Sigma a bit soft! (TEST SHOTS)

spencer

spencer

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I recently posted a thread about my "Sigma 24-70 2:8 EX DG Macro" bing a bit soft.

And I'm still not sure, I rang warehouse express who have said I can return it, but is there some way I can test it first before returning it??

I've attached an image I took earlier, & it just seems a little noisy???

_MG_7785Medium.jpg



F2.8, exp. 1/25",ISO 200, metering pattern, focal length 45mm.
I could really do with some help on this!:shrug:
Any help gratefully received.

Spence
 
Seems to be common with this lens..I purchased one at Jessops a few months back and it was terribly soft wide open and not a great deal better stopped down!..ended up returning it.Although if you get a good copy its supposed to be an excellent lens.
 
If you want some conclusive results then you really need to shoot some test shots with every other possible cause of softness, outside the lens , removed.

Bolt the camera to a tripod, shoot something placed right on the plane of focus, lock up the mirror for shooting and keep the shutter speed high.

If it's still looking soft after all that then it's pointing to lens, although a back to back test with another bit of glass is preferable.

HTH. :)
 
dazzajl said:
If you want some conclusive results then you really need to shoot some test shots with every other possible cause of softness, outside the lens , removed.

Bolt the camera to a tripod, shoot something placed right on the plane of focus, lock up the mirror for shooting and keep the shutter speed high.

If it's still looking soft after all that then it's pointing to lens, although a back to back test with another bit of glass is preferable.

HTH. :)
Click to expand...

Thanks guys, I have done this already against the 18-50kit lens & there did not seem to be much difference??

I will have another go tomorrow & post them here!!

Once again, thanks.
 
I think if your taking your shot at 1/25th of a sec at 45mm focal length then the image will be a bit soft?? I have one of these lens and it really is sharp and excellent. Tends to huant in low light?? might be another problem?? excellent advice from dazzajl, follow that step by step and you will be fine.

HTH :)
 
Ally said:
I think if your taking your shot at 1/25th of a sec at 45mm focal length then the image will be a bit soft??
Click to expand...

Thats right. Go outside with the kid and shoot it at ISO100, f/2.8 and a higher shutter speed.
 
I took mine out on a tripod in bright sun and it was terrible,but I do agree to test abit more before returning it.
 
I don't know anything about this lens but 1/25th is way slower than I would shoot, at any focal length, especially without any kind of IS.
 
I'm afraid I've always had this problem with Sigma lenses. If you get a good one it's really good... if not then... well it's next to useless! Sorry. 1/25 is too slow to be objective about it. Use a tripod and manually focus.

:LOL: @ Ally

I read that as "haunt in low light"... bet that gives ghostly images!
 
OK I have done a couple of test shots.
Both cropped at 100%.

No1. using the Sigma 24-70 2.8 EX DG MACRO
f2.8, 1/1000, ISO 800, focal length 70mm.

sigmasoftnesstest-28.jpg


No.2 using the 55-200mm, 4.5-5.6
F5, 1/100, iso 800, focal length 70mm.

sigmasoftnesstest-32.jpg

Any help gratefully received.:help:
Thanks in advance Spence
 
I'd expect to see some difference between a shot taken at f2.8 and one taken at f5 but I'd also expect to have to look for it. Pretty much all lenses like to be stopped down at least a bit to really perform.

That's way passed allowable though. It amazes me how much difference there can be on a sigma lens. Some are superb but that one it has to be said, is pretty poor. Definatley worth sending back.

Which is a pain but at least you'll end up with something really really sharp. If I had to go to the effort of sending it back and being without for a while, I'd be very fussy about what I accept back.:):)
 
LadyLens said:
Hmmm, I find both my Sigmas soften up a lot more than the nikon when I start upping the ISO's...often wondered why? :shrug:
Click to expand...

High ISO images are generally softer than their lower ISO counterparts. The image noise creates what I can only put as a smudge on the image. This generates a softer look.

Some tech body will put that into some kind of sense. CT most probably.

King.
 
ISO 800 is still not ideal.

You really need to test at ISO 100.
Click to expand...

I think that would make perfect sense. That way you wouldn't get any softness hiding in the noise and you could examine the details properly.

With this lens surely though, it's such a huge, dramatic and obvious differnce that you could shoot it any ISO and it's still going to be conclusive.

My take anyway. :shrug:
 
Slapo said:
I'd suggest shooting raw (to avoid built-in noise reduction) and at iso 100 if you really want to test it.

The lens is quite sharp at F5, is it really supposed to be a lot sharper at F2.8?
Click to expand...


I always do shoot in RAW, but I've not been happy with this lens since I got it, the Canon kit lenses have always seemed much sharper!! including the 18-55mm?

I only bought this lens after reading posts on here, & most gave it the thumbs up, but also there are some problems with faulty lenses being to soft!

Spence
 
King_Boru said:
High ISO images are generally softer than their lower ISO counterparts. The image noise creates what I can only put as a smudge on the image. This generates a softer look.

Some tech body will put that into some kind of sense. CT most probably.

King.
Click to expand...

;) yes, even my non-techno brain knows that - what I meant was that, say for instance, I shoot at same F stop, at 20mm on the sigma 10-20, and 20mm on the Nikon 18-70, both at 800 ISO, same shutter speed, the sigma will be noticably softer, albeit still liveable with [not nearly as dramatic as the examples spence has posted] than the Nikon. Ditto the 70mm end of 18-70 and my Sigma 70-300 - whereas if I use same settings but with ISO 100 for them all, I cant visibly see the difference. I have put it down to Sigma being good lenses, Nikon being better....possibly even a degree of Nikon lenses agreeing more with the camera, being a Nikon camera....I mean, any weakness in the lens will be more demonstrable at 800 ISO than at 100.... but I suppose thats why test shots need to be done at 100 ISO, not 800! :bonk:


I just answered my own query really didnt I? :wacky:
 
Cool but I'll be amazed if shots at 100 ISO show enough impovement in the difference between the two lenses.

The noise is not actually that bad, if you look the rubber grip on the handlebar there is plenty of texture in the black.

The difference in detail just in that section would be enough for me to send the lens back. If that's how much quality I'd have to sacrafice to up the ISO, I'd call the lens pretty useless. I'll still predict the difference will be much the same at any ISO though.
 
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