Sigma 17-50 (real-world shooting impression)

[cheesy]

but how do your really test if the lens is a good copy? me still noob at it.

 

[Kenneth67C]

but how do your really test if the lens is a good copy? me still noob at it.

Take a few test shots are different apertures, starting wide open and close down.
Even if you don't have a computer with you, use the zoom function and examine at maximum magnification the corners of the shot to see if you are comfortable with the CA, distortion, etc... If all the copies of the lens provide the same level of detail (roughly), they should be fine. If you're not comfortable with that sharpness, then probably you shouldn't get that lens.

Its not a full proof method of testing, but it gives you an idea.

 

[cheesy]

wah still kinda chim to me.. dont know how to do all these testing :bigeyes:

 

[magicianhisoka]

shoot at 2.8, then 4, then keep going up. making sure you stay focused consistently on an object and observe if the point where you focused is sharp by zooming in on your camera's LCD or transfer to a laptop to view. if it front or back focuses, you'll know because the part where you focused on is not sharp. i cannot make it any simpler.

if you still think this is too chim, please don't buy a new lens. just get to know how to use your camera.

 

[2100]

shoot at 2.8, then 4, then keep going up. making sure you stay focused consistently on an object and observe if the point where you focused is sharp by zooming in on your camera's LCD or transfer to a laptop to view. if it front or back focuses, you'll know because the part where you focused on is not sharp. i cannot make it any simpler.

if you still think this is too chim, please don't buy a new lens. just get to know how to use your camera.

Have to be careful. Most times on a real-world object, there is no AF inaccuracy. But at MFD 2.8, esp shooting stuff like newspaper wordings (say font 16 size), the AF gets confused, though it seems to be a very good idea coz there is lots of contrast. But the funny thing is, it might focus much better and more accurate on the eye than the newspaper wordings.

My AF-S 24/1.4, a 3k lens, is also never 100% accurate at MFD doing newspapers. But for flatter subjects on the focal plane with deep seperation from the background it is pretty much tack on. Funny thing is the side AF points no issue for MFD and for slanted slots, but center (cross type) is a bit off. It is pretty academic.

That's why you always see me asking people to go out to shoot. Best way to test in the shop, is to bring along someone and shoot, then check on a notebook LCD. A 10" LCD netbook works wonders. Camera LCD a bit restrictive, we want an expansive view.

 

[cheesy]

Take a few test shots are different apertures, starting wide open and close down.
Even if you don't have a computer with you, use the zoom function and examine at maximum magnification the corners of the shot to see if you are comfortable with the CA, distortion, etc... If all the copies of the lens provide the same level of detail (roughly), they should be fine. If you're not comfortable with that sharpness, then probably you shouldn't get that lens.

Its not a full proof method of testing, but it gives you an idea.

shoot at 2.8, then 4, then keep going up. making sure you stay focused consistently on an object and observe if the point where you focused is sharp by zooming in on your camera's LCD or transfer to a laptop to view. if it front or back focuses, you'll know because the part where you focused on is not sharp. i cannot make it any simpler.

if you still think this is too chim, please don't buy a new lens. just get to know how to use your camera.

Have to be careful. Most times on a real-world object, there is no AF inaccuracy. But at MFD 2.8, esp shooting stuff like newspaper wordings (say font 16 size), the AF gets confused, though it seems to be a very good idea coz there is lots of contrast. But the funny thing is, it might focus much better and more accurate on the eye than the newspaper wordings.

My AF-S 24/1.4, a 3k lens, is also never 100% accurate at MFD doing newspapers. But for flatter subjects on the focal plane with deep seperation from the background it is pretty much tack on. Funny thing is the side AF points no issue for MFD and for slanted slots, but center (cross type) is a bit off. It is pretty academic.

That's why you always see me asking people to go out to shoot. Best way to test in the shop, is to bring along someone and shoot, then check on a notebook LCD. A 10" LCD netbook works wonders. Camera LCD a bit restrictive, we want an expansive view.

thanks for the info guys! :thumbsup:

 

[tecnica]

Have to be careful. Most times on a real-world object, there is no AF inaccuracy. But at MFD 2.8, esp shooting stuff like newspaper wordings (say font 16 size), the AF gets confused, though it seems to be a very good idea coz there is lots of contrast. But the funny thing is, it might focus much better and more accurate on the eye than the newspaper wordings.

My AF-S 24/1.4, a 3k lens, is also never 100% accurate at MFD doing newspapers. But for flatter subjects on the focal plane with deep seperation from the background it is pretty much tack on. Funny thing is the side AF points no issue for MFD and for slanted slots, but center (cross type) is a bit off. It is pretty academic.

That's why you always see me asking people to go out to shoot. Best way to test in the shop, is to bring along someone and shoot, then check on a notebook LCD. A 10" LCD netbook works wonders. Camera LCD a bit restrictive, we want an expansive view.

man! you totally answered the qns i have in my mind! no wonder my EF 85mm f1.8 give inconsistent focus at times, because i was confusing the AF system by focusing on small words on my hairstyling paste bottle at near MFD. thanks man! :bsmilie:

i am still pretty much stuck in between the 17-50 OS HSM and 17-55 IS USM though.

 

[2100]

man! you totally answered the qns i have in my mind! no wonder my EF 85mm f1.8 give inconsistent focus at times, because i was confusing the AF system by focusing on small words on my hairstyling paste bottle at near MFD. thanks man! :bsmilie:

i am still pretty much stuck in between the 17-50 OS HSM and 17-55 IS USM though.

Yep, f1.4 is f1.4, with such a thin DOF even a good AF system can be somewhat confused with small details such as letterings, even though it may seem like a good idea as the black ink and plain background has "high contrast". Anyway in the real world this is pretty academic esp for human subjects (moving). And btw, it is pretty difficult to get a lock-on or even if you have a lock on slightly moving subject moving along the focus plane it might not be fully accurate. You can simulate by moving the camera on a STATIC subject, the AF will be erratic. Probably what you can best do is to AF and take 1 shot, re-AF and take another shot, all done as fast as you can. Or use AF con't tracking and burst shot and hope for the best.

 

[cmeptb72]

Thanks for sharing your info on the lens.

One question though... how does it perform when you are using AI servo on a moving subject such as a running person or a moving car?

 

[2100]

One question though... how does it perform when you are using AI servo on a moving subject such as a running person or a moving car?

Unfortunately no such tests done..... and anyway this greatly depends on your body as well.

 

[La Fontaine]

Unfortunately no such tests done..... and anyway this greatly depends on your body as well.

Love to read your real-world shooting impression. This is far more useful than those boring technical reviews that are churned out mechanically in some of those websites.

In particular, I have the same experience when I switched to MF and then, forgot to switch back immediately, ended up with quite a few pix OOF.

 

[Captain Juker]

Brought this lens recently and used it on a trip, I would said I'm really satisfied with lens, OS comes in handy and responsive. Most of my photo posted here are using this lens.

http://www.clubsnap.com/forums/showthread.php?t=805262

 

[bangchew86]

Hi care to share how long is the sigma's warranty?

 

[2100]

Hi care to share how long is the sigma's warranty?

They say locally can support 2.5 years. I think..... ;p

 

[bangchew86]

Thanks for the info..

 

[ch4ngs7er]

Hi care to share how long is the sigma's warranty?

Buyers do take note of the warranty period. I realise there's alot of ppl selling their sigma lens stating only 1year or 1year 6months warranty. Shops didn't inform them of the warranty period.

If bought locally with receipt, the lens will be 1year + 1year + 6months after registering online.