28-135mm purchased used - seems soft

Hi all

 

I recently purchased a used 28-135mm from a fellow photo.net'er, but I've been

playing with the lens for the last few days and it just seems soft. Is there a

standard method of testing the sharpness of a lens? I'm hoping to find something

that I can compare against to see how my lens rates.

 

Thanks

I owned one for about 7 years. It's decent wide open but sharpens up nicely by F8 at the wide

end, F11 on the long end. I have a lot of 11 x 14 landscape prints that look pin sharp, all

shot F8 to F16.

 

If you need a similar zoom that's tack sharp wide open, get the EF 24-105 4L IS USM.

Stopped down both zooms are about the same, but wide open the L zoom really kicks tail.

Ian,

 

there is a standard resolution testing chart. You have to print it on a good quality laser printer and make a range of test photos. The link to the chart: http://www.gpsinformation.org/jack/photo-test/pics/iso-rag.jpg

 

Good luck

 

Peter

I've owned one for years and it's on the digital camera I lend out. The 24-105 is considerably sharper but also 2.5 times the price. The 28-135 is an excellent value, but not sharp when compared to L zooms and inexpensive primes.

Stopped down it is pretty good. I made a few large prints from shots a friend took with my D60/28-135 combo. The prints are very nice. Easily sell-able as wall art at 16x24.

So what your are seeing is probably the normal expected performance of the lens.

Even the 24-105 is only fair quality at the wide end.

Ian, I had a 28-135 for a while and sold it for exactly the reason you describe - disappointingly soft unless stopped down a fair bit. For a rough idea of lens sharpness I put the camera on a tripod and shoot an average scene at several apertures and focal lengths with the lens being tested and then again with reference lenses which I know gives good results. Then compare in PS. This will give you an idea of where the more usable bits of the lens are.

<p>At one time, I upgraded from the 28-105/3.5-4.5 USM, which is not a bad lens, to the 28-135, which is a better lens. It was a worthwhile upgrade. The 28-135 was my best lens (of the two I had at the time; the 100-300/4.5-5.6 USM was the other). Now, it's my worst lens, and next in line to be replaced. It's not that the 28-135 got worse, but rather that I ditched the 100-300 and added the 17-40/4L USM, 50/1.4 USM, and 70-200/2.8L IS USM over the years, all of which are better than the 28-135. As well, going from film to digital hasn't helped, since I now examine every photo at 100% magnification instead of mostly looking at 4x6" prints.</p>

 

<p>Anyway, the point of my story is that whether or not this lens (assuming it's not actually a defective lens) is satisfactory may well depend on what other lenses you're accustomed to using.</p>

 

<p><a href="http://www.stevedunn.ca/photos/writings/eflenses.html" target="_blank">Here are the results of a test I did with this lens and two others</a> a few years ago. Maybe they'll be of use to you.</p>

A big thanks to Peter for the lens test chart. How to use it?

What other lenses do you have to compare it to? I have the 28-135 IS and I can say mine is not as sharp as any of Canon's primes I have 35f2.0, 50 f2.5 CM and 100 f2.8 macro, but it easily beats the 28-80 f3.5-5.6 and the 75-300 both IS and non-IS version. Bottom line is is should be better than most if not all Canon consumer zooms, but worse than any of their consumer primes.

My other lenses are the Canon EF-S 18-55mm f/3.5-5.6 Lens, Canon EF 75-300mm f/4.0-5.6 III USM and Canon EF 50mm f/1.8 II. Other than the prime, I would have thought that the 28-135mm should beat them all hands down in terms of sharpness. I'm setting up the resolution testing chart right now (thanks Peter!), I'll post the results later tonight.

My 28-135 beats the 18-55 and 75-300 (both of which I have) fairly easily, though the 75-300 stopped down at 75 is pretty closen and at 135 it probably beats the 28-135 at 135.