[Dave]

Have experienced focus & exposure problems with Canon 24-105mm @ F4, which disappear from f/4.5 upwards Anyone else experienced this problem with the Canon 24-105 ?

Shot taken on tripod, focused using live view at max zoom, to ensure perfect focus, mirror lockup plus 2 sec timer, to ensure rock steady shot. 100% crop shots for comparison. The gif will flick between F/4 & F/4.5 :-



You'll notice ther F/4 shot has a ghosting effect feel to the shot vs the sharp f/4.5 shot. Notice how the edge of the letters of "ROB" go grey & soft at F/4 vs black & sharp @ f/4.5

Have tried on both 40D bodies with same results, so proves it's the lens. Have also tried Canon 70-200 F4 on same test & you can't tell the difference between f/4.0 & f/4.5, once again proving the 24-105 lens is at fault

[silkstone]

That's odd. It looks like some form of flare - that was a problem with some earlier models of this lens, but should have been sorted by now. (See Canon EF 24-105mm f/4 L IS USM Lens Review)

It's particularly strange that there's such a difference with a very small change in aperture. Were you using a UV filter?

No doubt someone else with this lens will come along with the results of a similar test.

[brian wright22]

Dave what serial number is yours? is it below UT1000 if so there has been a recall from Canon.

Also did you have a filter on the front?

[Dave]

Originally Posted by silkstone

It's particularly strange that there's such a difference with a very small change in aperture. Were you using a UV filter?

Nope

[Dave]

Originally Posted by brian wright22

Dave what serial number is yours? is it below UT1000 if so there has been a recall from Canon.

Thanks Brian, can see that here :- Canon Special Announcement EF Lenses - Canon UK

Mine starts UV, so it was 2007 :- http://www.pixalo.com/community/came...tml#post221328

[Whipspeed]

Send it back. They have a really quick turnaround for warranty and other repairs. I've sent a lens back twice, once for warranty and once as it had been dropped and got it back in a week. That was the repair centre at Elstree.

[Dave]

I did send it back to supplier for replacement, but they appear to have sent me the same lens back <UPDATE> Supplier has confirmed this is a replacement lens

Do the warranty places cover your return P&P though, as under Sales of Good Act the supplier must. It's £10 for this weight lens.

[stepheno]

Tested an hour ago

f4


f4.5

[brian wright22]

Originally Posted by Dave

I did send it back to supplier for replacement, but they appear to have sent me the same lens back

Do the warranty places cover your return P&P though, as under Sales of Good Act the supplier must. It's £10 for this weight lens.

Dave I had to get my 17-85mm Canon Lens repaired and decided to send it to Canon @ Borehamwood UK. It cost me £11 to send it which I didn't get back but I was not charged for its return under warranty.

I think you would not pay anything either way if you take it back to the selling dealer because usually they have a pickup usually once a week. Well that was the case with my Minolta warranty return.
.

[P-E]

Did the supplier say if this lens was a new replacement Dave?

[Dave]

Originally Posted by P-E

Did the supplier say if this lens was a new replacement Dave?

Yep, I insisted on replacement lens . <UPDATE> Supplier has confirmed this a replacement lens

[P-E]

Originally Posted by Dave

Yep, I insisted on replacement lens . Not impressed.

Don't suppose you got the serial number from the one you sent in?

Have you contacted them again to say this one is showing the same problem.....or you have had the original one returned to you?

[labbai]

Turn the image stabilizer off when using the tripod...

[Dave]

Originally Posted by labbai

Turn the image stabilizer off when using the tripod...

I did . In fact I tried it both ways & no difference.

[Soupdragon]

I think you would be better off with the 17-40!

[brian wright22]

Originally Posted by stepheno

Tested an hour ago

f4


f4.5

Definately worse at F4 Stephano

[Dave]

Well this afternoon Dave Canon was good enough to host me, whilst we test my 24-105 vs his version. DC's lens has an UU code, so was produced in 2006. Shooting the same subject as in the 1st post, showed a difference between F4 to F4.5 but nowhere near as much as my lens (about only 20%). In addition it was sharper.

The worrying thing is though, although less prevalent than mine, there was still some flare at F4 . This is the 3rd lens I have tested now, where the 1st 2 (both mine) had bad flare at F4 & DC's to a lesser degree.

We then tested DC's 70-200 F/2.8 L IS at F4 & F4.5 on same subject, & you could see no difference in image quality at 100% crop. I performed same test previously with 70-200 F4 L lens, with same results.

So does this mean all 24-105's have this problem at some level or another, at F4 ??

Any comments DC ?

[Dave]

In a quandary now. I've been offered a full refund on this lens now, but this is one of the lenses I specifically changed form Nikon to Canon for The Canon cashback has now finsihed so I would be at least £45 worse off. In addition what if I buy elsewhere & it has the same problem

I could send to Canon under warranty, but I'm concerned if I am not happy with result I could jeopardize my full refund

What do others reckon ?

[dabhand16]

I'd take the refund. £45 is cheap for peace of mind.

Have you contacted Canon to see what they have to say on the subject?

[P-E]

With Graham on this one....refund.

It's a shame when it was the lens you really wanted

[Dave]

Bugger it then, I'm back off to Nikon

[silkstone]

Originally Posted by Dave

Bugger it then, I'm back off to Nikon

We should have had a sweepstake.

But... since the lens is exactly what you want in every other way, why not send it to Canon for a health check, swap it for another and see if that's better, or pretend that you'd never use it at f/4 anyway?

[brian wright22]

Originally Posted by Dave

Bugger it then, I'm back off to Nikon

Iv'e been following this thread because I have had interest in this lens.

May I suggest you get your money back and in a couple of months Canon will again launch their cash back offers and find a dealer that has a stock of the said lens and try them out at full aperture until you are satisfied its ok.

Don't go back to Nikon you may well be unhappy with their lenses at some point.

The best of luck and let us know which route you eventually take.

[JMitchell]

Oh dear Dave. That's all I can say, as unfortunately I can no longer offer any assistance on your chosen brand. (sorry mods, but no need to delete )

[Chris H]

Dave I took these with my 24-105L to see if there was a difference, as you can see I get the same results as you. A tad flary at f4.0 but gone at f4.5 the next stop down for the 40D.

Never noticed it before, very strange

F4.0


F4.5



Canon 40D, on-board flash, 100% crop

[silkstone]

It's interesting that there's a noticeable difference with just a tiny decrease in aperture, but if we desist from pixel-peeping I really doubt if it matters much in the real world, and it's easily corrected (or disguised) in PP.

Be hppy! Go and take some proper photos with the damn thing!

[Dave]

I can see where you are coming from Silky & if it was a £150 budget lens I could live with it. Problem is , this is supposed to be Canon's Pro lens with a circa £600-£700 price tag & yet it has this problem, which isn't there on a £300 70-200 F4

If even out of principle Canon should not be able to get away with this poor Quality Control

Rant over

[muscle750]

Obviously making sleepless nights with your concerns Dave posting at half 4 in the morning!! As the D300 heads for Dubai in 6 hours

[dabhand16]

Thinking back to your original reason for switching to Canon - that is much cheaper prices - maybe their QC is less stringent and they can pass the savings on th the consumer..........?

[Dave Canon]

The post by Chris H shows exactly the same effect through he is not using a grid so I feel sure that the effect is caused by lens flare. I have always been aware that lenses are imperfect at the edges and at maximum aperture so it does come down to what is acceptable. In fact I have always avoided using the max aperture (apart from focusing) unless I had no alternative. I do not feel we have enough information to say that this performance is unacceptable at full aperture. I know my 70-200 L looked fine at f4 but remember it is an f2.8 lens costing £1300. If we had looked at it a f2.8 would we have seen some deficiences? When I have compared my non L lenses with my two L lenses, they have looked blurred at the same level of enlargement so subtle differences in flare would be undetectable.

Perhaps you should get hold of several more quality lenses (including other brands) and compare in similar circumstances and perhaps compare to lower quality lenses as well. I am sure other Club members would be happy to cooperate in the interest of understanding more about what performance one would expect from a lens. Before I bought the 24-105 (apart from 3 strong recommendations from Club Members), I looked at a number of professional reviews which were excellent and, if this performance is inherent in this design, presumably these reviewers consider this to be good.

Dave