Sigma lens disappointment

Somelier

Somelier

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Name
Richard
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I recently bought a second hand Sigma 500mm f4.5 APO EX HSM lens and I'm really disappointed with the results. I just don't seem to be able to get a really sharp image. I've taken out all the variables, by mounting on a tripod, using a remote release, used autofocus and then live view, varied the aperture etc, but the pics just turn out slightly blurred, not what I was expecting at all. My Canon 100-400 knocks spots off it, even though I need to enlarge the images on the screen by a greater amount to compare side by side. Has anyone else got any experience of this lens?
 
It's generally considered to be a pretty good lens, does it look like it has been badly knocked since it's s/h. Using a long telephoto is a bit different to shorter lenses and technique plays a part in sharp images.
 
Agree with all of the above...failing that a return to Sigma UK for an overhaul (which won't be expensive) could be in order
 
This pic was taken last week. I focussed on the goose's breast, but the sharpest plane is indicated by the arrow.
goose.jpg


Now, interestingly, I went out on Monday and took quite a few pics and it seems that the lens is improving, as this robin shows
robin_04.jpg


All of a sudden, the focus confirmation led is lighting green, whereas last week it wasn't showing at all, so possibly the lens just needed using again after lying idle for a while.

I've been really impressed by the attitude of the retailer - who advertises on this site - they couldn't have been more helpful.
 
It might be something as simple as the contacts between camera and lens need cleaning, or maybe you just had a bad day on your first outing.
 
In between these pics, I cleaned the contacts and the filter in the filter mount, although it didn't look dirty, so maybe that helped too.
 
I wouldn't guauge a focus problem from that goose shoot, too little discernible detail. If you are concerned do some specific testing first. Where was the focus point in that shot, and also the Robin.
 
Somelier said:
In between these pics, I cleaned the contacts and the filter in the filter mount, although it didn't look dirty, so maybe that helped too.
Click to expand...

Get rid of the filter - at least until you're happy with the lens.
 
artyman said:
I wouldn't guauge a focus problem from that goose shoot, too little discernible detail. If you are concerned do some specific testing first. Where was the focus point in that shot, and also the Robin.
Click to expand...

Didn't want to upload too large a picture on here, but on the original, I can clearly see that the place where the focus is sharpest is where I have put the arrow, while - as I stated - I focussed on the goose's breast. The robin was much closer and again I focussed on the breast.
 
The filter is more than likely degrading your image - but please yourself.
 
I would wait for some really good light and do some further testing. I would say the goose picture is lacking detail rather than soft, but the robin, taken in better light looks fine. You need good light to pick out detail with any lens. If you try the lens at f8 in decent light, you may find that you dont have a problem.
 
awp said:
The filter is more than likely degrading your image - but please yourself.
Click to expand...

Judging by the size of the lens, I'd assume it's not a filter on the front of the lens, but a drop-in one somewhere near the rear. They're made for the lens, come supplied, and from what the OP has said, make up part of the optical system!

If it works without it, you could always see what happens?

As said, with any new lens it'll take a bit of getting used to. I thought my 70-200 was soft at first, but I just couldn't use it properly. Now a few months on, I'm really happy with it. Stick at it, and if it's consistently focussing out, perhaps think about getting in touch with the original seller?
 
...and as the OP is an optician - he'll probably know!
 
awp said:
The filter is more than likely degrading your image - but please yourself.
Click to expand...

Both Canon and Sigma big primes come with drop in rear filters that have to stay there. Having said that, a dirty element at that stage of the optical chain could have a big impact on contrast and image quality.
 
Hi,

nothing wrong with your lens in my opinion, I have owned one and it's as sharp as they come, the Robin shot shows it as being perfectly good, and the secret there is..... LIGHT, the goose is grey against a grey background with a grey sky, not exactly ideal, and why would you want to take shots of that subject in those conditions anway :shrug: unless for testing of course.

Here are a couple of samples of my 500mm F4.5.

1D Mark II - Sigma 500mm F4.5 @ F4.5

427250201_quBz2-XL.jpg



1D Mark II - Sigma 500mm F4.5
325485128_6CRHx-L.jpg

Also you need to be aware of the tiny amount of DOF that you get with this lens have a look HERE at 6m you get 2cm DOF and so on, you also need to have a solid base, my Manfrotto 055 tripod and Manfrotto ballhead were insufficient, when you fired it with the timer you could see the body/lens react, I ended up using a wireless trigger to set my combo off to minimize shake as much as possible. I ended up selling the ballhead and buying the Manfrotto Long Lens Head ( gimbal ) and that made a huge difference.

And as Paul has said the filter remains in situ otherwise there would be a great bloomin' hole for dirt to fall into :naughty:

Mike.
 
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