Lens issue

Snap_Happy

Snap_Happy

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Nigel
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First things first, I'd like to say thank you to all people who contribute to all forums - I signed up here about a month ago, and have learnt more in that month than in the past 3 years of owning my digital camera! :clap:

The only problem, is that with all this knowledge, comes a realisation... I bought a Sigma 70-300 when I bought my camera, as at £100, I thought that was a reasonable purchase, and a good starter lens. Reading on here, I am now much wiser, and whilst Sigma make good lenses, they clearly have quality control issues, and I think I got one of the bad ones! :bang:

I don't really mind - the images aren't quite perfect, but to be honest, I never used to be a good enough togger to notice!

Now that I am a better photographer [I'll not say good - that would just be lying!] I *think* that I may have a lens that has some sort of focussing issue, and what I'm after is just some advice on how I could go about confirming or denying that? :shrug:

Thanks in advance! :thumbs:
 
Good point...



This is the image, but if you click, and go to original size [watch out - quite large...], you can see the problem.

I know that this photo is high ISO, and therefore a bit noisy, but as my brother pointed out to me, ~1/300 should be enough to stop image stabilisation issues, and 1/1600 [as this is] should definitely avoid it, but this image still looks [what I originally thought was] motion-blurred.

Full image props are available via the side links on the photo [just below camera info where it says something like "more properties"].

If anyone can suggest a way of acquiring test images that would prove/disprove, then feel free to suggest!

I think I just want to know to check my sanity - I don't want to buy a new lens for the sheer hell of it - I want to buy a new lens only if I need to!
 
I used to get images like this with my old canon 90 - 300. Try a slower shutter speed and smaller apature, used to help with the 90-300. Try downloading Neat Image (free) to get rid of the noise.
 
Dave Stone said:
I used to get images like this with my old canon 90 - 300. Try a slower shutter speed and smaller apature, used to help with the 90-300. Try downloading Neat Image (free) to get rid of the noise.
Click to expand...

I'll give it a go - I've just spent ~£400 on new kit, so if I could get the best out of my current kit for a while before buying new stuff, that would be nice! :thumbs:
 
Dave Stone said:
I used to get images like this with my old canon 90 - 300. Try a slower shutter speed and smaller apature, used to help with the 90-300. Try downloading Neat Image (free) to get rid of the noise.
Click to expand...

A smaller aperture won't help matters here, Dave, if anything it would make things worse as the lens (assuming this shot is at 300mm) is already wide open at f/5.6.

Looking at the full-sized image I'm inclined to think it's down to camera shake,Snap. If you have a tripod try a similar shot from that, or failing that try leaning on/bracing yourself against a wall and see if that helps.
 
If only you knew... My camera was sitting on a tripod, with the shutter operated by [wired] remote, and I even went to the ridiculous extent of doing shutter lock-up before the photo.

Oh, it was also a still day.

You see, my thought was "camera-shake", but that's surely not possible here??? :shrug:

[I also tried focussing on the stumps, then switched from AF to MF, to stop the motor whirring and unbalancing the camera! Still no joy! :bang:]
 
I would think iso 800 is a little high to get a sharp image. I would be inclined to stay below 400 and lower the shutter speed.
Then, if you have to sharpen them up you have a cleaner image to start with.
Two other thoughts, is the lens clean and do you have a filter fitted? try without the filter.
Allan
 
With my old 90 - 300 at if I had the smallest apature (highest F stop) I could get away with the sharpness of the images definately improved. I am inclinded to agree that in this image camera shake is more than likely the problem. This combined with the high ISO makes the image look very soft.

Just read your post about the tripod, so not camera shake.

I think to a large degree with lenses you get what you pay for (i have found this out myself). Maybe its time to splash out on a new lens if you can. The Canon EF-S 55-250mm f4-5.6 IS by all accounts is a very capable lens at about £180. Or if you can the Canon EF 70-300mm f/4.0-5.6 IS USM is superb, sometimes refered to as the seceret L lens and is pin sharp all the way up to 300mm. Both have Image Stabalisation which is fantastic.
 
Snap_Happy said:
I *think* that I may have a lens that has some sort of focussing issue, and what I'm after is just some advice on how I could go about confirming or denying that? :shrug:
Click to expand...

I would find a nice brick gable end with good definition and pop off a series of shots at different apertures and length settings. Budget zooms (and even some higher quality ones) are notoriously soft at each end of their range. Treat this lens as a 100-260 zoomm and stop down a couple of stops to give yourself half a chance.

Bob
 
Just had a look at the exif data. You're shooting wide open at f5.6. That's not helping. Try another shot at f8 and f11 and see if that makes any difference.

Do as bob says and find a suitable object, and try some shots. Use a tripod to try and eliminate and camera shake.
 
Was this taken at the full 300 zoom ?
The sigma 70-300 lenses are well known for being soft at the extremes of focul length. I have the APO version that I don't use much any more.
Try dropping it back to around 270/280 and see if that sharpens things up.
 
Cheers guys - I will at some point in time in the future go out and try a few snaps as suggested.

Whilst I new that extremes of aperture had ill effects, I never realised that the extremes of zoom did as well... You live and learn - in my case, 99% of that learning [in photography-space anyway] has been in the past month on these forums, so thanks again - Great responses from people as per usual! :clap:
 
Here are the images (before and after) processed using unsharp mask, and then Neat image to remove noise. I don't thing noise is an issue - that's a function of the ISO used. I do however thing the image was OOF, and I'm not certain that it is a lens problem.

Before

cricket.jpg


After

cricke2t.jpg
 
dougdarter said:
Here are the images (before and after) processed using unsharp mask, and then Neat image to remove noise. I don't thing noise is an issue - that's a function of the ISO used. I do however thing the image was OOF, and I'm not certain that it is a lens problem.
Click to expand...

That is an improvement Doug but still not a remedy. Noise is an issue but that looks soft as in bad soft to me. Either user error or maybe a soft copy. '
I echo the right honourable Canon of Bob, Sanp Happy, do the tests he recommends, post up the results too and I'm more than certain you'll get a good diagnosis :thumbs:
 
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