[ilya80]

Hello fellow Pentaxians!

I hope this review and samples will help those who have either of these lens and think about getting the other.

I recently aquired my Tamron 70-200mm 1:2.8, the last "expensive" lens I planned to buy. Its a very nice piece of equipment: well built, feels solid and although a bit heavy at 1100g, very fun to use. Before that my "longest" tele was the Pentax SMC K 135mm 1:2.5, a great prime that is sharp wide-open, and about 2 times lighter and more then 2 times smaller than Tamron is.

At some point I wanted to see how the new zoom performs against the old proven prime. So I have taken them both to the country where I allowed myself half an hour of thoughtful measurebation. I have taken about 8 shots of the different flowers with both lenses, focusing on the same areas to compare sharpness, contrast, color and bokeh. When converting to JPEG no PP was added at all ( no sharpening, no WB, no levels )

The Tamron was set to approximately the middle between 130mm and 140mm ( this lens does not report 135mm focal lengh to the camera ). Most of the pictures were taken wide-open (F2.5 and F2.8), which is by far my favourite setting, and a few were taken with both lens set to F3.5. My short conclusion is that the zoom is being both sharper and more contrasty wide-open, which comes as a surprize. The mentioned difference is gone by F3.5. In regard to colors and bokeh - the lenses are completely different, Tamron being slightly warmer and its bokeh being more smooth, which is not necessarily an advantage. The K135 image is cooler and has a proprietary rendering, specific to older Pentax glass.

Below are sample pictures. Its left as a fancy exercise for the reader to make which one is which, however I`ll name it at the bottom. These are resized images and link to full sized images at my gallery.

First series taken wide-open.

Flowers #1, Lens #1 (full-size)

Flowers #1, Lens #2 (full-size)


Flowers #2, Lens #1 (full-size)

Flowers #2, Lens #2 (full-size)


Flowers #3, Lens #1 (full-size)

Flowers #3, Lens #2 (full-size)


Flowers #4, Lens #1 (full-size)

Flowers #4, Lens #2 (full-size)


Flowers #5, Lens #1 (full-size)

Flowers #5, Lens #2 (full-size)


Flowers #6, Lens #1 (full-size)

Flowers #6, Lens #2 (full-size)


Flowers #7, Lens #1 (full-size)

Flowers #7, Lens #2 (full-size)


Flowers #8, Lens #1 (full-size)

Flowers #8, Lens #2 (full-size)


As you have probably guessed Lens #1 is the SMC K135, and #2 is Tamron.

Thanks,
Ilya.

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Last edited by ilya80; 09-26-2009 at 06:44 AM.

[pentaxman]

Your pictures are not showing up.

[deadwolfbones]

They are for me.

[Just1MoreDave]

Very interesting comparison.

Flowers #2 and Flowers #3 have something in the corners that appears to be in the plane of focus. It looks to me to be sharper with the Pentax than the Tamron in both cases. The difference is very small and could easily be focus differences.

Out of focus highlights with the Tamron seem to have several lines running through them, rising left to right at about a 30º angle. Sometimes I can see (or imagine seeing) this pattern in other OOF areas. The Pentax OOF highlights have the typical look of a Pentax prime.

[newarts]

Thanks for the comparison. I've been thinking of getting myself a T 70-200:2.8 & it still seems like a reasonable thing to do. (I have no longish AF Zoom & already have the 135:2.5.)

Thanks again,
Dave

PS Want to sell your zoom?

[pacerr]

. . . My short conclusion is that the zoom is being both sharper and more contrasty wide-open, which comes as a surprize. . . . .

It interests me that we often express surprise in comparisons between modern and "elderly" glass. No matter how good that older prime lens is/was, there were still compromises in its optical formula and mount design and it would be rare indeed to find one optimized for the max f-stop in any case.

A modern zoom with at least a quarter century of advances in optical engineering should find at least some optimal range within its focal length where it can take advantage of those advances to meet or exceed the older lenses.

I have some 30-40 year old Pentax primes that I value for their special characteristics but I'm not hesitant to admit that newer glass with all its alphabet soup labels, coatings and special formula glass provides a comparable, and often more versatile, lens.

(But as it's said about mature lovers, there's something special . . . )

H2

[and]

Thanks for the work, am interested in the Tamron myself, dont see too many shots with it but it seems a very nice lens optically. and at a great price too.

[ilya80]

Out of focus highlights with the Tamron seem to have several lines running through them, rising left to right at about a 30º angle. Sometimes I can see (or imagine seeing) this pattern in other OOF areas. The Pentax OOF highlights have the typical look of a Pentax prime.

Interesting find! Never noticed it myself. Going to try more shots with OOF highlights to see if its specific to the lens.

[ilya80]

PS Want to sell your zoom?

No way! more over I seriously advise you to visit B&H and book one for yourself ASAP before Tamron follows in big boys wake and sends its prices up.

[jsherman999]

.


Nice comparison, thanks. I knew immediatlely which was which, having shot probably 1000's of shots like that with my 70-00 when I had it

You may not be aware, but you happened to pick the FL that's supposed to be weakest on the Tamron - 135mm wide open is supposed to be pretty soft. (Mine never dispayed this weakness that I could see.)


See This Post for 133mm f/2.8 examples.


I still like the rendering of that 135 2.5 - what were the shutter speeds of each, though, I don't think the exposure was exactly equal?


Thanks again, I really like seeing modern zoom vs. older prime comparisons, and do them myself informally all the time.




.

[ilya80]

Out of focus highlights with the Tamron seem to have several lines running through them, rising left to right at about a 30º angle.

I just checked and indeed this is true for point highlights that are behind the plane of focus. It has to be a perfect point lightsource though to be able to notice that.

Not sure if its a defect or why this is happening, but I refuse to get upset about it
Rather take more photos

[and]

.
You may not be aware, but you happened to pick the FL that's supposed to be weakest on the Tamron - 135mm wide open is supposed to be pretty soft. (Mine never dispayed this weakness that I could see.)

yes he did, thats why this comparison was extra nice for me After all those fantastic shots in your thread I cant believe you dont still own one

[GeneV]

Both lenses do an excellent job but have a different color rendering. Beyond that statement, it is very hard to make judgments from these photos, though. It is a challenge for me to evaluate sharpness on a three dimensional subject taken with little depth of field. For example, the focus point for Flower 1 is not exactly the same for the two lenses. When the photos are viewed in full size, it is clear that the focus of the first photo is slightly in front of the second photo. Notice that the front petal of the left flower is almost in focus on the first photo, while it is entirely OOF on the second. With the very shallow DOF, this makes it tough to judge any differences in sharpness on two lenses that are both excellent.

Also, as pointed out by another poster, the exposure seems different between the two lenses. This may tend to exaggerate some of the color differences as well.

Still, this is very interesting stuff. Thanks.

[Just1MoreDave]

I just checked and indeed this is true for point highlights that are behind the plane of focus. It has to be a perfect point lightsource though to be able to notice that.

Not sure if its a defect or why this is happening, but I refuse to get upset about it
Rather take more photos

It would only make me curious about what causes the effect. I haven't seen another lens do that but I haven't been looking either. In an actual print, those highlights are either bright and tiny or larger and much dimmer. It might be more obvious in a night shot, but not enough to ruin a shot.

[engl]

If you are still checking this thread, could you possibly see what the white balance is set to for the pictures? I find that the AWB picks way cooler colors when using old M/K glass, but equalizing white balance gives me fairly similar rendering between old primes and new zooms.