Does the Nikon 18-55 produce better quality images than Nikon 18-105?

My girlfriend has a D3100 with the 18-55… I have the D7000 with the 18-105… I have compared pictures I have taken with both and I think those taken with the D3100 are better…

Is it the lens as I'm sure the D7000 should be better than the D3100.

When I mean better I mean image quality only… The D3100 images look sharper and have more detail in them…

I took both sets of shots so it's not the photographer…

I'm not very sure about this. You may need to check for back-focus or front-focus on your D7000 lens.

But before that, have you swapped the lenses and compared the photos? After swapping your girlfriend's lens with yours, if you get the sharper pics from your D7000, then the issue is with the lens.

You can then check for focusing issues. Also make sure the lenses are clean.

Note: Do make sure both cameras are set on the same mode with same settings.

Also make sure the cameras are setup the same.

Even a difference in f/stops can exhibit sharpness limitations in a lens. Most lenses - especially the inexpensive consumer class lenses these are, will become sharper as you stop down. F/8 is usually the best f-stop for sharpness. So be sure you take a photo with both cameras at f/8.

For instance, if one lens were set at f/3.5 and the other lens set at f/8, you should see a difference in the sharpness of the two lenses - the one at f/8 should appear sharper.

And of course, use both lenses on the same camera for comparison as well, which will rule out any variables other than the f-stop.

You can dial in sharpness with either camera, and if you shoot RAW vs. JPG, that can make a difference as well. Go into the "Shooting Menu", under "Picture Control", then under "Vivid", "Standard", or whatever you use, if you go into it's submenu, there will be a sharpness control.

At least that is how it is set in my D90. But Nikon's cameras all use similar menu systems, so it should be the same for your two cameras.

But this only applies to JPG photos. Nikon cameras normally don't add any in-camera sharpening to RAW files - you are supposed to do that in post-processing (which is why you would shoot RAW in the first place.

It is typical for super zoom lenses to have a few aberrations at certain focal lengths, but the 18-105 is a moderate zoom (5.8x), which is not so much as to have these kind of issues.

Set up a shot on a tripod and put the 18-55 on the D7000. Then take off the lens and put on the 18-105 and take the same shot. Take a shot at 18mm and 55mm on both lenses at different apertures. That's the only way you're going to tell if the 18-55 is performing better than the 18-105.

I've shot both lenses on the same camera. I found no substantial difference on the same conditions. However, with cheap lenses such as these sample variation does become important, you may have a dud, she may have a very good one.

Additionally a D3100 comes out of the box with settings geared to produce appealing images to the newbie. A d7000 is aimed at the enthusiastic amateur and will therefore have more neutral settings.

In my limited experience, the 18-55 seems a bit better than the 18-105. The 18-105 has more geometric distortion towards the 18mm end and is a bit soft towards the 105 end.
However, be sure you are comparing the lenses at the same focal length, f-stop and camera sharpening is minimized.

If your cameras are set to record in jpg there's likely to be in camera sharpening applied - and this may vary between models.

Compare raw images for a start, both cameras in manual & on a tripod. Set them exactly to the same settings. Then compare.

if there's still an issue with your len then you may want to see if its back or front focusing.