Photoclubalpha

Well I was not that happy with my Tamron 28-75/2.8 and ordered another one to compare it. Well, that made me even more sad than I was...

So, I put my A200 on a tripod aimed at a map of Germany with a size of 125 x 100 cm at a distance of 220 cm. Lined out everything as best as I could and shoot some pictures at different apertures. Offcourse it is only a part of the map, but the files are fullsize jpg straight out of the camera.

This is my tamron 28-75 @ 75mm F2.8:
http://img571.imageshack.us/img571/4333/dsc03812.jpg

This is the Tamron 28-75 @ 75mm F2.8 that I ordered:
http://img87.imageshack.us/img87/1653/dsc03816x.jpg

And my Sigma 70-200 2.8 HSM II @ 70mm F2.8:
http://img14.imageshack.us/img14/3504/dsc03821ll.jpg

Inserted later...
Here the Sony 18-70 kitlens @ 70 and F5.6:
http://img29.imageshack.us/img29/8098/dsc03838aq.jpg
Didn't line this up too well I see...
end of insert...

At the tests at http://www.photozone.de the Tamron performed about the same as the Sigma at 75 mm, but mine does not and the ordered one is even worse. Yes, I did reshoot the session several times... and the results are about the same. Also with some shots outside the results were the same. The pictures are the best of the ones I shot

All comment is welcome. Stare at the pictures as long as you like, but you pay for the Asperin yourself

coen

I'm not sure it's an entirely fair comparison. The Sigma is at its worst wide open at the extreme long end too.

Having said that, I would 'expect' better from my own KM 28-75/2.8 - which is basically a rebadge of the Tamron - but still probably not up to the Sigma at 70mm.

At face value Coen it doesn't look too good especially the second 28-75. I'm sortof thinking it might be the repro size 'on screen' vs the original map. If you were to adjust the size of the map and printing as displayed on screen to match the actual size of the printing on the map how does it look then? any better or no different?
Greg

I'm afraid I don't follow what you want Coen.
Shooting at a plane subject is not a good way to test a lens.
I don't know how many times we forumers thought about having/creating a checklist for testing lenses/flashes etc. but without acting.

Dr. Harout wrote:I'm afraid I don't follow what you want Coen.
Shooting at a plane subject is not a good way to test a lens.
I don't know how many times we forumers thought about having/creating a checklist for testing lenses/flashes etc. but without acting.

I read all the reviews at Kurt Munger's site... Problem outside was the light early evening. Too much light for 1/4000 sec at 100 ISO and F2.8 and F4.... Now I think about it, forgot to play in manual mode and dial in Exposure-compensation... Hmm, too bad...

I did took the plunge and just started with the 28-75 at a concert of Miss Montreal in November last year, but focus was hard to nail in bad light. Number of keepers dramatically low, also on shorter focal length. I rapidly switched to my Sigma 70-200 2.8 HSM II and it delivered almost everytime. Sharper, more room for error (focus and shake), just so much easier to get the picture in bad light.

It took some shots at a house with both Tamron, at daylight at a distance of 15 meter and results are the same... Last one ordered not so sharp, more CA, on 28 mm and on 75 mm at several apertures. I know it is hard to get a decent test picture at the map at that short distance, but it was the best I could think off in the office last night, reproducable time after time...

The tamron's do shape up when stopped down, even in the centre... but I do need to use them full open most of the time... If it were only some bad corners wide open I could live with it, but it's the centres too and probably that's why the camera does have more problems to focus in bad light too... Wasn't it loss in contrast in the centre with KM28-75 @ F2.8 in Kurt Munger's review at http://kurtmunger.com ?