I recently bought a Sigma 17-70 2.8-4.5 DC. THis model has no IS.
I use it with my EOS 50D.


I made the following shot with it (pic was resized, no PS at all) :








In 100% view:



I did not use a tripod. Shot was made with 70mm, ISO 400, F/10 1/100 shutter speed.

How can I get the image sharper with the camera when I shoot next time?

Open the aperture up a bit more, honestly, 10/f is a bit steep for that photograph in my opinion.

ok, I know if I open the aperture more I can use higher shutter speed, but thats not what I was thinking of. Is there a way to test, measure and increase the lens sharpness ? Or I just should aim for a shutter speed above 1/300 or so ?

depends how stable you are but generally i find 125+ better
also manual focus might be better for shots like this

why not a tripod?

generally speaking, faster shutter speed more sharpness. it´s as simple as that. ofc you have to consider the aperture aswell. your lens prolly is the sharpest at around 8 or 9, so if you use a shutter speed of around 1/200 and a f8 aperture you might have to go for high ISO aswell. Or you could also just use a tripod.

Ty for all the comments.

Made another try with increased shutter speed: 1/250 and 4.5 aperture. Lens is still my $200 Sigma 17-70.

Used Flash here but no tripod again.

Thats the result:




Here in 100% view:



I think it turned out sharper than my previous shot. What do you think? Should I expect something sharper or thats the max with a $200 lens?

I don't think you got what kratos was trying to say.

The sharpest part of that lens is likely around f5.6 ... hence open it up. And yes it will increase shutter speed some, but that's an additional bonus. Your lens sharpness will be best around this area.

Best way to test which apertures are the best is to mount your camera on a sturdy tripod, manual focus (hopefully your eyesight is good), and then start at the bottom range to f/16 or so ... but really if you want the quicker version just test out 2-3 f stops above your lowest and go up from there. So on this lens, about f4-f8 should be checked. One will be sharper than the rest.

Try to use a release cable or MLU so that your motion doesn't obscure the test and keep it in manual mode so that the camera doesn't accidentally refocus on something else.

This post was edited by Solarves on Oct 22 2010 06:00pm