Hi All,
I have been on the market for a while, looking for a fast (and possibly cheap) prime lens for my old k100d. I got very excited last week, when I found a good bargain on eaby: a Sigma 24 1.8 EX for as much as 200€. What I knew about this lens, reading many forums on the net, wasn't excactly encouraging: it lacks sharpness wide open, has distortions, not to mention vignetting, aberrations, flares and ghosts. Moreover, it weights nearly as much as the camera body and the EX finish is well known to be very fragile. Well, I bought it
To be honest, I would have preferred the 28 1.8, because it is the perfect "normal" for an APS-C sensor. But, the bargain was on this one and I decided that a 24 could be a 28 with a couple of step towards the subject (well, I know this is not exact..)
So, I attached that huge piece of glass to my k100d and did some quick and dirt shot, first in my house and then, waiting for the sun and trying to see if such a fast prime could be used even when there's plenty of light.
First interesting feature: the lens is macro. so you can focus as near as 18cm. Given the size of the lens, that means that you can place the subject nearly attached to the front lens. To be honest, 24mm is a weird focal lentght for a macro lens, but it's not unusable; it allows you to take some interesting shot of macro subjects among with beautifully blurred background.
So, here come the test pictures. Shots are RAW and converted using Pentax Photo Laboratory, no post processing except the white balance. No extra sharpness, no extra saturation, nothing.
So, lets start with a violet cow:
f4, iso1600:
crop 100%:
Other cows at f2.8, iso400:
it's a nice bokeh, isn't it? it's only a 24mm....
other portrait at f2.8m, iso400
crop 100%:
another macro at f2.8 iso200
crop on the focus zone:
another classic subject: a flower, f5.6, iso200
crop 100% (focus on the petals):
f8, iso200
crop 100%:
I decided to make a few non-macro shots, so I managed to find another subject, a little bigger:
f8 e iso200, crop 100%:
Another landscape, f8 and iso200:
crop 100%:
So, what happens when the sun is not behind the camera? Sigma lenses are renowned to be flare-prone, so lets turn the camera towars the sun:
f8, iso200
crop100%:
With the sun nearly on the frame, the contrast remains good: f8 e iso200:
With the sun IN the frame, you can easily see all the 10 lenses and the optical scheme on the picture:
So, what about this lens? I like it, even though I've not tested it extensively. I like fast primes, and I've never been one on my DSLR. To purchase a FA* 24/2 or a 31 1.8 I would have spent 3 or 4 times the money I spent for this one, so I know this lens is kinda a compromise but, to me, it seems worth the money.
If you are interested, I will publish the next test. I will try this lens @f1.8 and, say, 400 iso and the 18-55 kit lens @24mm f4 and 1600 iso.
which of the 2 pictures will be better? Sigma fast primes are known to be very soft at full aperture, but will this softness be better than the noise of the increased sensitivity? let's see!
ciao
maurizio