Double image problem. Help please!

stylgeo

stylgeo

Suspended / Banned
Messages
832
Edit My Images
Yes
Don't know if this is the correct place to post this question but I seem to be having some problems. Several of my photos (not all of them) seem to show some ghost images on the left side of the subject. I am uploading an example to show the problem.
2796967267_a0ca893c8d_o.jpg

This photo is a 600*500 px 100% crop of a photo I took the other day and I am now uploading on the pc. I know it's a bad photo, the bird was really far away, but as you can see it appears to show a thick line on the left side of the bird.
This photo was taken with a 400D, the Sigma 120-300mm f/2.8 + 1.4X TC @ 420mm f/7.1 ISO 200. The bird is dead centre on the frame

2796965377_b1353cb4e5_o.jpg

This photo is from the same picture, on the same focal plane slightly on the bird's right. As you can see this photo is clear of any sign of the problem. On the left of the bird there were some branches that were totally out of focus due to the different focal plane so I don't have anything for comparison there.

Both photos are from the same picture, absolutely no PP, no sharpening, just converted from RAW and cropped.

The bird seems to be in focus. What's the problem here? Is it the lens, the camera or user error? The same problem appears in several of my photos but not all of them. It seems to appear where there is great contrast between the subject and the backround.

Can't remember if I was using MLU but I was defo using a tripod at the time.
Please help!
:bang:
 
THanks guys for the prompt reply but the reason I posted the second photo is to show that it's clearly no camera shake, since the second photo is from the same picture and it doesn't show the same problem. And if it were camera shake, wouldn't the same line appear on the right side of the bird too? :thinking:
 
What was the shutter speed? (from what I can see you've mentioned everything but)

And did you use a tripod?

:)
 
Oli beat me to it - if shutter speed was low, could be subject movement.
 
Yes, you are right, silly me.
For easier reference, full EXIF for the photo is

Camera: Canon 400D
Lenses: Sigma 120-300mm f/2.8 + Sigma 1.4X TC
Focal length: 420mm
Aperture: f/7.1
Shutter Speed: 1/800 sec.
ISO 200

Sturdy Tripod, remote shutter release (not sure about MLU though, don't think so)

Distance from subject, about 8-9 meters.
 
Well 1/800 should be ok even handheld. But if a sturdy tripod was used aswell... :thinking:
 
Yeah, it's really something isn't it? And it's not with all the photos but it's with some that i really like (not this one, I chose this one because the effect is more pronounced).

Any ideas?
 
You wouldn't happen to have a cheap filter stuck on the end of your lens by any chance? If this is a filter issue then I would expect that subjects predominantly a different colour could exhibit a different trait.

Bob
 
Just Dave said:
does this sort of thing happen without X 1.4 and what make is the X 1.4
Click to expand...

As stated above, the TC is the Sigma one, bought new about a month ago (sold the 2X). I seem to remember noticing photos with this problem earlier than that, so I don't think it's the TC.

As I said before, it's more evident when the subject is really contrasty compared to the backround.

Do you think it's the camera? I really hope so, it's a lot cheaper to change.
What I forgot to mention is that I also use a Heliopan 105mm UV filter to protect the front element. This is a really expensive filter and I doubt that that's what's causing this but I though I would mention!

Thanks btw for your help so far, I really appreciate it!
 
Canon Bob said:
You wouldn't happen to have a cheap filter stuck on the end of your lens by any chance? If this is a filter issue then I would expect that subjects predominantly a different colour could exhibit a different trait.

Bob
Click to expand...

Hehe, beat me to it Canon bob!
 
nto a case of using IS on the lens while your on a tripod is it? i know that can cause problems.
 
It looks like a lens issue to me. Not convinced by the shake argument. I think you will have to run some tests. Put something like a newspaper at a distance (you say it is more noticable with contrasty images) and try with and without the TC and with and without the filter. Mount on a tripod, use mirror lock up and try a range of apertures. That should help isolate the problem, but I reckon one element in the lens being slightly wonky could do this.

Paul
 
grumpybadger said:
It looks like a lens issue to me. Not convinced by the shake argument. I think you will have to run some tests. Put something like a newspaper at a distance (you say it is more noticable with contrasty images) and try with and without the TC and with and without the filter. Mount on a tripod, use mirror lock up and try a range of apertures. That should help isolate the problem, but I reckon one element in the lens being slightly wonky could do this.

Paul
Click to expand...

Thanks Paul. I was afraid that it might be a lens issue. That would be an expensive problem to fix. I'll try and do the tests you suggest as soon as I manage. Tha strange thing is that this problem doesn't appear in all my photos. Do you think it's not really broken but an element a bit loose?
 
It could be a loose element or even something that moves as the aperture changes. I think you'll only know by trying unfortunately. It could be the subject moving which is why I suggested taping up a newspaper. I don't think it is but you're running nearly 700mm equivalent and birds do move quickly...
 
grumpybadger said:
It could be a loose element or even something that moves as the aperture changes. I think you'll only know by trying unfortunately. It could be the subject moving which is why I suggested taping up a newspaper. I don't think it is but you're running nearly 700mm equivalent and birds do move quickly...
Click to expand...

Thanks again Paul. I'll do the test as soon as I manage, probably tomorrow! I hope it's nothing serious!
 
You must log in or register to reply here.
Back
Top