How sharp is your Tamron 28-75 @ 2.8???

[Maxima]

Sample #1, 75mm, 1/1600, ISO 100, 2.8 - 100% crop


http://i7.photobucket.com/albums/y253/maxima2000/test01.jpg




Sample #2, 75mm, 1/800, ISO 100, 4 - 100% crop


http://i7.photobucket.com/albums/y253/maxima2000/test02.jpg




Sample #3, 75mm, 1/400, ISO 100, 5.6 - 100% crop


http://i7.photobucket.com/albums/y253/maxima2000/test03.jpg



@5.6, the image is quite acceptable. Am I expecting too much?? How sharp is yours @ 2.8?? Do I not have such a sharp/good copy?





Here's one from the Canon 28-135 IS,

80mm, 1/500, ISO 100, 5.6 - 100 crop

http://i7.photobucket.com/albums/y253/maxima2000/test05.jpg

[slin100]

FWIW, my copy performs similarly. I kept it because, frankly, the softness wide open doesn't bother me. You really only notice it when pixel peeping.

You might try the test again using manual focus to eliminate any AF errors.

[Croasdail]

thats about right... a lot of lenses are not as crisp at wide open and my Tamron does the same. This used to be common as the faster shutter would mean less light saturation time on the film. At 2.8 you have a lot of light flooding the image for a very short period of time. Stopped down, less light is making in and is being burned it or saturated more on the media. Also remember that you are pixel peeping here and the true test is when printed at a reasonable size output (8x10 or 11x14). Also keep in mind a lot of the shots you see here have been digitally helped to be sharp in post production. Don't give up on it yet - I almost did - but now my Tamron gets used a lot more then my 17-40L.

[Cadwell]

Two full size images. The images are unprocessed and as they came out of a 10D on Large JPEG with standard shooting parameters.

Tamron 28-75mm @ f/2.8 (http://homepage.ntlworld.com/ukmotorsportpics/3waytest/IMG_4288.JPG)

Tamron 28-75mm @ f/5.6 (http://homepage.ntlworld.com/ukmotorsportpics/3waytest/IMG_4289.JPG)

Perhaps a touch soft at f2.8 but nothing a little USM wouldn't sort out.

[DavidEB]

The camera has moved between the photos (in the 2.8 shot the frame on the wall at top left is to the left of the "E" and in the third picture it's near the middle of the "E." It's hard to tell from your post if the subject is exactly perpendicular to the line of sight, and not clear where the center AF point was (eg, what did the camera focus on). Also the subject you've picked has only few edges, not the best test choice.

Without controlling these variables, it's not a great test. Much of the difference you see could be due to depth-of-field changes and inaccurate focus.

Tape a piece of flat newsprint on the wall, mount camera on tripod, use a t-square to mark perpendicular, ensure lighting is very bright to get good focus, use mirror lockup and a cable release. shoot raw and convert to TIFF so you don't have any JPG artifacts. Refocus and shoot each aperature test 3 times, pick best of 3.

My copy is very good at f4 and barely soft but easily useable at f2.8. I cannot tell the difference between f4 and f5.6. At the edges, at 50mm it beats the canon 50mm f1.8 (both lenses at f2.8) and is about equal at the center.

kind regards,

[CyberPet]

Mine sucks at 28 mm at any f-number. the AF is way off. It's not until I get to 35 mm it starts to perform well wide open, and it's perfect at 75 mm. Going to have the lens calibrated after the summer, since I know it *can* produce great images both at 28 mm as well as anything in between up to 75 mm, wide open.

[tombarn]

Well that's my first post (ever). But i would like to comment on the focus issues of the Tamron. I got mine over a year ago and straight out of the box it was really badly calibrated : severe front focus at 28 mm and the rest was really off too. After some testing I decided to take it to my dealer for a recalibration. Four weeks later I got it back from Tamron service and the difference is huge.

1. Now i get really sharp images wide open (compared to a good copy of a 70-200 IS and better than my 50 1.8 )
2. Focus is exactly on spot
3. Focussing is much faster now (not the drive of course) because the AF-system of the body isn't fooled anymore by a badly centered lens.

Bottom line is this. If you think your lens needs a recalibration send it to Tamron and you are likely to get the problems fixed.

[Keiffer]

How and where do you send it to? Where is Tamron in the U.S.? Good advice and been hearing alot lately about tremendous inprovements after coming back from Tamron.

[tim]

Mine's great at 28mm and 75mm, even at F2.8. Crops of random pictures like the ones above are pretty useless, use a focus test chart, that's reproducable and comparable between cameras.

[rizorith]

Has anyone found a place to get a Tamron 28-75? Every place I've tried online that doesn't say sold out turns out to be sold out anyways.

I'm already on two waiting lists but one thinks it will be a month or more before they have any in stock.

[Cadwell]

Crops of random pictures like the ones above are pretty useless, use a focus test chart, that's reproducable and comparable between cameras.

There talks a pixel peeper at his best. :lol: Thing is, most of us here use our cameras for taking pictures of real world things, not focus test charts and hence crops from real world images are very, very relevant indeeed. If a lens won't perform in the real world with real world subjects then it's not much use to anyone.

[accord]

There are two schools of people who justify the sharpness of a lens.
The first one will be the one who isolates everything other than optical sharpness. They test a lens using every effort to stop shacky and try their best to use the best focus, even manually. The best picture will be used as the output of the lens.
The other will use field test. They compare the images out of the situation in everyday use. The image quality is of course an integration of every characteristics of the lens and the shooter.
Which of the results above I refer? Definately I trust the second one. The testing method is much more close to the way I shoot pictures.

[JABACo]

Has anyone found a place to get a Tamron 28-75? Every place I've tried online that doesn't say sold out turns out to be sold out anyways.

I'm already on two waiting lists but one thinks it will be a month or more before they have any in stock.

I'll get this lens later in the Fall, however, there are a few on eBay. You may check them out.

[Andy_T]

Has anyone found a place to get a Tamron 28-75? Every place I've tried online that doesn't say sold out turns out to be sold out anyways.


I think user 'Maxima' is selling one in the 'Marketplace' forum.




:lol:




j/k!


My lens is also a bit soft at f/2.8, but the results at f/4.0 look better than the samples in this thread. That is, as far as I can tell without knowing more of the test.

I'd say that your lens is quite usable at f/4.0 for real world applications. Maybe the idea of having it recalibrated by Tamron is not a bad one ... but I would get more tests before.

Best regards,
Andy

[kram]

If we take the 'practical use' angle a little further - why should we even compare 2.8 vs 4 vs 5.6? Just take a few pictures and judge them individually.

As much as I hate to say this (coz I belonged to the other camp before), a preset image and standard setting is the most scientific way of knowing for sure what it is that the lens does well or not do well. What level is acceptable is of course entirely dependant on the person and the purpose.

And also, a good test helps down the road when you have one more new lens (has this happened to forum members here:) ) and you can calibrate using the same lens test 'setup'.

Just my 2c.