Sigma 500mm lens artefact?// (1 Viewer)

Tim Taylor · Feb 16, 2008

Sigma 500mm lens artefact???

I'm not really sure what the linear patterns are mainly down the left hand side of this shot but also a bit on the right. I'm assuming it's something to do with stray light and some sort of 'flare' but I've not seen this pattern before. Any ideas?

It's shot with the non-DG version of the Sigma 500mm f4.5 EX APO lens and a 30D body.

Thanks

Tim

Claymore · Feb 16, 2008

Hi Tim,
was it taken through glass or using a filter on the front of the lens? its rather strange did you use a lens hood?
Cheers
Brian
Ps still a very nice shot and nothing that Photoshop cannot sort!

Tim Taylor · Feb 16, 2008

Hi Brian. The standard lens hood was on but it is IMO a little short. There is a clear glass filter on the front of the lens - standard fitting I believe on this model. I'm not so concerned with cleaning it up which as you say is easily done but more with understanding it. I know that the DG model was supposed to reduce 'lens flare' but I don't know if this is lens flare at all or some other odd optical phenomenon.

I wonder if Steve, Andy Bright, Postcardcv, Rezmole or others with experience of this lens have experienced the same.

Tim

postcardcv · Feb 16, 2008

I'm not sure what's caused the effect but I never had any such problem in the two and half years that I used a non-DG Sigma 500 prime. I know that the lens hood looks short next to the huge ones that Canon/Nikon supply with the big primes, but I think the Sigma one is big enough. Given the apparent direction of the light I cannot see why you'd be suffering flare... all a bit odd.

martin kitching · Feb 16, 2008

Tim Taylor said:
There is a clear glass filter on the front of the lens - standard fitting I believe on this model.

I thought the standard filter on the Sigma 500mm f4.5 was a 46mm slot-in to the rear filter holder. Is it different on the Canon-fit?

cheers
martin

Tim Taylor · Feb 16, 2008

martin kitching said:
I thought the standard filter on the Sigma 500mm f4.5 was a 46mm slot-in to the rear filter holder. Is it different on the Canon-fit?

cheers
martin

You're right Martin, I was referring to a 'protective glass' in front of the objective lens. This is a second hand lens and of the two I saw before buying, one had this and the other didn't.

I hasten to add that I've been extremely pleased with this lens and have only noticed this effect shooting this grebe in this direction.

Tim

EDIT: I returned it to the dealer yesterday because of a squeak associated with the focus mechanism and they are sending it to Sigma. I've just emailed them with a copy of this picture as well in case they have any ideas or in case it needs mentioning to Sigma. If I get any feedback I'll post it here.

paul goode · Feb 17, 2008

Tim,
In my time with that lens I never noticed any thing like that. When it comes back I'd take the filter off the front of the lens. Unless its top quality it may well have an effect and there could well be a filter already in place in the slot. The lens should have come with a drop in UV and polariser.

Paul

rezMole · Feb 17, 2008

I have the newer (DG) version of this lens and it doesn't have a "filter" on the front. It does, however, have non-coated front element which acts like a protective filter - negating the need to have another filter attached (you cannot actually attach a filter to the front). This front piece of glass can easily be replaced by Sigma if it gets damaged. I think Sigma have done this to stop people adding extra filters to the front, which I suppose could cause this sort of effect.

I haven't had the lens that long, but haven't noticed anything like the effect in your picture.

Pluvius · Feb 17, 2008

Hi Tim I havent had the problem either. I am not sure what it is. By the way I bought the Lowepro Vertex 300 and with a squeeze I have got 40d 1d2n Macbook, sigma 500 canon 400 and 100-400 100mm 17-40 kenko extenders, sigma converters and a flash on board. Very Heavy

Claymore · Feb 17, 2008

Pluvius said:
Hi Tim I havent had the problem either. I am not sure what it is. By the way I bought the Lowepro Vertex 300 and with a squeeze I have got 40d 1d2n Macbook, sigma 500 canon 400 and 100-400 100mm 17-40 kenko extenders, sigma converters and a flash on board. Very Heavy

Don't forget to leave room in the Lowepro for plenty of cards and batteries LoL suppose you could alway buy a donkey to carry it all?
Cheers
Brian

Tim Taylor · Feb 17, 2008

Thanks for all the replies. Paul, I think rezMole is describing the same thing as I have on the front of my lens - ie a non-coated front element. As I don't have a lens handbook I wasn't too sure exactly what it was but it didn't seem to be removable although the other 2nd hand lens I saw didn't have one - presumably removed by Sigma or broken as the 'housing' for it was still there. Craig, thanks for your reply too (and for the info on your Lowepro vertex - geez, don't drop that lot!!).

I'll be interested to hear what Sigma has to say. I've had a reply from the dealer who didn't comment other than to say he'd passed the info on to Sigma.

Having let the lens out of my hands only to encounter those gorgeous barn owls yesterday, I can't wait to get the 500 back again.

postcardcv · Feb 17, 2008

Tim Taylor said:
EDIT: I returned it to the dealer yesterday because of a squeak associated with the focus mechanism and they are sending it to Sigma. I've just emailed them with a copy of this picture as well in case they have any ideas or in case it needs mentioning to Sigma. If I get any feedback I'll post it here.

Is the lens banging into focus or does it hunt alot? I have heard that a squeek when focusing can be an early indication of a problem (cannot remember what) so it will be worth getting it fully checked over.

a.dancy · Feb 18, 2008

Not a problem I have experienced or indeed seen before. Of course an assumption is being made that this is a lens problem. I don't know what the problem is but my guess is that it is a card glitch or a camera process problem...temporary hopefully. There also appears the same problem on the right hand side but to a much lesser extent.

It might have been worth down-loading the picture a second time.

Tim Taylor · Feb 18, 2008

postcardcv said:
Is the lens banging into focus or does it hunt alot? I have heard that a squeek when focusing can be an early indication of a problem (cannot remember what) so it will be worth getting it fully checked over.

Hi Peter

The lens is with Sigma so we'll see what transpires. It was focusing OK except with a TC in poor light when it couldn't quite do the last little bit ie it hunted through a very small range when it was nearly there.

Adrian, I suspect that odd edge effect might relate somehow to patterns on the water that day and that I may never see it again. Fingers crossed (and I'll reformat my cards).

Tim

Duke Leto · Feb 18, 2008

Tim Taylor said:
I returned it to the dealer yesterday because of a squeak associated with the focus mechanism and they are sending it to Sigma. I've just emailed them with a copy of this picture as well in case they have any ideas or in case it needs mentioning to Sigma. If I get any feedback I'll post it here.

Common problem then, when I bought mine I also had a squeak and hence negotiated a service as part of the sale. The lens only squeaked when focusing from near to far, from far to near it was silent. Happily the lens came back from Sigma squeak free and happily focuses relatively quick, the only time its a little confused is in poor light and with a 1.4TC on. BTW my lens wont AF with a 1.7 on :C unless the contrast is very high (such as the moon against the night sky) so the extra .5 aperture obviously impacts the AF cos my 300/4 AF-S works a treat with the 1.4 a 1.7 and even a 2x......

mjmw · Feb 21, 2008

Looks like patterns in the water to me Tim - although the colouring of the upper-left ones look a little odd...nice image BTW

Hope you get the lens back soon!

Tim Taylor · Feb 21, 2008

mw_aurora said:
Looks like patterns in the water to me Tim - although the colouring of the upper-left ones look a little odd...nice image BTW Hope you get the lens back soon!

Mark, one or two others have said that too and I'm inclined to agree. The lens is great otherwise and I'm looking forward to having it back soon minus its funny little focus squeak.

Cheers

Tim

a.dancy · Feb 22, 2008

I agree that the arifacts look like patterns in the water but the fact that they are sharp in the upper part of the image does seem odd.

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