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Weird Lens Problem  
User currently offlineDLX737200 From United States of America, joined May 2001, 1911 posts, RR: 19
Posted (2 years 3 months 4 weeks 1 day 23 hours ago) and read 5410 times:

These are not my photos but a friend has been having problems with his Canon 70-300 lens. Mainly on the right side of the image, the photo is considerably softer and even has this weird effect where the image blurs. See below.

Example Photo:




Full Crop of problem area:



So what would you call this problem and how can he fix it?

9 replies: All unread, jump to last
 
User currently offlinevikkyvik From United States of America, joined Jul 2003, 10036 posts, RR: 26
Reply 1, posted (2 years 3 months 4 weeks 1 day 18 hours ago) and read 5354 times:
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Quoting DLX737200 (Thread starter):
Canon 70-300 lens.

Is that the L, or the IS USM?

If it's the L, might be an element has become decentered (though I don't know if that would cause that exact effect). I get extreme softness on one side sometimes when I use my 70-200 with the 1.4TC. Haven't bothered getting it fixed because I don't need the 1.4 all that much anyway.

If it's the IS USM, and it's between ~250 and 300mm, that lens can get pretty awful up in those focal lengths, so I wouldn't be surprised.



"Two and a Half Men" was filmed in front of a live ostrich.
User currently offlineNZ107 From New Zealand, joined Jul 2005, 6431 posts, RR: 38
Reply 2, posted (2 years 3 months 4 weeks 1 day 17 hours ago) and read 5343 times:

My 70-300mm IS USM had a weird blur patch just like that. Made so many shots unusable even though only such a small portion of the plane was blurry. I haven't bothered touching it since I bought a 100-400 but it still sits around as a spare.


It's all about the destination AND the journey.
User currently offlineDLX737200 From United States of America, joined May 2001, 1911 posts, RR: 19
Reply 3, posted (2 years 3 months 4 weeks 1 day 11 hours ago) and read 5307 times:

Quoting vikkyvik (Reply 1):

Is that the L, or the IS USM?

IS USM.

Quoting vikkyvik (Reply 1):

If it's the IS USM, and it's between ~250 and 300mm, that lens can get pretty awful up in those focal lengths, so I wouldn't be surprised.

Most of the problem results seem to be above 200mm.

Quoting NZ107 (Reply 2):
My 70-300mm IS USM had a weird blur patch just like that.

My first lens was a Sigma 70-300 and within a year of getting it, I had this problem too. Heck, a couple of them even got past the screeners 8 years ago when the standards were more lax:


View Large View Medium
Click here for bigger photo!

Photo © Idle Photography



I ditched the lens shortly after and bought the 100-400 I still have today, which consequently is now having it's own softness issues and is currently in repair at Canon.

I would love to know what the name of this problem is. Is it lens flare? A shadow? Can my friend send the lens in to Canon to get repaired? Being the lens is only $300-$400 brand new, I can't imaging their going to charge hundreds of dollars to repair it. Who knows?


User currently offlineNZ107 From New Zealand, joined Jul 2005, 6431 posts, RR: 38
Reply 4, posted (2 years 3 months 4 weeks 1 day 1 hour ago) and read 5266 times:

Quoting DLX737200 (Reply 3):
I would love to know what the name of this problem is. Is it lens flare? A shadow? Can my friend send the lens in to Canon to get repaired? Being the lens is only $300-$400 brand new, I can't imaging their going to charge hundreds of dollars to repair it. Who knows?

I think it's more like the lens gets bumped around and one piece of glass becomes ever so slightly misaligned, causing it.. But that's all I can think of. Lens flare doesn't have anything to do with this. But yeah, I don't really see a point in getting one serviced, especially because they cost only so much.



It's all about the destination AND the journey.
User currently offlineJakTrax From United Kingdom, joined Jun 2005, 4936 posts, RR: 7
Reply 5, posted (2 years 3 months 4 weeks 1 day ago) and read 5251 times:

It's not lens flare and it's not shadow - it's just the limitations of the lens. Of course bumps and knocks can mis-align the elements but in the case of the Canon EF70-300 f/4-5.6 USM IS it's simply a design flaw, for want of a better description. Once the optics are stretched to their limits they don't perform as well as their L-series counterparts, and softness creeps in. More often than not this softness will emanate from the centre of the frame but it sometimes manifests itself as softness/blur in a particular area, such as the left or right side, or top or bottom of the frame.

Obviously the scale and extent of the softness varies from copy to copy, which is why it's important when buying new to be sure you have the best possible copy. The 100-400L is a serial offender in the softness department, with many people reporting issues right or left side (or both) at 400mm. In the case of the 100-400L there are perfect copies out there if you're willing to play the exchange game (I have one); however with the 70-300 IS expecting a copy that'll perform brilliantly at 300mm isn't going to happen.

Karl


User currently offlineNZ107 From New Zealand, joined Jul 2005, 6431 posts, RR: 38
Reply 6, posted (2 years 3 months 4 weeks 1 day ago) and read 5244 times:

Quoting JakTrax (Reply 5):
Once the optics are stretched to their limits they don't perform as well as their L-series counterparts, and softness creeps in. More often than not this softness will emanate from the centre of the frame but it sometimes manifests itself as softness/blur in a particular area, such as the left or right side, or top or bottom of the frame.

I suppose my lens acts differently then. Due to the rotating nature of the lens when zooming, the blur spot changes from the left hand side while using a focal length of around 100-150mm and ends up on the right hand side at 300mm. So I believe, though the lens does has its own limitations, that misalignment is the cause of the problems I had when using the 70-300.



It's all about the destination AND the journey.
User currently offlineJakTrax From United Kingdom, joined Jun 2005, 4936 posts, RR: 7
Reply 7, posted (2 years 3 months 4 weeks 10 hours ago) and read 5187 times:

Quoting NZ107 (Reply 6):
Due to the rotating nature of the lens when zooming, the blur spot changes from the left hand side while using a focal length of around 100-150mm and ends up on the right hand side at 300mm

Indeed, depending on the lens the problem area may be in a different spot at different focal lengths. I couldn't access the OP's crop when I posted yesterday, however looking now it looks more like a mis-aligned element than general softness. A mis-aligned element may only become an issue at very long focal lengths (remaining practically undetectable otherwise); but again such flaws are much more common in the cheaper lens ranges.

A friend of mine has a 70-300 IS and his is a very good copy. Above about 230mm it can be very soft (unless stopped down to f/11) but it doesn't display any sign of lens mis-alignment at any focal length. The key to getting a good lens is to be firm with the shop and ensure you can fully test and exchange if need be (if buying new) - there's little point in paying £400 ($600) for something that isn't going to do the job it's intended for. Too many people 'settle' and then realise retrospectively that their copy of whatever lens isn't quite up to par. At that point it's a bit late to do anything about it.

The only other way to make sure the elements stay as they should is to take very good care of your lenses. Even frequent slight knocks can cause internal damage.

Karl


User currently offlineaddew1 From Sweden, joined Mar 2010, 13 posts, RR: 0
Reply 8, posted (2 years 3 months 3 weeks 6 days 7 hours ago) and read 5094 times:

If you have a filter on try shooting without it. I had the same problem with my 100-400 and when I removed my filter it all disappeard. Try it out.

User currently offlineJakTrax From United Kingdom, joined Jun 2005, 4936 posts, RR: 7
Reply 9, posted (2 years 3 months 3 weeks 6 days 6 hours ago) and read 5088 times:

Quoting addew1 (Reply 8):
If you have a filter on try shooting without it. I had the same problem with my 100-400 and when I removed my filter it all disappeard. Try it out

This is good advice too. Sometimes it makes no difference but it's worth a try.

Karl


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