is only the coatings and hence contrast and flare resistance that are sometimes worse. As for cost, there is no comparison - used old manual focus Pentax lenses can be ridiculously cheap.

Some of my shots taken with old Pentax lenses :

SMC Pentax M 50mm f1.4
SMC Pentax A 50mm f2/f1.7
SMC Pentax M 75-150mm f4
SMC Pentax M 80-200mm f4.5
SMC Pentax M 135m f3.5

04-26-2014, 04:24 AM   #9
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QuoteOriginally posted by Dartmoor Dave Quote
Absolutely. Using the focus confirmation light with a manual lens will get you close to being in focus, but usually not perfectly. It's surprising how far you can turn the focusing ring while the focus confirmation light stays on.
Yeah, any problem you have with your auto focusing carries over to your manual focusing if you use that light.
04-26-2014, 05:03 AM   #10
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QuoteOriginally posted by Dartmoor Dave Quote
Absolutely. Using the focus confirmation light with a manual lens will get you close to being in focus, but usually not perfectly. It's surprising how far you can turn the focusing ring while the focus confirmation light stays on.

And focusing by eye with the stock screen might not give you perfect results either. In my experience, the screens in DSLRs tend not to be calibrated precisely enough straight out of the factory. I'm guessing that Pentax doesn't waste too much factory time worrying about exact focusing screen shimming with cameras designed for autofocus lenses, since the focusing screen is not part of the autofocus system.

Before you start blaming your lenses, get hold of a focusing test chart and a set of replacement shims from the Pentax parts department, and be prepared to spend a few hours carefully shimming your camera. Or you can even try cutting your own custom shims (worked for me). It can be a frustratingly fiddly job, but you'll be amazed at how sharp even fifty year old lenses can be once you're able to nail focus properly.
You're 100% right. I spent a lotta time shimming my split-prism screens. One's an Opti-Brite Katz-Eye, the other is a $15 Chinese generic screen. Both work very well, though the Katz-Eye is brighter and doesn't blackout with my f8 mirror lens.

I actually have pretty good luck with focus confirmation & catch-in-focus, but I had to go into the debug menu and tweak the values on both K-x's to get it in the sweet zone. It takes work, but it's worth the effort.

Last edited by GibbyTheMole; 04-26-2014 at 05:08 AM.
04-26-2014, 05:15 PM   #11
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QuoteOriginally posted by Dartmoor Dave Quote
In my experience, the screens in DSLRs tend not to be calibrated precisely enough straight out of the factory.
The issue is usually not calibration. The stock focus screen has a working minimum DOF approximately equivalent to about f/4. This is the case even with fast f/1.8 and f/1.4 lenses. The result is inadequate focus precision regardless of how accurately the screen registration is calibrated. An aftermarket screen with more precise indication of point of focus is often required. It was not until I installed the KatzEye in my K10D that I was able to get acceptable sharp results with my manual focus lenses. I am currently evaluating the S-type screen from focusingscreen.com in my K-3.

You are absolutely correct regarding the AF confirm. The best case precision (same focus point twice in a row) is with the K-5IIs and K-3 and then only with the center f/2.8 sensors. A good split-image screen, properly calibrated, will consistently outperform the AF confirm when used with any lens faster than f/2.8 on even the K-3.


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04-27-2014, 01:48 AM   #12
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QuoteOriginally posted by stevebrot Quote
The issue is usually not calibration. The stock focus screen has a working minimum DOF approximately equivalent to about f/4.
Of course, you're absolutely right about the microlens-type stock focusing screens only showing accurate depth of focus to f/4. However, of the four Pentax DSLRs I've owned, two have come from the factory with miscalibrated screens causing a slight focus error even with my f/3.5 maximum aperture Takumars. I know a sample of four is hardly scientific, but it's enough to make me wonder just how common miscalibrated screens actually are.
04-27-2014, 03:36 AM   #13
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As others have stated above many of the old Takumar, K, M and A series prime lenses from the 1980s and earlier can be excellent performers. The question here isn't the quality of the lenses but whether you are willing to take the time and effort required to master working with an older lens on a modern digital camera. One of the great attractions with the Pentax brand is the fact you have the option to use all their old legacy glass on thier new cameras if you so desire.This forum is full of great photos produced with lenses from this era. Working with them takes a lot of time and energy and not everone is willing to put in the effort. If you are an auto-everything point and shooter these lenses are not for you. If you don't mind a lot of trial and error, messing with exposure and manual focusing you might enjoy the experience. Personally, as I have a bag of older glass from my film days I actually kind of enjoy working with these old friends. It makes me feel that I am more a part of the image making process. That being said I also enjoy the ease and freedom of a modern DA lens on my K5. Let's be honest autofocus and autoexposure are pretty nice features. You can pick up an old manual 50mm lens for next to nothing. Buy one and try it for a while and see if you like the process. The lens will do its job if you have the patience and desire to make it happen. If you don't it will become very apparent very quickly that these old manual focus gems are not for you.

Tom G
04-27-2014, 05:17 AM   #14
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QuoteOriginally posted by Dartmoor Dave Quote
I know a sample of four is hardly scientific, but it's enough to make me wonder just how common miscalibrated screens actually are.
You can add my two cameras (K10D and K-3) to your four to make six. Neither of my bodies required other than the factory shims when I upgraded the screens. I agree, that it is somewhat disturbing to buy a modern camera and find that something as fundamental as the focus screen calibration is sloppily applied by the factory. I expect that sort of thing with my former Soviet film cameras, but back-in-the-day the idea of it being off on any quality Japanese SLR was inconceivable.


Steve
04-27-2014, 10:52 AM   #15
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>> " . . . it is somewhat disturbing to buy a modern camera and find that something as fundamental as the focus screen calibration is sloppily applied by the factory."


Pentax COULD design and produce bodies such that each incremental manufacturing tolerance was miniscule and each unit had a custom, hand-fitted VF shim to accommodate residual assembly variations -- and they COULD replace all tooling weekly to maintain perfect tolerances and QA goals -- and they COULD conduct 100% QA sampling -- and those of us with a Rolls Royce with driver and a gold Rolex or three could maybe afford 'em.

A more practical plan is to accept nominal, economical manufacturing and assembly tolerances and adopt a statistical QA sampling process using a medium shim that would allow adjustment in either direction if after-sales dissatisfaction deemed it necessary.

We can't have an affordable body that can use millions of lenses (including those built decades before the digital era!) and still expect perfection in every detail of practical use. Personally, I believe shims and software accommodation for AF adjustments is a practical solution and I'm very willing to accept that slight inconvenience in return for a highly versatile, affordable, modern digital SLR body regardless of the Brand Name on the front. And that includes the possibility of having to return, repair or adjust a body on rare occasions too -- incidentally, I've never personally had to do that in nearly half a century of using Pentax photo gear.

Face it, guys, mass produced, affordable photography gear isn't going to be designed and manufactured to space program or brain surgery tolerances. I'd invite everyone to conduct their personal business to the same degree of perfection and accountability they'd like to hold Pentax to.

It's not that the pig whistles so well, but that it whistles at all that should amaze us.

Last edited by pacerr; 04-27-2014 at 11:06 AM.
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