Tamron 28-75mm f/2.8

So, I ordered this lens from Amazon, I received it very quickly.

Excited to use the lens, I put it on my K10D, and started shooting around the yard. I took some shots of the yard in general, then I shot some flowers. I switched between AF and MF, because with MF, I was able to focus much better on closeup shots of the flowers.

I took the camera in and took a look at the pics. I immediately noticed that any pictures shot at 2.8--4.5 were EXTREMELY soft. On 2.8, the shots were so soft that it looked like there was a cloud moving through...

Above f5.6, the shots became pretty sharp.

Unfortunately, this lens was entirely unacceptable for me. I boxed it up and sent it back to Amazon this morning.

Hoping that this was an isolated case, I ordered an identical lens. If this next one is soft as well, I'm going to be pretty sad. What I am quickly learning about Pentax is that the selection of new, quality glass is not as big as I had hoped for...

Thoughts?

Here's an example of what I'm dealing with. These photos have nearly identical composition. The only difference in settings is that the first one is shot at f/2.8 and the second one is shot at f/6.7. Obviously, the 2.8 shot is completely unacceptable. The softness continues until about f/4.5 or so. ISO settings don't seem to change things either. EXIF data should still be intact for these files.

f/2.8:
http://i32.photobucket.com/albums/d2.../Example28.jpg


f/6.7
http://i32.photobucket.com/albums/d2.../Example67.jpg

As I've read but not experienced personally, many 3rd party lenses such as Tamron vary in quality. It is possible that you got one that is not up to par. If you have access to a camera store that carries this lens, maybe you could go test it against a couple of others. Good luck and hope you can get it replaced for a better quality lens. Tamron as I've read is pretty good for the most part.

I am fairly certain you got a bad lens. It happens...for future reference, bump the ISO a tad. In looking at the Histograms both images are underexposed by about 1/2 stop. It looks a little like hand shake to me..but not all. What leads me to believe it is the lens is that the F/6.7 Image is not that great...

Another thing, What version software do u have in your K10D?
How old is it?

Quote:

---

Originally Posted by jgredline

I am fairly certain you got a bad lens. It happens...for future reference, bump the ISO a tad. In looking at the Histograms both images are underexposed by about 1/2 stop. It looks a little like hand shake to me..but not all. What leads me to believe it is the lens is that the F/6.7 Image is not that great...

Another thing, What version software do u have in your K10D?
How old is it?

---

Thanks, Javier.

The first batch of pictures I took were at ISO 400, and looked a lot worse at f/2.8 than the one I posted. There may be a little camera shake, but the other pictures were very soft as well.

As far as the software goes, I don't have my camera with me, but I remember updating it in January of this year.

Update!!!

I got the new lens from Amazon today, and it is MUCH sharper than the first one. I think it could use a little adjustment, so I may send it in to Tamron.

Overall, I am pleased with lens #2, and I can't wait to start shooting more with it!

Quote:

---

Originally Posted by spiraleyes

Update!!!

I got the new lens from Amazon today, and it is MUCH sharper than the first one. I think it could use a little adjustment, so I may send it in to Tamron.

Overall, I am pleased with lens #2, and I can't wait to start shooting more with it!

---

Sounds great! Post up some images.. By the way, like most lenses, I find it to be best stopped down a half stop.

Glad to hear you're second lens is better. I have a Canon mount Tamron 28-75mm f/2.8 and love it. It's probably the lens I use the most. I shoot most of the product shots for the PhotographyREVIEW.com pro reviews with it.

The first photo you posted was shot at an angle and that will make a difference. At f/2.8 you have a very shallow depth-of-field and so you shouldn't expect much of that photo to be in focus. I don't know where you actually focused, but it looks like it was sharper toward the left. It does still look soft, though. I'd have to know more to really evaluate.

Also, it's unrealistic to expect any lens to be sharp wide open. There are some exceptions, but as a rule, stopping down a couple of stops will give the best results. And that's on top of the deoth-of-field issue. Every lens has its sweet spot. But with an f/2.8 lens, I would expect that f/8 will usually deliver the best results.

While I didn't expect the pictures to be sharp over the entire shot, I did expect them to be sharp somewhere in the picture. The shots with the first lens really were terrible across the whole range.

This new lens isn't just better than that first one, it's HOLY S**** amazing. That's how bad the first one really was.

I'll post up some pics tonight from the new lens. :)

I find that the 28-75 to be one of the finest zooms on the market. It falls in to my "Brutally Sharp" category.

A Sample:

Ben

Here's a pic from a series I shot this morning:

http://i32.photobucket.com/albums/d2...4489resize.jpg

Lokks great to me.

I have an Pentax K10D and the Tamron shuld replace the "18-55 kit" lens.
I bought the first one about one month ago, it had terribly front/back focusing problem so ive got it replaced, the second lens i got a week later had som centering problems and wasent sharp before f8 so i got it replaced too, antoher week later ive got the third lens and that one was extremly soft from 28mm to about 50mm after that it was sharp 50-75, this one will also be replaced and ive given up this len, now i'm ordered the Pentax 17-70 instead hoping it vill be allright.
I am very dissapointed and can not reccomend the Tamron lens.

Welcome to PR kjelle and thank you for your post. I'm sorry to hear about your bad experience with the tamron, but as we all know, lenses can be real iffy. I'm hoping that the Pentax lens will finally meet your need. Good luck and I look forward to seeing more from you.

Hey again

I have gone back to try the Tamron after all, ive had contact with Tamron and they tried too help me. I also sent them my camera so they could calibrate it vith the lens, then they found out that it is something wrong with the camera, the distance to the Focusing screen and the sensor isnt the same and now they shall try to correct the camera instead, at the same time i was told that this problem are very common among most consumer level cameras and many Canon cameras has this problems to. The problem is more visible on fast lenses than slow thats why i havent seen the problem on my kit lens or my Tamron 70-300/4-5,6. Tamron has serveral ROM's to kompensate the fault in the camera but in my case the fault was too big, in for example K20D there are a built in correction in the camera.

sorry for my poor english

Kjell

Thanks for the update, please give us another one once you receive your corrected camera and lens! :)

kjelle...sounds like good news may be on the way finally. I hope they get everything fixed for you. As for your english, it's great, keep up the good work!!!!