How Do You Test a New Lens?

[neuroanatomist]

A new item like that I usually tell the store "You call Canon and give me a different copy"

+1

I can understand them waiting to receive the returned item before shipping the replacement, but they should replace it as a clicking sound certainly isn't normal.

I'd be interested to hear what Canon tells you. Either way, Adorama should replace. Email Helen if the issue remains unresolved.

[HDNitehawk]

I'd be interested to hear what Canon tells you.

I would be interested to. After reading the CR thread it sounds like a batch of current lenses with the issue. It would be a surprise if it were the result of a fix of some other problem and it is now normal.

I think more likely from the reports on CR it sounds like they got a bad component that went in the lens by accident for a period of time.

[Kayaker72]

Quick update:

1. Adorama responded to my email from yesterday providing the return information. Also, I did reread Adorama's original response. They had said I was within 30 days, so they would exchange it, but wanted me to contact Canon first.
2. I did call Canon. They did not hear any clicking sound in any of their copies. They recommended that I exchange the lens.

The lens is now in a box waiting for UPS to pick it up.

[neuroanatomist]

The number of people reporting this issue suggests a bad production batch. Hope you get a good one next time!

[Kayaker72]

Me too! But, given the number of people having this issue, I am preparing myself that I may have to send a couple of lens back before they run out of this batch. Hopefully not. If Bryan is right and the DD is the month and the "C" is the batch number, I am hoping I do not get another 032 serial number again.

BTW, I asked the Canon rep that I spoke with if they had heard of this problem and they hadn't. I thought this was odd given the number of people stating they had an issue on the CR thread, so I referenced the thread. They said that they were a technician and were not (edit) aware of the thread but did say that "Canon USA" probably was aware as they do monitor several forums. I thought that was interesting. Expected, but interesting.

[Kayaker72]

I am almost done testing my third version of the 24-70 f/2.8 II. Most everything about this copy checks out, except I am concerned about two things:

1. It may be soft at 70 mm. In comparing the "quality of focus", the 24-70 II is ~100-150 units better than the 24-105 at 24 mm and 50 mm. But the 24-70 II is equal to or less than the 24-105 at 70 mm for apertures f/4.5-f/9.
2. In addition, at 70 mm, there is an odd dip in "quality of focus" from f/8 to f/4. Below are examples from two different runs with slightly different set ups.

I am thinking this goes back as well. No clicking while zooming, but it is soft at 70 mm.

Of course, this is based on my assumption that Reikan's "Quality of Focus" a reasonable approximation of sharpness...

[HDNitehawk]

I had similar charts at 70mm when I used different AFMA settings. It would peak at f/2.8 and have erratic results at other settings, but when I found the right setting it did great. Try running the same test at several different AFMA settings to see if you have similar results.

I think Reikan only focuses on the first shot then all the aperture settings after that are at the same point.

This looks like it might be a setting problem. I would try a few more tests.

Use the ISO charts on the site and compare at 70mm. the 24-70mm should be better than the 24-105 especially in the corners.

[HDNitehawk]

Also, I would set up a make shift chart and take pictures with both lenses at 70mm, same lighting same target and compare the two using live view and manual focus. Do not count on the Reikan results for a quality comparison, especially if you are using the AF to take the pictures.

[Kayaker72]

Thanks Rick. I'll definitely try different AFMAs and test chart shots before returning the lens. I am traveling for work Tu-F, so if I don't get to it tonight, I'll be next weekend before I can do the tests.

[Kayaker72]

Not an extensive test set up, but I did play with the AFMA settings this morning. 1/200, f/5.6, ISO 100 from ~2 ft (closer than what I ran the FoCal test). I just used the focal target.

24-105 @ 70 mm


24-70 f/2.8 II @ 70mm



I was say the 24-70 f/2.8 II is sharper than the 24-105 f/4. But, it was at -15 AFMA. FoCal's test ran at a greater distance (2.3 M) was AFMA 0 for 70 mm. Also, the AFMA, according to FoCal's results, for 24 mm was + 4. So, I am potentially ranging from +4 at 24 mm to -15 at 70 mm.

Of course, that is comparing results from two different distances, but I wouldn't want that to matter so significantly.

For comparison, this was the center from the 24-70 f/2.8 II @ 70 mm AFMA = 0:



I also just ran the FoCal's Aperture Sharpness test @ 70 mm with the AFMA = -15