abc1234 Loc: Elk Grove Village, Illinois

Thank you everyone for taking the time to respond. Here is the background followed by another question.

The setup was late afternoon with my Canon 60D set up on a tripod. Live view for focusing. Color balance with Expodisc. Manual exposure at 1/200, f/8, ISO 100 using a Canon 550EX flash with a Lite-Scoop II.

Lens 1 was the new Sigma 24-70 mm, f/4 ART lens. I sent the camera and lens back to Sigma to make sure the focus was accurate. Lens 2 was my old Canon 18-200 mm, f/3.5-5.6, kit lens. No image stabilization.

While no one said the kit lens was sharper than the Sigma, not everyone agreed that the Sigma was clearly superior. This might be more an issue of monitor and graphics card.

Here is my follow up question. Now that everyone knows what the two lenses are, how many people would still keep the Sigma?

PS I will conduct a few more tests and am waiting for some 8x12's to come back. Your input plus the tests will decide the issue for me.

joer Loc: Colorado/Illinois

No 1 by a very small amount.

Anandnra Loc: Tennessee

#1 ... sharper by just a tad bit that is all, but definitely a shallower DOF.

abc1234 Loc: Elk Grove Village, Illinois

The focus was probably a little different since at the same aperture and focal length, the depth of field should be the same assuming both lenses have the same circle of diffusion. Thanks for your opinion.

SharpShooter Loc: NorCal

abc, if those flower shots and manual focus are your typical M.O. for photography, then the Sigma is probably as good a choice as any.
Personally the ART line has so many focus issues, I might have a little trouble forcing one on myself. Maybe that particular model has no issues.
But just like cameras, IQ is a very small part of lens performance, and for me, the least important factor of either a lens or a camera. Good luck with whichever lens you choose. ;-)
SS

Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

This reminds me of the days when I used to sell high end audio gear. Detail, dynamic range, presence, tonal range, balance - were all characteristics that buyers would look for.

We also figured out that with proper room placement we could make a great pair of speakers sound average, and a mediocre pair sound great.

The last hitch was playing volume - you could use a system comparator to punch in an amp, receiver or speaker pair and switch it to another instantly. The trick was to make the setup that you wanted to sell ever so slightly - imperceptibly - louder. We would use a sound pressure meter with readings taken from the listening position (very important) which was a comfy chair in the middle of the room. It worked 95% of the time.

By turning up the volume (making it brighter, and slightly less saturated), and taking the images with slightly different focus, you have everyone convinced that image 2 has less contrast and is less sharp. Interesting that 2 was darker and you had to increase the exposure - which would indicate a lens that does not produce accurate aperture settings.

I have not looked at the exif data. But I would take 1 over 2 after pixel peeping both.

Jabe

Image 1(1378) appears significantly sharper on download and magnification. Color very similar on download but the initial image 2 does not seem as vibrant.

bull drink water Loc: pontiac mi.

to me number 1 is a little darker. number 2 has a slightly sharper background. too close for me to make a call.

jcboy3

The first image has better contrast and more vivid color, and is noticeably sharper. Focus in both pictures is on the petals and not on the stamen. Detail in the veins of the petals is clear in the first image, and blurry in the second.

Did you shoot these on a tripod with single point focus? There is a significant difference in scale, so I am guessing these are hand held, which can add some variation in your results. But I don't see the loss of sharpness in image two being attributable to hand shake.

In my opinion, the lens used for image one is the better of the two.

lukan Loc: Chicago, IL

#1 seems to be shot a tad "closer", with a little shallower depth of field. #2 seems stopped down a click. They're shot at slightly different focal lengths too.

BboH Loc: s of 2/21, Ellicott City, MD

Haven't downloaded either...
#1 looks more vivid, #2 looks a tad bit more realistic.
#1's background is darker and more indistinct than #2. I don't think one is any better than the other - they each have their own look

Jcmarino

I like the color and sharpness of #1, but it seems more underexposed than # 2 so the color may be just as good with #2 at the same exposure. The edges of #2 seem a slight bit sharper than #1. Tough decision. Based on these 2 photos alone, I would go with #1 but the difference is very small.

joer Loc: Colorado/Illinois

[quote=But just like cameras, IQ is a very small part of lens performance...
SS[/quote]

I wouldn't go quite that far but yes there are other things that matter as well.

jerryc41 Loc: Catskill Mts of NY

Tough call, since examining them in detail in the extreme enlargement doesn't reveal huge differences. One problem in deciding is finding a point of focus. If this were a two dimensional subject, it would be easier to tell which had the better focus.

If I had to buy one lens or the other, it would be Lens 1, although there is precious little difference between the quality of the images.

Retina Loc: Near Charleston,SC

I think #1 looks richer because the exposure or processing has it darker. They also seem to have a slightly different aperture setting. If sharpness matters you should test with a full image grid at different zooms (if zoom) and apertures, and look at the corners as well for blur or color fringing. If glare mattes shoot both into an off-center bright point source. Not to ignore is how the lenses feel in your hands with respect to focus and zoom (if zoom), checking your speed and precision when adjusting. That's just how I do it, but to each her own.