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02-14-2010, 01:43 PM - 1 Like   #1
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Vivitar 28mm/2.8 CF (K02) vs. Tamron 28mm/2.5 (02B)

Introduction
The various versions of the Vivitar 28mm have taken on sort of a cult status on the Pentax Forums. This is particularly true of the K-mount close focus versions made by Komine (catalogued as K01, K02, K06, A01, A02 by Robin Parmar...see Photografica). Incredible photos by jsherman999, igilligan, and others started to surface showing excellent sharpness and contrast as well as wonderfully clear and vibrant colors. In the depths of my dark inner LBA, the small voice said, "You've got to get yourself one of those". The notion was really sort of absurd. I already had a Tamron 28mm that I had owned for years and used extensively on 35mm film, but seldom mated to the K10D. I also have the FA 35/2 as a walk-around "normal". Still the temptation incubated and festered until I made the mistake of posting an interest in acquiring a K02. Within a few hours, there was an offer from a fellow forum member who was upgrading to the A01 and a few days later the lens was on its way to my house.

Initial Impressions (Size, Build, etc.)
When the lens arrived, I was pleasantly surprised at how compact and light it was. I had always considered my Tamron 28/2.5 to be small for a 28mm, but the Viv is darn-right petite by comparison. It was about this time when I thought it might be interesting to do a comparison test between the two lenses. After all, both were made about the same time and I had bought the Tamron over the Viv "back in the day". (The Tamron was more expensive at $79 + $17 for the adapter vs. about $59 for a Viv, but could be used with multiple bodies.) I had enjoyed the Tammy for many years on film and always considered its performance to be top class. Did I make the wrong decision 25 years ago?





Setting the two lenses side by side, it is hard to believe that they do basically the same thing. The Vivitar is physically both shorter and smaller around with a fairly large front element to support its f/2.8 maximum aperture. The Tamron, on the other hand, has a fairly small, almost hemispherical, front element set in a squat, flat-faced barrel. I always considered the Tammy to be handsome, but sort of odd looking. Handling the two lenses, the differences are even more obvious. Although the Vivitar has a minimum of plastic parts, the Tamron is all metal and significantly heavier. Focus and aperture controls on the Vivitar are about par for third-party lenses of the day. The focus is smooth and well-dampened. The aperture ring on my copy is rather stiff with indistinct detents. This may be correctable with a little disassembly and cleaning. The Tamron is also well-made, but the build is definitely a notch or two higher on the scale. All controls operate as well or better than the K and M series Pentax lenses of the same era.

In regards to focus, one of the features of the Vivitar is "Close Focus" capabilities. The lens will attain closest focus at 23cm after about 240 degrees of movement. This yields a magnification of 1:5. The is nowhere near macro, but still very impressive for wide-angle of the time. Interestingly, the Tamron is no slouch in this area either. It focuses down to 25cm. Unfortunately, as we shall see below, this is accomplished in only 120 degrees of arc. The focus direction of both lenses is opposite that of Pentax.

Another difference between the two lenses is the number of aperture blades. The Vivitar has 6 blades as opposed to the Tamron's five. In theory, the Vivitar may have a more pleasant rendering of specular highlights as a result.

While the Vivitar is really nice, I have to give the Tamron the edge in terms of build and physical design.


Optics
A lot was happening in the early 1980s in 28mm lens design. 35mm SLRs were incredibly popular and many people were interested in getting a good lens for general landscape photography. The relevant features were a relatively fast maximum aperture for easy focus, sharpness, minimal barrel distortion, resistence to flair and coma, and moderate price. The strong points for the Tamron were the BBAR coatings, low distortion and above average sharpness across the field. The Tamron has 7 elements in 7 groups and is able to stop down to f/32 (!) for maximum DOF. Minimum focus distance is 25cm. For a full description of the Tamron 28/2.5 02B including optical diagrams, see: Tamron Adaptall-2 28mm F/2.5 Model 02B.

The Vivitar was also well-regarded and was considered to offer above average performance. Available documentation for the non-CF versions indicate 7 elements in 7 groups, though it is not clear whether that design is shared with the CF version. If anyone knows of an online source for the specifics of the K02 design, please post a comment!


The Contest
As noted above, there has been a lot of discussion about the Vivitar 28mm lenses as well as many test shots indicating excellent performance. On the other hand, there is very little about the Tamron beyond a few user reviews (PentaxForums.com Third-Party Pentax Lens Review Database - Adaptall-2 02B 28mm F2.5). My purpose here is to compare and contrast the two lenses under controlled conditions. While I have not included the results, I did do a "cereal box" test for sharpness/contrast at 20x the focal length for both lenses at f/2.8, f/5.6, and f/11. The results were amazingly similar for both lenses at all apertures with a slight edge going to the Vivitar. The most valuable information from that test was realizing that the Tamron is incredibly difficult to fine focus. Typical of many wide-angle lenses, the Tammy has a very short focus throw, making critical focus at moderate distances a royal pain. The Vivitar, on the other hand, negotiates almost a full turn lock-to-lock...luxurious! So, without further discussion, here are a few comparison images...

All images were taken with a Pentax K10D equiped with a Katzeye after-market focus screen. Manual exposure was used with settings supplied by a Gossen Luna Lux hand-held meter measuring incident light. All images were shot in RAW and converted using Lightroom with the default development settings. Brightness was adjusted for some images.


Wide-open at Moderate Distance
Focus was on the doll's painted lower eyelashes



Moderate Distance at f/5.6
Focus was on the doll's painted lower eyelashes



Close Focus Wide-open
Focus was on the front star at the corner of the pewter box.



Close Focus at f/5.6
Focus was on the front star at the corner of the pewter box.



Close Focus Comparisons at f/8 (optimum sharpness)
Focus was on the flange edge of the watch bezel at lower left



Focus was on the flange edge of the watch bezel at lower left



Focus was on the flange edge of the watch bezel at lower left



Focus was on the flange edge of the watch bezel (not visible in this crop)


Edit:
My initial post did not include any outdoor photos in natural light. This morning the weather was cooperative and I spent a few hours at Cathedral Park in Portland adjacent to the very graceful and often photographed St. John's Bridge. To be fair and to show both lenses off at their best, all photos were shot in RAW and taken with a hood. All photos were hand held using SR (ground was too sodden for a tripod) with the K10D at ISO 100. I figure that it is best to show the worst first. The two images below were taken of the bottom of the bridge deck and the deeply shaded concrete supports. The sky beyond had high cirrus clouds and the sun is just outside the frame to the left. Exposure is center-weighted using the green button recommendation with no adjustment.


Lens Torture!

Default Lightroom RAW conversion


There you see it folks. Veiling flare on the Tamron! The Vivitar apparently has greater flare resistance. That and its higher contrast allows it to handle this mess fairly gracefully. Since this is digital photography, there is always a second chance at greatness. Below are the same two images after a little massaging of the curves. The Tamron required a little more attention (significant contrast bump), but the results from both are now fairly pleasing. That is if you are easily pleased by the underside of bridges!


Lens Torture After a Little PP



Turning my back to the sun, I shot a few of a large concrete structure at the base of the bridge. Under less challenging conditions, the two lenses delivered comparable results with the Vivitar showing a slight edge in contrast.


The Sun At Our Back

Default Lightroom RAW conversion with a small exposure adjustment to the Vivitar shot.

In addition to the outdoor shots, I also shot a blank wall indoors under controlled lighting as the basis for histograms showing the transmittance and contrast differences between the two lenses.

Blank Wall Histograms


End Edit


Conclusions
This exercise was a real eye-opener. For the most part, in actual usage, it is awfully hard to tell the difference between these two lenses. The only real thing that I noticed is that the Vivitar required about a stop more light, regardless of aperture, than the Tamron. Whether this is due to coatings or optical design is anybody's guess. Edit:After spending some more time with the lenses, I think the difference in light transmission is closer to 1/2-1 stop.End Edit In summary:
  • Both lenses are sharp with good contrast
  • Both lenses have little or no CA
  • Distortion is not an issue for either lens on APS-C
  • Both lenses have pleasing color rendition
  • The Vivitar requires 1 stop of exposure compensation on average
  • Colors were somewhat cooler with the Vivitar
Yet to be done is some real-world outdoor shooting. The weather here has been crappy; but when it clears up, I will post additional comparison shots that will test how these lenses handle outdoor lighting and more varied subjects.

What does this mean? Maybe the Tamron will emerge as another cult-classic along with the Viv As for my personal decision as to which lens to keep...that is a hard one. I will have to see the results from the outdoor shots as well as do some comparisons on film where the winner will be my workhorse landscape lens.

Edit:

After today's outdoor shots, I have to add a few more bullet points:
  • The Vivitar has better flare resistance than the Tamron
  • The Vivitar's contrast edge is readily apparent in outdoor shooting
  • Both lenses benefit from a hood
My conclusion remains much the same except that I have to admit that the Vivitar tended to be more rewarding on the subjects I was working with today. I also took a couple dozen B&W film shots. Those will likely determine which lens gets voted out of the bag.

End Edit

Post Script
I should probably not include these next two images, but feel that they are important to help maintain perspective in the continuing discussion of lens performance. Below are shots taken in the f/8 (optimum) test setup using the Pentax-DA 18-55/3.5-5.6 AL kit zoom set at 28mm. Dang, if the results aren't pretty decent...except for some mild CA...







Steve

(Still not sure if I should have thrown in those last two images...)


Last edited by stevebrot; 04-25-2011 at 11:22 PM.
02-14-2010, 05:01 PM   #2
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Thanks for sharing your comarison results. I really enjoyed reading it. If you do outdoor tests, please compare them for flare. I would be very interested in the results. Thanks again.


Cheers


(*_*)
02-14-2010, 05:06 PM   #3
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Wow I like the tamron wide open by a little bit... but at F5.6 and especially at F8 the Vivitar really spanks the tammy... I wonder why the tamron looks softer at f8? It almost looks hazy


Good tests and makes me want to go look for the Tamron lens as I tend to shoot wide open more than at F8
02-14-2010, 07:08 PM   #4
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QuoteOriginally posted by Igilligan Quote
Wow I like the tamron wide open by a little bit... but at F5.6 and especially at F8 the Vivitar really spanks the tammy... I wonder why the tamron looks softer at f8? It almost looks hazy


Good tests and makes me want to go look for the Tamron lens as I tend to shoot wide open more than at F8
I will have to look at the f/5.6 and f/8 comparisons using a different monitor. On mine (Samsung 2443 BWX), the f/5.6 shots are virtually indistinguishable from each other. To be honest, I had to be careful to keep from mixing the two up when I was adding the label text.

In regards to the f/8 shots, it was a challenge to get comparable exposure between the two lenses. When set to the same shutter speed, the Viv shot was very dark. I had to go a full stop slower with the result that the Viv shot is "brighter". The Vivitar also has higher global contrast than the Tamron. You can see the compressed range in the histogram. For a given exposure, the Vivitar will have more values at the extremes.

The real puzzle from my perspective was the f/8 full resolution (100% crop) comparisons. The point of focus for both images was the flange edge of the watch bezel. What is strange is that even at f/8 DOF is very narrow when pixel peeping at full resolution. On the watch detail, the Tamron holds the edge for the bezel and the adjoining face of the pewter box, while the Vivitar has cleaner edges on the watch face itself. I should note that the Vivitar shot was the best of three. The first shot with the Tamron was acceptable and is posted here. The first two attempts with the Vivitar were so far off that I decided to redo it until I got a good one! The third try looked about the same as the Tamron shot in the camera LCD, so I called it good. The plain of focus is not quite the same, but they are close.

That brings the discussion around to the "sun/star" detail on the pewter box. The Vivitar definitely wins here if you are only looking at the sun. The star is better rendered by the Tamron. Again, I think the difference is due to plane of focus. The contrast characteristics of the two lenses might also be playing a part.

I sort of figured that it was a toss-up on the full resolution images in that you really cannot compare region to region, but instead have to pick the best area from each crop. This is readily apparent on the full-size tiffs. Unfortunately, I found it difficult to find comparative crops that both met the forum restrictions and showed the strengths/weaknesses of the two lenses at full detail. I think it enough to say that the Vivitar has a crisper look even at full resolution, while the Tamron captured fine detail (scratches in the watch crystal and such) that were entirely missing from the Vivitar image.

For now, I am calling it a draw until I can do some more images in a less controlled setting. My bet is that the Vivitar will really shine with outdoor light.

Steve

P.S. For ease of comparison, I am going to edit the review and give an indication of the intended point of focus for each set of images.

P.P.S. What is scary is the "sun/star" detail from the DA 18-55. It is much better than it should be.


Last edited by stevebrot; 02-15-2010 at 03:40 PM.
02-14-2010, 07:12 PM   #5
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I'd say the Tamron is unnoticeably sharper than the Vivatar, only if you pixel peep hard and compare pixel by pixel then you can see. Otherwise they are both the same from how I saw it. Nice comparison.
02-14-2010, 07:20 PM   #6
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QuoteOriginally posted by Stratario Quote
Thanks for sharing your comarison results. I really enjoyed reading it. If you do outdoor tests, please compare them for flare. I would be very interested in the results. Thanks again.


Cheers


(*_*)
I am also interested in flare resistance and overall contrast with the digital sensor. Now if we could only get some dry days so I can get out and shoot!

Steve
02-14-2010, 07:25 PM   #7
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QuoteOriginally posted by LeDave Quote
I'd say the Tamron is unnoticeably sharper than the Vivatar, only if you pixel peep hard and compare pixel by pixel then you can see. Otherwise they are both the same from how I saw it. Nice comparison.
Well put! When I was putting the report together, I was amazed at how close the performance was between the two lenses. There is one difference that is readily apparent. That being the difference in light reaching the sensor for the Vivitar. It truly requires almost a full stop more exposure to get comparable brightness. The Vivitar also has significantly cooler color rendition. Next time I should shoot with auto color balance turned off!

Steve
02-14-2010, 09:10 PM   #8
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QuoteQuote:
stevebrot: Did I make the wrong decision 25 years ago?
No, you did not--you made the right decision, from what I see and read here. Here is my breakdown:

IQ= wash
Aesthetics =Tamron +1
Build Quality =Tamron +1
Speed/Use of light=Tamron +1


One of them needs to go to the Marketplace: looks like the Vivitar to me. The only way I can see justifying the Vivitar in my bag, is if close-focusing was a priority in my shooting, which, at 28mm, it clearly would not be for me. Also, you can give the Tammy a +1 for being slightly faster, and another +1 for use of light. The only way the Vivitar could make some of that up, IMHO, is if the coatings were superior in reducing flare. However, I would guess the Tamron BBar coatings are at least as good as the coatings on the Vivitar.

Excellent presentation! Thank you, very much.

02-14-2010, 09:53 PM   #9
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QuoteOriginally posted by Jewelltrail Quote
No, you did not--you made the right decision, from what I see and read here. Here is my breakdown:

IQ= wash
Aesthetics =Tamron +1
Build Quality =Tamron +1
Speed/Use of light=Tamron +1


One of them needs to go to the Marketplace: looks like the Vivitar to me. The only way I can see justifying the Vivitar in my bag, is if close-focusing was a priority in my shooting, which, at 28mm, it clearly would not be for me. Also, you can give the Tammy a +1 for being slightly faster, and another +1 for use of light. The only way the Vivitar could make some of that up, IMHO, is if the coatings were superior in reducing flare. However, I would guess the Tamron BBar coatings are at least as good as the coatings on the Vivitar.

Excellent presentation! Thank you, very much.
Well, we will see! I will try and get out tomorrow and do some outdoor shooting. Maybe some architecture or bridges.

Steve
02-14-2010, 10:51 PM   #10
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Nice comparison, I had own the same Vivitar but later sold it and still have the Tamron, I never did any comparison like you have here. Both lenses are very close and I cannot see much of difference. Except I do agree that @f8 the Vivitar are little sharper. Look forward to your outdoor tests.

David
02-15-2010, 07:11 AM   #11
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Would love to see the Pentax-M or K 28mm f3.5 in this shootout for IQ. Maybe not as fast as these, but great IQ.
02-15-2010, 07:53 PM   #12
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QuoteOriginally posted by jeffrey r Quote
Would love to see the Pentax-M or K 28mm f3.5 in this shootout for IQ. Maybe not as fast as these, but great IQ.
It would have been nice to include either of those two lenses and the thought did occur to me. Unfortunately, I don't have access to a copy. Maybe sometime in the future?

Steve
02-15-2010, 07:56 PM   #13
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I was able to get out today to do some comparison shots in the low-angle winter sun. I added those to the original posting along with comments:
https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/90340-vivitar-...m-2-5-02b.html
Steve
02-15-2010, 09:35 PM   #14
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Very interesting results outdoors...
02-15-2010, 10:47 PM   #15
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Here are a few other pictures taken with both lenses today.

St. John's Bridge (Tamron 28/2.5)



A Little Rust (Tamron 28/2.5)



Robot Trains (Vivitar 28/2.8)



Stone Shield (Vivitar 28/2.8)

Monochrome conversion


Brand New Empty Condos (Vivitar 28/2.8)



Steve
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