"soft" 70-200mm f2.8 USM - DPChallenge Forums

06/05/2014 02:25:31 PM · #1

As some of you may know I recently switched from Pentax to Canon. I picked up a Canon 70-200mm f2.8 USM and received it a few days ago. I am new to "L" glass and shooting about 100 picture with the lens, that my image were soft at 100% or 1:1 magnification. I tried wide open at f2.8 and at f8 as well with the same results hand held and with a tripod. I have since contacted Canon and they told me to send it in for an inspection and they will go from there. I have read a few other threads online about people getting soft 70-200mm IS II USM and the like. What I wanted to know is how often does it happen? I mean getting a soft lens. I can provide some example as to what I am experiencing. I am using a Canon 70D and I think I have it set up right I tried one shot and several AF modes. I looked into getting FoCal software because I thought it was a micro adjustment issues possibly but my 17-55mm f2.8 IS USM is pretty sharp and doesn't show any signs like the 70-200mm does. I also have a lot of noise with the lens as well in certain situations. Even at a low ISO of 200 I seen to be getting a lot of noise and grainy type. I do have NR on but not on such a low level of ISO.

Canon 12x IS USM (S3 IS built-in Lens) -- 36-432mm (35mm EQ)

06/05/2014 02:41:25 PM · #2

Just some examples. They look fine at thumbnail size but zooming in does not reveal much sharpness.

GeneralE

Canon PowerShot S3 IS

06/05/2014 02:55:47 PM · #3

Originally posted by DustDevil:

I looked into getting FoCal software because I thought it was a micro adjustment issues possibly but my 17-55mm f2.8 IS USM is pretty sharp and doesn't show any signs like the 70-200mm does.

I think that the whole point of that software is that you might need a separate setting for each lens. Your camera may be right-on right now for the 17-55 and still be "off" for the 70-200.

For test shots you should probably create/print a test grid with fine straight lines and circles, and shoot using a tripod, mirror lock-up, and from a known (measured) distance. You might want to compare manual vs. auto-focus at each aperture/focal length combination.

kirbic

Canon EOS R5

Canon RF 24-70 f2.8 L IS

06/05/2014 03:28:59 PM · #4

I suspect this *is* a focus offset issue, and not a "soft lens" issue. I can't, of course, be absolutely sure, but I think this is the case. The problem with the focus issues is that it is really the combination of lens and body that makes all the difference. It would be a good idea to try micro-adjustment before you decide to send the lens in.
On the subject of image noise, there is no instance I can think of where the lens contributes to image noise, as long as we are talking like exposure settings. That said, you might *notice* noise more when you have very smooth OOF areas such as provided by the long focal length and wide aperture of the 70-200.

Canon 12x IS USM (S3 IS built-in Lens) -- 36-432mm (35mm EQ)

06/05/2014 03:30:58 PM · #5

I purchased FoCal software late last night. I printed one of its test patterns out and let it do its thing with my 70D hooked up to a laptop. The automatic micro adjustment setting showed the lens was off but only 2-3 "ticks" but the preview section before you hit apply didn't show any improvement on the live view of the test screen. I will wait and see if there is a problem with the lens once Canon receives it. If there is nothing wrong I will continue with FoCal and have the wide and tele focal lengths adjusted. I know there can be a lot going on with a camera and settings and lighting and so on so forth.

GeneralE

Canon PowerShot S3 IS

06/05/2014 03:57:18 PM · #6

Originally posted by DustDevil:

I printed one of its test patterns out ...

Here's a DIY version of one if anyone can use it ...

Cory

Canon EOS-1D Mark IV

Canon EF 85mm f/1.2L II USM

06/05/2014 05:29:50 PM · #7

Hey, if you want to stop out by my place, or meet up sometime, I'd be glad to give you an objective comparison. You're even welcome to use my 100-400 as a comparison test.

06/05/2014 07:13:55 PM · #8

Thanks Cory Yeah I sent the lens off already will see what happens with it. Chances are it just like everyone else suspects and needs micro adjustment. There are so many settings on this camera I just do not know about and not covered in the manual at all. I just used FoCal software to adjust my 17-55mm f2.8 and it turned out at 55mm it needed +5 adjustment and at 17mm it was fine.

After more reading and some micro adjustment YouTube videos, I heard that the 70D does not like center selective focus point. It randomly gives soft images with the setting and I know for a fact the deer picture above was shot with that setting. Not sure if its all 70D's or just a handful but seems like its prevalent. Will just go from there and watch my settings and see what I get with them.

Frakster

Canon EOS-450D Rebel XSi

Canon EF 50mm f/1.8 II

06/05/2014 08:02:34 PM · #9

I'm sorry but I'm interested in what FoCal is? You're camera needs adjustments like a tune up? I never knew this. What is FoCal and what does it do?

Samsung Galaxy S21, S21+, S21 Ultra

06/12/2014 11:13:43 AM · #10

Looks like something was wrong with the lens after all its currently being worked on at a Canon Repair Facility. I would have figured it was a micro adjustment issue and I am sure once I get it back I will have to calibrate it.

Bear_Music

Sony 24-70mm F4 Vario-Tessar T* FE OSS

06/12/2014 12:14:17 PM · #11

Originally posted by Frakster:

I'm sorry but I'm interested in what FoCal is? You're camera needs adjustments like a tune up? I never knew this. What is FoCal and what does it do?

Long story short:

Every piece of manufactured *anything* is built to tolerances. In other words, if you expect a centimeter, the manufacturing tolerance of the item might give you .9 or 1.1 centimeters. Whatever...

So let's assume that both Canon L glass and Canon dSLR are built to tolerance of +/- 3 units, whatever the unit might be. Therefore, if you have a lens that is at the +3 range mated to a body at the -3 range, you have 6 whole units of "drift" from zeroed up available, and there are consequences. Newer Canon bodies have the capability of microadjustment to match each lens in the arsenal. FoCal is one company marketing a solution to measurement and calibration.

ETA: Most "sweet copies" of lenses really are an optimized mating between body and lens. The lens may not look so sweet mounted on MY body...

Message edited by author 2014-06-12 15:43:15.