Tested My Returned 70-300 f4-5.6 IS USM

[chuck_c_charlottenc_]

I received my 70-300 IS lens back from Canon Factory Service on Tuesday of

this week. The packing slip from Canon Factory Service said "Replaced Inner

Lens Unit". The total time that I was without the lens was 12 days. I thought

that was excellent turn-around, since there was two weekends involved during

this time.

 

As I had stated in my other posts about this lens... I could not see a problem

with my copy of the lens, but because a fellow Photo.Net person said that his

lens also didn't show any signs of a problem until after a extended vacation

where he used the lens extensively. He said when he came home and copied his

photos into the computer, he was shocked to see all the photos that showed the

problem that his lens didn't have before the trip.

 

So, since it looks like the lens will degrade eventually, I decided to send my

lens in, because of his experience.

 

Below is the result of my test of the lens after the "repair".

 

 

I took many photos at both the landscape and portrait orientation, but have

concentrated most of my photos on the portrait orientation. I have also

concentrated on taking photos at 300mm and have used apertures from f5.6 to

f29.0 and speeds of 1/500 to 1/6 sec. I decided to take photos of a portion of

my home's brick wall... and I used the same portion of the wall for all the

photos. I have taken these photos on different days and in different lighting

conditions, from early evening (acceptable light) to mid-day (bright

sunlight). I also decided to take this sequence of photos both hand held and

with a monopod. I did a total sequence of each of the various conditions and

aperture/speed and then copied the photos into my computer and reviewed the

results. When I saw a photo that was not absolutely clear, in my opinion, I

went back outside and re-shot at that specific aperture/speed and re-reviewed

those photos on the computer.

 

I took nearly 80 photos, and the fallout rate was 10% (8 photos). And everyone

one of the "failures" were at either 1/6 or 1/10 sec. When I re-shot

those "failures" at the same aperture/speed, I found that I could capture a

clear photo.

 

So, I've come to the conclusion that the lens currently takes excellent photos

throughout it's total range at 300mm.

 

I have not done any thorough testing at the shorter focal lengths, but I do

plan to do a subset of my test above. I really don't expect to find anything

wrong at the shorter focal lengths, though. If I do, I'll be sure to write a

new post.

 

I hope this helps. I'm happy, and I sure hope this lens works like it works

now for many years to come.

 

//Chuck

[mark u]

Yours is the second positive response to the repair in this forum. It sounds as though Canon's fix really works (although I have come across one report of a botched repair elsewhere). I think that other owners should have no fear of getting their lenses repaired, and those who await fresh stocks to reach retail outlets should also be able to buy the lens with confidence.

[mars c]

CHUCK, did you try mirror lock up mode on the body when you shot at 1/10 or 1/6 sec? could you try it again in mirror lock up mode at that speed? and see if the image improved?

[chuck_c_charlottenc_]

Mark,

 

I agree. I think that Canon has provided a valid "repair".

We will see what the future shows.

 

//Chuck

[rjacksonphoto]

I'm not sure I understand. So, you are pleased with the repair and performance of your lens, which was functioning without noticeable aberration before you sent it in for repair?

[dcains]

My lens was back in hand just a week after sending it to Canon, and I'm pleased to report that the repairs were beautifully done. My lens didn't exhibit the vertical orientation problem, but I sent it in anyway, and I'm glad that I did. As a bonus, the zoom creep my lens had from new is now gone, and while it doesn't feel quite so nice as my 'L' lenses, the 70-300 certainly handles much better. Anyway, here's a link to just a few test shots I took in the back yard:

 

http://deanwcains.smugmug.com/gallery/1694188

 

FWIW, I'm not really nuts about lens "testing", which is to say I'm not going to use mirror lockup, a tripod, f/29, and so on, simply because that's not what I bought the lens for. The 70-300 is a nice. lightweight walk-around zoom, and that's how I use it.

[yannig]

I just got mine back, and it didn't improve anything at all ...

[yannig]

Late edit: they did repair it, accidentally there was some wind when i tested the portrait position which caused some blur ... :|